Timing Chain Help!

[z32dreamer]

Well I believe this is my first real post on here so If I botch it up to bad take it easy on me.

When I bought the car (77 280z) it had a blown head gasket but still had compression. I took the head off to find that it was pretty warped and deffinatly could use a valve job. I sent it off to the machine shop where they put all new valves in and shaved the head.

So now I have the head back and decided to put a new timing chain in while im in their. I put the new head on, set the number one cyl to tdc on the compression stroke. Then sat the head on it torqued it down to spec installed the cam sproket on the number 1 dowl hole. Then put the lighter colored chain link on the number one mark of the cam sprocket and the other light chain link on the crank sprocket that is maked.

Now when I bring the no.1 cyl to tdc the valves are closed just as they shold be so I put the entire thing back together and go to crank it over and have absolutly 0 compression accross all cylinders. How is that possible? I have redone the same procedure as the book describes 4 times now with the same end result 0 compression.

Any ideas guys or should I just part the car out?

[Nissanman]

Just a quick thought, make sure that the valve clearance is set correctly.

If there is none, the valves won't seal, therefore no compression.

[z32dreamer]

would the valve clearance be set by shimming the cam up... I noticed when installing it, the came did have a set of shims already I am curious it it needs more.

[hls30.com]

It sounds like you sent the head to the machine shop without the cam. If you did, there is no way for the machine shop to adjust your valves. Adjusting your valves would more than likely take care of your issue-assuming the turn over you have already done hasn't bent anything. Valve adjustment is done with two wrenches, and stepped(or plain) feeler gage.

Will

[Nissanman]

would the valve clearance be set by shimming the cam up... I noticed when installing it, the came did have a set of shims already I am curious it it needs more.

The shimming that you describe is referred to as "head saver shims".

When the alloy head is machined too much, the cam drive mechanism dimensions are restored by raising the cam towers in relation to the top head surface. Usually, the machine shop does the necessary machining then supplies the necessary shims to correct the cam height issue.

All this is quite separate from setting the valve clearances.

This is done by adjusting the tappets for each valve to the recommended clearance.

In your case, the tappets may be so tight that there is no clearance, preventing the valves from closing and therefore sealing.