cam timing question

[big83chevy4x4]

how would a engine run if the cam is one tooth off?

with the base timing where it should be (tbi) it will idle just fine, but when you touch the gas it back fires threw the intake. if you advance it to 8-9* it runs like it should up to about half throttle, then just has nothing.

 

[fabjunkie]

Is it vacuum advance? Sounds like what my carbed motor was doing when I bought the truck. The advance canister was shot, along with the weight pivots in the dizzy being worn out. Dropped a new one and and it was running like a top.

 

[theperfectgarage]

I think your symptoms could very well be a camshaft out of phase. Can you drive it ? Is it weak, and at about 2500 rpm's it hits a wall and just wont " go "?. With the air cleaner off, rev it by hand, does it seem like the air/fuel mix is blowing out? Like enough to lift the air cleaner base gasket up ?
If you can answer yes to any of these questions, it's time to break out the degree wheel and dial indicator or pop that timing cover.
Good luck,Cary

EDIT- I like fab junkies thought also, I had a 350 running really weired one time, and it was the centrifugical weights in the dist. tangled up with each other .

 

[big83chevy4x4]

its a TBI so no weights or vacuum advance in the dizzy.

Can you drive it ?

yep

Is it weak, and at about 2500 rpm's it hits a wall and just wont " go "?.

quite a bit of power right off the bottom end for what it is (stock with RV cam) just the tach is way off (factory v6 converted the WRONG way ) but it seems just a bit lower than that, maybe at 2000 or somewhat but it does seem to fall on its face even with the timing way retarted. the hotter it is outside the better it is.

With the air cleaner off, rev it by hand, does it seem like the air/fuel mix is blowing out? Like enough to lift the air cleaner base gasket up ?

no not really, deffinetly not enough to lift the air cleaner gasket.

i just don't want to pull the front of the motor off to find that it isn't it. its gonna be almost impossible just to loosen the pan enough to get the timing cover back in.

 

[jekquistk5]

still cant figure out your cousins s10??

 

[theperfectgarage]

I dont have any great ideas right now, and I agree, hate to pull the timeing cover if I dont need to.

 

[mouse]

My timing chain was a tooth off (due to extremely poor markings on the crank gear), and it wouldn't rev past about 2500. Pulling the pan is a pain, but for me not so bad since it is a new one-piece gasket. Its a few hours to pull it down and put it back together, but will be worth it if you find it is off.

 

[big83chevy4x4]

still cant figure out your cousins s10??

nope, i had a half a though that maybe we were looking at the wrong thing with the TBI, thought it might be this.

My timing chain was a tooth off (due to extremely poor markings on the crank gear), and it wouldn't rev past about 2500. Pulling the pan is a pain, but for me not so bad since it is a new one-piece gasket. Its a few hours to pull it down and put it back together, but will be worth it if you find it is off.

what way was yours off? not sure what would be retarted and advanced, but was it to the left or to the right? just curious.

its not possible to pull the pan on this, you can bearly fit your hand between the pan and the front diff, damn IFS. we are gonna try to drop the front of the pan enough to get the timing cover in easily.

the 1 piece pan was a very good idea on MY motor, paid for it self more than a few times but being reusable. we didn't put it on this motor, we were on a tight budget and couldn't find one cheap enough.

 

[mouse]

The timing mark was to the right of where it was incorrectly sitting at...

I guess that IFS thing is a pain in more ways than one.