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Good evening, as my login indicates I have A Lemans 66 OHC6. I have it since last year. The previous owner had it for several years and hardly drove it. I noticed a significant amount of smoke coming out of the breather. I also have oil on the floor of garage. When I took it in for the AC and an oil change I asked them to check for a leak. The mechanic said there’s a minor leak from the fuel pump gasket. Then he showed me all the oil coming down the breather pipe. Thinking the little use previously caused the rings to get gunned up; We discussed using an engine flush, I think EPR. It was suggested to wait till the next oil change. I was back this week and they checked for a PCV valve. I had thought there wasn’t one. He found it and checked it to be ok. Now they are talking about a ring job. My problem is I don’t want the car sitting outside the shop while the engine is sent out. Would using marvel mystery oil or the flush cause anymore damage? I’m thinking trying that first.
thanks for your thoughts.
Bob
 

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When I pick up my 67 Tempest 326, the engine was all sludged up. I was very paranoid about flushing it from all the so called pros and cons you find on the dark web. I researched and what I ended up doing was running the engine with straight ATF to clean it out.

I drained the oil and installed a new filter. Filled with 5 qt of ATF. I ran the car at mostly idle and gently brought the RPMs up a few hundred then let it go back to idle (about 1100rpms). I kept a very close eye on oil pressure. After running for 25 minutes I noticed the oil pressure dropped 3 lbs so I shut it down. I take that to mean the oil was getting thin as she heated up. I then changed out the ATF and filter with a standard oil change. It was pretty dirty when I drained it. I run 20w-50 as I live in a very hot climate. I change oil about every 3000. No question this cleaned everything out.

When I first got the car I thought I was in for a ring job. After doing the flush and regular oil changes I see no reason to rebuild for mechanical reasons as she runs like a top now. I use maybe a half quart between oil changes but I do have a leaky oil pan so that may be some of it. This procedure would not be a fix for a bad engine but it did no harm to mine. I would do this again on a vehicle if I Needed to.

Also one thing I do to keep the engine from sludge beside a good oil, I never run the car for short periods if I can avoid it. I make sure I drive the car and bring it up to operating temp to burn out any contaminates in the crankcase.

Jim
 

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Maybe a little mystery oil in the cylinders to free up the rings since they may be sticking. Let it soak for a few days.
You may want to get some second opinions over on the PY forum. There's a few OHC experts there. The more information you have, the easier the decision.
 

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Very common issue with our OHCs
Here is a post on our FB forum that should assist;

 
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