Stock short block,1.6 rockers, 202 160 valves in head, heads are SLIGHTLY milled just to be clean up, and the exhaust valve is slamming into the piston enough to snap a pushrod in half and turn another into a snake. Called comp cams and they said to retard the cam, Not sure why I would have to even think of doing that for a cam swap that shouldnt have these kinds of issues. The cam is a descent size cam, but not big enough to have this happen, well I guess it is eh? Some help from people who run this setup would be appreciated.

Thanks,
Nick

 

Did it run right before doing that to the pushrods? Perhaps the timing gears were not indexed correctly or the cam was ground wrong.

 

All this happend when cranking the car over. Car hasnt run since installation of the new cam. Ran the lt4 hot cam b4 this set up and had 0 problems used the same timing gears as well. Just plain STUMPED

 

The hot cam was it the kit or just the cam????

 

The kit, springs, cam, rockers

 

I would definitely check the timing gears, then.

 

Have you verified it isn't something more simple such as coil bind on the valve springs?

What makes you think it is piston-to-valve contact?

 

LT4 springs are only recommended to .525 lift, and the 306 especially with 1.6's is bigger than that

 

I also have this bad feeling that he might be trying to use LT4 or other inadequate springs. I didn't want to jump right into it, thinking maybe he'd realize the mistake before admitting it to the world

Sounds like he has had some head work done and I can't imagine someone using the LT4 springs if that's the case. The springs should still be verified to work with the cam though!

 

if its springs call cmotorsports.com and ask for the 612 kit.

did it bend any valves

 

With the cc306 and 1.6's your looking at .540/.570 lift wise, not something I would run on the LT4 springs...... I would change out the springs to a bigger size. I am running Crane Dual Springs and have no problems whatsoever.....

 

I guess I should have not assumed the valves were hitting the pistons as the title said. The suggestions about checking coil bind are valid ones and easy to do.

 

Im starting to sound like a CMS ***** but I just got these springs and they rock. Not a bad price either. Good for .600 lift.

http://www.cmotorsports.com/93-97-fb...ine-valvetrain

 

If you are using LT4 springs then its more likely coil bind and not valve to piston contact.

 

I would double check the timing chain gear orientation also.