Piston to Valve clearance problem "PROBLEM FOUND" Well I'm not as close as I thought ! My pushrods came and I was setting the valves and noticed I have a piston to valve clearance problem. I know I should have checked this before but I didn't think that Ross pistons with notches would have to be re-notched, If I would have known that, I would have ordered them flat and had them cut. Is this common or am I missing something ? The 308S cam degreed out fine at 108. :ball: I guess I need to tear it all back down and get out the clay. This is a fine example to never assume anything!!!!
Todd, Get you some of those weak valve check springs like they use on flow benches. Once you install these on an intake and an exh. you can just turn the engine over a couple of degress and measure the clearence up top. I don't know if this is acceptable practice or not, but it worked for me when I changeed to a 308s. By the way, I also have Ross pistons with notches and a 308s cam. My cam is ground on 106 centers istead of 108. good luck.
Hi Shane, Did you have to do anything else to the piston notches ? What deck clearance ? What gaskets ? My pistons are .027 above the deck and I have the block o-ringed and using .060 copper head gaskets. So it is like running the orange crush with pistons .006 above the deck.
I have venola pistons with small 3 cc notches. JE pistons in the nitrous motor came with 7cc notches. I am running the venola pistons .005 in the hole with orange crush gasket 308s cam. I have just enough valve clearance for the KB 1.55 rockers but can't run my TA 1.6 rockers. This setup gives me 13.1:1 with my stage2 SE heads. What rockers are you using?
I just have the stock notches. Also my pistons are in the hole pretty far as I only had like .010 taken off the deck, I think I had a little more taken off the heads. I'm useing a .020 steel shim. Also my rockers are 1.65:1. Maybe your cam is way advanced. I can't remeber what center line mine is dialed in to, but it's 3 degrees advanced, I was shooting for 2 degrees.
I was talking with the man today (Mike T) about this and he thought Ross did not compensate for the valves being .030 farther out on Stage 2 heads intake and exhaust for a total of .060 when notching. So I get to tear it apart and fly cut the pistons. Hmmmm! maybe smaller cam and a big blue bottle aint so bad and idea :Brow:
Todd, Don't get to bummed out about this. It's just part of "stepping it up". It's better to find out now than after your first pass.
I feel like and "IDIOT" But I will have to tell everyone so maybe it will save someone else some grief. I pulled the heads today for some clay checking, well I had #2 and #5 pistons switched around so the intake was trying to go into the valve relief for the exhaust. I did check the clearance and the valves line up to the notches perfectly I didn't measure the clay yet but there is a gob of clearance this explains why I really only noticed the problem on two cylinders. Oh well live and learn. I want to give a special thanks to JW, Shane D, and Stage 2 man on the helpful coaching. :beer I think a few of these are in order after this.
No.. Feeling like an idiot comes right after you start it, and smack the valves into the pistons.. I saw the aftermath of exactly the same thing, that happened to a local guy, who's motor was built by another local guy. Ugly is the only word that can describe it. Good job in catching it.. Now, put the pistons in the right holes, and we can talk dyno session! Let me know when it is ready. JW
Dyno??? It's racing season! Mssed ya' at Norwalk Jim........ Don't get lost at the Dyno for the whole summer dude.
Thanks todd for posting your situation. as you know I am in a similar situation. Although I have Iron heads. and .018 out of the hole. :TU: had me scared there.
