Thread: piston to valve clearance, JWT c3 cams

Hey all,

I have a question, I was hoping you guys could help me out with.

I have a SR20DE, which I am planning on putting in some new bits:
Supertech dual valve springs
JWT Bronze Valve Guides
Rocker Arm Stoppers
Tomei .6mm head gasket

Now, with these obviously comes cams. I want to get JWT C series cams, and am tossing up between the c2 and c3s.
the C2s have .5" (12.7mm) of lift
and the c3s have .527" (13.3mm) of lift.
Will I run into valve clearance issues?

Is anyone able to help me calculate the piston to valve clearance?

Thanks,

Timbo

You probably will with OE pistons.....but get some 16VE pistons in there you should be ok.

I don't know for definate though.

SR16 and 0.6mm gasket is just over 13:1, race gas only...

an SR16V N1 piston with the same gasket will be about 12.2:1, tricky tuning, but just about possible if it is kept rich to slow down the flame.

Mike

Thankyou fellas, however, at this stage (not quite yet! (: ) I'm not doing the block and not doing sr16ve pistons.

Could someone please help me figure out whether or not I'm going to run into trouble? Should I be going for a stock thickness (or thicker) gasket?

I'm only really interested if you can either help me do the math or have actually done this and know there won't be any problems.

Thanks again.

stock thickness head gasket will net a CR of 11.7:1 and you will have enough valve clearance. There are a few guys out there running C3s with sr16ve pistons.

Yep, but dont even think of running them on stock pistons. Should look at Brian Crower Stage 3's with your setup and use the factory thickness gasket.

what about the c2's?

And have you figured this out, done it and failed, or are you guessing?

Even C2's you would most likely need a flycut on the piston.
A little while ago I did a CAD drawing of where the flycuts needed to be, but the HD had the click of death and they are currently lost.

Mike

Your gonna be lifting the head off anyway to change the gasket....changing the pistons is a quick job. And might aswell be done now while your at it.

Thank you everyone for your help so far.

However, whilst someone on the net says "I wouldn't do it, or I would do it" etc....
What I am really interested in are people who:
Can help me do the maths to actually calculate the clearances
Have done this before without doing the sr16ve piston change

As for the c2's needing the pistons to be possibly flycut, then how come the Tomei procams which have .2mm less lift don't require this?

Really, I'm trying to get in the biggest cams I can without having to do the block.