EDIT: forgot to add, this is a '92 Accord LX coupe

This may sound like a stupid question, but I would think that you'd know if you were cranking an engine that had a busted timing belt. You'd hear the valves getting all mashed up, right?

Reason I'm wondering is that I found another car that might be worth fixing up for some extra cash. The previous guy who looked at the car told the lady (the owner) that the timing belt was bad. The car cranks fine and sounds pretty normal, it just never catches. I'm kind of thinking this guy, who called himself a mechanic, could have been pulling her leg so she'd sell it for a lower price.

But, if it's not the timing belt, and maybe the coil just went out, there'd be some good money to be made here. She said the car just all of a sudden died one day, no signs of anything coming. I know a timing belt could very well cause that, I would just think that you'd definitely be able to tell if that was it by listening to the engine crank.

What do you guys think? Thanks for any help!


Modified by Flatland2D at 7:25 PM 5/8/2007

 

Well you can take out one of the spark plugs and see if the engine is going through all four cycles.

If it doesn't, then the timing belt is the primary culprit I can think of...

 

Thanks for the suggestion. I'd feel a little uncomfortable doing too much diagnostic work on the car before buying it. That's why I don't want to remove the valve cover or anything... maybe I can ask to check the spark plugs for other reasons. I didn't think about it at the time, but I read about looking at the valve train through the oil cap while cranking (by hand). I may try that one.

But about my original question, wouldn't you know something was up when cranking the engine if the timing belt was gone? Or could the valves get mashed all the way up there that you wouldn't hear them hitting the pistons anymore?

 

Thankfully I've never heard pistons obliterating valves first hand. But after the first time it was cranked, any valves that were going to get hit would have been smashed pretty good. I mean even if the engine was idling when the belt went you've got the crank turning at ~600-750RPM, which means that in one second one piston would hit the valves it would hit at least five times. That's alot of damage in one second. And most times the engine doesn't completely stop rotating for at least a few seconds.

As long as you have a friend there and the guy isn't looking right over your shoulder you can check that real quick.

That'll save you from turning a fixer upper with a likely ignition problem into a car in need of a new top end.

Oh and a good way to check since you have the spark plug tubes and all, you should be able to take a piece of rubber tubing. You'd be able to hear the air rushing in and going out of the spark plug hole.

 

compression test will tell you if a t-belt is busted as all cylanders with an open valve will read "0" psi. but it is by far easier to take off the inspection cover and look

 

Well I didn't have much expierence taking off the inspection cover on the F22 motors. And what can I say, the old spark plug trick is just an old method that I use for alot of my own things.

That's what I get for learning alot of my beginning knowledge from my old school hot-rodder dad. Your finger works as a quick and cheap, yet inaccurate compression tester. Good way to find a busted valve with limited time and tools.

 

Go with compression - it's going to be hard to hear the valves getting "crunched" since they may only be bent. And if it was already cranked with a broken timing belt, then they are likely pushed up as far as they're going to go. With the noise from cranking the engine it would be very hard to hear any kind of interference.

 

and view if rotor turns when you crank the starter.
if won't turn if no timing belt is fastened to the cam sprocket.
the starter may sound ok as engine turns, but you are getting no spark generated.

my experience is from a mazda when the engine goes dead and i too feared valve damage from my inter. engine. yet, i had none. and i was on freeway at speed.

my model mazda is easier to work on than my accord, so it is so easy to remove upper timing cover to see a broken belt- sorry honda.

 

see if it sparks, if the engine spins without a spark then your likely looking at cap/rotor>coil>iginition/control module in order from least to most complex

 

if the coil or igniter is bad, sometime it will still spark, it will just be a week spark.
and if there is no spark at all the it could also be that the distributer isn't spinning b/c of the broken belt. Best bet is to unplug the distributer harness and remove the cap.

 

Ok, so here's the deal. Went and had another look at the car tonight.

The spark plug boots for cylinders one through three were completely soaked in oil. So of course the spark plugs were dripping wet when I removed them. Cylinder 4 was perfectly clean an dry, and had a good healthy gray color on the plug.

Did a quick compression test on all four cylinders. I didn't sit there and crank till the gauge stopped because I didn't want to kill the battery, but each cylinder was able to get to at least 180psi (highest was 210psi, but that one I cranked just to see how high it would go, I think it was cyl #3).

Cranked the engine some more with all spark plugs in. Pulled out #4 plug since it was the only dry one and it smelled like gas. Fuel pump good. Held the plug against the engine (to ground it) and no spark.

So I'm thinking the reason it died all of a sudden on the lady is maybe a bad coil (just had to replace one in a '91 Accord I bought), but definitely something spark related. It still needs a new valve cover gasket to fix all that oil, and it's obvious it's leaking from the outer edges of the gasket down the head. It could probably use a good head cleaning if I decided to get it. One nice thing about the car though is that except for some faded paint on the roof, the rest of the paint is still really shiny and the interior is near perfect.

What do you guys think? Agree that it's probably just a no spark issue? I'm thinking of offering a low ball number since the car isn't running. I think I'll start asking at $400.

 

i can tell by ear if timing belt is snapped.. most can't it just that i know how it sounds like because its crank 2 rapidly but never catches... i mean real rapid...

 

Yes you can tell by sound. I've heard it many times kind of sounds like a wheezing sound when the engine is cranking

 

I think I've pretty much narrowed it down that it's not the timing belt.

Do you think it's still worth saving with all that oil? All it should need is a new valve cover gasket, right? I suppose the valve seals could be leaking, too, but it'll be impossible to tell without first fixing the oil on the outside of the plugs.