Question on interference engine failure, does this sound right?

Don is right on the nose on this one. BUT, I had assumed the mechanic had replaced the belts, rephased everything, and had the valve train working before he tried to run a compression test.

If he didn't, he is not competent to do this sort of work, and you should run, not walk, away from his shop.

Yeah, I agree with you, to a point. I understand that there's a chance that the pistons might be OK. But then, even so, I'd only save about $800 on the total repair job, IF the pistons were OK. To me, that $800 is not significant enough to worry about. It's not like I'm made of money or anything, but I had to make some kind of decision. Pulling the head might have cost me even more money in the end, so I decided not to do that. The other thing I had to consider is that rental car charges are piling up fast. (we can't put our lives on hold just because one car is in the shop) So if pulling the head would have added a couple of days to the repair job, then the savings would have been something -less than- $800, as opposed to replacing the entire engine. And again, that's assuming that the pistons are all OK. -Dave

Yup, as I wrote elsewhere, pulling the head might have saved me only about $800 at most, and that's before rental car charges were figured in. A couple of days longer in the shop (to pull the head, have the head rebuilt, etc.), and the savings might have been ($800 minus increased rental car charges). It was a tough decision, but I decided to replace the engine. Again, it was a tough decision. But sheesh, I had to make some kind of decision. So, the engine goes. :( -Dave

Twenty years ago, I was a poor, starving college student with access to the department machine shop.

A friend of the family bought a 1982 Ford Escort. After about 15,000 miles, the timing belt broke. Ford was very good and replaced it under some sort of warranty. At 40,000 miles or so, the timing belt broke again, and they paid to replace the engine. Come around 60,000 miles, the timing belt broke a third time, and they gave me the car.

I called around to junkyard, and everybody had a bunch of '82 Escorts on the lot, but nobody had one with a good cylinder head. This was a sign.

I actually rebuilt the head and put oversized valves in, which was an awful lot of work and I learned a whole lot about machine shop work in the process.

I got about 10,000 miles out of the thing before, with no warning, the timing belt broke. I gave it to a friend of mine who was a mechanic and he rebuilt it and gave it to his daughter, who got around 12,000 miles.

This is a clear example of good money after bad.

--scott

I would assume they slapped a new rubberband on the thing and THEN checked compression. That's what I'd do in their place.

You should have read this thread properly.

You only have to remove the valve cover to inspect the valves. This takes 10 minutes.

They cannot have tested the compression with a broken belt. The numbers only mean the mechanic is a liar and a crook.

They are incompetent, you need to 'run' away from this shop.

The fix is likely less than $100.00....

Sheesh.........

You are getting 'suckered'!!!!

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Jan/06 (More Off Road album links at bottom of the view page)

yup, that's what was done. New rubber bands. :)

Perhaps so -- there was no mention of it that I saw, however.

Not me, I would remove the valve cover, rotate the camshaft (first turning the crank where to where are no pistons at TDC) and and see if all the valves close properly. If a valve gets bent it is usually very easy to see.

Don

Really, I am not kidding, that is the real problem.

Ditto. In my family we have gotten lucky in the past. We snapped a belt and let the car coast to the side of the road. I thought it was bad news when I found out it was an interference engine. figureing it couldn't hurt, I put in a new timing belt and hit the starter. The car fired right up and ran fine until we sold the car about a year and 10k miles later.

--------------- Alex

You are getting your old engine back, right?

What makes you think they did?

No but another mechanic is getting shitcanned by a moron without all the facts.

And what shop do you of know that will fix bent valves or even replace a timing belt for under $100? Bob

Ok, then lets start with some 'facts'.

He has a slipped or broken timing belt.

To test the compression, the valve cover 'must' be taken off to reset the belt first. This means the valve stems are visible. This means the valve lash is visible.

A valve bent bad enough to cause 0 compression must show a lash issue.

If they did not remove the valve cover and they checked the compression with the slipped or broken belt, then 100% FOR SURE he is being ripped off!

A slipped belt can easily give 0 compression on 2 cylinders. A belt put on improperly, by 'accident' for sure eh..., can also show 0 compression on 2 cylinders.

If they don't know how to check for a bent valve by checking the lash, then they are not competent enough to do the work.

The sparkplugs were removed to check the compression. This means the top of the pistons are visible through the spark plug hole. Usually just a flashlight is enough to see the piston tops, but a good shot of oil onto the top of the piston will tell immediately if there is a hole in the piston causing 0 compression. The oil will run away instantly. If the oil stay put, the engine is likely just fine.

If they cannot see in there or don't have the equipment to look in there or couldn't be bothered to do a standard wet test, then they are not competent enough to do the job or are pure rip off artists.

So in my opinion, either they are just plain incompetent or they are a bunch of crooks.

Mike

Bob wrote:

I have no history with the mechanic, but have met him, and he seems nice enough. The garage has a very good reputation, locally. That's GOT to be significant, as it's easy to get a bad rep. doing work like that, and very difficult to get a GOOD rep.

I know the engine might not be totally trashed. What I've decided to do is, I've asked a friend of mine to haul the original engine back to my house for me, and I'll store it in our garage. When the weather warms up a bit, I will tear it apart myself to inspect it. If it just needs a valve job, I have a few options at that point. I'll probably just keep it around as a spare engine in case I have another belt failure. I HOPE not, but I wasn't expecting 2 year old belts to fail on me, so . . .

Was thinking of giving this car to my niece in four years, when she gets her first license. With minimal work, it will easily last her through college anyway.

Yup. Will tear the head off to inspect it when the weather is warmer.

HAD is the key word here, the mechanic put a new belt on and then checked compression.

There are some engines out there which require valve cover removal as part of a timing belt job. A 95 Mitsibishi with a 2.4 isn't one of them.

No it can't, if the belt slipped enough to bend 2 exhaust valves it would have bent ALL the exhaust valves.

The fact is you're opinion is based on things you don't know much about. Bob

Right, so it likely has only slipped enough to kill the compression on those two rather than punch out things...

If it smells, well...

Mike

I suspect they threw a belt on.. personally, I generally remove the rocker arms and do a leakdown test.

Gates calls that engine an interference engine.. I take that to mean that the piston can come up and smack the valve.. doesn't mean it will. A non-interference engine won't hurt the valves. When a customer comes in on the hook and it's a borken timing belt on an interference engine I tell them that there's a possibility of valve damage. If it's listed as a non-interference engine I tell them that it's likely only to need a timing belt.

Agreed.. I still like to do a modified leakdown test though.. but bent valves are sometimes pretty obvious.

I don't diagnose long distance.. I don't badmouth other shops unless I'm positive I know what's going on..

Jim

Yes. It was fitted with new belts before the compression test was done. It was actually running on 2 cylinders. The mechanic noticed right away that it wasn't running right. Thus, the compression test.