7 bolt rod bearings on a 6 bolt crank?

[getusum]

Anyone ever done this? The only differance is the 7 bolt bearings are 100 thousands narrower. My machine shop said it would help reduce fricton and should work. Has anyone done this?

 

[Defiant]

Which will increase load and heat generation. Are you planning on driving this car, or just punting it down a dragstrip twice a week?

 

[getusum]

Driving it all the time. Not a daily but alot. My shop builds Nascar engines for FORD only. The only reason hes building mine is because I married into the family. He said thats something they do. But I dont know? I dont like it personally.

 

[motomattxxx]

And how long does a typical nascar engine last?

 

[Purevil]

So the dude at the machine shop has done this before?

How much of a difference do you really think this is going to make? Bearings are engineered to work with each engine type and they work very well. The gains whether there are any or not would be so miniscule that this isn't even worth your time.

Stock 6 bolt bearings are all you need.
-Buschur has made well over 1000hp on them.
-Factory engines have lasted well over 300k miles on one set of bearings.
-Stock bearings have been rev'd to 10-11K rpms with no ill effects.

 

[95blackGsTurbo]

If it was such a great idea someone would be doing it already. Stick with what works.

 

[aero_sallee]

Bearing width is not the only difference. 7 Bolt bearings have smaller tabs on it that prevent bearing rotation. Don't do it, it cost me a stroker crank. Early 7 bolt eagle rods are made to use the 6 bolt bearings with the larger tab. The set I bought a few years back didn't have any documentation with them that stated that.

Cost me a crank, eagle rod, and a HX40 turbo from the metal circulation.

 

[getusum]

You guys were right, we didnt use them. The tabs didnt match up. Thanks.