Timing Belt Question

[Trunk Monkey]

1990 4door EX.....My son drove his car on a short round trip. 180 miles approximately. This car is usually used a daily beater to school and home. Well, the Alternator belt broke when he got home...I fixed that for him..NOt 15 minutes, 3 miles later he calls me and tells me the engine just gave out. WTF?? So I get to the Gravesite, and asked him to turn the engine over and Woe and Behold the sound I hate. The sound of an engine with NO compression like it has jumped timeing or has no timing at all. I think the Timing belt broke. My question is is this an Interference Engine? Also I caught hell getting that alternator belt on since I have hands like a Baseball glove. From the looks of things the timing belt looks like a pain in the AS$. Someone enlighten me. Thanks in Advance. I will check it out again tommorrow. Its too dark now.

TM

[Pandemic]

Not sure about if it is or isnt an interference engine. Not even really sure what that means. If the timing belt went, then you have some major head work to replace.

[bigjoegood1]

It is an interference engine. At the least I think a valve job will be needed, maybe more but I hope not. Expect the worse but hope for the best.

[Pandemic]

Not to steal this, but what determines an interference engine?

[bigjoegood1]

Not to steal this, but what determines an interference engine?

Interference Engines and Timing Belts
By: Ralph Hoffmann

Interference Engines: ........ Useful information by AutoTruckData.com

An interference engine is an engine design that has been avoided by some manufacturers for well over 80 years. General Motors, Chrysler, etc., typically use a metal chain-type timing belt on push-rod engines (often called a timing chain) to transmit torque from the engine crankshaft o the engine camshaft that opens the valves that admit air and fuel. (Note: on some new cars the fuel is admitted not through the valves but through injectors in the top of the cylinder. Rather than use a steel timing chain, interference engines may use a rubber timing belt with its limited life, whereas steel timing belts typically last 150,000 to 200,000 miles or more.

Valves open further in an interference engine and project further into the combustion chamber than in a 'free-running' engine. This allows outside air at atmospheric pressure flow faster into the combustion chamber through the larger valve opening. The engine can therefore inhale more air, be a little smaller, and still create as much power while reducing its manufactured cost and also guaranteeing future repair business for its dealer. If a rubber timing belt breaks by not being replaced soon enough, some of the valves stuck in their open position will collide with the top of the pistons, thereby breaking or irreversibly damaging one or the other or both. To make matters worse, it is not possible to measure the wear on such a rubber belt so that it could be replaced when there is some indication of imminent failure. Failure in these belts is catastrophic, without warning. This will require a whole new engine be installed. Woe to the owner. Finally, the rubber belt may have to be replaced long before 60,000 miles solely due to its age. This is really playing a bad poker hand. Interference engines are like a time bomb waiting to explode unless replacing the timing belt at the recommended interval. Be aware of that guaranteed future expense before buying a new car, or especially a used car, " with such an engine.

For details on this subject or for recommended mileage to replace rubber timing belts on interference engines, connect on the Internet to ©Gates Rubber Company, a worldwide manufacturer of such belts. When its web site appears, click on Replacement parts/Automotive. Look for 'Timing belt replacement Guide'.

When buying a used car always insist on determining if the vehicle has a rubber timing-belt. Be aware that about five years ago an International Oil Company did a follow up on 5,000 cars it had turned back after 3 year leases and traced them to their eventual private owners. All the cars had by then passed through wholesale auction markets and likely one or more retail dealers before being sold to a private owner. The survey disclosed that 50% of the cars had their odometers illegally turned back.

When buying a used car, supposedly with 40,000 miles for example, and determining it has a rubber timing belt, insist on a written guarantee from the seller to guarantee in writing to replace the timing belt at no charge if it fails within another 20,000 miles, a typical recommended total amount (call any Dealer to get the recommended amount for the particular make of vehicle). After all, the vehicle may in fact already have 55,000 miles on it. If the seller will not make that guarantee, then he is admitting that the mileage is probably not accurate and by implication may well have been turned back. If the seller will not make that guarantee, consider a compromise, such as $100 maximum cost. If not acceptable, walk away and look elsewhere."

Before buying any car, especially 4-cylinder foreign cars, or even 6-cyl. BMW’s, be aware of the unavoidable cost of $400-$800 to replace the timing belt at anywhere from 50,000 to 70,000 miles if the car has an interference type of engine. The sales person will invariably not mention that an interference type engine powers the vehicle and may not even know what one is. If a timing belt on an interference engine is not replaced at recommended intervals, the repair cost when the belt breaks (not gradually, but always catastrophically) could increase to $3,000 to $5,000 due to engine failure because parts have smashed into each other

If the sales person does not know if the vehicle has an interference engine, walk out to the repair shop and ask the 'Service writer', who is probably a former mechanic. Finally, since words are cheap, write on the purchase order that the seller guarantees the engine is not a "interference engine" and will indemnify you 100% if it turns out that it is and the engine breaks when the rubber timing belt breaks.

Copyright 2004 by Beacon Data LLC All rights reserved

[bcjammerx]

yeah and it's no cake walk to just check it either...but not too bad.

and the damage depends on the speed at which the engine was running when it broke...but...most likely a valve job.

Once you get the upper cover off you could check compression on each cyl and do a leak test...turn the crank and cam by hand, can't hurt anything if you do it by hand with a small wrench, just don't force anything. You'll still need a valve job but at least you'll know how bad everything is.

[AD5OS]

Wouldnt it just be cheaper and easier to swap the engine? at least you know you are getting a good engine... I would try to figure out what cause the alternator and timing belt to break so quickly in the first place.

[Fake Thug]

Good info, but not all T belt driven engines are interference. Though I'm pretty sure most Hondas are. You can confirm the belt being broke by pulling the cap and watching the rotor while cranking. It should move. Or pull the vc and look at it. Worst case scenerio is bent valves, maybe a hole punched into a piston, either way the head will be coming off. If you know its broke dont turn the motor at all.

[Trunk Monkey]

Timing Belt

Thanks for all the information. I have been down this road many times from back in the VEGA days...and Chevy Chevette...OMG! some of you guys have probably never heard of those cars. They all had what we called "Rubber Bands". Rubber timing belts. The Vegas engine wasn't an interference engine I don't think but the block was aluminum with NO cylinder sleeves so they didn't last long. Basically a 4 cylinder Briggs and Stratton lawn mower engine. I will check his car today. This time of year in NC, Rain is my worst enemy. Just got my shop put up but the backyard stays so wet and Muddy I can't get any cars into it!!!
Has anyone on here ever had a Timing belt break on you? If so did you bend any valves?

Thanks

[Trunk Monkey]

Whoa!! News Flash!! This just in.....

I just Read this...
"F series is a non-interference engine...especially since you don't have VTEC." Hmmmm Interesting... I need verification though from someone who has been there.

[bcjammerx]

where did you read that?

The f22 is an interference engine

also, while you could turn the crank and check the dist cap, don't use the starter to do that...turn the crank by hand

[benji]

Thanks for all the information. I have been down this road many times from back in the VEGA days...and Chevy Chevette...OMG! some of you guys have probably never heard of those cars. They all had what we called "Rubber Bands". Rubber timing belts. The Vegas engine wasn't an interference engine I don't think but the block was aluminum with NO cylinder sleeves so they didn't last long. Basically a 4 cylinder Briggs and Stratton lawn mower engine. I will check his car today. This time of year in NC, Rain is my worst enemy. Just got my shop put up but the backyard stays so wet and Muddy I can't get any cars into it!!!
Has anyone on here ever had a Timing belt break on you? If so did you bend any valves?

Thanks

I had the little key fall out of my crank pulley once, so the cam stopped turning. It messed up 4 valves, I ended up just swapping the engine.

Next time (different car), when my water pump seized up, the timing belt just shredded. I don't know if it killed any valves or not, I just swapped it again, but for an H22A.

[Trunk Monkey]

...UPDATE.....Camshaft Turns!

Bumping the Starter, I can see the camshaft turning a little inside the valve cover. I didn't remove the VC because it was raining and all my tools are like 30 yards thru a lake of red mud since my building is that far away. That tells me that it either jumped timing or or something else is weird with the Belt..I will try to dismantle as much as I can when the rain subsides... Glad the belt isn't broken though whooopeee!

[Dan9]

so is it all good now?