toyotablue

joez,

Correct me if I'm wrong, but If the chain fell off the the Crank gear, the chain wouldn't turn at all.

What is weird about this situation is that there is no compression in any of the cylinders.

Is it possible that when my engine was running & the chain jumped that it caused a bent valve for each cylinder?

Ducky

Yea I had a DSM (98 mitsu eclipse GSX) it was known you dont go over 60K even 1 mile with a timing belt or bad things happen... like a quick disassembly of your major engine components...

Im coming up quick on the 60K mark on my 01 3rd gen... not looking forward to it...

Info from 4roc site and toyota's site:

Year Engine Belt/Chain/Gear
1990-2000 4 Cyl Chain
1990-2002 v6 belt
2003 v6 chain
2003 Engine v8 belt


If your vehicle is a 1999 model year or newer and is equipped with a timing belt, you should replace it every 90,000 miles or six years, whichever comes first.

For all other Toyota vehicles equipped with a timing belt, we recommend that the timing belt be inspected with the other drive belts at 60,000 miles or four years, whichever comes first, and every 15,000 miles thereafter and replaced as necessary. Because the costs involved with inspecting the timing belt may be similar to those of having it replaced, many customers may find it more cost effective to replace the timing belt at 60,000 mile intervals.

Should the timing belt break while you are driving the vehicle, severe engine damage could result. The higher the speed that you're traveling at, the more extensive the damage could be.

My99

First of all, what's the difference that causes 99's needing timing belts to be replaced at 60K but 98's not? Also, what risk do i run if a timing belt breaks on a non-interference motor? I can't think of any problem, other than the belt itself flopping around and I being inconvenienced.

joez

if the chain fell off the crank, no the chain would not turn.

another thing that could have happned, is that there was slack in the new chain when it was all installed, and it was loosely on the crank gear. the tensioner is driven by oil pressure. so you crank over the engine, the crank gear skipps who knows how much, until there is just enough pressure to put tesnion on the chain, causing the chain to grab. but it still would not explain why you have no compression in any.

did you use a new head gasket? did you torque the head bolts in the factory order to spec? did you drop the head at all, warping it?

i have had a car skip 180* on the cam, and i had my toyota spit the chain off of the cam gear. never had any bent valves or problems.

i am still leaning towards the chain not being on the crank gear, but if you say the chain is turning, then i would say rip the motor appart and do it again.

did you try to cut any corners when doing this. did you take the motor down to the block, only leaving the crank and pistons in?

toyotablue

Yes, I did cut corners. I did not take the head off. I was able to remove and replace the timing chain cover without any difficulty. The most difficult part was remembering where each of the bolts goes.


I think I'll spend this weekend tearing it back down. Since I didn't take off the head & I'll try doing this again without taking off the head (I may not have a choice if the valves are bent). Since I didn't take my starter off, I could actually set the timing chain again & turn the motor over before I put the chain cover back on to see if there is compression. Then I can put it back on TDC so that when I put the distributor in my timing works.

Thanks for your help folks. I'll let you know what happens after the weekend. It will probably be something silly -- I'll let you know.

Danno

toyotablue

O.K. I took the timing chain cover off again. It only took about 2 hrs this time taking everything off. I'm getting good at taking this thing apart.

Anyway, everything lines up still. The engine is at TDC & all of the timing marks match including the distributor(& rotor).

With everything off I added a couple of squirts of oil into the number one spark plug hole to make sure rings were sealing & turned it over for approx 10 seconds. Then I tested the compression. Still zero on the compression test.

Do you think I munched the valves since everything lines up on TDC & there is still no compression on all cylinders?

joez

was it running fine before you did the chain? did the old chain break?

toyotablue

I was sitting at a stop light when the engine kind of hick-up'd and I heard a not-so loud crunch & then the motor died. I tried starting and it sounded like the starter was just winding but not turning the engine over (now I know it was because there was no compression). The chain was in tacked & still on the gears when I tore the timing chain cover off. I failed to check to see if everything was at TDC when I did the tear off. The timing chain guides were munched up pretty bad, so I knew I needed to replace. I figured it just jumped a couple of teeth & was not at TDC & that was why I didn't have compression. But now that I see everything is at TDC now & there is still no compression, I'm starting to think the worst & that "not so loud crunch" was the sound of my valves being munched. Even thought the engine was idling, I guess at 700 rpm (or whatever the rpm is at idle), it would only take a second for a valve over each cylinder to get munched. What do you think?

joez

this is one reason it is recomended to remove the head while doing this job. now you HAVE to remove it to inspect the engine. could you have munched up the valves, you bet. pull the head and inspect everything, look for cracke pistons( this also could be why you have no compression), check to see if the valves are seated properyly, just look everything over.

chances are, if you pistons are marred up, and/or craked, your valvetrain is toast. you may be looking at a total rebuild. when my chain jumped off the sprocket, i was lucky, no damage, but others have destroyed motors. good luck, and keep us updated.

My99

I agree, valves have probably met the pistons.