924Board.org

[Alex Roy]

I am going to be putting on my replacement head I have been porting and thought that while I was at it, I might also replace the piston rings. If I just replace the rings with stock size rings, do I need to do any thing to the cylindars, or can I just put the new rings in?

Also, I just bought a Paxton Supercharger to fit to my 924!!!

[Guest]

You should buy my engine....but I'll tell you what shoud be done anyway. If you are going to the trouble of taking the pistons out and installing new rings. You need to hone the cylinder walls in a crosshatch pattern. This can be done buy an amature but I wouldn't recomend it. Too much material can be taken off at the top of the cylinder wall if not done correctly. Since you have the pistons out, it would be silly not to change the rod bearings and main bearings plus putting crank seals. The point of you changing the rings is to extend the engines life and doing these things to me goes hand in hand. Plus the extra work involved is minimal. The costs of doing so in parts would total around $250.00. Hey maybe Lars can get you a good deal try him. Did you change your valve guides and seals?

[Joes924]

Um the block can be honed inexspensively at least up here in salem. A 4 cyl.is around 25-50us. Tell me about your port job Alex really Im fixen to do a little head work..did you do it or have it done.



[ This Message was edited by: joes924 on 2001-10-18 09:54 ]

[Alex Roy]

I just got a neumatic die grinder and some tips and started grinding to the size of my DCOE manifold... I just opened up the ports as large as I was comfortable with and made the edge on the curve shorter and rounder. I haven't polished the exhaust side yet, and I am not going to polish the intake side (it is actually supposed to be bad to polish the intake side, but porting is still good). If I am able to get money to get Adam's rebuilt, I will just do that and I may sell the ported head....we'll see.

[John Mueller]

Correct, when you polish it is actually bad well not bad just not optimal. People pay to have their heads polished because they think it is good, but actually air flows better over a slightly rough surface, basically an engine builder once told me that it creates something like a ballbearing effect. Also that engine builder won the Legend car road race nationals in his first year, and built my kart engines, I wish he would do a NA 924...

[Alex Roy]

The only plus to polishing is that it deters carbon deposits, and that only means something on the exhaust side anyway.