.Ok so I have an LS-V with GSR head/cams that I got and took it apart because was not sure of the condition of the motor. When the head came off I can see were the Intake valves were hitting the pistons. There is a perfect grove on all the pistons. The valves look fine as far as I can tell. It had the stock head gasket also. My question is why are the valves are hitting the pistons. I thought there should be more clearance.

 

well if the head and cams are stock, the pistons are stock, look at cam timing. there should be enough clearance.

 

good thanks i didnt even check that before i ripped it apart but it did have adjustable cam gears. Makes sence.

 

that is prolly your problem stock cams with stock pistons should have plenty of clearance

 

are you sure it's not the valve reliefs on the pistons.....?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2fast4u831 &raquo;</TD></TR><TR><TD CLASS="quote">are you sure it's not the valve reliefs on the pistons.....?</TD></TR></TABLE>

thats what i was thinking

 

imo i would say your cam timing is off like stated above.

 

No the marks are on the valve reliefs. Almost like the vale relieves were to small or some thing. I really think that it was the cam timing. Also the pistions say PR4 the 0.8 Never seen the 0.8 on a piston before.

 

Here is what it looks like

 

yeah most likely timing is off. might wanna get ur head checked.. you might have bent some or all ur valves

 

valve reliefs need to be cut to fit the larger valve face of the gsr head. especialy if you are using a higher lift cam. and clay the motor to make sure they don't hit

 

ls-v with stock gsr cams should clear.

 

do the pistons stick out of the hole?

 

No not at all

 

there should be tabs on three sides of the cylinder head. place a straight edge and see what feeler guage can you fit in there.

this tells you how much the head has been surfaced/decked.

i think piston to vlave clearance is somewhere near 150 thousandths so even a head milled .050", it should be fine.

 

Cool thanks for every ones help

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">valve reliefs need to be cut to fit the larger valve face of the gsr head. especialy if you are using a higher lift cam. and clay the motor to make sure they don't hit </TD></TR></TABLE>

DOHCter is correct in this instance.

That is a PR4, a stock LS piston. The intake valve on a stock LS head is 2mm smaller than the VTEC ones. That groove was worn by a bigger valve trying to fit in a smaller area.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MoonScryer &raquo;</TD></TR><TR><TD CLASS="quote">

DOHCter is correct in this instance.

That is a PR4, a stock LS piston. The intake valve on a stock LS head is 2mm smaller than the VTEC ones. That groove was worn by a bigger valve trying to fit in a smaller area.</TD></TR></TABLE>

Again, both correct!

 

Once again thank you to every one.

 

sometimes they will clear depending on the deck/head castings, but most times they will hit even with stock cams. thats why claying the motor is best. if you don't want to cut the pistons (which i've seen many times by my shop) you can do like me, and buy some RS pistons with an itr dome height and larger valve reliefs. but i have a b20 block. or you can get actual itr pistons. remember to change the rod bolts for a set of arp's and you can rev to 8500 all day long with the stock rods if they are already straight.

good luck with your engine setup