Rod Resizing?

[BJ91T]

Well The current motor in my 91 is on bone stock rods and reused rod bolts with a rod bearing clearance that is the max allowed (per TSRM) 0.0028 inch. Now I am going to be going inside the motor this week to see whats up and try to solve some rear main seal/oil pan issues. I also plan to pull the rods out of the block and have them fitted with ARP rod bolts and have them shot peened/stress relived and have new piston pin bushings installed aswell. While I am that far I figured now would be a good time to get those rod bearings dead on what I want them to be. so my goal is to get them within the toyota spec (0.0008-0.0021 inch). To do this the rod will need to be resized??? I would assume. If I have the rods resized will i still buy STD rod bearings??? what do i need to tell my machinist to get these rods right? I am gonna be slowly building a backup block but I need this one to last a while so I can take my sweet time building the all forged internal back-up block. this motor only has 300 miles on it since my last rebuild I just cannot attemp to make power or anything with stock rod bolts and loose rods. I will be reusing the stock pistons and adding new rings.


Thanks In Advance
BJ

 

[IJ.]

BJ: As soon as the bolts are changed Rods MUST be resized.

The shop should have a book with specs or you can supply the size from the TRSM.

 

[BJ91T]

ok so if i supply them with tsrm specs std bearings my crank arps and my rods they will do the rest? (setting proper tolerance)

 

[IJ.]

If they're any good they will

 

[BJ91T]

well thanks for putting up with me newb questions it really helps me understand



thanks
BJ

 

[IJ.]

Glad to help out BJ!

Better to ask the question than chance getting it wrong and losing a motor

 

[BJ91T]

yeah i neaver understood just what happens on a rod resize

 

[IJ.]

They machine a little off the Cap parting surface this makes the hole smaller then they will either machine then hone or just hone it so it's perfectly round and the correct size.

When you change bolts it can distort the hole so they need to be changed then resized.

The next step is replacing the little end bush if needed then balancing the rods end for end so they weigh the same in total and each end weight is the same.

They will also check Length and straightness as well as magnaflux them to make sure there aren't any surface cracks. (shot peening helps toughen the surface)

There's quite a bit involved to correctly prep a set of rods.

 

[BJ91T]

ah ok someone at work tried to tell me i could not use STD bearings if i did that .....but i assume i can

 

[IJ.]

Depends on the crank size BJ.

 

[BJ91T]

yeah i forgot to add my crank is uncut and smooth

 

[IJ.]

They'll need to measure it