FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: blykins on June 09, 2020, 02:50:55 PM
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(https://live.staticflickr.com/65535/49989127281_0744f0d199_z.jpg)
This was done by one of our highly thought of crank grinders...
Luckily, it's the crank for my 352 project and not a customer's piece. But still....
He ground it a couple of years back and I'm just now getting around to checking the balance on the crank.
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I think the question should be, "How long will this work??"
Holy stress-riser, Batman! At least you'll be getting lots of earl to that rod ;D
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Maybe that rod and piston will be faster
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I have seen similar stuff before and I have pretty much hated it all the time.
Never caused a problem that I was aware of, but that oil crater gets really close to be exposed to the outside of the rod bearing - a major no-no
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Those aluminum rods fit a Honda journal?
here's mine with a 2.20
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That's the second crank that I've had issues with from this guy. Last time, I paid $1400 to have a 391 crank ground down and then had to have it ground again locally because the thrust surface had .004" of run-out.
As George Bush would say....
"Fool me once, shame on — shame on you. Fool me — you can't get fooled again.”
I know he saw it because he chamfered the hole.....
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Those aluminum rods fit a Honda journal?
here's mine
No sir, they are BBC rods.
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That's the second crank that I've had issues with from this guy. Last time, I paid $1400 to have a 391 crank ground down and then had to have it ground again locally because the thrust surface had .004" of run-out.
As George Bush would say....
"Fool me once, shame on — shame on you. Fool me — you can't get fooled again.”
I know he saw it because he chamfered the hole.....
My 391 above was done for $700.00 (plus a discount for the long wait)
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Anyone got a 361 crank they wanna sell?
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Were you changing the stroke and he offset it incorrectly?
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I have one, its been turned .020 on mains and rods I think. Never been used since it was turned. Still in a bag and just collecting dust. I'll sell it for a decent price plus shipping. Its in billings mt. Rob
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Were you changing the stroke and he offset it incorrectly?
No sir, just going to BBC journals. It happens but it would have been nice if he had stopped when he saw that so I could have cut my losses. It was sent to me ready to roll.
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It looks like it has nice radii. But for that one funky hole. Why not weld the crank? Too much investment?
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I don't think it's fair to blame the crankshaft grinder here, assuming that the grinding operation was not out of index, but rather solely the result the journal diameter reduction for the 2.200" diameter; adding stroke in the process changes the outcome some, but this observance is due to where Ford Motor Co. placed the oil drilling. The only appropriate statement would be oh-well, it-is-what-it-is!
And not intending to make excuses for the operator, but generally one grinds the mains first, then the rod journals, and perhaps this was a latter position in the grinding operation, and even when in the grinding process sometimes visibility is not so good until stopped at which point, well it-is-what-it-is; and hopefully the person contracting for the nonstandard operation is aware of the possible shortcomings of the modification, and that person must decide the usability of their creation, not the contracted machine operator, although that person may be willing to supply previous observations and opinions, particularly if inquired upon, it's not fair to make this result that persons' fault.
But yes, with the proximity of this oil hole breaching the surface so near the journal radius, it would not be considered "ideal". ;)
Scott.
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It looks like it has nice radii. But for that one funky hole. Why not weld the crank? Too much investment?
Worthless to weld. The weld will actually cause it to break sooner by the stress cracks from the welding process.
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Worthless to weld. The weld will actually cause it to break sooner by the stress cracks from the welding process.
+1 ;)
It-is, what-it-is!
Now, the question is: to-use-it, or-not? :-\
Scott.
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I'm with Barry here. I had a 302 crankshaft offset ground to use Chrysler rods and get stroked which uncovered the oil passage for a full inch. I called the crankshaft guy and he said they had done dozens like that without issue. I put it together for a customer, and he raced that engine for several years using nitrous, pulling the wheels and running in the nines with a Fox mustang. Looked terrible, but didn't lose oil pressure, didn't weaken the crankshaft, and didn't hurt the bearings. That is just my experience, yours may be different. Joe-JDC
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That's the second crank that I've had issues with from this guy. Last time, I paid $1400 to have a 391 crank ground down and then had to have it ground again locally because the thrust surface had .004" of run-out.
As George Bush would say....
"Fool me once, shame on — shame on you. Fool me — you can't get fooled again.”
I know he saw it because he chamfered the hole.....
My 391 above was done for $700.00 (plus a discount for the long wait)
Who did yours? Guys around here won’t touch an fe crank going to bbc journals.
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Castillo’s crankshafts in La Mirada, CA. Offset ground to 3.990 stroke, 2.20 x 1.90 journal.
They also did my 427 TP back in early 2000
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Is it just me that it looks like a really crappy polish job also? The ones I've seen/done have a more mirrored finish.
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Brent ,
Does Cornett Machine in Somerset still do cranks? They used to do billets .
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Short-Lived Certain Death
There are two forces to harness in crankshafts: bending stiffness and torsional stiffness.
Bending stiffness deflections occur from firing load and inertial forces, and is essentially the crank webs opening and closing. Main to pin overlap area, material strength, and fillet radius are the key input factors. Failures occur typically in the fillets.
Torsional stiffness deflection occurs from firing and management of driveline inertia and post dampening. The flange end is typically dampened, while the post is free. Inertia mass is added to the post to counteract this force. Key input factors for controlling torsional deflection are mass management, cross sectional thickness between the oil hole and web, and to a lesser extent material strength as if torsional are not managed, no material can contain torsional deflection.
As for this crank with its oil holes, both the torsional hot spot and bending fatigue hot spots are in the same area, the fillet, and the oil hole is so broad, it is likely into the peak area for torsional stress - not good.I
As another member noted, the oil hole breakout location is set when the holes are drilled, and their proximity is strategically placed to keep away from the stress hot spots. This condition is not the fault of the crank grinder other than he should be aware of it when reducing journal size, and caution against it. Apparently that wasn't the case of he didn't know.
Hope this helps; you can trust this info as I'm FoMoCo's Global Mfg. Engineering Technical Specialist for Crankshafts.
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Short-Lived Certain Death
There are two forces to harness in crankshafts: bending stiffness and torsional stiffness.
Bending stiffness deflections occur from firing load and inertial forces, and is essentially the crank webs opening and closing. Main to pin overlap area, material strength, and fillet radius are the key input factors. Failures occur typically in the fillets.
Torsional stiffness deflection occurs from firing and management of driveline inertia and post dampening. The flange end is typically dampened, while the post is free. Inertia mass is added to the post to counteract this force. Key input factors for controlling torsional deflection are mass management, cross sectional thickness between the oil hole and web, and to a lesser extent material strength as if torsional are not managed, no material can contain torsional deflection.
As for this crank with its oil holes, both the torsional hot spot and bending fatigue hot spots are in the same area, the fillet, and the oil hole is so broad, it is likely into the peak area for torsional stress - not good.I
As another member noted, the oil hole breakout location is set when the holes are drilled, and their proximity is strategically placed to keep away from the stress hot spots. This condition is not the fault of the crank grinder other than he should be aware of it when reducing journal size, and caution against it. Apparently that wasn't the case of he didn't know.
Hope this helps; you can trust this info as I'm FoMoCo's Global Mfg. Engineering Technical Specialist for Crankshafts.
The location of the hole is certainly not the crank grinder's fault. However, when you see something like this, you don't finish the crank up, chamfer the holes, do a polish, etc., then ship it out. Just as an off-the-wall example, if I were boring a block, was on the last hole, and the last pass on the boring bar exposed a crack, I wouldn't go ahead and hone the cylinders, deburr the tops/bottoms, and then ship it out.
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At 2.200", that is still a lot of strength for a cast crankshaft, and should be able to handle quite a lot of horsepower. My stock 292 Ford crankshaft is ground down to 1.88" on the rods, has the oil hole close to the edge, and has made 15 dyno pulls at 450+ hp., with several over 460 hp. I know you want to wring this thing out and make as much horsepower as possible, but lightweight rods, light pistons, and good balance should make this survive all your testing and work well in the vehicle for years to come. The only issue is not much left for a polish or regrind later on if needed. The only other option is aftermarket forged from one of your suppliers. Joe-JDC
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It's not like it is a customers engine that you will lose sleep over worrying if it's gonna survive.. Think of it as a dyno mule. Da Mule II.
Run it. You did buy 9 rods, right?
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With a little chamfer on the bearing you won't need a piston oiler in this bore; and maybe if the intention was to use low tension oil rings, substitute a standard or high tension oil control ring in this bore. :o
Just trying ta help! ::)
Scott.
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I'm just not gonna chance it guys. My cost on the pistons was $1300......not gonna take a chance of destroying parts, even if it is my own junk. Got a lot of plans for this engine and don't wanna see it go away without making a full pull.
I know what bleeders under a rod bearing can do. I smoked a 400 Pontiac on the first pull because of a crack that developed in a rod journal radius.
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Smart move.