CHEVY VEGA. Just bad!
Engines with questionable designs
- Thread starter Snagglefoot
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1976 Pontiac Sunbird 4 cylinder. Ask me how I know!!!
Originally Posted by Kibitoshin
Add another one to the list the Ford 4.0L V6. Just a poor implementation of trying to use a single head on both banks so you have to use a jackshaft from the front chain to spin the rear chain on the back of the engine. And it requires pulling the engine out to service the chains and guides.
+1 on this one^ I believe 4 chains.
Add another one to the list the Ford 4.0L V6. Just a poor implementation of trying to use a single head on both banks so you have to use a jackshaft from the front chain to spin the rear chain on the back of the engine. And it requires pulling the engine out to service the chains and guides.
+1 on this one^ I believe 4 chains.
Originally Posted by kschachn
Originally Posted by ZZman
Yep, Chrysler 2.7 is a joke. If you do the water pump or timing belt you might as well replace the other.
The Chrysler 2.7 had a timing chain however.
The Chrysler 2.7 suffered from early timing chain tension failure however.
Not an internet fueled comment, it happened to a neighbor.
Originally Posted by ZZman
Yep, Chrysler 2.7 is a joke. If you do the water pump or timing belt you might as well replace the other.
The Chrysler 2.7 had a timing chain however.
The Chrysler 2.7 suffered from early timing chain tension failure however.
Not an internet fueled comment, it happened to a neighbor.
My entries
1. 351W. Had a nylon middle timing gear guaranteed to fail after the first overheat. Mine failed. Fortunately mine was not an interference engine, but my vehicle was still Found On Road Dead.
2. Chevy Vega engine. A lot of people don't know the aluminum engine was full of silicon nodules, etched and honed to make it wear harder. But they were brittle and broke off and you got a worn out bore in 30K miles. Plus the radiator was undersized and it had an aluminum block and an iron head, so it would blow its head gasket on the first inevitable overheat. It was pretty much designed to fail top and bottom by 30K.
3. Iron Duke. One steel timing gear meshed directly with one "phenolic resin composite" gear. Designed to fail in under 100K miles. Mine failed at 86K miles. It was a Pontiac but it died on the highway and I had to call a rollback. The FSM said to pull the engine to change it in a Fiero. Dealer cost was nearly $2K, back in the day. I cut a whole in the shock tower and assembled the gear puller through that. Total cost was one gear and one gasket set, plus one gear puller.
4. Chrysler 3.9L Magnum engines. A hair's width between the Intake and Exhaust valves. Every time I pulled, or had a head pulled, there was at least one crack at that spot in one or more cylinders. Valves would shift in their seats and you had an oil burner. The problem is so bad there are non-performance aftermarket heads available for the engine.
1. 351W. Had a nylon middle timing gear guaranteed to fail after the first overheat. Mine failed. Fortunately mine was not an interference engine, but my vehicle was still Found On Road Dead.
2. Chevy Vega engine. A lot of people don't know the aluminum engine was full of silicon nodules, etched and honed to make it wear harder. But they were brittle and broke off and you got a worn out bore in 30K miles. Plus the radiator was undersized and it had an aluminum block and an iron head, so it would blow its head gasket on the first inevitable overheat. It was pretty much designed to fail top and bottom by 30K.
3. Iron Duke. One steel timing gear meshed directly with one "phenolic resin composite" gear. Designed to fail in under 100K miles. Mine failed at 86K miles. It was a Pontiac but it died on the highway and I had to call a rollback. The FSM said to pull the engine to change it in a Fiero. Dealer cost was nearly $2K, back in the day. I cut a whole in the shock tower and assembled the gear puller through that. Total cost was one gear and one gasket set, plus one gear puller.
4. Chrysler 3.9L Magnum engines. A hair's width between the Intake and Exhaust valves. Every time I pulled, or had a head pulled, there was at least one crack at that spot in one or more cylinders. Valves would shift in their seats and you had an oil burner. The problem is so bad there are non-performance aftermarket heads available for the engine.
Originally Posted by 2004tdigls
the audi/VW V8 engine, garbage
https://jalopnik.com/here-s-why-the-v8-audi-s4-is-an-awful-used-car-1676466510
the engine has to be removed to complete repairs, nice
http://auditimingchainproblem.com/audi_4.2.html
Big engines in small bodies usually spells maintenance nightmares but these are especially evil. You better really know what you are doing before tangling with one of these.
It doesn't get much easier the second, third or tenth time you only know where the bolts and parts goes better.
On the other hand, if you are competent have a garage to work in and find an otherwise nice example they can be had for dirt cheap with the $8-12K (dealer price and not many indies can/will even attempt it) defect not done.
the audi/VW V8 engine, garbage
https://jalopnik.com/here-s-why-the-v8-audi-s4-is-an-awful-used-car-1676466510
the engine has to be removed to complete repairs, nice
http://auditimingchainproblem.com/audi_4.2.html
Big engines in small bodies usually spells maintenance nightmares but these are especially evil. You better really know what you are doing before tangling with one of these.
It doesn't get much easier the second, third or tenth time you only know where the bolts and parts goes better.
On the other hand, if you are competent have a garage to work in and find an otherwise nice example they can be had for dirt cheap with the $8-12K (dealer price and not many indies can/will even attempt it) defect not done.
No North Star oil burning, block leaking oil, blown head gasket owners? So common it's sad. These were high output motors for the 90s though. The water pump and starter mentioned earlier are some of the better parts of the motor.
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I gladly nominate the Subaru flat 4's up until at least 2015. With poor piston ring designs that lead to significant oil consumption and terrible head gasket problems that lead to a difficult and time consuming task.
But, as mentioned above the packaging of the engine probably matters more. V6 FWD setups often are impossible to deal with.
But, as mentioned above the packaging of the engine probably matters more. V6 FWD setups often are impossible to deal with.
Originally Posted by demarpaint
I had a 95 Caprice Classic with the 4.3L V8, what a load of crap that car was. It had the distributor cap and rotor behind the water pump. I often wondered how the person/people that would design something like that gets hired.
Our 1991 Caprice has a 5.0l / 305 ci engine . Traditional Small Block Chevy V-8 . Water pump and distributor where they always were .
Besides , with electronic ignition , little need to mess with the ignition / distributor . Unlike the old distributors with points & condenser .
I had a 95 Caprice Classic with the 4.3L V8, what a load of crap that car was. It had the distributor cap and rotor behind the water pump. I often wondered how the person/people that would design something like that gets hired.
Our 1991 Caprice has a 5.0l / 305 ci engine . Traditional Small Block Chevy V-8 . Water pump and distributor where they always were .
Besides , with electronic ignition , little need to mess with the ignition / distributor . Unlike the old distributors with points & condenser .
Originally Posted by Chris142
Originally Posted by pbm
The GM 3.1 was a good engine with a terrible LIM design....there weren't enough bolts to properly tighten it....
You ever done a thermostat on one?
Yep .
Originally Posted by pbm
The GM 3.1 was a good engine with a terrible LIM design....there weren't enough bolts to properly tighten it....
You ever done a thermostat on one?
Yep .
Anything where they tuck the engine under the windshield
Originally Posted by pbm
The GM 3.1 was a good engine with a terrible LIM design....there weren't enough bolts to properly tighten it....
The 3.1. the Chevy Luminas gave more transmission problems than engine problems .
The GM 3.1 was a good engine with a terrible LIM design....there weren't enough bolts to properly tighten it....
The 3.1. the Chevy Luminas gave more transmission problems than engine problems .
Originally Posted by Cujet
I gladly nominate the Subaru flat 4's up until at least 2015. With poor piston ring designs that lead to significant oil consumption and terrible head gasket problems that lead to a difficult and time consuming task.
But, as mentioned above the packaging of the engine probably matters more. V6 FWD setups often are impossible to deal with.
Many of the issues were caused by the open deck design as much as anything, The old closed deck EJ engines were very solid with few issues, they were the engines people came to love in the Subaru for their reliability.
I wish I knew the reason for going to and staying with an open deck block especially when specialty companies are making deck slugs for the open deck engines with great success..
I gladly nominate the Subaru flat 4's up until at least 2015. With poor piston ring designs that lead to significant oil consumption and terrible head gasket problems that lead to a difficult and time consuming task.
But, as mentioned above the packaging of the engine probably matters more. V6 FWD setups often are impossible to deal with.
Many of the issues were caused by the open deck design as much as anything, The old closed deck EJ engines were very solid with few issues, they were the engines people came to love in the Subaru for their reliability.
I wish I knew the reason for going to and staying with an open deck block especially when specialty companies are making deck slugs for the open deck engines with great success..
There's been some good ones here! Although the thread went a little off the rails talking about all designs problems, not just problem engines.
The ones I agree with:
Original intake gasket design on 3xxx/3800 SII and above. Terrible design flaw, along with the EGR stovepipe flaw on the 3800.
The Toyota 1UZ starter vs. the Northstar starter: N*? Intake off in 15 minutes. 1UZ? Plan on a day's job, easy. Also, the starter on the 1UZ bolts from the BELL HOUSING side! Who thought that was a good idea?
BMW alternator gaskets AND the M62 coolant crossover pipe gaskets. Terrible, terrible design.
GM Optispark ignition. Completely unnecessary.
Ford 3.5/3.7 water pump. Yes, a poor design. I have yet to replace one, however. And I see a LOT of those engines.
I'll add:
The Volvo/Yamaha 4.4 V8. Sweet, sweet engine with a major flaw: the balance shaft bearing at the rear of the block was originally a non-sealed design. When dealer's and detailer's would pressure wash the engine, water would work it's way down a hole in the block and rust the bearing solid, which usually happened while the engine was running. Bearing seizes, timing chain jumps, engine blows. Yamaha put a sealed bearing and drain hole in later blocks.
The electric water pump on the BMW N54 twin turbo. I haven't had to do one, but I watched my co-worker fight with one for hours. Why, oh why BMW.
The ones I agree with:
Original intake gasket design on 3xxx/3800 SII and above. Terrible design flaw, along with the EGR stovepipe flaw on the 3800.
The Toyota 1UZ starter vs. the Northstar starter: N*? Intake off in 15 minutes. 1UZ? Plan on a day's job, easy. Also, the starter on the 1UZ bolts from the BELL HOUSING side! Who thought that was a good idea?
BMW alternator gaskets AND the M62 coolant crossover pipe gaskets. Terrible, terrible design.
GM Optispark ignition. Completely unnecessary.
Ford 3.5/3.7 water pump. Yes, a poor design. I have yet to replace one, however. And I see a LOT of those engines.
I'll add:
The Volvo/Yamaha 4.4 V8. Sweet, sweet engine with a major flaw: the balance shaft bearing at the rear of the block was originally a non-sealed design. When dealer's and detailer's would pressure wash the engine, water would work it's way down a hole in the block and rust the bearing solid, which usually happened while the engine was running. Bearing seizes, timing chain jumps, engine blows. Yamaha put a sealed bearing and drain hole in later blocks.
The electric water pump on the BMW N54 twin turbo. I haven't had to do one, but I watched my co-worker fight with one for hours. Why, oh why BMW.
Originally Posted by Chris142
You ever done a thermostat on one?
Used to have a Buick Century and did that job once. Didn't think it would be that big a deal until I got started. Push the wrench a little, flip it over, push the wrench a little, flip it over, rinse, repeat, a whole bunch of times. At least I didn't have to drop it and pick it up like the poster above had to.
You ever done a thermostat on one?
Used to have a Buick Century and did that job once. Didn't think it would be that big a deal until I got started. Push the wrench a little, flip it over, push the wrench a little, flip it over, rinse, repeat, a whole bunch of times. At least I didn't have to drop it and pick it up like the poster above had to.
Originally Posted by HangFire
Originally Posted by kschachn
Originally Posted by ZZman
Yep, Chrysler 2.7 is a joke. If you do the water pump or timing belt you might as well replace the other.
The Chrysler 2.7 had a timing chain however.
The Chrysler 2.7 suffered from early timing chain tension failure however.
My bad. You are correct they have a chain. We owned 3 Sebrings with 2.7 engines. Thankfuly the water pumps never failed. Thanks for the correction.
Originally Posted by kschachn
Originally Posted by ZZman
Yep, Chrysler 2.7 is a joke. If you do the water pump or timing belt you might as well replace the other.
The Chrysler 2.7 had a timing chain however.
The Chrysler 2.7 suffered from early timing chain tension failure however.
My bad. You are correct they have a chain. We owned 3 Sebrings with 2.7 engines. Thankfuly the water pumps never failed. Thanks for the correction.
Originally Posted by 14Accent
There's been some good ones here! Although the thread went a little off the rails talking about all designs problems, not just problem engines.
The ones I agree with:
Original intake gasket design on 3xxx/3800 SII and above. Terrible design flaw, along with the EGR stovepipe flaw on the 3800.
The Toyota 1UZ starter vs. the Northstar starter: N*? Intake off in 15 minutes. 1UZ? Plan on a day's job, easy. Also, the starter on the 1UZ bolts from the BELL HOUSING side! Who thought that was a good idea?
BMW alternator gaskets AND the M62 coolant crossover pipe gaskets. Terrible, terrible design.
GM Optispark ignition. Completely unnecessary.
Ford 3.5/3.7 water pump. Yes, a poor design. I have yet to replace one, however. And I see a LOT of those engines.
I'll add:
The Volvo/Yamaha 4.4 V8. Sweet, sweet engine with a major flaw: the balance shaft bearing at the rear of the block was originally a non-sealed design. When dealer's and detailer's would pressure wash the engine, water would work it's way down a hole in the block and rust the bearing solid, which usually happened while the engine was running. Bearing seizes, timing chain jumps, engine blows. Yamaha put a sealed bearing and drain hole in later blocks.
The electric water pump on the BMW N54 twin turbo. I haven't had to do one, but I watched my co-worker fight with one for hours. Why, oh why BMW.
Those water pumps on the n54 aren't bad I have done a few but not in a long time. It was on a 335i.
Any duramax powered van is terrible. 40+hrs for a head job. I pull the entire bodies right off the chassis like a cab off. Cut it to about 18 hrs that way.
The 6.7 powerstroke is very tight in its chassis and makes it difficult for in depth repairs especially in a rescue chassis where the cab cannot be removed.
There's been some good ones here! Although the thread went a little off the rails talking about all designs problems, not just problem engines.
The ones I agree with:
Original intake gasket design on 3xxx/3800 SII and above. Terrible design flaw, along with the EGR stovepipe flaw on the 3800.
The Toyota 1UZ starter vs. the Northstar starter: N*? Intake off in 15 minutes. 1UZ? Plan on a day's job, easy. Also, the starter on the 1UZ bolts from the BELL HOUSING side! Who thought that was a good idea?
BMW alternator gaskets AND the M62 coolant crossover pipe gaskets. Terrible, terrible design.
GM Optispark ignition. Completely unnecessary.
Ford 3.5/3.7 water pump. Yes, a poor design. I have yet to replace one, however. And I see a LOT of those engines.
I'll add:
The Volvo/Yamaha 4.4 V8. Sweet, sweet engine with a major flaw: the balance shaft bearing at the rear of the block was originally a non-sealed design. When dealer's and detailer's would pressure wash the engine, water would work it's way down a hole in the block and rust the bearing solid, which usually happened while the engine was running. Bearing seizes, timing chain jumps, engine blows. Yamaha put a sealed bearing and drain hole in later blocks.
The electric water pump on the BMW N54 twin turbo. I haven't had to do one, but I watched my co-worker fight with one for hours. Why, oh why BMW.
Those water pumps on the n54 aren't bad I have done a few but not in a long time. It was on a 335i.
Any duramax powered van is terrible. 40+hrs for a head job. I pull the entire bodies right off the chassis like a cab off. Cut it to about 18 hrs that way.
The 6.7 powerstroke is very tight in its chassis and makes it difficult for in depth repairs especially in a rescue chassis where the cab cannot be removed.
I've had issues with the GM AFM stuff, 3 times in one truck and once in another.
My entries:
1. Ford 4.6/5.4L 2 valve that didn't have enough threads to keep the spark plug in the head, resulting in the spark plug being ejected (admittedly it was mostly a problem after a DIY spark plug change, but still).
2. Ford bested that with the 4.6/5.4L 3 valve where the spark plugs wouldn't come OUT due to carbon build up and a 2 piece plug design, remedied in later models. At least they weren't being blown out of the head? Oh, and the cam phaser issues.
3. Anything to do with the 2.5L Mazda CX-7. Nothing like having to half way remove the engine to get a serpentine belt replaced, and corrosion is everywhere. They built a trap door in the plastic pan underneath to drain the oil, nice, but not the filter? You have to completely remove the thing anyway. Changing a headlight becomes an all day affair, which apparently needs to happen about every 4 months. A/C compressor replacement takes less time if you remove the engine. It's buzzy, rides like a dump truck, has a baffling and horrendous interior. It literally does nothing well except fuel mileage, but you pay a penalty everywhere else. Easily our most regrettable purchase.
4. 1.9T Volvo S40 flame trap/PCV service.....They would block up and cause crankcase pressure, blow out all the seals, requires removal of most of the accessories, intake, hoses, etc. to service. VVT actuator would fail religiously, cam seals leaked like a sieve. Motor mounts require replacement often.
My entries:
1. Ford 4.6/5.4L 2 valve that didn't have enough threads to keep the spark plug in the head, resulting in the spark plug being ejected (admittedly it was mostly a problem after a DIY spark plug change, but still).
2. Ford bested that with the 4.6/5.4L 3 valve where the spark plugs wouldn't come OUT due to carbon build up and a 2 piece plug design, remedied in later models. At least they weren't being blown out of the head? Oh, and the cam phaser issues.
3. Anything to do with the 2.5L Mazda CX-7. Nothing like having to half way remove the engine to get a serpentine belt replaced, and corrosion is everywhere. They built a trap door in the plastic pan underneath to drain the oil, nice, but not the filter? You have to completely remove the thing anyway. Changing a headlight becomes an all day affair, which apparently needs to happen about every 4 months. A/C compressor replacement takes less time if you remove the engine. It's buzzy, rides like a dump truck, has a baffling and horrendous interior. It literally does nothing well except fuel mileage, but you pay a penalty everywhere else. Easily our most regrettable purchase.
4. 1.9T Volvo S40 flame trap/PCV service.....They would block up and cause crankcase pressure, blow out all the seals, requires removal of most of the accessories, intake, hoses, etc. to service. VVT actuator would fail religiously, cam seals leaked like a sieve. Motor mounts require replacement often.
I nominate the GM LT1 of the 1990's. I only had my Vette a few years and never really had any problems out of mine, but man lots of other people sure did. The optisparks were an expensive abomination against humanity, almost impossible to get to without several hours of surgery, and putting it underneath the typical 1990's GM quality water pump was a big bowl of stupid with stupid sprinkles wrapped up in a big ball of stupid topped with stupid sauce.
For the runner up, I have to leave the automotive world and nominate the Mercruiser 3.7 four cylinder boat engine. Iron head off a Ford 460, on top of a Mercruiser aluminum open deck block, running 460 pistons cranking a tractor crankshaft. Topped off with a GM distributor and quadrajet carb, a water pump which was an impeller bolted to the end of the camshaft that separated the crankcase and water jacket with tiny seal riding on the corrosion prone camshaft surface, and fitted with a crankshaft mounted permanent magnet alternator that sent excess output to a block mounted water cooled carbon pile voltage regulator whose claim to fame was an amazing ability to boil high dollar marine batteries at a conveniently rapid pace. A fuel sipping high-torque beast, I'll give it that, and when new they were reliable and powerful little monsters. But after just a few short years in stock form and even a tiny lack of nonstop attention what a maintenance turd that lump of metal became. With a fully loaded checkbook, a bit of OCD and a strong desire to tinker, they can be made to be reliable and you can get a good deal of HP out of them, but in stock form and with 3 more years of boat payments staring at them, the average owner was probably suffering major depression, drinking heavily and considering leaving the boating world after a few short seasons of ownership. Putting it mildly.
For the runner up, I have to leave the automotive world and nominate the Mercruiser 3.7 four cylinder boat engine. Iron head off a Ford 460, on top of a Mercruiser aluminum open deck block, running 460 pistons cranking a tractor crankshaft. Topped off with a GM distributor and quadrajet carb, a water pump which was an impeller bolted to the end of the camshaft that separated the crankcase and water jacket with tiny seal riding on the corrosion prone camshaft surface, and fitted with a crankshaft mounted permanent magnet alternator that sent excess output to a block mounted water cooled carbon pile voltage regulator whose claim to fame was an amazing ability to boil high dollar marine batteries at a conveniently rapid pace. A fuel sipping high-torque beast, I'll give it that, and when new they were reliable and powerful little monsters. But after just a few short years in stock form and even a tiny lack of nonstop attention what a maintenance turd that lump of metal became. With a fully loaded checkbook, a bit of OCD and a strong desire to tinker, they can be made to be reliable and you can get a good deal of HP out of them, but in stock form and with 3 more years of boat payments staring at them, the average owner was probably suffering major depression, drinking heavily and considering leaving the boating world after a few short seasons of ownership. Putting it mildly.
Originally Posted by slacktide_bitog
Anything where they tuck the engine under the windshield
+1
I would add those where the alternator is not removable within 5 minutes.
Anything where they tuck the engine under the windshield
+1
I would add those where the alternator is not removable within 5 minutes.
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