Prasius

iTrader: (1)

Is a new OE V9 crank at all needed if doing a rebuild of a currently running '02 EJ20 STI engine? Will new ACL race bearings be fine?

While I understand the standard piston size is 92.0mm on these engines, is it advisable to have the block honed and bored anyway and use a 92.5mm piston?

What other effects on the engine may this have? compression and the like?

For the record the maximum desired power will never be much more than 400bhp.

I'm a bit of a novice at delving this deep - I have some more experienced people available to mentor me but these are just some questions I have now. The Scoob is off the road come road tax running out at the end of the month as I need to replace what seems to be the only corroded front cross member in the history of Subaru's. I am considering making the most of the "off-road" time and just get a whole bundle of bits done!

Can anyone recommend some good books on this type of subject that are reasonably understandable by someone with an intermediate level of mechanical knowledge?

Thanks for any advice.

merlin24

iTrader: (1)

A Version 9 Nitrided crank with ACL race spec big and mains would be good 'insurance' if you intend on running around the 400bhp mark and the crank does not cost a lot more than a standard Version 5 onwards rear thrust crank.

Chances are you will have some taper and ovality on your original bores, so if your going down the Forged piston route on the rebuild then reboring and honing to suit the forged pistons is a must.
You will get a small increase in engine size from the oversize pistons - an extra 25cc or so depending on engine build spec.

If your old engine failed due to big end failure - have the Modine oil cooler replaced as its almost impossible to remove debris from inside the Modine.
Also make sure the cylinder head oil restrictors are removed (and refitted) to clean the oil gallerys in the heads prior to final assembly.

Mick

Prasius

iTrader: (1)

Thanks for the reply.

The current engine (bugeye Type-UK STI EJ20) is still running fine.... it's got to come out though because I have to replace the front cross member. I thought that as it's out.. well, I might as well just get on with it!

I was just going to use my current crank if there is nothing wrong with it on disassembly. There isn't much (if any) difference between my crank and the Ver9 crank is there??

The occurrence of cranks failing is pretty small right? It is usually the bearings that fail?