Hey everyone, I got a 94 z28 with the stock lt1 inside of it. I picked it up with problems, guy I got it from said the timing chain has broken or slipped. From what he told me he said that he was driving the car and then it just died and wouldn't start back up. After trying to start for a while it started to knock and assumed it wasn't getting oil delivery because the timing chain wasn't connected to the cam. That's all I have to go off of what actually happened right now.
Now I have been fighting with the crank hub trying to get it off for quite some time and come to a point to where I just had to grind it down enough to pull the timing cover off. (still trying to figure out how to get this hub off now that its just a nub without damaging the crank) I was able to find out that the timing chain had a little play in it, but doesn't look like it has slipped at all.
So I figured that this sound has to be coming from somewhere, and now I must have 2 completely different problems, a no start issue, and a knock. The knock seems to happen once every rotation but I really didn't have a way to crank the car over and listen for the sound at the same time.
So I figured I would start digging into the engine so far I got the valve covers and the intake off while working on removing the head. I noticed that most of the lifters were pretty loose, but I don't see anything out of the ordinary. (I also don't have the new timing chain on yet either though)
What I'm mainly trying to find out is, is there something specific I should be looking for? Or any recommendations on where to go to find out this sound? Should I stop and tighten the lifters, throw on the chain and see if it stops the sound, or go ahead and just remove the heads to see if there's piston or valve damage? Also are the lifters for these lt1 engines set by valve lash or torque specs? I have really only dealt with internal sbc 350's.

 

I'll add that this is being done outside in the snow lol. So the less I have to do the better even though I believe I already made my work a lot more difficult when I didn't do a compression test or check for spark or anything before hand. So if at all possible I can keep the stock engine and not have to resort in trying to remove it from the car I will try to go that route. Especially since I don't even have a driveway to work in at the moment.

 

I doubt that trying to crank the engine with the oil pump not turning would cause that kind of damage.

Applying heat to the damper hub would have made it much easier to remove, particularly if the car is outside in the cold. Were you using the correct puller? Are you sure the center pin was small enough to fit through the hole in the hub and bear on the crank? Were you pushing against something inserted in the crank snout bolt hole, like a socket extension?

Won't start - scan it for codes, check the fuel pressure for starters. Probably lost the codes though, if the battery has been removed or worn down excessively.

Have you been cranking it WITHOUT the timing chain installed?

 

I was using the proper puller for the crank. Had to be given advice from others about these crank hubs because at first I was using some attachment on the puller which wasn't actually pushing on the crank itself. Even once I found out how to get it off with the proper puller, it was on so tight that I bent the bolt on the puller broke 3 wrenches and had to use a good 5 ft worth of leverage until I broke all my wrenches. I also had the bolt that goes to the puller threaded into the crank to push on it. Unfortunately the best source of heat I had access to was this little micro torch which didn't do anything at all to help.
Most likely I have lost the codes since my battery has been disconnected for a while. And no I have not moved the crank or the cam since the timing chain has been removed.

 

I found out more info. I managed to get the driver side head off and here is the result.
http://i114.photobucket.com/albums/n...ps542030eb.jpg
http://i114.photobucket.com/albums/n...ps7ece1741.jpg
http://i114.photobucket.com/albums/n...ps46ad3c39.jpg
http://i114.photobucket.com/albums/n...psd4624fba.jpg
http://i114.photobucket.com/albums/n...psca0dd070.jpg
http://i114.photobucket.com/albums/n...psc59a78c3.jpg
http://i114.photobucket.com/albums/n...ps0b5059a2.jpg
http://i114.photobucket.com/albums/n...psec5e5b84.jpg
http://i114.photobucket.com/albums/n...ps8724b1ce.jpg
I posted into a sloppy mechanics page on facebook and they told me that the cylinders are okay and could of been due to the fact that the intake and valve covers have been removed and the engine is still in the hood of the car. (It's either the engines under the hood or in the yard, I don't have a garage to do this work lol.) Unless this is the cause of the knock, I have yet to find any other problems. I still need to remove the passenger side head, and then look at the bearings. Something is telling me that it may be a rod or main bearing issue.

 

Bumping, with the information above if the passenger side head comes off with around the same, or no extra damage should I start digging into a bearing problem as a knock or would cleaning this up and getting a head gasket most likely fix this knocking sound I hear?

 

if you used the "proper" hub removal tool it would have easily come off. It is made by Kent Moore. There are other "ways" to remove it but cutting it off is not one of them.

Now you are pulling the motor further apart...your "knock" may be a bearing or wrist pin. you first should have done a leak down test but you are past that chance now.

You need to look at bearings which means the "bottom" of the motor needs to come apart. This is best done with motor out of the car