I just installed an LT4 hotcam, I thought everything went smoothly but when I started it it blew smoke out the tailpipes and would stall from any rpm the moment you took your foot off the gas. It is very ROUGH at all rpm. When I tried to start it the second time it took a few minutes before it would even turn over. Any thoughts to what my problem is?

 

Did you degree the cam??? Rockers too tight maybe???

 

Degree the cam??? I was thinking the rockers might be a little over tight. I used the tighten till the pushrod stops spinning method, I suspect I went a little overboard.

 

Is this the specs on a hot cam? mPlease let me know...

Intake valve lift .525 (1.6 ratio)
Exhaust valve lift .525 (1.6 ratio)
Intake duration @ .050: 218
Exhaust duration @ .050: 218
Lobe separation: 112 deg

Thanks!

 

Almost.

Exhaust duration @ .050: 228

 

I'd check the basics first. Make sure no vacuum leaks. Do you have the silencer back on underneath the rubber elbow? If it's a 1LE elbow then never mind. Make sure your spark plug wires are correct. Did you place the dowel pin of the cam in the correct spot on the opti?

 

MAF facing the right way?

Jeff D.

 

You dont tighten them until they stop spinning. If you did, thats your problem

 

i wonder if this is the problem we are having with my friends lt4 cam install... he set the rr untill the pushrods almost stopped turning... Is this to tight??? The car backfires, misfires, and has no pick up and go at all... Could this be it???

 

It's either rockers or valve seals since you mentioned the smoke...

 

Hellllllllllls no. You tighten them until you feel the VERY SLIGHTEST resistance. Then 1/4 turn more.

 

Until there is zero lash...

 

I did mine with the car running... BUT to find zero lash with the car off. Make sure the valve is closed. Then move the pushrod up and down while tightening the nut. When the pushrod stops moving up and down you will be at or very close to zero lash. That spinning pushrod method will get you zero lash but it's not accurate every time.

 

thanks for the input... im on my way to go fix that now...

 

It's not an exact science, but adjusting the valves is very important and to some people its a black art. Luckily, most people here on the board ajusting valves are not running the stock style rocker arms, should have some poly locks on there which make it easier to adjust.

Here's a quick way... put the car's front end on stands, then turn the balancer (assuming you haven't f'd with its position and its on properly) so the arrow is pointing up @ the 12 o'clock position, with #1 @ TDC. Check to see how close you are by having somebody turn the crank very slightly until its @ true TDC. Then adjust the proper intake/exhaust valves, turn the crank another 360º and repeat with the corresponding valves. But not too tight, I need to readjust mine because I think they may be a bit tight and I'd rather do it a third time an know for sure.

Just my $0.02.