[Johnny406]

I expect some ridicule for this one but just curious, has anyone ever used a .050 bearing on a Pontiac rod to use it on a Chevy journal crank? Does such a bearing exist?

I ask because it's ridiculously difficult to find a 3" main 4" stroke 2.25" rod crankshaft these days. I already have pistons and rods. Yes, I can certainly sell what I have and my spare kidney and buy a rotating assembly from KRE or the Butler's but I'm trying to find a more feasable solution to my problem.

Thanks,
John

[b-man]

.040 is the limit and probably not easy to source.

And even that would be a poor rod bearing choice for a race engine.

[25stevem]

You only find oversizes like that available for earth moving equipment engines.

What a competent machine shop can do however is bore and hone out a set of Pontiac bearings to then accept the BBC bearings.

Basically all that would remain of the Pontiac bearing would be the steel back.

You would also have to rebalance everything and add weight.

This was done all the time in the 70s with SBC 400 motors to get a 283 or 327 crank in those 400 size mains if I recall right?

[mgarblik]

King bearings have part numbers listed in their master catalog for .040, .050. .060 sizes in several lines of products. Personally, I would have no reservations running them on a properly ground, properly polished crankshaft. We ran .040 and .050 bearings to save billet Crower crankshafts. Unfortunately, for a Pontiac, once the mains are dead at -.030, your welding the shaft back up to save. But rods in the Chevy sizes, they just keep making the backings thicker and go way undersize. Not sure of in stock availability, so I would call them directly and see what's available. Here are some part numbers: CR 808 SI This is a Bi-metal bearing .040, .050. .060 CR 808 HPN Alecular race bearing CR 808 XPN race bearing , tri-metal CR 808 XPNC coated race bearing

Find a set and go racing!

[Nobuddy]

King lists these for Pontiacs - CR 815CP 050 and CR 815CP 060. I have no experience with these but it seems they should work.

[hurryinhoosier62]

King bearings are excellent bearings. We found them to be more consistent in thickness than either Clevite or FM main and rod bearings.

[mgarblik]

I looked today through all my rod bearings and I am sorry to report I don't have anything beyond -.030 unfortunately. However, I do have way, way too many sets of 2.200 rod bearings in general. I will list them in the performance parts for sale area. I probably have 20 sets to sell. I have STD, +.001, -.001, -.009, -.010, -.011, -.019, -.020, -.021. Summit gets $94.00 a set for them. All have the hole for aluminum rods on the cap end. Makes no difference, you can run them on any rod. That comes from King as well as Federal Mogul. $50.00 a set 2 set minimum. All are Federal Mogul 7200 CHA race bearings.

[Johnny406]

Thank you all for your replies, the King .050 bearings is very tempting.

I just thought of this, I remember it was quite common to chrome plate crankshafts back in the day, would this be a feasible solution to a 2.20 journal crank to a Pontiac 2.25 rod? Not necessarily the whole .050 but some of it?

[hurryinhoosier62]

Originally Posted by Johnny406

Thank you all for your replies, the King .050 bearings is very tempting.

I just thought of this, I remember it was quite common to chrome plate crankshafts back in the day, would this be a feasible solution to a 2.20 journal crank to a Pontiac 2.25 rod? Not necessarily the whole .050 but some of it?

Not .050. On most cranks the chrome plating is normally .003-.005 thick. We used to see hard chroming a lot on marine cranks. It’s a PITA to has to chip the chrome plating off if you need to grind or polish the journals.

[25stevem]

I would not chrome plate a cast Crank for fear of failure due to hydrogen embrittlement even in a motor that would only see street rpm's.

[hurryinhoosier62]

Originally Posted by 25stevem

I would not chrome plate a cast Crank for fear of failure due to hydrogen embrittlement even in a motor that would only see street rpm's.

Good point, Steve. That is the same problem Chevy had with their BBC hi-po cranks back in the day from the Tuft-Ride process.

[Steve Barcak]

If you wanted quality welding repair, or enlarging of journals of racing crankshafts, look up Marine Crank shaft in Santa Ana, Ca.
they specialize in repairing Top Fuel/Funny car and other billet cranks as well as forgings. they perform state of the and, top quality welding, machining repairs and changes, including enlarging journals.
I got a personal tour of the place some years back and am very impressed with their experience and quality of work.
Have had them modify and repair a few Pontiac forgings and quite happy with their work. Highly recommended to top quality work. here is alink. I hope this helps you and others reading this.
Have not needed any of my billets repaired but, should that need arise, Marine Crankshaft is who I will deal with again.

https://marinecrankshaftinc.com/

[Tom Vaught]

Originally Posted by Johnny406

Thank you all for your replies, the King .050 bearings is very tempting.

I just thought of this, I remember it was quite common to chrome plate crankshafts back in the day, would this be a feasible solution to a 2.20 journal crank to a Pontiac 2.25 rod? Not necessarily the whole .050 but some of it?

I think honestly, Jim Butler was one of the very few having Chrome Plating done on Pontiac Crankshafts, years ago.
Once Bob and Frank started having Scat cranks made for Pontiacs at a much lower price vs a Moldex Crank/Kellogg
crank, most of the Chrome Plated stuff went away as the government was going after the Chrome Plating shops at
the same time.

Tom V.