Eagle cranks and unusual pilot bearing sizes - Team Camaro Tech
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post #1 of 17 (permalink) Old Feb 17th, 04, 12:15 PM Thread Starter
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Wow, this is one thing after another..where a 3 hour job of installing a clutch & scattershield on an a 350 chevy turns into 3 weeks.

I have a brand new 4340 forged steel Eagle crankshaft. It is supposed to use the standard SBC pilot bearing. I went to install the pilot bearing and it is too small, flops around in the bore and the hole is ever so slightly too big for the bearing. I called Eagle and they said that should not be the case, but a while back, they did have a bunch of SBC cranks that went out with a bore drilled for Pontiac pilot bearings. He said people didn't notice because most use an auto trans, but that was a while back and shouldn't be the case with my recently purchased crank.

Anybody hear about this problem, and if so, what size pilot bearing fits the darn thing? I don't have a micrometer to measure. No one can give me an answer.

1973 RS Z28: 401ci Dart Little M, Littlefield 6-71 supercharger @14lbs boost, Callies Magnum crank, Lunati rods, JE pistons, 7.8:1, AFR 227 Comp heads, T&D 1.6 shaft rockers. Reed solid FT cam (240/250@.050-.523/.542 lift-112 LSA), QFT 750 carbs
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post #2 of 17 (permalink) Old Feb 17th, 04, 12:32 PM
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Where did you get the pilot bushing? An aftermarket parts supplier, CHAMP ITEMS used to list three different part numbers for Chevy V8 pilot bushings. The all had different O.D.s

John N.

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post #3 of 17 (permalink) Old Feb 17th, 04, 02:22 PM
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There is one that might fit. It was made for cars with auto trans (not the early turboglide thing). The 350 I just built was a 71 motor that came with an auto. Std pilot bearing was a lttle small on the od. Got the one listed for the conversion to a manual using an auto crank it worked fine.
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post #4 of 17 (permalink) Old Feb 17th, 04, 03:27 PM Thread Starter
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I got the bearing from the dealer that sold me the Tremec TKO kit..he sells many and what he sent me was the bearing for the auto to manual conversion, supposedly.

I don't find anyone with the Eagle crank prob, then I suspect they sent me the wrong part, but I have to buy a micrometer to prove them wrong.

mike

1973 RS Z28: 401ci Dart Little M, Littlefield 6-71 supercharger @14lbs boost, Callies Magnum crank, Lunati rods, JE pistons, 7.8:1, AFR 227 Comp heads, T&D 1.6 shaft rockers. Reed solid FT cam (240/250@.050-.523/.542 lift-112 LSA), QFT 750 carbs
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post #5 of 17 (permalink) Old Feb 18th, 04, 07:07 AM
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TT,
I just measured the back of a new Eagle 4340 crank I have here at the shop. It measures 1.090" where the bushing goes. I also measured a brand new GM steel crank and it is the same. According to my bushing book, the pilot bushing should measure 1.094" which sounds just about right .004" press fit.
Hope this helps,

Bill Koustenis
Owner
Advanced Automotive Machine
Waldorf Md
1971 Chevelle "Heavy Chevy" original owner

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post #6 of 17 (permalink) Old Feb 18th, 04, 08:25 AM Thread Starter
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I just miced the bearing I have with a cheap micrometer, it measured 1.119" and the stock chevy breaing is 1.093". This is really strange and sounds like a screw up on Eagles part.

1973 RS Z28: 401ci Dart Little M, Littlefield 6-71 supercharger @14lbs boost, Callies Magnum crank, Lunati rods, JE pistons, 7.8:1, AFR 227 Comp heads, T&D 1.6 shaft rockers. Reed solid FT cam (240/250@.050-.523/.542 lift-112 LSA), QFT 750 carbs
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post #7 of 17 (permalink) Old Feb 18th, 04, 10:22 AM
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i've never heard of Chev V8's having different sized pilot bearing holes- i've changed a few auto cars over to manuals and just used either stock pilot bushings or stock roller bearings. they always fit snug.

you don't plan sincerity.
you have to make it up on the spot.

wanna hear about 20 years ago when i was too smart to know any better?
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post #8 of 17 (permalink) Old Feb 18th, 04, 01:13 PM
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TT,
Have you measured the hole yet ?? If you dont have an inside micrometer, just cut a pc of wire untill you can barely get it into the hole, and then measure the wire. You can get pretty close that way. If the hole is actually cut for a Pontiac bushing, then use the Pontiac bushing, I am pretty sure the transmission input shafts are all the same size. You are going to have to figure out a way to measure the hole, one way or another.

Bill Koustenis
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1971 Chevelle "Heavy Chevy" original owner

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post #9 of 17 (permalink) Old Feb 19th, 04, 06:50 AM Thread Starter
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Yes, I measured the end of the crank...1.097". I have the correct SBC pilot bearing measuring 1.093".

I talked to Eagle again..they said they had a bunch of cranks go out 6 or 7 years ago w/ the wrong size hole machined but shouldn't be my case since I just bought directly from them and this is a high turn over item. The kindly agreed to send 2 1.111" solid bronze bushings they were keeping on hand for this issue. I just spent $3,600 on a new Tremec TKO and am not thrilled about throwing away my nice roller pilot bearing i think I will have another roller machined. What they did was use the larger Pontiac bearing which has the same ID as the chevy bearing and machined down to 1.111". I guess most people use auto trans and this slips by.

Anyway, since .004" is required for the press fit, I think someome screwed up when they set the specs for the crank and made the hole .004" larger than the bearing rather than .004" smaller, because the difference between the stock 1.093 bearing and the one they recommend is exactly .008" difference.

Now I have had to become an expert overnight on Chevy pilot bearings, not that I wanted to. I would have preferred to shove the bearing in and move on. This little mistake cost me an extra $100 bucks (buy micrometer, another bearing, machining, shipping) and a lot of wasted time & aggravation. Crank was already balanced, journals prepped and installed, so easiest to fab a new bearing.

1973 RS Z28: 401ci Dart Little M, Littlefield 6-71 supercharger @14lbs boost, Callies Magnum crank, Lunati rods, JE pistons, 7.8:1, AFR 227 Comp heads, T&D 1.6 shaft rockers. Reed solid FT cam (240/250@.050-.523/.542 lift-112 LSA), QFT 750 carbs
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post #10 of 17 (permalink) Old Feb 19th, 04, 04:13 PM
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Mike,
I would not be too concerned about using the bronze bushing instead of the roller bearing. The only time the input shaft actually turns in the bushing is if the clutch is pushed in, not very often compared to total running time. I have seen enough failed roller bearings out of 5.0 Mustangs that I would personally not even think of using one. If the transmission is properly aligned, the bronze bushing will last a lifetime without any problems.
Just my opinion,

Bill Koustenis
Owner
Advanced Automotive Machine
Waldorf Md
1971 Chevelle "Heavy Chevy" original owner

Enginerepairshop.com
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post #11 of 17 (permalink) Old Feb 20th, 04, 08:42 AM Thread Starter
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Many thanks for your input Bill. It was very helful.

mike

----------------------------------------------
RS Z28: Littlefield race series 6-71 supercharger on a 355 w/ AFR 195 heads, 10 lbs boost, 7.6:1 static compression, CompCams hydraulic roller (276/288 advertised, 224/236 @.050 duration, .510/.527 lift w/ 1.52 rockers on a 113 lobe separation), AFR Hydra-Rev kit, Eagle Forged Steel crankshaft, ARP studded bottom end, Eagle ESP H-beam rods, TRW forged reverse dome pistons, Comp Pro-Magnum 1.52 roller rockers with 7/16 studs, twin 750 Edelbrock carbs, 1&3/4 inch Hooker Super Comps, 3" dual exhaust with cross over pipe. MSD 6AL ignition & Pro-billet distributor, Tremec TKO 5-speed, Moser 12 bolt with Eaton posi & 33 spline axles & 3.42 gears

1973 RS Z28: 401ci Dart Little M, Littlefield 6-71 supercharger @14lbs boost, Callies Magnum crank, Lunati rods, JE pistons, 7.8:1, AFR 227 Comp heads, T&D 1.6 shaft rockers. Reed solid FT cam (240/250@.050-.523/.542 lift-112 LSA), QFT 750 carbs
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post #12 of 17 (permalink) Old Apr 1st, 09, 10:31 PM
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Re: Eagle cranks and unusual pilot bearing sizes

I am going to bring this one out of the grave. I have a tremac TKO 600 conversion from auto to manual kit.
I have read through the instructions and made my notes.
Went tap in the provided pilot bearing and it just slid in and I was able to easily remove it.

Crank is Eagle Specialty Products 435037505700

My bearing measured 1.093 but I was not able to measure the inside diameter of the crank because my caliper was not long enough

Any one else...
Rick
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post #13 of 17 (permalink) Old Apr 2nd, 09, 09:35 AM
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Re: Eagle cranks and unusual pilot bearing sizes

Quote:
Originally Posted by dukemd66 View Post
I am going to bring this one out of the grave. I have a tremac TKO 600 conversion from auto to manual kit.
I have read through the instructions and made my notes.
Went tap in the provided pilot bearing and it just slid in and I was able to easily remove it.

Crank is Eagle Specialty Products 435037505700

My bearing measured 1.093 but I was not able to measure the inside diameter of the crank because my caliper was not long enough

Any one else...
Rick
Hi Rick, the nominal size on the crank hole should be 1.092"/1.093". I realize you can't measure the I.D. but the pilot bushing size you listed is too small at 1.093"?

All the "Pioneer's" we have in stock here measure a minumum of 1.094" and go up to 1.0955". Big difference from the one you have now!

Have used numerous "Eagle" cranks over the years and have had issues on the front-end, but never at the rear! Many snouts were way under on the SB's, both the cast's and the steel's? The steel's are fine now, and we rarely use cast ones!

Thanks, Gary in N.Y.

P.S. The part number for the "Pioneer" piece is PB656! This is a "bushing" not a roller bearing! We won't use the roller's!
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post #14 of 17 (permalink) Old Apr 2nd, 09, 02:50 PM
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Re: Eagle cranks and unusual pilot bearing sizes

I will say this and I didn't catch it before I installed my engine and that is a cheap bronze/iron CHI-COM bushing is way tight vs a stock one!

pdq67
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post #15 of 17 (permalink) Old Apr 2nd, 09, 03:58 PM
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Re: Eagle cranks and unusual pilot bearing sizes

Same with my scat....take a center punch and put three dimples every 1/4 inch and some red loctite just to be safe. Mine went in snug and so far no problems.
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