Some cars have interference engines, which means that if the timing chain or timing belt fails there is the possibility of internal engine damage from pistons hitting valves or from intake and exhaust valves hitting each other. This usually results in having to repair or replace the cylinder head. Every now and then the damage is more severe.
Here is an example of complete engine destruction on a Kia that broke a timing belt while driving. Valves broken, pistons cracked, engine would not even turn with a breaker bar.
We have been recommending a timing belt service for 2 years now, customer always had an excuse to put it off. Now, a routine $500 timing belt service has turned into a $2400 used engine transplant.
Another example of a stitch in time saves 9, or penny wise and pound foolish, or as my grandfather in the catering business used to say, if you need eggs it does not matter what they cost!
I wonder why any interference engines were ever built, especially now that it’s been demonstrated time and again that it’s perfectly possible for non-interference motors to get excellent fuel economy with plenty of power.
Interference engines have been around for over 50 years. Some of the old school cast-iron engines were interference design. The old Ford 302 that many people are fond of would bend valves when the timing chain slipped. So would the Cadillacs of the 60’s. I’ve seen a Chevy 350 bend valves if the chain went when the car was banging down the freeway at 75mph. Even the modern-day workhorse Ford 4.6 found in police cars and taxis is an interference design.
Thanks for the photographic evidence of the importance of following maintenance guidelines for timing belt changes, asemaster!
I just hope that the customer isn’t trying–somehow–to place the blame on either you or the vehicle manufacturer. As we all know, failure to accept personal responsibility is at epidemic proportions nowadays, and I wouldn’t put it past somebody to claim that he/she was never told about the need for timing belt maintenance.
I just hope that the customer isn’t trying–somehow–to place the blame on either you or the vehicle manufacturer. As we all know, failure to accept personal responsibility is at epidemic proportions nowadays
Nope. No blame being thrown around, just–in my opinion–poor decision making. First is putting off a $500 routine maintenance. Second is deciding to put $2500 into a $2000 car. But that’s not my call. All I do is fix them.
With compression ratios of modern engines at 10:1 and more there’s less and less room (without interference) for valve lift at TDC.
Are there any OHV diesels that are non-interference?
Looking at the block, and where the pistons are, it appears at least one rod is snapped, too (or the rod bolts let go). Isn’t this a typical 1-4-3-2 firing order engine? Normally 1-4 are in time, and 2-3 are also, but 180 degrees out from 1-4. That helps engine balance and vibration.
No @chaissos the engine wouldn’t turn and we had to access the torque converter bolts to remove the engine. We pulled the oil pan and rod caps in order to get the crank to turn. Some of the bearings did look a little flat though.
Still I think it shows a poor design and weak materials. I have no problem with an interference engine design that results in a valve bending when timing is off. But sheared off valves and broken pistons?
I have found myself the unhappy owner of several Hyundais and Mitsubishis that were in a somewhat similar condition. The owners were cringing at the estimate for replacing valves and all the incidentals but let the warning that damage to the bottom end was possible and very costly go right past them. Then when faced with the worst possible $cenario they walked away leaving me with a srcap heap that often wasn’t worth the labor involved to open the engine. There was a time when a Hyundai’s cash value was determined by how much fuel was in the tank.
There was a time when a Hyundai’s cash value was determined by how much fuel was in the tank.
Hyundai has come a long way since then, and today I would put them up against most other major brands as far as reliability and ease of service. They’re reliable, simple to work on, easy to maintain, and are quite durable. I think you’d be hard pressed to find someone who’s bought a Hyundai in the last 5-10 years and isn’t happy with the car.
btw.