No compression in cylinders

[RichardPryor]

Truck was fine. 2 days ago it didn't start, making a weird noise that sounded like the started, but engine was turning. Mechanic had it for 2 days and today his helper said there is no compression on all 4 cylinders. What does this mean and why did this happen? Truck was driving no problem and oil had been changed 3k miles ago.

[tortron]

Strange. No compression on all 4 is very odd. I'm struggling to think of something that would do that

Possibly the head has warped very badly? I would compression test it again and check the engine is actually turning.
Then valve cover off to check if th valves are moving.
If the head is warped or you have somehow blown the head gasket on every cylinder you will have very milky oil and coolant so that's easy to check.

[Giovanni89]

Timing belt/chain broken? No compression on all four makes me think the valves aren't moving

[geezer101]

Do a TDC check on the crank pulley and then do a visual check on the cam alignment mark and distributor. If the crank shows TDC and the cam is out, the belt has stripped a few teeth somewhere.

[royster]

Timing belt/chain broken? No compression on all four makes me think the valves aren't moving

This, along with Mr. Geezer's observation, are what I think the problem is. When my 2.4 stripped teeth on the timing belt, it did make a strange sound while cranking, although the engine turned. It wasn't until I started opening things up that I located the real problem. (And from there, my adventure began).

It's easy enough to check: take the top timing cover off and crank the engine. If the timing belt isn't moving, then it needs to be replaced.

A sudden loss of compression indicates the valves are in an open position, though Tortron may be correct. Again, you won't know until you look deeper.

[geezer101]

This, along with Mr. Geezer's observation, are what I think the problem is. When my 2.4 stripped teeth on the timing belt, it did make a strange sound while cranking, although the engine turned. It wasn't until I started opening things up that I located the real problem. (And from there, my adventure began).

It's easy enough to check: take the top timing cover off and crank the engine. If the timing belt isn't moving, then it needs to be replaced.

A sudden loss of compression indicates the valves are in an open position, though Tortron may be correct. Again, you won't know until you look deeper.

It doesn't necessarily mean the cam won't spin as it only takes a few teeth to be stripped out of the belt for the cam to no longer be synchronised enough to close the valves on a compression stroke. The give away will be that cam timing alignment mark.

[RichardPryor]

Mechanic said internal engine problems and I needed a new engine. The guy building my house told me he's full of it and told me to bring the car over. He quickly checked it today and said the alignment issue you guys are talking about was off by almost 90 degrees. He will open something tomorrow and see if the timing belt had issues. At least that's what I understood he said.

Engine is turning.

[geezer101]

If the starter motor will crank the engine over you know it hasn't taken catastrophic damage. I bet a new belt and resetting the timing marks will get it firing in no time. Your 'mechanic' shouldn't be allowed near anything more complicated than a spoon...
EVERY conventional 4 stroke engine works on the same principal :slap:

[LSR Mike]

mechanic is looking to make a boat payment....

[claych]

With Permission Honored Posters,One caveat_
RichardPryor...
Your single cam 8 valve head is not an interference design,
i.e. belt fails , no piston to valve contact.

[RichardPryor]

Timing belt replaced and cam or whatever aligned. He spent 6 hours and charged $600 with parts. Put in new oil (had none) and replaced all tubes and spark plugs etc as well. My truck is running better than ever!

[Giovanni89]

Right on!:thumbup:

[royster]

Yay! Another success story - we like to hear those :)

The mechanic's fee seems pretty reasonable. It would be great if he saved the old timing belt, so you could see it.

And I wonder if he came to MightyRam50 for specs??!!

Anyways, congratulations, and get some pictures posted up of your beast :D

[geezer101]

Awesome. 6 hours seems way too long for a mechanic to do a RWD SOHC timing belt but he didn't gouge you like a wounded bull for it, so it's forgivable. I would recommend that in the course of the next oil change you flush the block. Running an engine really low on oil will cook the oil and foul up hydraulics and bearings etc. I've got a write up on how to DIY and it works very well.