Thread: CP Custom 92mm 14.5:1 Pistons

This piston was based off of my 13.5:1 cr 92x86 pistons. I had they leave the done alone and raise the pin 3mm. Which was now 14.3:1 cr......

My point in saying that I don't think we need the reliefs that deep was that I think we can get a higher cr..... the reason this was as high as they could get was because the reliefs being as deep as they are. Once I clay the motor I believe I will find that the reliefs are deeper then needed. Yes I know how they work on a 92x86 motor w kelfords because that's what I ran just with les dome. Same reliefs....

so you are telling me these are 86mm bore 14.5:1 comp ratio normal stroke!!!!????!!!

mike told me he had nothing to refrence it agianst and needed the piston i claimed they made. i sent it in and then finally after monttttthssssss they started cranking out some pistons. either way im glad they got it done.

id rather have the deeper reliefs in hopes that kelford one day comes out with a even bigger cam.

you could always go flat faced valves and re-worked cc to raise compression. or figure out how much more you can go and take the head down to raise compression.

honestly 14:5:1 is plenty imho, well see what these motors make.

i can tell you this, they like really aggressive timing if fuel allows. we had a car on the dyno for all day this past friday, we learned alot in this one dyno session. if i was to post details it would drop jaws !

cory your motors gonna make some really nice power man !!

stratton.

There is nothing special we can do because of the angle of the valve... just extend the reliefe out till they intersect... that's why I'm not sure how jun got a 15:1 piston on 90x86, unless he had a welded chamber, miled head or something like that. This pistons dome will be 13.5:1 in a 92x86... so the only way to achieve a higher cr would be to have shallower reliefs... so that's why I'm saying. Either the reliefs are overly deep on these pistons or juns pistons have shallower reliefs or its is not as high cr as you guys think... idk its just hard to see how its 15:1 w 86 stroke when this piston is only mid 14s on 92mm stroke. Wow I'm rambling sorry.. not bustin balls just don't se how his is different.

And yeah, no doubt, all these 2.4s are going to be puttin the hurt on some hondas this year at the strip!

I want to ask a simple question here, And think fora moment before you answer this:

What happens when the valve Float???

Before it contacts it bleeds of power.

We expierienced this this past weekend on the dyno. Valve float at 7700 rpm stock valvetrain and n1s.

Stratton.

Stratton what happens to the valve?

Its put under alot of stress. It could break if the float is violent enough.

On high reving motors such jap bike motors reversion occurs. Also crank case pressure can go up.

Stratton.