Engine needs a rebuild?

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Brian Bearor

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Took a 30 mile drive last weekend and smoked a ton. Under acceleration and just driving. Used a quart of oil.

Then yesterday a short drive and minimum smoke after warm up.

Am I missing anything or is the blow by enough indication that a rebuild is necessary?
 
What Oil are you using? Slant 6? Compression check? Leakdown? Miles? Original?
Slant 6, Castrol GTX high mileage 10w40, supposedly 63k, purchased in the summer, did sit for a bit without use, original engine, have not completed a compression test yet.
 
For starters, change oil and filter to 20w50 Valvoline Racing. Might be valve guide seals. May just need to be run more. Good tune, starts easy? Nice low mileage slant six should run forever. Maybe a sticking PCV valve.
 
For starters, change oil and filter to 20w50 Valvoline Racing. Might be valve guide seals. May just need to be run more. Good tune, starts easy? Nice low mileage slant six should run forever. Maybe a sticking PCV valve.
I will give it a shot thanks. Cold starts are an issue due to a bad sensor. After warm runs excellent and starts easily.
 
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Thanks. Would that effect cold running if in operable?

It could. First thing to check is if the choke is closing when cold, can be checked with engine off. Second thing is if the vacuum pull off holds vacuum. Next is if the vacuum pull off is opening the choke slightly when it starts. Last is if the choke is fully open when at operating temp.
 
What you're experiencing isn't blowby. Blowby is when compression gets past the rings into the crankcase. That's not what's happening. You're getting oil past the rings into the combustion chamber and it's burning and going out the exhaust. Only a few things can contribute and the most likely is worn rings, valve stem seals and or valve guides. The PCV system being inoperative can also cause some, but it will not be as pronounced. Does it smoke heavily on acceleration? If it does, that's most likely worn rings. Has the car sat up for any length of time?
 
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What you're experiencing isn't blowby. Blowby is when compression gets past the rings into the crankcase. That's not what's happening. You're getting oil past the rings into the combustion chamber and it's burning and going out the exhaust. Only a few things can contribute and the most likely is worn rings, valve stem seals and or valve guides. The PCV system being inoperative can also cause some, but it will not be as pronounced. Does it smoke heavily on acceleration? If it does, that's most likely worn rings. Has the car sat up for any length of time?
Before I purchased it did sit. I put less that 1k on it
 
Before I purchased it did sit. I put less that 1k on it
In that case, what I would do is get a can of Seafoam and add to the gas tank and one to the crankcase oil. Then drive the wheels off it. You can also take a third can and dribble it down the carburetor while keeping the idle around 2500. It's gonna smoke REALLY bad, but that will help clean the combustion chambers out. Don't do it idling too low. You can actually hydrolock the engine if you don't keep the idle up. Seafoam is good stuff. It might clear up and be ok.
 
What you're experiencing isn't blowby. Blowby is when compression gets past the rings into the crankcase. That's not what's happening. You're getting oil past the rings into the combustion chamber and it's burning and going out the exhaust. Only a few things can contribute and the most likely is worn rings, valve stem seals and or valve guides. The PCV system being inoperative can also cause some, but it will not be as pronounced. Does it smoke heavily on acceleration? If it does, that's most likely worn rings. Has the car sat up for any length of time?
I am running an oil treatment currently. Would you recommend an oil change before adding seafoam?
 
What you're experiencing isn't blowby. Blowby is when compression gets past the rings into the crankcase. That's not what's happening. You're getting oil past the rings into the combustion chamber and it's burning and going out the exhaust. Only a few things can contribute and the most likely is worn rings, valve stem seals and or valve guides. The PCV system being inoperative can also cause some, but it will not be as pronounced. Does it smoke heavily on acceleration? If it does, that's most likely worn rings. Has the car sat up for any length of time?
Last sentence was the my first thought when reading the op opener post.
Light surface rust in a cyl from moisture getting in. Choke is a good idea too, also the heat flapper/stove in the exhaust manifold if theres a perf issue along with it.
 
Assuming blue smoke considing you said it used alot of oil, but could be leaking too. Black smoke would be more indicative of fuel problems. I'd be a little concerened about additives in a can. Mine sat for a long time befor I got it and had a poorly rebuild carb when I got it. I think it thinned out the oil and loosened a bunch of old sludge and did clog the oil filter. Got luckly and didn't do any long term damage.
 
In that case, what I would do is get a can of Seafoam and add to the gas tank and one to the crankcase oil. Then drive the wheels off it. You can also take a third can and dribble it down the carburetor while keeping the idle around 2500. It's gonna smoke REALLY bad, but that will help clean the combustion chambers out. Don't do it idling too low. You can actually hydrolock the engine if you don't keep the idle up. Seafoam is good stuff. It might clear up and be ok.
Tried the treatment. After running 20 miles it fowled the plugs. Pulled them and they were covered with chunks little of oil and oil. Replacing the plugs. Definitely loosened something up. Should I just run or try another treatment?
 
Tried the treatment. After running 20 miles it fowled the plugs. Pulled them and they were covered with chunks little of oil and oil. Replacing the plugs. Definitely loosened something up. Should I just run or try another treatment?
Sounds like a lot of carbon buildup. I would run it for a bit and recheck the new plugs.

...but 20 miles is the tip of the iceberg with the driving you need to do.
 
Sounds like a lot of carbon buildup. I would run it for a bit and recheck the new plugs.

...but 20 miles is the tip of the iceberg with the driving you need to do.
Thank you. Appreciate it.
Do you know of a source for replacement intake and exhaust manifolds?
 
In that case, what I would do is get a can of Seafoam and add to the gas tank and one to the crankcase oil. Then drive the wheels off it. You can also take a third can and dribble it down the carburetor while keeping the idle around 2500. It's gonna smoke REALLY bad, but that will help clean the combustion chambers out. Don't do it idling too low. You can actually hydrolock the engine if you don't keep the idle up. Seafoam is good stuff. It might clear up and be ok.

We used to do the same with ATF, then about 8 oz of water dribbled in at about your 2500 rpm idle to blow the gunk out. Same warnings.
 
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I suggest doing some checks, compression test, (wet and dry, do it correctly with throttle plate wide open ignition disabled etc.) hook up a vacuum guage, pull and inspect plugs etc. A bit of diagnostics will point you in the direction.

You can run the seafoam in the meanwhile and drive it, consider that part of the diagnostic process.
 
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