On my 84 z i have a 70 vette motor supposedly 70 anyway. it was over heating and so my shop teacher messed with the timing now i have knocking i drove it about 10 miles without any knocking and then about 2 miles from home it started knocking. during this 12 mile trip the car had no pwr. it felt very weak. do you think i messed anything up. i just moved the dist back to where it originally was and it still is knocking. what gives.

If you are very, very lucky, it'll turn out to be the fuel pump.

Realistically, you better check your oil pressure when hot. I'm guessing it's low, which would signal engine rebuild time.

Hopefully your timing is too far advanced and you
can just back it off.

Is it knocking or pinging? If your teacher messed with the timing and the engine feels weak, I'd suspect a timing problem first of all. I assume you used a timing light when resetting the timing yourself, or did you just mark the manifold/distributor before your teacher adjusted it? If that's the case, get a timing light and readjust.

How badly did it overheat? I would think that the bearings have to be in really bad shape to cause any power loss, and that doesn't (usually anyway) happen just like that. Check the oil pressure though. If it's low, I'd say that Shurkey is right...

nope about 50 psi of oil pressure idle and 60 or so at 2500. when the guy put the cam in i think he degreed it wrong cuz it says 60 degrees advanced so....

when the guy put the cam in i think he degreed it wrong cuz it says 60 degrees advanced so....
I don't think the cam was degreed wrong, I think maybe you are on the wrong plug wire (?) If you think the timing marks/tape is off you should check TDC using the positive stop method.

Regardless of how far the timing is off you should be able to back the distributor off and at least determine whether the noise goes away, then you will know whether it's a timing problem or a mechanical problem.

Knocking(metallic banging) or pinging(rattley sound)?

i put the timing back and it still is knocking. im on the #1 spark plug wire and we did the valve check where you make sure that both are all the way up. the sound is almost as if a wire is hitting my fan thats what i thought it was at first. i thought a wire was getting knocked around by my fan but it wasnt but thats the sound that it is making.

Loose lifter ?? Doesn't go with the timing symptoms, but maybe there are muliple problems here. If a new cam was installed the lifters need to be adjusted properly too. That could be the "wire in the fan" ticking.

nope no new cam the engine was said to have about 4000 miles on the rebuild. before i got it.

how hard is it to take off my lifters.

Is it just a "ticking" sound its making? Check the bolts around your headers or exhaust manifold, and check your gasket. Might even be a rocker hitting your valve cover (ie valves need adjusting). Maybe the timing issue is a seperate problem. You need to really stick your head in there and find out where the noise is comming from. Mechanic's stethascopes work great for this.


ps: You'll need to get your intake manifold off to get to your lifters... but I doubt they're at fault from what you're telling us.

Chris

so you think its a exhaust leak. ok i hope thats the problem that would be a nice simple fix. how will the stethascope help me.
jon

some of the rocker arms were lose so i tightened them up but still knocks

ok so i had my uncle over and we did a compression test and all the cylinders are 135-145 so thats good. were pretty sure that its the lifter on the intake side of #7 cylinder. to make sure my dad said to see if i can start the engine with out the pushrod on the #7 intake. or will this cause damage to the valve?????????????? thanks jon