Valve reliefs in pistons
09-26-2004, 02:01 PM
#1
Valve reliefs in pistons What happens on a car that has valve reliefs cut into the pistons, but doesn't need it for the cam he's running? Does it hurt anything?
JPR built me a motor in February of 2002. He made Stage II heads with ISKY 295D springs, TR 224 112, forged pistons with unknown valve reliefs cut in, claimed 10.8-1 compression ratio, stock rods with ARP rod bolts. Not known if he bored the block for the distortion of the ARP bolts on stock rods.
I'm asking because I broke a valve spring and dropped a valve. Removed the heads between yesterday and today. The piston was fine; although the valve dropped it did no damage.
The plan is to have the heads sent off somewhere, check the flow numbers and redo if necessary along with new valves and patiot duals, titanium retainers and CStraub's lockers. The pushrod where the spring broke has a 40 degree bend in it. So new pushrods as I assume you can't just buy 1 of the hardened one's from vendor's.
Finally with the motor I plan on pulling it too and rebuilding it. Oil pressure has been real low since I got the motor 15K ago, so I want to make sure THIS time it's done right. White smoke has always came out the exhaust when idling. Any suggestions on whom for the rebuild? Any ideas on what to do with the existing valve reliefs? As in make use of them with a different cam?
I've got a pretty bitter taste in my mouth on motor's and rebuilds; I'm already 7.5K in the hole from the last round. I'd really like to have a much better running car this time around.
Thanks.
JPR built me a motor in February of 2002. He made Stage II heads with ISKY 295D springs, TR 224 112, forged pistons with unknown valve reliefs cut in, claimed 10.8-1 compression ratio, stock rods with ARP rod bolts. Not known if he bored the block for the distortion of the ARP bolts on stock rods.
I'm asking because I broke a valve spring and dropped a valve. Removed the heads between yesterday and today. The piston was fine; although the valve dropped it did no damage.
The plan is to have the heads sent off somewhere, check the flow numbers and redo if necessary along with new valves and patiot duals, titanium retainers and CStraub's lockers. The pushrod where the spring broke has a 40 degree bend in it. So new pushrods as I assume you can't just buy 1 of the hardened one's from vendor's.
Finally with the motor I plan on pulling it too and rebuilding it. Oil pressure has been real low since I got the motor 15K ago, so I want to make sure THIS time it's done right. White smoke has always came out the exhaust when idling. Any suggestions on whom for the rebuild? Any ideas on what to do with the existing valve reliefs? As in make use of them with a different cam?
I've got a pretty bitter taste in my mouth on motor's and rebuilds; I'm already 7.5K in the hole from the last round. I'd really like to have a much better running car this time around.
Thanks.
09-26-2004, 06:51 PM
#3
Sounds like JPR was the whole problem. Alot of his stuff was never up to par. Any of the sponsors to the right can build you a good short block. Just do a search and decide for yourself who you like best. I choose APE for the shortblock, and TEA for the heads. Your cam should still be good, but you can upgrade for more power if you like. There are many new cams out these days.
09-27-2004, 06:30 AM
#4
Sounds good, I need to contact a sponsor to see if it's cheaper for them to rebuild my exisiting block or just go ahead and buy a shortblock flat out then sell my existing block. As far as the heads, just need to make sure whoever I choose uses patriot duals.
Any comments on the original question about valve reliefs?
Any comments on the original question about valve reliefs?
09-27-2004, 08:18 AM
#5
valve reliefs increase the volume for combustion and reduce your compression ratio. If they are pistons that came with valve reliefs from the manufacturer, you could loose up to .5 on the CR unless the piston was domed or designed to maintain the stock (or higher) CR.
