HKS cams, piston/1mm o/s valve clearance

[dsmpower1]

hey, I have HKS 264/272 cams. I searched the forums for this question, but i couldn't find the answer i was looking for. Alright so i have the cams, and 1mm over sized valves. Most people with this set up run forged internals(aftermarket pistons) Instead I ran new 1g rods with new 2g pistons. I am using a cometic head gasket from slow boy racing which is .054 mls in thickness. I looked in the exhaust and intake chambers when the head was on and turned the crank while the engine was out of the car. I couldn't really hear anythign hitting or see anything strange. Then engine is now in the car and ready to start in a matter of days. I need to know if i will have any valve piston clearance issues. Does anyone else have this set up while keeping to 2g pistons? Someone help before I start and possibly kill my engine. THanKs

 

[bfdahl]

hey, I have HKS 264/272 cams. I searched the forums for this question, but i couldn't find the answer i was looking for. Alright so i have the cams, and 1mm over sized valves. Most people with this set up run forged internals(aftermarket pistons) Instead I ran new 1g rods with new 2g pistons. I am using a cometic head gasket from slow boy racing which is .054 mls in thickness. I looked in the exhaust and intake chambers when the head was on and turned the crank while the engine was out of the car. I couldn't really hear anythign hitting or see anything strange. Then engine is now in the car and ready to start in a matter of days. I need to know if i will have any valve piston clearance issues. Does anyone else have this set up while keeping to 2g pistons? Someone help before I start and possibly kill my engine. THanKs

You will be fine, but any time blocks and heads are resufaced tolerances change, and you will need to "clay" the engine to find the exact clearance.

 

[tmizer]

How much was taken off the head and how much off the block? You really should understand what is going on. I suggest going thru the exercise of determining compression ratio to learn this . Then, you should good thru the exercise of degreeing in your camshafts as material taken off the head and block slightly alters timing belt geometry and thus timing.

Finally, as bfdahl suggested, use the "clay" method to determine actual valve to piston clearance (with light springs installed in one exhaust, one intake valve).

Search, search, search.

 

[dsmpower1]

yeah i didnt hear about the clay method until it was too late. I had already put the head on and torqued it down. I just wanted to know if anyone who had/has the same set up as me has run into any problems with it. I think the thickness of the gasket and the valve reliefs on the pistons should help with the clearance issues.

 

[RoasT BeeF]

I have 1g rods with 2g pistons and 1mm oversize valves. I do not have any clearance issues. I also ran 2mm oversize valves with the same rods and pistons with no clearance issues so I am sure you will be fine.