FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: My427stang on February 03, 2018, 05:07:53 PM
-
Unfortunately it was by replacing it with a 390 LOL
I will dive in to the 445 in the next few weeks, but wanted to let everyone know how the 390 did. It was a bench build, leftover parts I had, a roach std/std 360 I bought locally, Brent shared a leftover cam he had, and I went real low budget.
Now: 390 cid, cast 4V piston, .004 below, for 9.45:1. square decked, line honed, 427 cast crank at .010/.010, CJ big bolt rods resized and mag'd, C8AE-H heads, unported, new guides, cheap Elgin stock valves with back cut and decent multi-angle valve job, Alex's springs, Viton seals, HMV-272 cam, on 109 ICL, headers, unmodified Streemaster and a 750 3310 with a 4 hole 1 inch spacer.
Of course it was a heavily ported solid lifter, 10:1 445, custom cam, Ersons, ported RPM, 1000 Holley, etc. etc etc etc
Is it slower? OMFG it is WAYYYY slower LOL NP435, 3.50s, 2nd gear used to light them up, now chirps a little and pulls hard to 5000, 3rd used to break loose and pull hard to stupid speeds, now it just sort of goes faster....4th is sorta snoozy now where before it would scare you in the 4x4 and 4 inch lift very quickly
That being said, it is a very nice combo, and I had a blast just cruising around today, all you hear is a little header noise at acceleration, all the growl behind you, and no more of the noise. Now I can get to dialing in the rest of the truck to where it used to be
For those following over the years :o :o :o, the 445 had been apart more than you'd expect and unlike any job I have done before, I ended up starting to just swap parts. Anyone who gets paid to do this work knows how much of an insult it is to say you are blindly swapping parts, but I got there with the blessed 445 LOL
The only thing I haven't checked or replaced is that I never zyglo'd the Probe pistons, but from day one it has always made this noise and did so with different block, valvetrain and all kinds of different components. My hunch is I will find a cracked piston at a pin boss, but I hadn't seen anything using just my eyeball in the past. I won't assemble this 445 again until I definitively find the noise though!!!
This little 390 is sure a sweetheart, going to be hard to get me to pull it back out, but another 200 hp will eventually be welcome again, once I figure out what next with the 445
-
Just transfer your 445 parts to the 390 short block, AND put 4.56 gears in the differentials. You'll think your 445 is back in there. Just don't go far.....
I hope you find the cause of your noise. I think you will.
paulie
-
Good luck on the 445 teardown, Ross, I'm hoping you find the problem quickly, and I'm curious to see what it might be. With the new engine in and the noise disappearing, there is certainly no doubt that it is in the motor. I had to laugh at your comments about how much the truck has slowed down with the 390, those extra cubes sure make a big difference. And to think you actually have to talk some people into a stroker kit...
-
Jay, you have no idea how hard it is to talk someone into using low gears and some rpm. It's cheaper than a stroker kit!
Well, being four wheel drive ups the cost a fair amount.
JMO,
paulie
-
Naive question, but are the pistons offset properly?
-
Well they were installed properly LOL I never measured the offset of the pin
We will soon see, but the noise was much more pronounced than simple piston slap, I expected that it would go away pulling plug wires, but it never made the noise at idle and hard to kill individual cylinders driving down the road :)
-
Jay, you have no idea how hard it is to talk someone into using low gears and some rpm. It's cheaper than a stroker kit!
I did it both ways at once.
-
Jay, you have no idea how hard it is to talk someone into using low gears and some rpm. It's cheaper than a stroker kit!
I did it both ways at once.
This one will eventually get EFI, the stroker returned, gears, and a tranny I can actually shift quickly (with OD) LOL I am pretty good with this NP435, been banging the gears on it since 1984, but it's no car tranny
The problem was, I spent so much time on the 445 I haven't had the desire to do anything else to it. Driving the little 390 was actually a good thing, motivated me to work on the truck again.
Another option is to fix the 445 and sell it, put the 489 from the Mustang in the truck and do the blower motor I have been wanting for the car. Options are endless once I get the 445 done!
One thing I will say, other than this little bench build, buying parts from all over is rarely a good thing. I went Probe pistons on clearance from Summit, SCAT BBC rods were clearance on Amazon, SCAT crank was a bulk buy where I bought 4 and did some horse trading. All the parts were new in the box and high quality, and supposed to be what they were advertised, however clearance stuff is clearance stuff. Rods and crank were beautiful, and the pistons were new, but I still think something was fishy with the pistons in hindsight, the timing is right as Probe went belly up almost immediately after I ordered. Didn't see anything with the naked eye, and no skirts measured poorly in any of the tear downs, but it has to be something I missed without doing a good zyglo
If I can't decidedly find the bad one, or maybe even more so if I do, I will likely just stab a set of Racetechs in it
-
My bet is a small end rod issue. :o
-
That opening line got me. Lol Good luck on the hunt, Ross. Look on the bright side...swapping to the 390 will save you from having to build ladder bars. ;D
-
Ross, you're preaching to the choir on that one.
I pulled the 428 out of my '56 'Bird because I couldn't get it to run cool. Stuffed a 352 I built from my junk pile in it.
The little motor ran so well I never pulled it back out. Funny how burned out you can get trying to fix something that you just don't want to fix it again after you've "fixed" the problem.
Glad the 390 runs well. give it a rest for a while.
-
Ross this tell some thing about you it takes a lot for us to admit we can not find the problem, but you did it openly that is Cool, on the truck transmission when I used to race my 61 Unibody with the 390 then 428 and junkyard rear ends out of 1949 or so Ford trucks, all were vary low posy gears I would start in third and all I needed to do was pull the shifter down it worked vary well. Leny Mason
-
That way too funny, but so true... When frustrated, sometimes just go a different direction for a time. Can't wait to hear what is was. My last motor had really loose Pistons, but they were not at noisey as my mechanic season they might be. Then it ate a sodium valve for lunch one day...oops, I'm the fool for missing those in the old CJ heads.
My bench build is running great except for a minor oil issue in cylinder 1 and 3.
Good luck!
-
Funny, the last Big Block Mopar I built back in the late 90's for my Roadrunner I used Probe pistons, Broke it in, ran great, really revved with those light piston! Then I decided to put my exhaust on and run it on the street......Hey whats that noise?????? Tore the thing apart with the help of a very good mechanic I worked with at the time.....found nothing, put it back together still there.....Mine was present at idle only though, and the thing ran strong till I sold the car a couple years later.
-
We will see, might start pulling it down this weekend. The 390 is a sweetheart and anyone, including me, would be happy with this motor. However, the goal is an EFI 445. So far it's been my Moby Dick, but it's only metal, and with the miles I put on the 445, there has to be a hunk in there that is different than the rest.
-
Moby dick! Now that's funny! :D
Yah know, Pro Stock racers long ago gave pet names to their engines, often writing same,with a Sharpie, on the valve covers. Maybe you should do the same. Examples: Satan, Hell on Wheels, Bat Out of Hell, Smokey, Bad Boy, etc.
Hey, fellas, chime in with more names!
-
Every 5 or 6 years at work I get these 11,000 lb Bingham vacuum pumps to rebuild from pulp mills.They are a nightmare.The second one I rebuilt I named Damien the 3rd one was named Lucifer..Names are a gentle reminder sometimes....
-
Most of my EMC entries had names.
On the cover of the book you can see one - "plan B" is visible.
Others had cartoon dinosaur names when my kids were little
One had "extinct my ass" written on it...PHR used that one in a picture...
-
I called it Moby Dick, but it's pretty much been known to me and my friends as the "F-ing 445" (of course I don't shorten the name when I say it) :)
-
The old 445 continues to be elusive
Slowly disassembled, and looked at everything as it came apart, and I am down to just the crank hanging in the block, thrust is where I had it originally, and no evidence of anything unhappy. No marks on pistons tops, quench pads, nothing ugly
Pistons are still on rods, but stripped the rings, nothing broken, ring land clearance good, bearings look new. No marks on counterweights, pins tight (although I will measure when apart)
Going to clean up, get the parts and tools put away and wash and measure pistons, if I don't find something, we'll zyglo pistons like an old fool and mag the rods. There has to be something in there :)
-
From the sound on the video my first thought
was a piston sound....interesting to see if and
what you find
-
From the sound on the video my first thought
was a piston sound....interesting to see if and
what you find
Heo, I sure hope I find something. I was really hoping to find a broken/tight ring or oil ring spreader. So far the pistons look like new pistons, and all measured good last time, but we'll see
-
Measure the piston skirts all the way down to the bottom of the skirt. You may find one/or some with collapsed skirt/s. Measure in correct place, and then go down measuring each one. The variance, if there, will become evident. Old timers used to squeeze a collapsed piston in a vice to get them back in shape. Not! LOL. Joe-JDC
-
Measure the piston skirts all the way down to the bottom of the skirt. You may find one/or some with collapsed skirt/s. Measure in correct place, and then go down measuring each one. The variance, if there, will become evident. Old timers used to squeeze a collapsed piston in a vice to get them back in shape. Not! LOL. Joe-JDC
Thanks Joe, sure will. Did the skirts last time it was apart for the same problem, so I don;t expect to, but now stone unturned. FYI, the slight wear pattern in the crosshatch is also exactly the same from bore to bore, so it doesn't seem they are flopping around. However, because it goes away with heat, still looking there yet again.
-
Just sell the 445 to me.... After 12 years in an engine room with 2 strokes I probably couldn't hear the ticking sound anyway.
-
Just sell the 445 to me.... After 12 years in an engine room with 2 strokes I probably couldn't hear the ticking sound anyway.
That's funny, and tempting, but I got to figure this one out...you'd think 4000 hours in the jet would do me right too, but still hear it
-
did you check the under side of the piston , where the wrist pin goes through , maybe something , crank , just barely touching . just a thought .
-
did you check the under side of the piston , where the wrist pin goes through , maybe something , crank , just barely touching . just a thought .
Great advice, appreciate it, and it was a known issue with some SCAT crank and piston combos, but I have tons of room. Keep them coming!
-
Check the camshaft lobes for a nick. Look at the rod bolt areas for sufficient clearance when hot. We had an engine on the dyno that the camshaft was moving backward and forwards ever so slightly, and it nicked the edge of a lifter just enough to make a noise. One lifter hole may just be off a few thousandths, etc.. Joe-JDC
-
Check the camshaft lobes for a nick. Look at the rod bolt areas for sufficient clearance when hot. We had an engine on the dyno that the camshaft was moving backward and forwards ever so slightly, and it nicked the edge of a lifter just enough to make a noise. One lifter hole may just be off a few thousandths, etc.. Joe-JDC
Will do Joe, and will follow great advice, noise seemed to change a little when I went from the 270H to the Bullet solids, but it was so long ago and so many times in the engine, it could have been my imagination. Also, 2 different blocks.
What's everyone's thoughts on 2618-t61 at .0045 clearance? Any chance it could be piston slap? Seems ridiculously loud to me for that but it does reduce with heat. This is the first stroker I built with 2618 pistons, all the others were 4032 and run at .0025. Seems pretty loud for that to me.
Here is a link to the video again with specific times the noise is there
Focus on "tapping", almost like a Chebby with a loose rocker, noise happens under light load at :29, :45, :50-:52 (especially good there because I come off and on the throttle) and 1:08 ignore the grind you hear at the end, 1:22, my daughter leaned on the transfer case shifter while filming
https://www.youtube.com/watch?v=gnSd_lMyFNM
-
That sounds just like a friends 426 Max Wedge. It would get more quiet as the engine warmed up. It was the piston to cylinder wall clearance.
Kirk
-
Almost sounds like spark knock from here, but hard to tell. I have heard similar "chatter" from timing/compression related issues. You may have already ruled that out......
-
Kind of cold Diesel sound ???
-
I have had the timing all over the place and it really doesn't sound like that in person. I am leaning toward the pistons yet again
They were at .0045, recommended clearance, Probe lists min .003 max .007, first build they were between .007 and .0075 but given it was my own and having run some very loose forged pistons, I figured I'd live with it. If that is the issue, maybe I reshaped them the first time bouncing around :)
They are 2618 no pin offset. I see wear on the both top and bottom (thrust, non-thrust) on every cylinder, surprising for so few miles. I'll measure again and see what I find
-
Not a whole lot found with measuring the pistons
4.075 across all 8 with the micrometer flush with the end of the skirt, at the .500 measuring point, all were 4.074, 40 degree garage temp
Zero'd my bore gauge, checked cylinder clearance all nothing wild, as garage warmed up, checked again, tightest is .0055 after a few hundred miles, no taper, loosest is under .0062, looser than I put it together, but well within spec for the pistons. Could chalk it up to summer temps in the garage when measuring the pistons the first time plus break in, but nothing jumps out
Overall height of the piston at the skirt is 2.325 and compression height is 1.33, these numbers are not that important, but it does show a pretty short piston by FE standards, we'll see if other manufacturers use slightly longer skirts as I research
Here is what the base of a couple cylinders look like, I cannot feel these marks, and they don't measure with the bore gauge, but odd for only a few hundred miles, the last one isn't as "shiny"
(http://s20.postimg.org/wiv0ln825/541002594.jpg)
(http://s20.postimg.org/icf9qf4wt/541002618.jpg)
(http://s20.postimg.org/4vib7jf5p/541002635.jpg)
-
I think you finally have the answer. I would think those pistons needed closer to the .003" clearance instead of the .0062, and the skirts maybe need a fuller skirt with the longer stroke. Joe-JDC
-
I think you finally have the answer. I would think those pistons needed closer to the .003" clearance instead of the .0062, and the skirts maybe need a fuller skirt with the longer stroke. Joe-JDC
Joe, thanks you may be right. I have never used a Probe piston before, but the 2618 alloy, plus an advertised "low drag skirt" could mean "narrow contact area" combined with the relatively small bore could be letting them flop around
Likely going to go with a 4032, talking to a couple manufacturers about skirt design for 445s, both length and barrel and I may even ask what the cost would be for a little bit of pin offset
-
How about a few piston pics? The bottom wear pattern of those walls seems to flare out a tad and that's a bit odd. Usually the pattern is straight (like the pattern up the wall) all the way down the wall (could be the pic though).
I think Joe and you nailed it as short skirts + piston rock at BDC may have caused the sound. We though as an FYI ran a .007 minimum wall on new ForgeTrue 4.30 and up bores w/o any issues in the 70's but that's IIRC what they called for (maybe it was a .0065 minimum) and all were unmuffled race engines.
Who even knew if they clanked when cold!
-
How about a few piston pics? The bottom wear pattern of those walls seems to flare out a tad and that's a bit odd. Usually the pattern is straight (like the pattern up the wall) all the way down the wall (could be the pic though).
I think Joe and you nailed it as short skirts + piston rock at BDC may have caused the sound. We though as an FYI ran a .007 minimum wall on new ForgeTrue 4.30 and up bores w/o any issues in the 70's but that's IIRC what they called for (maybe it was a .0065 minimum) and all were unmuffled race engines.
Who even knew if they clanked when cold!
Sure! BTW, I have never feared loose pistons, in fact, I ran the old TRWs in my 433 at almost 10 thou! However, they were longer and likely a different shape
Interesting when I took the pics, look at the wave-like shadow on the skirts. Not sure what it means, but another "not normal" thing
(https://s20.postimg.org/f9nqe7cbt/541025276.jpg) (https://postimg.org/image/f9nqe7cbt/)
(https://s20.postimg.org/csbz6xkpl/541025327.jpg) (https://postimg.org/image/csbz6xkpl/)
(https://s20.postimg.org/6emw3ov95/541025341.jpg) (https://postimg.org/image/6emw3ov95/)
-
Yeah, they are clanking around until warm. I've never seen that weird wave pattern on a gas powered car but oh, yes, on blown race engines!
Before the nylon buttons were used on the lower skirts of pistons in blown alky and nitro engines, similar waves would appear. These on a aluminum Donovan 417 that Diamond Dave Miller ran on a R.E. TAD and on a 426 KB aluminum Hemi that John Sinibaldi ran on a R.E. T/F dragster. Nobody gave a damn as clearances were IIRC .008+ on the Donovan and .009+ on the KB Hemi (man, my memory is good but that was a long time ago!) but I do think the numbers are close).
Anyway, crewing for both over time, the then kinda' new button pistons prevented rocking until the engine heated up. Still, the pistons didn't stay long (burnt, 'backsided', collapsed ring lands and worse!) but they did work. No waves on the button pistons but the pre-button pistons did look similar to yours on the skirts.
Btw, not suggesting at all that buttons are needed!
-
Thanks Bob, I am not in a hurry to get this one together. So I have time to think about it, but likely will go with a set of 4032 Diamonds. I'd like to see if it's possible to build a set of 4032 Racetecs with some pin offset too, if I am going to go big, may as well overdo it :)
Might just put the ported heads and intake on the bench build 390 and see how it does LOL
-
Loving this diagnostic work.
-
Go big! That's the spirit! Hah!
-
Ross, would you mic those pistons laterally where that wave shows up? It sure looks like they aren't round there. I know the skirts are not round, but if you mic them in several places left to right laterally you may see a collapsed/flattened spot that causes the phenomenon. What I am trying to suggest is twisting the piston in the micrometer to see if there is a low spot where the wave is located. Joe-JDC
-
This may be a dumb question but is the mark inside the bores on one side of the wall? Inner side on each left and right bank, vice versa, or on both sides of the bore? Just curious and not sure it makes a difference. I would agree it is likely in the piston like everyone else and like Joe D-C said, I would like to know the measurement around it to see if there is a variance/flat spot. I would not think short skirts would be the absolute cause. Definitely some contact going on...
-
Welcome Harley as I see your new. Please jump in as more is better!
Think of a piston skirt side as a tall letter T....or a quite short t where a stroker crank/rod requires a shorter t to prevent the pistons bottom edge from hitting the counterweight on the crank. I wonder if the pistons in use have a too short skirt for the combo in use, meaning the piston at BDC is rocking too much. Point is, the longest skirt (the tall T part) one can run is beneficial in minimizing rocking.
This btw is somewhat divorced from the idea of too much wall-to-piston clearance. Given ideal wall clearance for the piston design + the aluminum material its made from will minimize rocking. Yet, also having a nice long-tail T as possible on the lower skirt in combination will give the best results.
-
Ross, would you mic those pistons laterally where that wave shows up? It sure looks like they aren't round there. I know the skirts are not round, but if you mic them in several places left to right laterally you may see a collapsed/flattened spot that causes the phenomenon. What I am trying to suggest is twisting the piston in the micrometer to see if there is a low spot where the wave is located. Joe-JDC
Joe, copy all, I will get some numbers tomorrow and post
This may be a dumb question but is the mark inside the bores on one side of the wall? Inner side on each left and right bank, vice versa, or on both sides of the bore? Just curious and not sure it makes a difference. I would agree it is likely in the piston like everyone else and like Joe D-C said, I would like to know the measurement around it to see if there is a variance/flat spot. I would not think short skirts would be the absolute cause. Definitely some contact going on...
Not a dumb question, that's part of the odd thing that tells me the piston is flopping around, they are on both the thrust and non thrust side. The odd thing is how few miles on the engine, I expected clean cross hatch with just a path where it rode on the thrust side
Here is my hunch though, and it's based on nothing but a hunch. These Probes are supposed to have a "low friction skirt" There is nothing fancy about the skirt surface, so IMO, it either is low friction because it's smaller overall OR it's got more curve to it, both of which would reduce surface area and allow it to flop around more.
I have nothing to compare it to, but lots and lots of 445s out there, most with 4032 pistons, but of course some with 2618 like these. Also, there are a ton of 482s, 488s, 489s, 462s, and they all run quiet with a 1.325 or 1.33 CH piston, so my hunch is this low friction design, however they got there, needed to be tighter than what they said OR somehow were cut wrong. I haven't found anyone else using Probe pistons in a 445, which is a message too
Who really knows? I can't compare to much when the company is out of business. I'd like to think I could either coat these or tighten the clearance in another block, but I am not sure I want to do it with this particular engine LOL
-
Be careful with using coatings to take up clearance. I did that a long time ago and the coating flaked off partially. I found that at disassembly, and the engine did not have a lot of miles. I don't doubt some places are more competent at coating than others, but still... I'd rather spend the money on new pistons.
JMO,
paulie
-
I am not saying instead, I am saying after this F-ing 445 is fixed, I may play with them because I cannot get myself to toss 500 dollars worth of pistons in the trash :)
ON EDIT:
Paulie, it's snowing and I am bored....
So, these pistons, 3.98 crank, 6.8 BBC rods and a shim head gasket....quarter inch less stroke and .003 clearance, it'd likely be a stable 9.5:1 truck motor if the skirts didn't hang out the bottom (OK, so it's a waste of money LOL, but like I said, snowing and bored)
-
I am not saying instead, I am saying after this F-ing 445 is fixed, I may play with them because I cannot get myself to toss 500 dollars worth of pistons in the trash :)
I hear ya. I don't know the answer for sure, but you know that old saying about "throwing good money after bad"?
JMO,
paulie
-
Sometimes throwing together a leftover parts engine runs the hardest, takes the most abuse, and defies logic. Build a spare with tight .003" tolerance, and have fun. Joe-JDC
-
Knurl them ;D
-
I have a set of (circa 1989) Ross pistons in my 427.I don't know the alloy nor do I have a pic.They were spec'd for .007 clearance when new but like a lot of people I had trouble with the engine when new.They are now up around .0085-.009 clearance.You can hear them when the engine is cold but by 160 deg they all go quiet.Things have certainly changed with good pistons now running as tight as .003
Ken from Ross racing used to visit a shop I worked at up here in B.C..He swore I would never break one and to not worry about it..I don't worry about them but they don't make strange intermittent noise...
I have CSI'd a engine before.It can be very frustrating but at the same time you sure learn a lot..
-
I guess I'll throw out an experience of mine. I had several small 4 cylinder engines disassembled due to noise problem. I was stumped to see wear on both the major and minor thrust of the pistons. Fairly low hours of use. I asked the lead engineer to take a look, a gent who had worked for Cadillac.
He came back with the piston pin bore was not exactly machined. He told me when you see wear on both thrust face's it is a piston pin bore that is slightly off true axis.
Not exactly sure what you have in your pictures, so I'll throw that out for some thought.
-
I looked again at the last picture of the cylinder wall and you see the wider rub area and then as one travels down the cylinder it narrows until at bdc it flares a bit. The idea of what was happening in the engines I had was that with the pin slightly off axis that when maximum combustion force was on the piston, it would bind on the piston pin. Once this happened the damage was done and the wear on the thrust surfaces accelerated. In this case the pistons were sent back to the engine manufacturer and they got their piston supplier involved.
Maybe or maybe not. Just a case of odd experience with piston/ engine noise.
-
Knurl them ;D
That brings back memories. Old school, if it rattles, knurl em. Bottom 1/8" or so of piston skirt looks to me like piston a piston issue. I think JDC is dead on.
-
Yeah, I thought of knurling the skirts too to 'save' those pistons but didn't since say so it's not a typical machining operation found in a hi-po engine. But, it is a long used engine rebuilding practice and would work better I think than a coating.
-
Took this photo as a visual aid to help in explaining to a friend why the old school thought that a longer stroke = slower revs due to several factors that were likely true in the 70's. The purpose was to provide a visual picture of the weight reduction due to reduced mass versus the a "stock" 390 assembly. These are Mahle, coated and zero noise in a 445.
-
Good pic that shows the big difference in the skirt length.
Obviously a stroker piston needs a shorter skirt but...I've wondered if the makers supply a shorter-than-necessary skirt to accommodate a wide range of stroker cranks. Put another way, perhaps they go a tad too far than needed. Since I do think most makers, like Probe and others, make stroker pistons on a as-ordered basis. Maybe they could make longer skirt pistons but don't to avoid some combos interference with specific stroker crank counterweight designs. Just a guess.....
-
Curious - Why zero pin offset for this shorter skirt stroker street engine? I think you've discovered how hard it is to stabilize a forged piston using just clearance.
Pin offset is your friend on the street :) It doesn't cost much HP and it gives you more arrows in your quiver to set up a happy engine. I learned this from Don Sullivan at Ford when he was brought in to quiet down the noisy pilot-build 4.6 Modulars.
-
Pin offset is your friend on the street :) It doesn't cost much HP and it gives you more arrows in your quiver to set up a happy engine.
Explain this for me. Offset the pin in which direction to cause what result?
-
I always selected for an offset pin if I had the option. All my cars were/are street cars, with mufflers...
more here, with an interesting graphic;
http://www.kfz-tech.de/Engl/Biblio/Kurbeltrieb/Desachsierung.htm
-
Reply #4 to this thread, 20 days ago...
-
Pin offset is your friend on the street :) It doesn't cost much HP and it gives you more arrows in your quiver to set up a happy engine.
Explain this for me. Offset the pin in which direction to cause what result?
Not being a engineer I hope you can make me understand also.
-
Oil controll and stops the piston from rocking in
the cylinder. Gives less fricktion with centered
pin they say. Ford flatheads have the whole crank
off center. An oldtimer trick was to put the piston
backwards suposed to give less friktion but more
rattle more oil consumption
-
Yes Ford flathead engine used the Desaxe principle. The practice of offsetting the whole crankshaft centerline. Originally developed in steam engines. I believe I read that VW uses the Desaxe principle in their V type engines.
-
What you can not see in a piston picture is inside a stock piston casting is often a bar of steel to help reduce piston expansion when hot.
Offset pins are usually standard option especially on overbore sizes, and I prefer them if I have a choice.
-
http://blog.jepistons.com/piston-orientation-rights-lefts-tops-and-bottoms
To stabilize and quiet the pistons on street engines, the manufacturers typically offset the wrist pin towards the major thrust side by about 1 mm - 1.5 mm. The pin offset shifts the piston over to the thrust side earlier as it reaches TDC, usually with much less "rocking" motion. The rocking of the piston creates most of the slap noise you hear when cold.
There is a small increase in friction, which will cost a race engine a few HP at high rpm. The good thing pin offset gives us on the street is more even cylinder wear and better oil control. For me it's a no-brainer if I'm not chasing a hundredth in the quarter mile.
-
http://blog.jepistons.com/piston-orientation-rights-lefts-tops-and-bottoms
To stabilize and quiet the pistons on street engines, the manufacturers typically offset the wrist pin towards the major thrust side by about 1 mm - 1.5 mm. The pin offset shifts the piston over to the thrust side earlier as it reaches TDC, usually with much less "rocking" motion. The rocking of the piston creates most of the slap noise you hear when cold.
There is a small increase in friction, which will cost a race engine a few HP at high rpm. The good thing pin offset gives us on the street is more even cylinder wear and better oil control. For me it's a no-brainer if I'm not chasing a hundredth in the quarter mile.
Best explanation yet. I have all ways known of pin offset and need to install pistons in correct orientation but never really understood the engineering need for offset. I think I get it. This old dog learned a new trick!
-
I am toying with the offset idea if it is an option, I haven't used Racetec, but Brent mentioned they have a lot of options, when I am ready to put this one back together I may consider it if affordable.
-
Well, two lessons learned here.
1 - When you don't verify something, you can get bit
2 - When you go cheap, you increase the chances of it going wrong
Brent recommended seeing where I was with the heads bolted up, measuring from the bottom, I trust him like a brother and didn't have a smoking gun, so I did it, but really didn't expect it to pan out, I was wrong! Sent Barry the pics too, he saw the odd marks and the numbers below and agrees that it would be noisy. I appreciate both of their advice.
Despite me wanting to hate the pistons, looks like it likely is the block, and likely my "reblock" would have worked if I did my normal block prep (sonic check, square deck, torque plate hone). I guess the good thing is that the Probe pistons have been checked 8 ways to Sunday and a cause was found, so they are good pistons, just won't work in my block.
When I replaced the block knowing it was .0075 clearance, I used a block that was already finished for a buddy's 390, it measured at .0045 clearance (no torque plate) and looked nicely done. In the end, I have one of two issues, or both, need to figure it out. But, knowing the shop by buddy uses doesn't have an FE torque plate. it's either just crooked when things are bolted up, or the cylinders are thin and moving around.
1 - Mocked up cylinder to see how far the piston skirt hung out. Did not hang out very much, .250 max and checking point on skirt never exited bore
2 - Pulled crank, installed heads, torqued caps and heads with head gasket
3 - Checked 6 points on each cylinder from bottom, 3 pin direction and 3 thrust direction, checked bore gauge vs piston after each bore
Summary
- Pin direction - 7 cylinders the same behavior at .0045 to .0055, growing toward bottom of bore, most measurements between .0045 and .005 (one oddball at .005-.006)
- Thrust direction - All 8 cylinders were bigger than pin direction, but 2 cylinders grew bigger as approaching bottom of stroke, 6 cylinders got smaller at the bottom
When I look at cylinder #7 in multiple pics, it is certainly the weirdest, but it's hard for me to show you, but it does correlate with the numbers. Numbers in bold are outside of Probe's limits, and all of #7 is bold because it is likely the noisiest, but the inconsistency is the odd thing. I put away my tools and went to lick my wounds, but I do intend to pull the heads and crank and do this again, just to see how far off the numbers are without the heads. When I originally asked the question, I took a lot of measurements, but not as many as I did here, and not in as regimented locations. My hunch is that numbers will get closer, but when I map it out there will still be something to see
In the end, if the cylinders are thick enough, my intention is to torque plate hone at a minimum oversize and put a set of 4032s to fit maybe shifting compression height up to 1.335 for a zero deck, but that is likely overkill
Cylinder Clearances
Top/Middle/Bottom - Thrust direction----------Top/Middle/Bottom - Pin direction
#1
.0065/.0070/.0070----------.0045/.0045/.0045
#2
.0070/.0065/.0060----------.0050/.0050/.0050
#3
.0075/.0070/.0065----------.0045/.0050/.0050
#4
.0070/.0070/.0065----------.0045/.0045/.0045
#5
.0060/.0065/.0065----------.0045/.0050/.0055
#6
.0075/.0070/.0065----------.0045/.0050/.0055
#7
.0080/.0080/.0065----------.0050/.0060/.0060
#8
.0055/.0070/.0070----------.0045/.0050/.0050
One thing I need to point out is, before yesterday, without the heads on, I had absolutely no numbers in the .007 or greater range. I have not been a torque plate nazi, although I like to when I can, if this block checks good for thickness, you won't see me prep one without a plate again.
-
If you end up needing a new block are you considering using your Probe pistons and fitting the block to them? Just wondering. I'm glad you definitively found the issue.
paulie
-
Good find Ross. I'm a tad amazed at the large variances from bore-to-bore but that's the cause of all the noise I'm sure. Interesting too if this was a pure race engine w/o any exhaust system you'd have never heard the noise!
-
Great detective work Ross, sounds like you found the problem. Have you thought about just getting a new block and getting it machined to fit the pistons you have?
-
I have a standard bore 390 block If you need it, never been re-worked, still has the factory head gasket pattern in the top of the deck. I was going to post it on Craigslist this week.
If that sounds interesting, you have my email.
-
If you end up needing a new block are you considering using your Probe pistons and fitting the block to them? Just wondering. I'm glad you definitively found the issue.
paulie
Great detective work Ross, sounds like you found the problem. Have you thought about just getting a new block and getting it machined to fit the pistons you have?
Paulie,Jay, I have to decide the plan for the engine. I am torn between a resurrection of what it was and delaying for a small centrifugal blower and FITech at the end of the summer. The truck has a fresh little 9.5 390 with a SM and 750 in it now, runs great, and really needs disc brakes up front and some rear traction control & less spring out back first.
I have a standard bore 390 block If you need it, never been re-worked, still has the factory head gasket pattern in the top of the deck. I was going to post it on Craigslist this week.
If that sounds interesting, you have my email.
Thanks! I will email you, might go that route
-
Crazy thought Ross
What if a guy would harblock the block up to the water pump holes without the heads(torque plate) on and then will the clearances stay there once you put the heads back on? On the other hand when a guy harblocks a block does he do it with the torque plate in place? If so, what happens when you remove the torque plate? If every thing stays the same after it is harblock then would a guy need to retorque plate the block to bore it again with the harblock already installed? In your pickup it would not run nearly as hot as in a mustang because of the room under the hood. If a guy wanted to get crazy could you kneer just the couple of the loose pistons? I am just trying to learn and sorry if this is off base.
-
Crazy thought Ross
What if a guy would harblock the block up to the water pump holes without the heads(torque plate) on and then will the clearances stay there once you put the heads back on? On the other hand when a guy harblocks a block does he do it with the torque plate in place? If so, what happens when you remove the torque plate? If every thing stays the same after it is harblock then would a guy need to retorque plate the block to bore it again with the harblock already installed? In your pickup it would not run nearly as hot as in a mustang because of the room under the hood. If a guy wanted to get crazy could you kneer just the couple of the loose pistons? I am just trying to learn and sorry if this is off base.
It's not crazy, but I think this block was prepped without a torque plate and that is the only issue, assuming it sonic checks good.
The hard block wouldn't hurt, but, I would expect the guy would hardblock it, then torque plate hone and it'd stay in one place.
The base of the cylinders having a little hard block shouldn't make it run hot, but not sure it's needed. As far as knurling, I have certainly done it years ago, but the 2618 piston likely would wear pretty quick and I still wouldn't have a straight bore, causing rings to crap out pretty quick as well as lose power
In the end, should have not used the block, should have had one prepped properly, but it's a good learning tool because I only 1/2 cared about torque plates before. I used them on the upper end stuff, and didn't worry about the mellow stuff. I'll always use one now
-
... I only 1/2 cared about torque plates before. I used them on the upper end stuff, and didn't worry about the mellow stuff. I'll always use one now
Another conversion!
Can I get an amen!
-
Amen! Hah!
Here's my now 15 year old post from the old 351C Net 54 Forum on thin walls, the Chinese Lantern effect and odd bore marks. Point is, loose wall clearances can produce the odd bottom-of-cylinder marks that My427stang showed us. Big fan of torque plates here on any, even low-po builds.
August 25 2003, 9:52 PM
that's a new one to me. The "Chinese lantern" effect is most apparent near the top of the bores in overbored 351C's. Thinned walls, head bolt torque and heat create a lantern pattern of small checks or boxes. This also usually occurs in the pin bore areas (where 12 o'clock is top of bore towards intake side, bore marks show up at the 2-4 o'clock and 8-10 o'clock positions) since the thrust sides (piston skirts) are thicker and the pin bore areas between each cylinder are thinner to allow for water flow.
Although it's hard to tell, my guess is your picture shows the effects of pistons sitting in the same position for a long time. Note that the rough "Y" shape corresponds to the contact areas on a piston and its skirt, below the rings. However, if all the Y's are in the same position (say, down 2" in each bore) this can't be it since all eight can never stop in the same postion as long as they were hooked to a crank.
Is this a std. 4.00 bore block?
Respond to this message
glen
(no login)
63.155.4.148
... I only 1/2 cared about torque plates before. I used them on the upper end stuff, and didn't worry about the mellow stuff. I'll always use one now
Another conversion!
Can I get an amen!
-
... I only 1/2 cared about torque plates before. I used them on the upper end stuff, and didn't worry about the mellow stuff. I'll always use one now
Another conversion!
Can I get an amen!
ROFL!
I often wonder how some things ran as good as they did in my early years
-
Gotta chime in and just say that this thread has been great from an educational standpoint. It does make me wonder though, the more I read I would agree that I've been "fortunate" at least in the past by not experiencing any of the problems that garage build short cuts can produce. I can appreciate the level of frustration and then patience it takes to get to the bottom of this. The whole ordeal expresses the "never say die" attitude of a true motorhead.
-
Ross, you're preaching to the choir on that one.
I pulled the 428 out of my '56 'Bird because I couldn't get it to run cool. Stuffed a 352 I built from my junk pile in it.
The little motor ran so well I never pulled it back out. Funny how burned out you can get trying to fix something that you just don't want to fix it again after you've "fixed" the problem.
Glad the 390 runs well. give it a rest for a while.
Off the subject of the noisy 445. I am considering putting an FE in a little Bird. Any info you can supply would be appreciated. Things like how you did the motor mounts, who made the headers etc.
Thanks in advance
-
ROFL!
I often wonder how some things ran as good as they did in my early years
Ha! In my early years, I wouldn't have known to listen for a noise like that, and would have probably figured that was the way it was supposed to sound with those new, high tech TRWs in there. As long as it was going fast I would've been happy. I'll bet going back 35 or 40 years, knowing what I know now, I'd have been horrified by the noises my engines were making LOL!
-
See Jay, this is the benefit of being partially deaf in certain ranges..... I just don't worry that much :P
Just messing around, good job finally finding it (hopefully)
-
I used straight thru Thrush mufflers bolted to the headers with no tail pipes. My engines never pinged or rattled. 8) Now I am all most legally deaf.
-
First, good work finding what appears to have been the issue, Ross.
I'll admit it took me a while to warm to the idea that torque plates are a necessity, even argued about it with several guys back then. But then I saw some pictures that someone posted on the old forum, many years ago, of cylinders in the early stages of honing while using torque plates. I saw the high and low spots that appeared from the cylinders being pulled out of shape. It was pretty dramatic and very noticeable. That was enough to convince me.
I think the simplest solution is to drop a flathead in there. I've got several if you need one ;)
-
First, good work finding what appears to have been the issue, Ross.
I'll admit it took me a while to warm to the idea that torque plates are a necessity, even argued about it with several guys back then. But then I saw some pictures that someone posted on the old forum, many years ago, of cylinders in the early stages of honing while using torque plates. I saw the high and low spots that appeared from the cylinders being pulled out of shape. It was pretty dramatic and very noticeable. That was enough to convince me.
I think the simplest solution is to drop a flathead in there. I've got several if you need one ;)
So here is the bad part, by slipping the bench build 390 in there, (cast zero deck pistons, CJ rods, cast iron 427 crank, stock D2s, 272 Crane, recurved Duraspark, Streetmaster, 750 vac sec) the truck fires up silently, runs well, not too fast but does OK, looks pretty and is happy on cheapo regular
If the engine bay was empty, I'd be in a hurry, now, I have all these parts sitting around and don't care that much LOL
I have half a mind ready to sell off the stroker parts or put on the shelf, slap the ported D2s on the little motor and put EFI and disc brakes on the truck. The Mustang would sure be happy if I paid a little attention to it too!
-
Lot to be said for having a solid always ready truck.
Mustang prolly misses you and maybe a new project (he said with little devil horns) ;)
-
Lot to be said for having a solid always ready truck.
Mustang prolly misses you and maybe a new project (he said with little devil horns) ;)
So those devil horns exist. The problem is the next level of Mustang would be unnaturally aspirated and the right way to do that is build from scratch and put the 489 in the truck.... 8)
One disclaimer, hard to call my truck a truck anymore, my daily driver is a crew cab 4x4 diesel, the truck is just sort of a bench seat hell-raiser. So, yes, hard to swap a good running engine out, but hard to keep it in there too LOL