maroe624

So I picked up this 3.4 block for 200 bucks for a swap sight unseen. Came off a 95 guy said. Car was in a wreck with 150xxx miles. Was mated to a t5. So I check oil when I got it home and it looked good . I go to turn the crankshaft and it spins freely. But when I rock it back and forth there is this clank noise. I don't know much about the internals of an engine yet but I know clunks are bad. Is this normal play? Or did the guy stiff me and engine has rod knock. Crank has no front to back play just what you see. Give me some good news someone. I'm going to be tearing into it soon.

heres is the link.

sofakingdom

iTrader: (1)

That's ... not good. Something is loose inside there that shouldn't be. Could be just the timing chain, but I'd sure be looking to pin it down definitively before going to the trouble and expense of putting it in a car.

If it's farkled, I'd just go get another, rather than "rebuild" that one.

Vader

That play is abnormal. I'd be surprised if the whole crank was actually turning, and suspect you may find some issue at the balancer, key, or snout.

maroe624

Timing chain was stretched and causing the noise.

maroe624

So I replaced the timing set and I still have a bit of in and out play on the cam, not as much as before but still has it. Is this normal on the 3.4 ?? Also the timing mark on the cam seems to point at 12 oclock and the crank at 12 oclock instead of 12 on the crank and 6 on the cam like the 3.1. Is this correct ?? I also removed this sensor that goes in the hole right above the camgear by the intale manifold. Should I plug the hole or leave the sensor in there? Could this be causing the play in the cam. Sorry for all the questions. Also how do I remove the dizzy hole plug?

sofakingdom

iTrader: (1)

Turn the crank EXACTLY one full turn and see.

So... earlier on you had trouble with crank end-play; now you ask about the cam end-play. 2 very different things. Not even the same chunk of metal. Please clarify?

The crank should have something in the range of let's say .008" ± .005" of end play. The cam should have probably something more on the order of .015" ± .010". That's just based on the nature of the parts holding them still. "Ideal", "dangerous", "normal", "NO!!!!!", "mine is just like that", all that is something COMPLETELY else.

What is the end-play of each shaft REALLY?

Can't comment on the sen-sore hole (hehehe), I've never even seen one of those motors that I know of. Although, the hole looks ALOT like a cam postion sen-sore location, which, I don't have nay clue whatsoever whether you need or not. You could put a freeze plug of the correct dia in there to keep the oil from coming out, if you don't. Somehow though I doubt that it's related to end play... most sen-sores are somewhat remote from the thing they sense.

maroe624

At first I had this clanking on the "Crankshaft". Later I found out It was just a worn timing chain. My "crankshaft" has no play at all real tight. It's my "camshaft" that has a bit of play. I posted another thread asking this and found out that some play is normal. Now I'm just wondering why the timing mark on the cam sprocket is pointing to 12 o clock instead of 6 o clock like the 3.1 v6. This is the 3.4.

GeneralDisorder

iTrader: (1)

The cam turns at half the crank speed. If you rotate the crank one turn it will be in the orientation you desire.

GD

sofakingdom

iTrader: (1)

It's nothing about 3.1, or even 6-cyl vs V8.

In GM V8s, when the crank & cam sprockets are "dot-to-dot" (crank at 12:00, cam at 6:00) the motor is at #1 & #6 TDC, with #6 at firing and #1 at the point where the exh valve is just closing and the int valve is just opening. When the crank makes one full turn from there, the dots are both at 12:00, the engine is once again at both #1 & #6 TDC, but this time it's at #1 firing and #6 valves "rocking". We usually assemble motors at the former position because it's easier to see; then rotate the crank one turn to reach #1 firing if that's where we want it to be. No idea whether the 6-cyl motors are the same, but I strongly suspect that they are. IOW your motor is currently at #1 firing, but you're thinking you want it at #6 firing for some odd reason.