POP Rocker stands

[galaxiex]

If I go for some Molnar rods (or other) I'll likely have to re balance, Yes?
Currently it's still external balance with the weight on the flex plate.

The Molnar rod is listed as 769 grams. Have a stock rod that is 742 grams. That is a 27 gram difference, maybe yours are different don't know.  What I do know is big end weight difference will affect balance more then small end, but most will say rebalance at a 20 gram bobweight change (actually a lot will say so at 10 grams) and considering it will be heavier not lighter it matters more. I'd plan on a re-balance.

While we are on the suspect parts subject may want to replace that factory 428 crankshaft too. Are threads on here of them failing too for no good reason.  All I will say is either go buy that stroker kit or if you think the shop knew what they were doing trust in that.  Engine building is like Domino's when one falls a bunch of others do too and you can end up forever changing things. Well is all I will say on the subject. Good luck with it.

Thanks.

A little more info...

I had the block, crank, and rod work done so long ago it's hard to remember,
tho the machine shop was well known and did good work. (Pro race engines)

Prior to assembling the short block, a buddy was over visiting and the crank was standing on end in the corner.
Well... he being a klutz somehow knocked it over and it hit the concrete floor with a big KLANG!

I took it back to the shop to check for straight and make sure it was still good.
Told them what happened and they checked it and said it was ok....

I'm still considering the stroker kit.
For what I have in the bottom end right now, (not much)
It wouldn't be too much of a hardship to spring for a stroker kit.

I can probably sell the existing bottom end to offset some of it.

My main concern is the .040 overbore and how much the stroker would stress the cyl walls.

I guess I could always go for a stock stroke aftermarket crank and related parts.

I'd base it all on how much horsepower you want and then do a pro/con of each scenario.  The TFS heads make a lot of power, but I think the cork would be your 3x2 intake and that would become more apparent on a larger engine. 

It's hard to know what to do in this situation.  When you start looking at other options, then you open Pandora's box. 

I don't think I'd be scared to run the stock 428 crank and remember, when you add displacement, the camshaft needs change.  It takes more duration to fill the cylinders of a larger engine.  Keeping the same cam and adding cubes would make the peak hp rpm go down.

I just built two 428's and used Molnar rods.  One rod set averaged 757g and the other set averaged 759.  I haven't built a factory rod FE in awhile, but a reference book lists 62-up factory rods at 761-775g.   Not sure how ARP rod bolts play into that, but it could be that you may not need a re-balance at all.  Just have to weigh some parts and see, or ask for the balance card from where your crank was balanced.

Factory cranks don't really scare me, I've used a lot of them over the years.  This isn't a race application, or high rpm application, and the factory cranks are pretty stout.  I was going to stick a 428 crank in JJ but decided to stick with the 3.500" stroke just because it's an underdog stroke.   I'm sure if it's been ground that it's been magged as most crank grinders do that as a default. 

Thanks for weighing in Brent.

Since I got the cam from you and that part of the build is pretty much set, (heads, cam, intake),
and I don't intend to run this too hard, (spirited street driving) I'm leaning towards keeping the 428 crank,
maybe just get some better rods and re-balance, and have the crank checked again while it's apart.

If the crank shows any issues I'll decide at that time which way to go.

To go with the new rods and I have to re-balance anyway, maybe some modern pistons too?

[galaxiex]

I better get out in the garage and start tearing down the short block..... again....

This will be the fourth time.... 

[67xr7cat]

I'd base it all on how much horsepower you want and then do a pro/con of each scenario.  The TFS heads make a lot of power, but I think the cork would be your 3x2 intake and that would become more apparent on a larger engine. 

It's hard to know what to do in this situation.  When you start looking at other options, then you open Pandora's box. 

I don't think I'd be scared to run the stock 428 crank and remember, when you add displacement, the camshaft needs change.  It takes more duration to fill the cylinders of a larger engine.  Keeping the same cam and adding cubes would make the peak hp rpm go down.

I just built two 428's and used Molnar rods.  One rod set averaged 757g and the other set averaged 759.  I haven't built a factory rod FE in awhile, but a reference book lists 62-up factory rods at 761-775g.   Not sure how ARP rod bolts play into that, but it could be that you may not need a re-balance at all.  Just have to weigh some parts and see, or ask for the balance card from where your crank was balanced.

Factory cranks don't really scare me, I've used a lot of them over the years.  This isn't a race application, or high rpm application, and the factory cranks are pretty stout.  I was going to stick a 428 crank in JJ but decided to stick with the 3.500" stroke just because it's an underdog stroke.   I'm sure if it's been ground that it's been magged as most crank grinders do that as a default.

OK so here are a few examples of factory 428 cranks that failed:

In this case he just shifted into 5th gear at 50mph and felt a vibration and that was it.  The broken crank took out the block. You may note in the pictures the nice H beam rods...
http://fepower.net/simplemachinesforum/index.php?topic=7597.15

General discussion that has some comments and opinions on the factory 428 crankshafts.
http://fepower.net/simplemachinesforum/index.php?topic=8539.0

Just like the rods they have a fatigue life and the same concerns apply. 

Regarding the rod weight the number I had was from an old bobweight sheet.  May have been an early rod, the sheet did not say.  So I just weighted a C7AE rod that came out of a virgin 1969 390-2V motor.  So that one weights in at 774 grams.  Now keep in mind you really need to know what the big end and little end weight. Reason is the balance factor is 2 x big end and 1 x small end.  So any change on the big end will be twice as big as far as how it affects the bobweight.  I'd say plan on a rebalance.  If it was within 10 grams on the bobweight I'd buy a lottery ticket as is your lucky day.

Glad to see Brent agrees with me that the 3x2 intake is holding you back.  428 or 462 it is leaving power on the table, but not everything is about the last HP on a street/strip deal IMHO. Add another 30 cubes and change nothing your peaks will likely come down 200 - 300 RPM.  You likely will not make much if any more peak HP, but everything down lower will be more.  You will be making a good bit more torque at 3k-4k for sure. If we want to talk about what is hard on an engine it is RPM.  the magnitude of the forces go up exponentially with RPM.  So if you get it done at say 5,500 RPM instead of 6,000 RPM it is easier on everything. Now yes a 1/4" longer stroke your piston speed for a given RPM is higher, but your piston weight is less and that matters.

If it was mine I would either leave it alone or put a stroker in it as I said.  Only thing that bothers me is it took a fall.  My concern would be that there is not an internal crack in that crankshaft.  Magging the crank will not detect an internal crack.  You would have to x-ray it.  Now I've seen stuff that took a fall, I did it years ago with a 351w.  That engine would see 7,000 RPM every time I drove the car because I was young and stupid. It never broke.  Now that I am old and know what can happen I'd be concerned.  Guess sometimes is better not to know too much...

Anyway good luck with it.

[galaxiex]

I'd base it all on how much horsepower you want and then do a pro/con of each scenario.  The TFS heads make a lot of power, but I think the cork would be your 3x2 intake and that would become more apparent on a larger engine. 

It's hard to know what to do in this situation.  When you start looking at other options, then you open Pandora's box. 

I don't think I'd be scared to run the stock 428 crank and remember, when you add displacement, the camshaft needs change.  It takes more duration to fill the cylinders of a larger engine.  Keeping the same cam and adding cubes would make the peak hp rpm go down.

I just built two 428's and used Molnar rods.  One rod set averaged 757g and the other set averaged 759.  I haven't built a factory rod FE in awhile, but a reference book lists 62-up factory rods at 761-775g.   Not sure how ARP rod bolts play into that, but it could be that you may not need a re-balance at all.  Just have to weigh some parts and see, or ask for the balance card from where your crank was balanced.

Factory cranks don't really scare me, I've used a lot of them over the years.  This isn't a race application, or high rpm application, and the factory cranks are pretty stout.  I was going to stick a 428 crank in JJ but decided to stick with the 3.500" stroke just because it's an underdog stroke.   I'm sure if it's been ground that it's been magged as most crank grinders do that as a default.

OK so here are a few examples of factory 428 cranks that failed:

In this case he just shifted into 5th gear at 50mph and felt a vibration and that was it.  The broken crank took out the block. You may note in the pictures the nice H beam rods...
http://fepower.net/simplemachinesforum/index.php?topic=7597.15

General discussion that has some comments and opinions on the factory 428 crankshafts.
http://fepower.net/simplemachinesforum/index.php?topic=8539.0

Just like the rods they have a fatigue life and the same concerns apply. 

Regarding the rod weight the number I had was from an old bobweight sheet.  May have been an early rod, the sheet did not say.  So I just weighted a C7AE rod that came out of a virgin 1969 390-2V motor.  So that one weights in at 774 grams.  Now keep in mind you really need to know what the big end and little end weight. Reason is the balance factor is 2 x big end and 1 x small end.  So any change on the big end will be twice as big as far as how it affects the bobweight.  I'd say plan on a rebalance.  If it was within 10 grams on the bobweight I'd buy a lottery ticket as is your lucky day.

Glad to see Brent agrees with me that the 3x2 intake is holding you back.  428 or 462 it is leaving power on the table, but not everything is about the last HP on a street/strip deal IMHO. Add another 30 cubes and change nothing your peaks will likely come down 200 - 300 RPM.  You likely will not make much if any more peak HP, but everything down lower will be more.  You will be making a good bit more torque at 3k-4k for sure. If we want to talk about what is hard on an engine it is RPM.  the magnitude of the forces go up exponentially with RPM.  So if you get it done at say 5,500 RPM instead of 6,000 RPM it is easier on everything. Now yes a 1/4" longer stroke your piston speed for a given RPM is higher, but your piston weight is less and that matters.

If it was mine I would either leave it alone or put a stroker in it as I said.  Only thing that bothers me is it took a fall.  My concern would be that there is not an internal crack in that crankshaft.  Magging the crank will not detect an internal crack.  You would have to x-ray it.  Now I've seen stuff that took a fall, I did it years ago with a 351w.  That engine would see 7,000 RPM every time I drove the car because I was young and stupid. It never broke.  Now that I am old and know what can happen I'd be concerned.  Guess sometimes is better not to know too much...

Anyway good luck with it.

I appreciate the insights on this.

Ya wow those broken cranks look nasty.

This 428 crank came to me as an unknown, bought from another shop.
Aside from the .020 .020 cut and the fall it took, I know nothing of it's history.

Rods came from yet another shop that parts out engines, so are also an unknown. C7XX casting
Basically I "pieced together" a 428.
The block did come with it's original main caps.

Thinking more on this.... I may just run it the way it is.

I have tucked in a corner of my garage, a spare used (was a good running) 2V 390 from a truck of unknown year,
(maybe early 70's) that has been torn down to the short block.
Std bore still. Probably clean up at .030.

I can use this as a back-up to build a stroker in case the 428 pukes the crank and/or rods.

On the 3X2 holding it back...

The manifold has been ported to within an inch of it's life.
Runners hogged out waaaaay far in, and all 6 throttle bores opened up to 45mm, approx 1.75"
Welded and port matched to the TFS heads.
The FITech 3X2 throttle bodys each flow 500 cfm with 45mm bores, so 1500 cfm potential.
I'm not so sure that the manifold will be all that much of a restriction.....

[blykins]

I'd base it all on how much horsepower you want and then do a pro/con of each scenario.  The TFS heads make a lot of power, but I think the cork would be your 3x2 intake and that would become more apparent on a larger engine. 

It's hard to know what to do in this situation.  When you start looking at other options, then you open Pandora's box. 

I don't think I'd be scared to run the stock 428 crank and remember, when you add displacement, the camshaft needs change.  It takes more duration to fill the cylinders of a larger engine.  Keeping the same cam and adding cubes would make the peak hp rpm go down.

I just built two 428's and used Molnar rods.  One rod set averaged 757g and the other set averaged 759.  I haven't built a factory rod FE in awhile, but a reference book lists 62-up factory rods at 761-775g.   Not sure how ARP rod bolts play into that, but it could be that you may not need a re-balance at all.  Just have to weigh some parts and see, or ask for the balance card from where your crank was balanced.

Factory cranks don't really scare me, I've used a lot of them over the years.  This isn't a race application, or high rpm application, and the factory cranks are pretty stout.  I was going to stick a 428 crank in JJ but decided to stick with the 3.500" stroke just because it's an underdog stroke.   I'm sure if it's been ground that it's been magged as most crank grinders do that as a default.

OK so here are a few examples of factory 428 cranks that failed:

In this case he just shifted into 5th gear at 50mph and felt a vibration and that was it.  The broken crank took out the block. You may note in the pictures the nice H beam rods...
http://fepower.net/simplemachinesforum/index.php?topic=7597.15

General discussion that has some comments and opinions on the factory 428 crankshafts.
http://fepower.net/simplemachinesforum/index.php?topic=8539.0

Just like the rods they have a fatigue life and the same concerns apply. 

Regarding the rod weight the number I had was from an old bobweight sheet.  May have been an early rod, the sheet did not say.  So I just weighted a C7AE rod that came out of a virgin 1969 390-2V motor.  So that one weights in at 774 grams.  Now keep in mind you really need to know what the big end and little end weight. Reason is the balance factor is 2 x big end and 1 x small end.  So any change on the big end will be twice as big as far as how it affects the bobweight.  I'd say plan on a rebalance.  If it was within 10 grams on the bobweight I'd buy a lottery ticket as is your lucky day.

Glad to see Brent agrees with me that the 3x2 intake is holding you back.  428 or 462 it is leaving power on the table, but not everything is about the last HP on a street/strip deal IMHO. Add another 30 cubes and change nothing your peaks will likely come down 200 - 300 RPM.  You likely will not make much if any more peak HP, but everything down lower will be more.  You will be making a good bit more torque at 3k-4k for sure. If we want to talk about what is hard on an engine it is RPM.  the magnitude of the forces go up exponentially with RPM.  So if you get it done at say 5,500 RPM instead of 6,000 RPM it is easier on everything. Now yes a 1/4" longer stroke your piston speed for a given RPM is higher, but your piston weight is less and that matters.

If it was mine I would either leave it alone or put a stroker in it as I said.  Only thing that bothers me is it took a fall.  My concern would be that there is not an internal crack in that crankshaft.  Magging the crank will not detect an internal crack.  You would have to x-ray it.  Now I've seen stuff that took a fall, I did it years ago with a 351w.  That engine would see 7,000 RPM every time I drove the car because I was young and stupid. It never broke.  Now that I am old and know what can happen I'd be concerned.  Guess sometimes is better not to know too much...

Anyway good luck with it.

I appreciate the insights on this.

Ya wow those broken cranks look nasty.

This 428 crank came to me as an unknown, bought from another shop.
Aside from the .020 .020 cut and the fall it took, I know nothing of it's history.

Rods came from yet another shop that parts out engines, so are also an unknown. C7XX casting
Basically I "pieced together" a 428.
The block did come with it's original main caps.

Thinking more on this.... I may just run it the way it is.

I have tucked in a corner of my garage, a spare used (was a good running) 2V 390 from a truck of unknown year,
(maybe early 70's) that has been torn down to the short block.
Std bore still. Probably clean up at .030.

I can use this as a back-up to build a stroker in case the 428 pukes the crank and/or rods.

On the 3X2 holding it back...

The manifold has been ported to within an inch of it's life.
Runners hogged out waaaaay far in, and all 6 throttle bores opened up to 45mm, approx 1.75"
Welded and port matched to the TFS heads.
The FITech 3X2 throttle bodys each flow 500 cfm with 45mm bores, so 1500 cfm potential.
I'm not so sure that the manifold will be all that much of a restriction.....

The issue isn't so much the port opening or the bore sizes, it's the directions that the air/fuel charge has to travel.  The 3x2 intakes are designed the way that the early 352/406 intakes are.  The runners go straight down from the bores and then have to come back up in order to meet the port opening.  In addition, the angles are almost 90°. 

I do think you'll be ok with the factory crank.  I tend to look at things in risks and trends.  Aftermarket parts tend to be the least troublesome and the least risky (except for Eagle cast cranks).  All factory parts will hold some degree of risk, but I've seen far more instances of factory rods failing than factory crankshafts. 

I also wouldn't worry too much about the crankshaft falling.  Have it checked out and go from there. 

[galaxiex]

Ok, Here we go......
Molnar rods are ordered.

$771.80 USD = about a million bucks CAD.      


Actually $966.71 CAD Whew!


Now to get the crank back out and when the rods get here,
find a local shop I can trust to check and balance everything.


These ones...

[blykins]

I'm confused on the pricing.  These rods sell for $656 USD.   How did you get to $771.80?  Is that with shipping to Canada?

[galaxiex]

I'm confused on the pricing.  These rods sell for $656 USD.   How did you get to $771.80?  Is that with shipping to Canada?

Yep, shipping and handling charges.

Probably gonna be Duty charges on top of that...

[galaxiex]

Well I'm not too surprised...

Molnar cancelled my connecting rod order. 


Here's a snippet from the email I got from them...


"Thank you for your order for a set of FH6488ANPB-FE8-A connecting rods.
Unfortunately those are currently out of stock and on national back order.
I checked with Mr. Molnar and it is going to be a while before more are available.
Until he receives the cores required to make those rods it is hard to give an accurate estimate of when more will be ready to ship.
It is probably going to be at least 8 more weeks."

So project on hold for now unless I can come up with a plan B.

[Gregwill16]

I'm probably in the minority, but if you have a competent shop that you trust, put that thing together with them factory rods and crank and get rolling. There is probably far more FE's out there on the street with factory rods and crack than there is aftermarket. I just don't see this application needing a $1k set of rods.

[galaxiex]

I'm probably in the minority, but if you have a competent shop that you trust, put that thing together with them factory rods and crank and get rolling. There is probably far more FE's out there on the street with factory rods and crack than there is aftermarket. I just don't see this application needing a $1k set of rods.

Yep, I get that.

I'm gonna mull it over for a while.

I do trust Brents advice tho, he has the build and dyno experience,and might have a good idea on how much power this would make,
since he supplied the custom Hyd roller.

Maybe Brent could weigh in on a guesstimate range of what my combo would make? 

[blykins]

I'm probably in the minority, but if you have a competent shop that you trust, put that thing together with them factory rods and crank and get rolling. There is probably far more FE's out there on the street with factory rods and crack than there is aftermarket. I just don't see this application needing a $1k set of rods.

Yep, I get that.

I'm gonna mull it over for a while.

I do trust Brents advice tho, he has the build and dyno experience,and might have a good idea on how much power this would make,
since he supplied the custom Hyd roller.

Maybe Brent could weigh in on a guesstimate range of what my combo would make? 

If it had another intake on it, I'd say it would make 520-525 hp.  Your intake is the variable and I just don't see it performing well, I could be wrong. 

The issue with the rods is that not only have they been subject to fatigue stress, but factory rods can deform the big end with loading because the strength just isn't there, like a modern rod.  I know this doesn't apply to you, but "back in the day", builders would hone the big ends out of round so that they wouldn't pinch a bearing under load.   If your shop is comfortable with it, knows how to prep them, and knows how to setup the rod bearing clearances correctly, you could potentially take the chance on them.  Remember, these rods were mainly designed for 250-300 hp applications with 4000-4500 rpm operating constraints.  I know that guys obviously subjected them to a lot more than that and still do, but just remember that the instant you hit the key, everything in the bottom end of an engine is trying to get out. 

[galaxiex]

Well I didn’t mention this before but I have a Performer RPM intake new in box down in the basement that I originally was going to use, until I got the bug for the 3X2 setup.

Obviously I could swap the RPM on any time.

I got the trips mostly for the cool factor.
I knew going in the trips would not be as good as the RPM.


Having said that, there are other forum posts where they made well North of 500 hp with a 3X2 on a stroker.

[My427stang]

Just my opinion but, if you want the 3x2, I'd do a couple things

1 - Work on the top side, consider the roof of the plenum and port entry to be the short side radius of that first turn.  As much of a nice tailored curve as you can will help, any sharp edge anywhere in the plenum will try to pull fuel out of suspension too

2 - Make some spacers, and not sure how the 3x2 works, never used a Ford one, but you could consider something sorta tall if it fits, and open, to give it a little more plenum volume.  A big inch motor likes a decent size plenum to soften pulses, and the more you can give it the better.  Also, if not trying to keep it stock, the spacers may let you be more bold on the top side of the intake. 

3 - If there are bigger carb options, by all means do it.  Again, I don't know my 3x2s but almost as a rule, more carb the better, especially if you have #1 and #2 done

That being said, my feeling is that it will be down compared to the RPM, and even less effort on the RPM would bring that intake to the next level, but multiple carbs are cool to look at

[67xr7cat]

HP is not what kills rods is RPM. Longer the stroke and weight hanging off the rod is what matters.  Stock 428 cj with factory rev limiter was what 5,800 rpm? 

Doubt your going turn it more than 6,500 rpm and you probably not making power up there anyways.

As I ask everyone what are your goals? What is needed to meet them?  Shift at 5,500 rpm and is all a non-issue. 

Just bought a 427 SO off a friend a few days ago. He is an old SS racer. He said you know I had a 390 used to race. Made 580hp at 7,500 rpm and had stock rods. Never broke it. 

Just JMHO but sounds like a street cruiser and your getting hung up on a HP number. If you really interested in making the car faster you have to look at the power range not peak hp. As to the rod to me is a non-issue, but whatever makes you happy.