Buddy of mine told me warped head or blown head gasket. That was the first thing outta his mouth when i told him 30 psi.

 

It is rare for an HG to cause compression drop across all 4 cylinders. It is possible, but very unlikely.

Check timing and valve lash first, especially since you just changed the timing chain. Also, be sure that your timing chain tensioner is working properly, and correctly installed.

Changing the head gasket is not a bad idea on general principles on these motors, but I would troubleshoot one problem at a time if I were you. Do the easy, obvious stuff first before you add more potential points of failure.

 

And also, no disrespect to your friend, but I swear, everybody has a friend that says any compression problem is always a warped or cracked head, or a blown head gasket.

There is actually a really good reason for this:
Most people in the US have either learned about motors from working on domestic overhead valve engines, or learned from a friend who learned on domestic overhead valve engines

Overhead valve engines have fewer potential causes of compression loss. The basic options are blown rings, cracked head, warped head, blown head gasket, blown valves, timing chain out of place (cam/crank out of alignment with each other). Timing chains are much easier to replace on many domestic V8's (350's spring to mind here), so other than putting a cam in 180 degrees out, this is not a usual issue. As a result, blown HG and warped/cracked head are among the most common reasons for compression loss on an OHV motor.

Overhead cam motors have some unique opportunities to lose compression. Typically, the timing chains are longer, which make the potential for jumping links or messing up a TC install much more likely. Also, any movement in the head, or heat expansion, or many other factors, can cause the valve lash adjustment to go out of whack, causing premature or late valve opening.

The typical reason for a loss of compression across an entire cylinder bank like you are experiencing comes from an intake valve closing too late, or being held open too long by improper valve lash. What this means for you is:

Try valve lash adjustment. It is painfully quick. Look at the links in the earlier post, and try backing all the adjustment screws all the way out first. Be sure to lock the nuts back down when you're done. Run the compression test. If your compression problem goes away, run the truck until it warms up, and set the adjustment screws per the previous instructions.

If this does not fix it for you, troubleshoot the timing chain, and make sure everything is right. Make sure the cam and the crank are both resting at TDC, and then get the timing chain on.

Good luck!

 

I looked at it but Im not exactly understanding what to do lol. I've never messed with anything in the head!

 

I understand how to get it started but idk what the lash is supposed to be set to or know how to tell if its set right.

 

Took the head off an it blew between 1-2 & 3. Head goin to machine shop to get a valve job an shaved. What are the torque specs?