Bearing and piston size

[dannyj1092]

Can anybody give me some advice ive recently bought a bent cam sr20, carried out a leak down test to find leaking valves and piston rings, so decided to rebuild the engine, ive scoursed some new valves and have decided to go with forged pistons and rods, but im unsure of which ones and and which sizes to choose for the pistons and crankshaft bearings, can anybody advise me on how to determine the correct size to buy? Thanks in advance

[Mike41288]

Standard pistons are 86mm, anything above that is for bored out cylinders. Standard bearings (not race bearings unless you have been advised to) should be fine if your crank doesn't need any more than a polish but I'd get a machine shop to double check that if it was me.
Also might be worth mentioning that aftermarket valves differ in length so the standard valve shims will need to be measured to make sure they are right. It's best to do this before the valves are installed as you can have the difference machined off the valves instead of having to source new shims.

[dannyj1092]

So if i was to buy forged pistons id have to get 86mm ones? Ill take the crankshaft to newton cams who are just roumd the corner with me, ive bought standard valves, and have some tomi pon cams with uprated springs and caps that im goimg to fit, ive also noticed that the rocker arms i have dont have one flat side and one notched side they are both flat should i replace these also?

[hooky]

So if i was to buy forged pistons id have to get 86mm ones? Ill take the crankshaft to newton cams who are just roumd the corner with me, ive bought standard valves, and have some tomi pon cams with uprated springs and caps that im goimg to fit, ive also noticed that the rocker arms i have dont have one flat side and one notched side they are both flat should i replace these also?

Have you built many engines before? a forged engine build requires some pretty specific knowledge about suitable clearances & material specs Etc, so unless you REALLY know what you're doing then i'd suggest handing over the entire build to an expert. When it comes to forged builds there are realistically no Generic answers, there are so many factors involved that you cant really just buy a pile of parts and expect it all just to happily bolt together. The parts alone are going to be expensive, but unless they're engineered together properly then it could be a very short-lived mistake

[dannyj1092]

Ive built a standard rs turbo chv engine and a ford v8 but never a forged engine,