Performance Rod Bearing Question

[GTSTwNCaM]

I have a 88 Corolla GTS Big Port 4age. I'm looking in replacing the pistons with high comp 10.5 : 1 82mm Wiseco pistons. I also damage the rod bearings... so if I was going to put high comp pistons on do I still use the std size rod bearings? Any help will be great!

[tashirosgt]

I don't know the answer, but I think you should explain whether you are going to do normal driving or some kind of racing. Aren't racing engines "loose" compared to normal driving engines? (I, myself, only do normal driving.) If you want precise clearances you may have to use OEM Toyota bearings since they come in a finer size divisions than aftermarket bearings. You should measure the clearances and figure out what sizes you need before ordering them. It may take a different size bearing for each rod.

[94_Rolla_Guy]

ok i can help a bit the first thing you gotta do is inspect your crank for scouring and damage next you need to measure it up and compare with specs in a chiltons haynes or from some reputable source if its all good which i doubt you can spec bearings with the aid of the manual using the grading scheme. On the flip side if its damaged or out of spec then you will have to have the crankshaft reground then spec oversize bearings

Do this with both your mains and rod bearings...

If your not comfortable seek help from an engine builder.

[toyomoho]

Have a competent engine shop look at the crank. They can quickly inspect for damage, check diameter and tell you if standard bearings will fit. The cost will be minimal compared to the rest of the parts you are picking up. The crank journals may be Ok, just need polishing, etc.

Determine what caused the damage to the engine in the first place. Swapping bearings without finding the cause might result in the same problem.

Pick up a few good books on performance engine rebuilding. They should cover crank bearing selection, clearances, journal damage and other issues. Talk to a few engine rebuild shops that do custom work. Increased bearing clearances effect oil pressure, consumption and the bearings ability to handle loads. Too much clearance can detrimental. Do a TN search, the subject of bearing damage has come in this and other forums.