elliot told me that you cannot use this piston with the bigger valves and cams. is this true?

 

I dont know about the RWR head, but Ive got the big valves, and aggressive cams with the 14:1 piston. When I put this motor together, I did a squish test with clay, and I had anywhere from .130 - .155 clearance between piston and each valve. Heck, I thought I should shorten up the gasket to get some more compression. LOL. Not really. Like I said, this may be different for the RWR head. Ive got the HPR.

Hope this helps,

Gary

 

ya thanks, hey didnt you make your swigarm?

 

I believe the issue is not the valves, it is the lift of the cams. I know HP research runs their 14:1 piston with their race head with no problems, but their cams are made to work with the package. Only sure way to find out is to have a builder clay the combustion chamber to measure the clearances.

 

wouldnt that be the $hit$ to buy a piston and find out it will not work.[img]i/expressions/face-icon-small-mad.gif[/img]

 

Generally speaking, a 14:1 piston will NOT work with the Ron Wood Axtell (A1A2) cams with these specs Intake lift .433 in. duration 267 degrees, Exhaust lift .406 in. duration 278 degrees. Clearance .008-.010 in. A 14:1 piston will work with the Ron Wood Wood9 cams with these specs Lift .425 in. duration 260 degrees (Intake & exhaust). Clearance .006-.008 in. Some well financed young buck will make cams (if he hasn't already) like the A1A2 wood cam but with lift somewhere between .425 and .433. on the intake so that clearance issues are nixed.

The reason why they would is because the Ron Wood Axtell (A1A2) cams are quicker revving than the Ron Wood Wood9 cams but do not provide enough clearance. It is true that the .425 lift cams provide more horsepower, but the A1A2 gets you there quicker. If you think about the numbers on the intake and exhaust on the A1A2 long enough, you'll figure out why they are so quick revving. The same concept has been in use with Indy cars for a while.

Just because I said it, and somebody actually gets the financial backing to grind such a thing for the DS, does not mean they are copying me. - Sorry I just had to add that! It's not rocket science, just common sense.

 

Hey shmee, if you don't have enough V/P clearance with the 14:1 piston, it's a very simple proceedure to machine the valve relief's deeper.
We machine the valve reliefs on almost all of our piston's (30-40 per month)
Dynoray

 

whats that worth?

 

Any good engine builder will have a piston vise for their milling machine and can machine a 4 valve relief (two plane) piston in under 15 min.
So it shouldn't cost more then $20-$40.
Dynoray

 

Shmee,

Yes, I do build the swingarms. All aluminum. If you want more info about it, pm me.

Gary