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Bronze pin bushing vs. no pin bushing

General engine tech -- Drag Racing to Circle Track

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tsanchez
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Re: Bronze pin bushing vs. no pin bushing

Post by tsanchez » Wed Apr 11, 2012 11:59 am

ProPower engines wrote:Done a bunch of 340 rods lately. The have a similar looking big end.
They must have been bushed to last that long.
No steel on steel, hole drilled on top with a chamfer to let oil in

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Re: Bronze pin bushing vs. no pin bushing

Post by Greens Nice » Sun Nov 25, 2012 7:03 am

Hi all, just curious would love to know your thought's.
I'm looking to float a set of rods for an Aussie 6cyl with no bushing, 202ci, engine might make 340 flywheel Hp 7500rpm max.
would 1 thou clearance with .866 pin's be adequate?
will a .100" hole drilled in the top with a large chamfer weaken the rod some if any? Thanks.

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Re: Bronze pin bushing vs. no pin bushing

Post by ProPower engines » Sun Nov 25, 2012 6:26 pm

I believe you would have no issues.
Some Nissan L6 skyline engines use a similar pin size (.844) and slightly larger displacement size and more HP and higher RPM range are done that way. There are others as well. No problem. :D
Real Race Cars Don't Have Doors

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Re: Bronze pin bushing vs. no pin bushing

Post by hodge » Sun Nov 25, 2012 8:43 pm

steel on steel no problem .001" minimum with 15w 40 oil thinner oil less clearance but best oil. more is always better, less clearance will bite you

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Re: Bronze pin bushing vs. no pin bushing

Post by Kevin Johnson » Sun Nov 25, 2012 10:48 pm

ProPower engines wrote:The original GM Z302 had floating pins. GM dipped the rod in copper and then sized the pin end. They lasted for many years of street driving and abuse.
This was mentioned in another thread but in the sense that offspec rods were given another chance to be used by the factory. Were complete engines outfitted with these or was that just a sign of a bad day for production tolerances?

Aside: Probably a topic for another thread -- A tech once told me that returned and refurbished machine tools with as-new warranty were not such a bad idea since they were gone through carefully by a tech and bad parts replaced. I can recall other discussions regarding rebuilt alternators where the high quality ones basically only re-used the castings for the body and everthing else was new.

ProPower engines
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Re: Bronze pin bushing vs. no pin bushing

Post by ProPower engines » Sun Nov 25, 2012 11:22 pm

I have seen that as well where certain components with a repair and as new warranty out performed the off the shelf stuff.
A bit off topic but Home Depot had some weed wackers on sale as new warranty refurbished units discounted for a sale.
They ran better then the off the rack one did.
Same thing applies to lots of stuff in our industry.
Real Race Cars Don't Have Doors

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Re: Bronze pin bushing vs. no pin bushing

Post by Adger Smith » Mon Nov 26, 2012 12:01 am

Steel on steel with approx .001 clearance and 3 oil holes. (top and both sides) It needs a Real fine finish on the hone job. Same thing when going with DLC coated on steel. The advantage to bushings is they are softer than the steel and will deform when the engine detonates or goes into pre ignition and the pin/rod end is knocked around. When the engine detonates it knocks the oil film away from the pin/rod causing contact in that area. The right lube, clearance and tuneup will work with steel on steel . Get any of that wrong and you will be singing the praises of bushings.
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Re: Bronze pin bushing vs. no pin bushing

Post by Greens Nice » Mon Nov 26, 2012 4:40 am

thanks! :notworthy:
love the info on this site.

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Re: Bronze pin bushing vs. no pin bushing

Post by In-Tech » Mon Nov 26, 2012 5:34 am

Adger Smith wrote:Steel on steel with approx .001 clearance and 3 oil holes. (top and both sides) It needs a Real fine finish on the hone job. Same thing when going with DLC coated on steel. The advantage to bushings is they are softer than the steel and will deform when the engine detonates or goes into pre ignition and the pin/rod end is knocked around. When the engine detonates it knocks the oil film away from the pin/rod causing contact in that area. The right lube, clearance and tuneup will work with steel on steel . Get any of that wrong and you will be singing the praises of bushings.

I agree with Adger, there's been plenty of rods in racing run steel on steel for various reasons. Detonation is the killer. Go 1.15 x pin diameter steel on steel with at least a top oiling hole and it will work. Less aggressive honing as he mentioned will help aid as well.
Heat is energy, energy is horsepower...but you gotta control the heat.
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Re: Bronze pin bushing vs. no pin bushing

Post by rcull » Wed Jul 29, 2020 5:47 pm

Don't mean to bring an ancient thread back to life, but I read this and then found this:
CALLIES CS1-SB Bushing Piston Pin Bushing Small Block

https://www.a1racing.com/callies-cs1-sb ... block.aspx

Thought someone else might want to find it too. It looks like the wall thickness is 0.026" without and fitting.

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