Having a hell of a time with my brother's 94 dodge colt 1.5L. He snapped the timing belt and bent all 4 exhaust valves. So I put new exhaust valves and tested all valves by filling the ports with liquid. All checked out good after I was done. Bought a new head gasket, cam seal and timing belt, got it all back together and tried to start it. Seemed like it was running funny, pulled out the compression tester, two cylinders on the passenger side put out 30psi each, the other two where they were supposed to be at 150. Checked and rechecked the valve lash and cam timing, all good there. Pulled the head back off, cleaned everything thoroughly, chased the threads in the block to clean them up and did the same to the threads on the head bolts. Gave the head gasket (the new one I just took off) a good layer of copper coat on both sides, made sure everything was super clean and and put it back together. Same readings on all 4 pistons again. 30-30-150-150.

I can try another new head gasket, maybe trim down the head locating dowels in case they're too long for the new gasket. Could check the head and block for straightness although I don't see how that could be a problem, I followed the fsm recommendations for removal/install pattern. Is there anything else I'm missing that it could possibly be?

Some head bolts are torque-to-yield. One use only.

Have you filled those cyls with compressed air with cam on base circle to find leak point?

you need to buy new head bolts

Two things...

1) Obviously, you need new head bolts. Not sure if this is the case, but with other Chrysler heads, you torque them to a specific value, then turn them an extra 90 degrees. This definitely stretches the bolts...

2) If the head is aluminum, it could be warped or cracked. I blew a head gasket on my K-Car and took the head to a shop "just to have it checked", and it ended up being cracked...

Just my

Does that engine have the air injectors that pumps fresh air into the combustion chamber?

Jet valves, can get carbon between the seat and the valve and become a compression loss

Get the head milled and do a valve job. You can't tell by just eye balling it.

I don't see how the head could be warped. The head gasket didn't blow and it's not like the motor cooked itself, but I will check it for straightness when I pull it off next, just in case it got warped when I was removing the head bolts, even though I removed them in 2 stages and in the order the fsm indicated.

I checked my fsm again, and it didn't say anything about these bolts being torq to yeild. FSM has a 'N' beside non-reusable parts and neither the diagram, description or specs sections mentions anything about the head bolts. All the instructions for installing them say is torq in 2-3 stages to 53ft-lbs following the tightening order in the book. That's it. I thought with torq to yeild bolts you're typically supposed to torq to the value indicated then another 1/4 turn?

No air injectors and I don't think it would be the valve job that's the problem because I poured gas into all the ports and checked for leakage and they were fine.

Check the hydraulic lash adjusters on it... If you whacked the valves you mayhave compressed and stuck the ajdusters.

I suspect your valvejob, or lack-there-of...

Maybe it is coincedence, but usually when you have two cylinders side by side with low compression, you look for a problem between the two cylinders. Especially since they are both reading the same low pressure. Check for a low spot on the cylinder deck between the two or the same thing on the head. Last of all the head gasket itself between the two offending cylinders.

I thought once you remove a little aluminum head like that, it would warp a litlle. That's everyone resurfaces the head during a valve job?
But I'm no expert on small 4 cly engines with aluminum heads. Anyone know out there?

Did you pull the pistons? Usually when the valves contact the pistons they damage the top ring land and cause the top ring to seize in the groove. That could explain the lack of compression.

Did you follow the factory service manual procedure for checking the block and head for warping?
It sounds like this is a basic fix it and go, but after the troubles you have had, I'd suggest doing it the way most shops do; send the head out to be pressure checked, checked for warping (yeah, it never got hot) and have the shop check your valve job. Stuff like what you have run into is why every aluminum OHC head gets sent out before bolting it back on.

You bent valves, are the valve guides ok?

Did you check?

Maybe once the rocker arms opens the valve and closes it, the valve is no longer seating correctly.

I did check all the guides and they were fine, and I did rotate the cam over many times to make sure everything was seating correctly. The way it's two cylinders beside each other that are reading bad and the other two beside each other are good I'm starting to lean towards head warpage, which I did not check for when I had it off because I thought I removed the head properly as per the FSM instructions. I think you're right, I should just send the head out and have it checked. This was supposed to be a simple weekend repair.

Only other ohc aluminum headed motors I've worked on are the chrysler 2.2/2.5's and I never had this kind of trouble with their heads.

Can you remove the rocker train with the head still bolts down?If not can you somehow get all the valves to close.If you can,inject air pressure into one of the cylinders with low compression and see if air comes out the plug hole of the other low cylinder.if it does you have a cross leak problem,if it doesn't then that is not your problem.While the air is still hooked into the cylinder listen for leakage out the tailpipe or out thru the intake manifold.Whichever one leak that valve has a sealing problem. John.

hi you need to do a leak down test bring one of cly. the low comp. tdc compression stock ad air through the spark plug hole not leting the crank to turn then with a small rubber hose up close to your ear an listen to the intake for air then exhaust & the other low cly.at spark hole were you hear air leak is were the compression is going

What happened, what was the fix?