NickyCamaro

I have an 89' Iroc with a TPI 350. I have made lots of mods one of them a Crane Powermax cam. The original cam did not have a button so I didn't bother to put one on the new cam. I am concerned it might be walking because when I tromp on it from a dead stop it losses a lot of power around 2000rpm and it comes back to life around 2500rpm. It seems much more powerful and doesn't hesitate if I only tromp on it to about 3/4 pedal and then put it to the floor once it gets going. However there is a dowel sticking out of the cam on the end and I question if a button would stick out any farther than the dowel. A friend suggested it could be due to my sad 2.73 axl ratio.

Thanks

kevinc

Your engine should have had a thrust plate holding the cam in place, two bolts holding it to the block and located directly behind the timing gear that bolts to the cam. Was it there, and did you reinstall it when you popped the new cam in?

That said, your symptoms don't sound like cam movement. Go back and recheck the initial spark advance w/ your timing light and the ESC connector open. Should be 6deg BTDC or whatever the manual says.

If that checks out, I'd pull and read the spark plugs to see what's happening. A scan tool or laptop rig will make diagnosis much easier also.

Kingtal0n

heh sounds like me. no power from idle to 3500 rpms... but after... watch out!

post some cam specs / tranny stall speed / tire size / timing profiles / engine specs / etc.. it will help diagnose your problem.

ronterry

I read a walker will make the timing jump around real bad. You should check it with a light from idle to 3 grand.

Ron

NickyCamaro

It had a thrust plate and I did install it on the new engine when I was building it. The cam is pretty mild In. 194 Ex. 204 @ .050. Lift is In. .407" Ex. .429". The converter and tires are stock. As far as the timing goes it was not done accurately. I don't own a good gun and I have been meaning to have done by someone but I haven't gotten around to it yet. The plugs are black on the threads and a light grey on the tips with a little bit of orange-red powder on them.

Thanks

Nick

kevinc

...whoops double-post...

kevinc

OK, no need for a cam button if you have the thrust plate and a cam designed for it.

All that work and you didn't set the initial spark advance? Shame on ya. Night and day difference on mine between 4 deg BTDC and 10 deg BTDC and symptoms very similar to yours, gas pedal was like a wet sponge but then ~4000rpm it would wake up and take off.

Get the timing set right and see if that doesn't get it moving.