Today the car I bought from my friend who said it had a blown timing belt (blew when engine blackfired while cranking the engine after he just repaired it b/c a roller froze, he said). After doing the usual cleaning it up and pushing it uphill and into the garage things I had a peek under the hood. I went looking for the timing belt since that's what I've been reading up on for so long. The cover is off but in the trunk and the accessory belt isn't there. The balance belt was easy to spot and it felt good. I also spotted the timing belt - odd since it was supposed to be broken, but ok... It felt tight, so tight that it felt like it was in one piece and tensioned like a non-broken belt should be. I don't think it's broken at all, knowing the person I got the car from it wouldn't surprise me if this car with a broken timing belt doesn't have a broken belt at all!

So now what to do... maybe turn the engine by hand a little and watch what happens? Pull all the spark plugs, turn it carefully by hand a revolution or two, and feel for resistance (valves contacting pistons)? What size bolt is on the front of the engine? I'm used to turning engines literally by hand but I have a feeling this one will require a socket. Maybe I got really lucky here or something.

 

Even turning the engine by "hand" (socket) can be enough to bend valves if they're not already bent. It might be that the timing belt jumped a tooth, but is still intact. The only true way to safely tell (not do any additional damage) is to pull the head. Some might see this as over cautious, but valves add up quickly. Good luck!

 

But, just for your information, the crank bolt is a 24 mm.... I've taken the damn thing off at least 8 times in 2 years... Also, should you remove it, it's torqued to 151 ft-lbs....and the water pump bolts to 6 ft-lbs, as well as those on the belt cover. both inner and outer.

 

yes my 8 new valves ran me $800...don't wanna mess those babies up again

 

I agree. Your best course of action is to remove the head. Inspect for bent valves, crushed valve seats, bad seals, etc. If all checks out- get new timing, balance shaft belts, then re-install everything to OEM spec. Skipped timing belt consequences range anywhere from hard running, all the way to an exploded cylinder(MY CAR). Good luck!

Zach

 

Why not just pull the cam tower and then and then put a straight edge on the valve stems? With the cam tower off all of the valves are closed and should all be the same height. Any bent valves will be "shorter". If the valves check out, set the engine and cam tower to TDC, install the cam tower, install the cam belt, and then run a compression check.

Hint: If the engine back fired it was not properly timed. Look for crossed spark plug wires or a loose ignition rotor.

 

how about turning the crank bolt slightly each way while watching to see if the belt moves, you may have a stripped timing belt....thats how mine went. I cranked and cranked and cranked it, and only had 1 bent valve.

 

Thanks, all - I'm working on figuring things out right now. I can say this - I turned the crank bolt a little in one way and both the timing and balance belts moved. It still may be either: timing not alligned for some reason or have stripped teeth somewhere other than on the front of the engine or where I can see them. Both mean that it's time to pull the head for sure (I'm leaning towards pulling it no matter what just because what I see isn't lining up very well with what I was told).

I'm going to try and find the timing marks and see if they're alligned - that should help out some. I know this: the belt broke because a roller froze up. He had the head sent out to be repaired, and they did the valves and also the valve guides. He put new rollers, a new water pump, and of course a new belt on.

 

I'm having trouble finding the mark on the flywheel - I could swear the engine is at TDC (the forwardmost piston is at its highest point) but I can't find any marks down there. The mark on the camshaft sprocket is exactly oposite where the hole is. Could the flywheel have been taken off and not put back on the same way?

 

The cam sprocket mark should be lined up with the mark on the back cam sprocket cover when the engine is at tdc. Get this lined up, and you will see the mark on the flywheel.

 

The two marks couldn't line up any more perfectly, they're dead on... what I see vs. what I was told by the PO really is conflicting a lot now.

 

When you crank the engine over, does it crank over really fast? If it doesn't, that means you have compression and probably dont have any bent valves

 

I don't have a battery for it yet - it sat for about a year and a half and the battery is dead. I took out the spark plugs and have been turning the engine by hand. In general it hasn't been too hard to turn, I'm tempted to take my compression tester out and see if it's possible to get a reading. If there are any bent valves I'm sure it'd be 0 for that cylinder (assuming I can turn it fast enough to get a reading).

edit: nope, I tried cyl. 1 and 2 - no compression there but then agan I was also turning a dry engine by hand. The battery is 100% dead and so odds are it won't recharge fully. Time for a battery I guess.

 

So I have a new battery to turn the timed engine with in order to do a compression test. I go down the line:
#1 0psi
#2 0psi
#3 0psi
#4 0psi

The tester worked just fine on my truck, and I could see the oil gauge in the dash bouncing around and peaking out so there has to be some oil getting up around the pistons. I guess I'm looking at at least 1 bent valve/cylinder, but since the timing marks were lined up it couldn't have hurt anything trying.

Before I start following the steps to remove the head, is there a chance that the readings are 0 because the car hasn't been run in about a year and a half?

edit: same reading after putting a capful of oil down the spark plug hole, looks like all possibilities have been looked into so it's got to be the valves.

 

No