Engine Question...- internal cleaning?

[NC_John]

I just ordered the parts to pull and reseal the 350 in the '70. Its running great and doesn't seem to burn any oil, but leaks a ton! I have zero tolerance for leaks so its coming out to be resealed.

I've got new gaskets all around, new seals etc. While its open I'm replacing the timing set and oil pump but nothing else. If I can get another year or two out of it before a real rebuild, I'll be able to get a bunch of other stuff done on the truck first.

I'm going to pull it out of the truck to do this but before I yank it, I'm wondering if there is anything I can put in the oil and coolant and run through it to do a "pre-cleaning" to try to dissolve what I would expect to be a lot of sludge and crap in the oil galleys/passages and in the cooling jackets. I usually don't like that stuff, BUT, since the engine is coming out, I should be able to do a decent job of making sure its all drained out and cleaned out before I button it back up.

Worth the effort or just scrape out what I can get to??

[chevytruckguy70]

Thats a question that has been asked ever since the engine was invented and you will probably get a hundred different opinions on the subject. In my humble opinion and experience from a few attempts at what you are asking I'd have to say do not in any way try to "flush out" the engine with any cleaner of any sort.

The reason being is that as your engine heated up and cooled down the used oil would leave deposits on all the surfaces which over time harden up and start to close oil ports. Just like cholesterol in your veins. And just for the same reason DRs do not scrape or run cleaners through your veins to loosen the cholesterol I would not scrape or run cleaners through your engine. Yes there may be a slow down of oil running through your engine now, but cleaners will cause this hard deposits to slowly loosen up (well after you have put you engine back together) and the pieces that come off will end up blocking off all oil flow in cam or crank bearings and lifters or even clog your oil pump screen.

My experience with this is that if you are not fully tearing the engine apart and cleaning everything then only clean the gasket surfaces and put it back together.

[trac209]

The only way is to strip it down and get it hot tanked really. You can try some of the engine flush products but I doubt they really do anything. I've found if your not rebuilding it just change the seals and leave it alone your just going to have stuff all around loose in there if your not taking it all apart. My two cents^^^^^^ beat me to it lol

[joesgreen67]

Just put a hand full of sand down the carb to "sandblast" it....

JUST KIDDING!! haha

Seriously I wouldnt run any cleaner of any kind through it. Since your pulling the entire engine you'll be pulling off the oil pan, right? You'll be able to clean the sludge out of the pan with it off way better anyways.

[MARKDTN]

I have heard of all kind of crazy stuff-kerosine, ATF, even milk. In my experience leave it alone. If you can't take it down and tank it, you are just wasting time and may do damage.

I used to put used engines in as a weekend business. Bought a TBI Dodge 318 to put in an earlier carbureted truck. I did my usual oil pump, strainer, and timing chain while it was out. When I pulled the intake to swap it, I noticed a lot of stuff in the lifter gallery so I put the engine on a stand and pressure washed it extensively and dried it with compressed air. Put it together and about a day later it came back with no oil pressure. Turns out all that gunk that got loose but didn't get out was trapped at the pickup screen and it was starving for oil. I got out easy with just another pickup screen, but from then on I don't try to get gunk out of a complete engine.

[NC_John]

Good points fellas. I'll leave it alone so I don't end up having to rebuild it 1,000 miles after resealing it!

Thanks for the input!

[sublime1996525]

I have good luck with Seafoam on newer cars, ie I've got check engine lights to turn off and better gas mileage. I wouldn't hurt to give it a shot.

[trac209]

Originally Posted by sublime1996525

I have good luck with Seafoam on newer cars, ie I've got check engine lights to turn off and better gas mileage. I wouldn't hurt to give it a shot.

Never put seafoam in your engines crankcase unless your trying to kill it.

[mmiddle]

Marvel-Mystry oil. or a little diesel. Your best bet it to leave it a lone.

[sublime1996525]

Originally Posted by trac209

Never put seafoam in your engines crankcase unless your trying to kill it.

I've have no problems with that before. Just change the oil after 100 miles or so. Can I ask why?

[MARKDTN]

Originally Posted by sublime1996525

I've have no problems with that before. Just change the oil after 100 miles or so. Can I ask why?

See my post above