I thought that I had posted this a couple of days ago but, must have forgotten to press "Post Reply"
How about Piston Rings as an internal engine failure?
How about Piston Rings as an internal engine failure?
Most common internal engine failure
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I know it's been mentioned, but I have to think that the most common engine failure mode has got to be valvetrain related given the relative complexity of multi, overhead cam valvetrains, compared to pushrod engines.
If it's not a cooling system failure or oil starvation that kills an engine, I'm voting on valvetrain failure.
If it's not a cooling system failure or oil starvation that kills an engine, I'm voting on valvetrain failure.
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Originally Posted by JTK
I know it's been mentioned, but I have to think that the most common engine failure mode has got to be valvetrain related given the relative complexity of multi, overhead cam valvetrains, compared to pushrod engines.
I agree, and this seems to coincide with the fitment of VCT/VVT.
I know it's been mentioned, but I have to think that the most common engine failure mode has got to be valvetrain related given the relative complexity of multi, overhead cam valvetrains, compared to pushrod engines.
I agree, and this seems to coincide with the fitment of VCT/VVT.
My guess is that the most common engine failure is a timing belt failure on an interference engine.
Originally Posted by zzyzzx
My guess is that the most common engine failure is a timing belt failure on an interference engine.
A failed chain drive will do the same damage. Worn chains and or busted plastic chain guides and tensioner's, jumped teeth, and broken chains are all a failure mode for chain type cam drives.
Timing belt engines seem to be very easy to change belt in place compared to some chain drives, especially the flywheel end driven type chain systems like on the W8, on those the engine has to be removed.
My guess is that the most common engine failure is a timing belt failure on an interference engine.
A failed chain drive will do the same damage. Worn chains and or busted plastic chain guides and tensioner's, jumped teeth, and broken chains are all a failure mode for chain type cam drives.
Timing belt engines seem to be very easy to change belt in place compared to some chain drives, especially the flywheel end driven type chain systems like on the W8, on those the engine has to be removed.
Originally Posted by blufeb95
There was the Cadillac Northstar problem where GM's engineers weren't quite used to how building an engine with solid aluminum so the head bolts they spec'd would eventually strip the threads out of the block and the heads wouldn't be sufficiently clamped down anymore causing issues similar to head gasket failure.They tried to correct it a few times by lengthing the bolt in 2000 and coarsening the threads in 2002, but from what I hear just don't touch any Northstar built prior to the 2005 redesign.
Well, first of all, the engine was designed by Lotus. Secondly, GM had produced many aluminum block engines before the Northstar. Third, it's not just a Northstar thing. There are specialized head bolt thread repair kits out there for many engines from all manufacturers. Not a Northstar specific failure.
But anyway, on topic, I'd agree with some of the other posters that valvetrain problems seem to be most common.
There was the Cadillac Northstar problem where GM's engineers weren't quite used to how building an engine with solid aluminum so the head bolts they spec'd would eventually strip the threads out of the block and the heads wouldn't be sufficiently clamped down anymore causing issues similar to head gasket failure.They tried to correct it a few times by lengthing the bolt in 2000 and coarsening the threads in 2002, but from what I hear just don't touch any Northstar built prior to the 2005 redesign.
Well, first of all, the engine was designed by Lotus. Secondly, GM had produced many aluminum block engines before the Northstar. Third, it's not just a Northstar thing. There are specialized head bolt thread repair kits out there for many engines from all manufacturers. Not a Northstar specific failure.
But anyway, on topic, I'd agree with some of the other posters that valvetrain problems seem to be most common.
Originally Posted by CR94
Overall, probably head gasket leaks (excluding troubles caused by neglect or abuse).
From what I read , seems that most / many HG failures seem to be caused by over heating the engine ?
When I was young , it was generally the case that by 100,000 miles the engine was worn out and drinking ( or leaking or both ) oil . Now , 100,000 miles seems to be no big deal ?
Overall, probably head gasket leaks (excluding troubles caused by neglect or abuse).
From what I read , seems that most / many HG failures seem to be caused by over heating the engine ?
When I was young , it was generally the case that by 100,000 miles the engine was worn out and drinking ( or leaking or both ) oil . Now , 100,000 miles seems to be no big deal ?
Originally Posted by WyrTwister
When I was young , it was generally the case that by 100,000 miles the engine was worn out and drinking ( or leaking or both ) oil . Now , 100,000 miles seems to be no big deal ?
It hasn't been for me. It does seem as though engines last a lot longer now than they did 40 years ago.
When I was young , it was generally the case that by 100,000 miles the engine was worn out and drinking ( or leaking or both ) oil . Now , 100,000 miles seems to be no big deal ?
It hasn't been for me. It does seem as though engines last a lot longer now than they did 40 years ago.
Originally Posted by super20dan
from what I read -its timming chain failures. with todays complex engines we would be better off with timming belts and I never thought I would say this. its chronic with gm and ford especially
I 100% agree! Was doing a DI 2.4L Ecotech timing chain in a 2010 Equinox today thinking the same thing! Near $600 in parts (my cost) on a engine that won't last much longer because the metal that got shed from the top guide being completely cut in two by the chain.
But some of this lands at the feet of the owner/driver of the vehicle....That thing must have been sounding off for MONTHS before it jumped time & stopped running. Amazingly....It didn't bend any valves & has excellent leakdown numbers.
from what I read -its timming chain failures. with todays complex engines we would be better off with timming belts and I never thought I would say this. its chronic with gm and ford especially
I 100% agree! Was doing a DI 2.4L Ecotech timing chain in a 2010 Equinox today thinking the same thing! Near $600 in parts (my cost) on a engine that won't last much longer because the metal that got shed from the top guide being completely cut in two by the chain.
But some of this lands at the feet of the owner/driver of the vehicle....That thing must have been sounding off for MONTHS before it jumped time & stopped running. Amazingly....It didn't bend any valves & has excellent leakdown numbers.
My wife's 2005 Legacy GT (turbo) burned a valve at 170k. Apparently the factory tune had something to do with it burning lean. The people who flash their cars early on never experienced the issue and got more power.
Wicked expensive to fix but we did recoup the $3k+ till 240k. We never serviced the engine after except oil as all sorts of things were changed when engine removed.
Wicked expensive to fix but we did recoup the $3k+ till 240k. We never serviced the engine after except oil as all sorts of things were changed when engine removed.
I didn't read the whole thread but it seems things changed over the years. When I first started the guy who taught me started in the 20's he recalled changing leather engine bearings every 2K in his dads shop. Later they used unshelled babbitt that lasted a little longer but not much until they get steel shells. I never saw any.
Then the rings and block wore they used to bore the straight engines right in the car body not hone but actually bore them, I did see this machine in action.
rings and bearings continued to be the major source of engine failure right up to the aluminum block era which many early ones failed, then it was the early aluminum heads failing and hydrolocking the engines.
Overheating was always a problem back them before modern coolants, the old alcohol coolant boiled off and the engines quickly overheated. Today I would say we see coolant and cooling system issues causing outright engine failures more than almost any of the other problems that plagued older engines.
Sure rings and bearings still wear but rarely cause an outright fail and destroy the engine if the engine lubrication and correct oil level is maintained.
Then the rings and block wore they used to bore the straight engines right in the car body not hone but actually bore them, I did see this machine in action.
rings and bearings continued to be the major source of engine failure right up to the aluminum block era which many early ones failed, then it was the early aluminum heads failing and hydrolocking the engines.
Overheating was always a problem back them before modern coolants, the old alcohol coolant boiled off and the engines quickly overheated. Today I would say we see coolant and cooling system issues causing outright engine failures more than almost any of the other problems that plagued older engines.
Sure rings and bearings still wear but rarely cause an outright fail and destroy the engine if the engine lubrication and correct oil level is maintained.
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