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major engine issues with my 74 buick


Guest classic.car.fan

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Guest classic.car.fan

my 74 electra.. first time i have ever started it. anyway it is very difficult to start takes a few tries to get it going and when it does it makes a horrible very loud rapid knocking sound and shakes( i will post a video tomorrow) and the motor only stays running for like a min. then it dies. also it is spitting oil and gas. what is wrong? is the engine shot? or is it a rod knock? should i even bother working on it or just junk it? thanks

Edited by classic.car.fan (see edit history)
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Hogwash.

Yes, there may be big problems or it might just be out of time. Nobody can diagnose it here, without being there to hear it run. First, run a compression test. Check the timing with a light. Make sure the plug wires are on the correct plugs. Check all of the easy stuff first.

Don't overlook the obvious in search of the obscure

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Running a compression check will not "punch a hole" in the block. If he's that afraid, he can do a static check of the timing. Close enough to get it running if it's way out. An engine with mixed up plug wires or one that is badly out of time will make quite a racket. Bad lifters are another thing to consider, too. The possibility also exists that the engine has crapped the bed, but he needs to eliminate all the other, less than fatal, problems

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I agree with 58Mustang--check the easy stuff first before you write it off. Yes, it's possible that everything inside is bad, but if it's been sitting for a long time, there can be a lot of other stuff going wrong that would cause mischief. We recently brought a bunch of '60s and '70s cars out of long-term hibernation, and they all smoked, belched, rumbled, and made one hell of a racket when they first fired up. The lifters will sound like they're ready to fly out of the block before they pump up, which could take a few minutes. If there's a knock, then maybe it's bad news, but until you have it running smoothly enough to eliminate other sounds you won't know for certain. Even if it does have a knock, you probably won't grenade the motor and wreck the block unless you rev it up aggressively. Idle probably won't do serious damage even if something lets go (and I don't think it will).

Do you have a manual? Set and check everything you can--timing, plugs, carburetor, compression, leak-down, etc--before you turn the key again to give it the best possible chance for running. If it starts, fine-tune it to narrow down the sounds and issues. If the knock persists after it smooths out and gets full oil pressure, then yes, it's probably going to need a rebuild. But eliminate the easy, cheap stuff before you go tearing into the bottom end.

Good luck and let us know what you find.

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I have to agree with John and Matt; no harm should come to the engine (usually) if one troubleshoots with a little care. The history and

tendencies of the car, and its last owner, would be helpful to we website analysts. Just offhand, I am for some reason tending to think

timing chain or sprockets may not be in order. Also, I believe the symptoms are sometimes indicative of a distributor pulled out, then placed

in a few teeth, or 180 degrees, out of phase. On Fords, I have seen the roll pin which anchors the distributor driive gear in place, sheer. This can be

really puzzling, since the gear will come tight on scored distributor shaft, which makes one think it is tight, occasionally returning to its

original position, at which time the vehicle may suddenly, but temporarily, run fine! Very speculative offerings, but the best a remote philosopher can answer.

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There could be a hundred things wrong, some of them trivial, some disastrous. There is no way to know for sure without a careful inspection and diagnosis by an expert mechanic. Hopefully, an old gray haired or bald headed one who knows the old cars.

Anything an amateur can do will only ball things up and make it harder and way more expensive for the mechanic to fix it. So, tow it to the garage and get it checked out. It may only need a good tuneup and the carb cleaned.

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i did pull them. the plugs and the plug wires look really bad. i'm going to replace them tomorrow

Pictures would be nice. Were any damaged or look significantly different than others? Were some oily and others dry?

Good time to check static timing to see if timing mark and distributor rotor line up. And...................

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Guest classic.car.fan
Pictures would be nice. Were any damaged or look significantly different than others? Were some oily and others dry?

Good time to check static timing to see if timing mark and distributor rotor line up. And...................

i will try to post photos tomorrow. yes 3 of the spark plugs were all covered in oil and in very bad shape. and the others were dry.

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Guest classic.car.fan
Time for an update, Got those valve covers off yet and pics of those spark plugs?

not yet, it's been raining a lot here. hopefully i can take the valve covers off and get the pics tomorrow.

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  • 3 weeks later...
Guest classic.car.fan

update. thought i would start it once more. and the carb started to catch on fire. luckily i had a damp towel. so i was able to put it out :D anyway my focus right now is too work on my mark V. but when i do get around to working on the buick i will post on this thread.

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Guest classic.car.fan
Next step, remove valve covers and check for loose rockers and bent pushtubes.

valve covers are off. everything looks ok

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Focus on the 3 cylinders that had oil fouled plugs. Remove the coil wire and have someone crank the engine while you watch rocker action, especially those 3 cylinders. There should be something irregular going on, short travel or pushtube wobbling,etc. It may not be obvious to the untrained eye.

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  • 6 months later...
Guest classic.car.fan

alright while it's been awhile since i did anything with the buick. today i took another look at the rockers. somehow i missed it the last time i looked. but one of the rockers is very loose. i assume they are not supposed to move this much?. here is a video. the one at 5 seconds is the worst

how do i tighten these? there are no bolts on them like a lot of others have. Edited by classic.car.fan (see edit history)
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Looks like the lifters are collapsed and not pumping up. Usually is a sign that there is wear to the point that there are holes worn though the bottom where they ride on the cam. And the cam is most likely also worn. Not the end of the world. A new replacement cam and lifters can be had reasonable. If you chose to fix it, be sure to add zinc additive to the oil. The older GM's also had plastic teeth on the original timing gears. Not uncommon for them to come apart. Replacements are solid gears. Best to replace this also while you are at it. Dandy Dave.

Edited by Dandy Dave (see edit history)
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alright while it's been awhile since i did anything with the buick. today i took another look at the rockers. somehow i missed it the last time i looked. but one of the rockers is very loose. i assume they are not supposed to move this much?. here is a video. the one at 5 seconds is the worst
how do i tighten these? there are no bolts on them like a lot of others have.

unbolt and remove the entire rocker assembly. Look for a valve spring that sets up higher than the others, that will be the one that dropped the head off the valve. If you find one spring setting lower than the others, that one is bent and is probably on the same cylinder. Pulling the head off that bank would be next step.

Please post some pics after removing rocker assembly, I can't download videos with my setup.

Edited by TexasJohn55 (see edit history)
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Long distance, Braille engine diagnosis is an art practiced well by few. You came asking for opinions and help. Here are my thoughts: Stop taking your engine apart. Find and make the acquaintance of a local-to-you old car guy. Tell him your story and ask if he knows someone that has a long and substantial reputation for fixing things, specifically late-ish-model GM engines. You might even stumble across the old, senior, recently retired head mechanic at the local Buick dealership. Go to that guy and offer to pay him to come and look at your engine. Think about what he says, look and read about it in a service manual on your particular engine, think some more and then make some repairs, pausing as needed to consult in person with your new friend. Come back and tell us your tale.

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It could just be a stuck lifter that will free up with a few minutes running. Hard to tell for sure without inspecting the engine.

I would be checking the points (if it has them) and distributor, timing, and make sure the plug wires are installed correctly, to the right cylinders. Then I would check if the carb is getting gas, and is not full of old stinky gas, and that the gas in the tank is good.

If the loose rocker is only slightly loose (like, less than .050") it is probably a stuck lifter that will come free with a little running once it gets some oil to it.

In that case I would try starting and running the engine till it warms up.

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Guest classic.car.fan
unbolt and remove the entire rocker assembly. Look for a valve spring that sets up higher than the others, that will be the one that dropped the head off the valve. If you find one spring setting lower than the others, that one is bent and is probably on the same cylinder. Pulling the head off that bank would be next step.

Please post some pics after removing rocker assembly, I can't download videos with my setup.

alright i removed the assembly. the 2 in the middle are lower then the others. post-97794-143142755791_thumb.png

post-97794-143142755778_thumb.png

post-97794-143142755778_thumb.png

post-97794-143142755791_thumb.png

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Guest classic.car.fan
unbolt and remove the entire rocker assembly. Look for a valve spring that sets up higher than the others, that will be the one that dropped the head off the valve. If you find one spring setting lower than the others, that one is bent and is probably on the same cylinder. Pulling the head off that bank would be next step.

Please post some pics after removing rocker assembly, I can't download videos with my setup.

alright i removed the assembly. the 2 in the middle are lower then the otherspost-97794-143142755832_thumb.png

post-97794-143142755822_thumb.png

post-97794-143142755822_thumb.png

post-97794-143142755832_thumb.png

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Could be that the valves are stuck from sitting. Spray them with a penetrating oil. Then tap on them with a hammer. If they are free you will feel it. If not, then spray them and tap on them every once in a while. Dandy Dave!

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See if any springs can be easily rotated by hand, then grab each valve spring retainer with channeloks or vice grips and see if any will pull out of the head.You could alsomeasure the distance from retainer to the spring seat surface on the head to see if any are too high. Rapping each one with a hammer will ensure each returns to seat normally each time. Don't try to drive them thru the head because some pistons may be near top of travel and the valve will strike the piston.

PS: If any valves high enough to have little or no tension on the spring AND the spring is not broken, that valve has dropped the head off the stem and will usually pull out of the head. The two low valves are simply badly bent.

PPS: lift out each pushtube one at a time and roll them on a flat surface, make note of which ones are bent.

Edited by TexasJohn55 (see edit history)
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  • 3 weeks later...
Guest classic.car.fan

good news. yesterday i sprayed some penetrating fluid on the the lifters that were lower. and hit them with a hammer. i started the car and it was knocking but not as bad as before. i revved the engine a bit and it stopped knocking! started it up again a few more times and the knock is gone! thanks for all the help you guys.

Edited by classic.car.fan (see edit history)
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