rod bearnings

[4g63awdtalon]

dose oversized rod bearnings affect proformance?

 

[Mindslayer]

no

 

[Defiant]

Did you mean "undersized"?

Still, no.

 

[Rick@AP]

Actually, there is a theory that by tuning the bearing journals you effectively reduce the drag on the crank thereby increasing power. The reason being that you have reduced surface area on the face of the journal.

There is also a theory that smaller journals are stronger. (this one I've yet to figure out why).

However, unless you are planning on racing in LeMans and need every bit of hp you can find I don't believe it is worth performing, especially at the risk of a broken crank, thrust related problems or a badly turned crank in general.

But you wouldn't be turning a 4g63 crank without having it re-nitrated would you?

 

[4g63awdtalon]

Rick@AP
But you wouldn't be turning a 4g63 crank without having it re-nitrated would you?

the clearence's are off so i needed to get the crank mechined and i will see if the mechinst is going to renitrate the cran. what would happen if he didn't renitrate the crank?

 

[Kingdom]

Originally posted by Rick@AP
Actually, there is a theory that by tuning the bearing journals you effectively reduce the drag on the crank thereby increasing power. The reason being that you have reduced surface area on the face of the journal.

There is also a theory that smaller journals are stronger. (this one I've yet to figure out why).

However, unless you are planning on racing in LeMans and need every bit of hp you can find I don't believe it is worth performing, especially at the risk of a broken crank, thrust related problems or a badly turned crank in general.

But you wouldn't be turning a 4g63 crank without having it re-nitrated would you?

I never about nitrating, can you explain further?

 

[Rick@AP]

The 4g63 cranks are supposed to be nitrated from the factory (I've found one now that isn't, which makes me think there may be more).

You should never turn a nitrited crank without having it re-nitrited because you loose the surface hardening (the nitried) on the journals. I've found that the 4g63's are pretty hard on the journals. If you leave out the nitriding then you risk more surface damage to the journal and shorter times between rebuilds.

Also make sure they don't cut out the radius, that can cause MAJOR problems on a turned crank.

 

[Kingdom]

the radius you mean the surface around the edges of the journals?

also are the main bearing nitritid?

 

[4g63awdtalon]

i talked to the mechine shop today and he said some are nittrated and some are not