Dealing with an engine with oil blow-by - hoping for some thoughts and coaching on options |
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Dealing with an engine with oil blow-by - hoping for some thoughts and coaching on options |
Tdskip |
Jun 25 2019, 01:13 PM
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#21
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Advanced Member Group: Members Posts: 3,686 Joined: 1-December 17 From: soCal Member No.: 21,666 Region Association: None |
OK - so here is the scoop on the '74 AZ car that has me about to learn new things.
This is the car that has the 2.0l case with 1.8 heads. Runs strong, good pulling power, no bad noises, and has good oil pressure. Came to me with a recently put together engine with no guarantees but believed to be redone heads and fresh bottom end. Price was right on everything so I bought it, no regrets. The issue I am seeing is that the engine has too much blow-by. After a short time (under 30 miles) it started smoking very noticeably from the breather and blew out the oil seal on the breather tower. Since then I've changed the oil and done more heat cycling and it's smoking significantly less (barely noticable now) but I still have too much blow-by. I don't think I have much to loose by driving it some more and seeing if the rings seat better but I am working on the expectation that isn't going to work. Assuming the most likely case, which is that the rings don't seat any better, I believe I would need to pull the heads and pistons off and start again. Yes/no? Should I be thinking of just replacing the jugs and pistons with a new set from AA or do these clean up (in general). I believe replacement is the usual approach these days. I think I would plan to send the heads out for servicing as a precaution so I know I have good ones with good oil control going back on. Assembly from this point should be pretty straight forward I'd think? Thanks, appreciate the continuing education here. |
Tdskip |
Jun 28 2019, 07:22 AM
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#22
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Advanced Member Group: Members Posts: 3,686 Joined: 1-December 17 From: soCal Member No.: 21,666 Region Association: None |
@IronHillRestorations
@tejon007 @jcd914 @rhodyguy First of all, good morning and happy Friday gentlemen. I drove this car quite a bit yesterday and heat cycled the engine, did lots of rolling full throttle acceleration pulls and no change in the blow-by. I didn’t really expect it to suddenly improve but not much to lose by giving it another go. Going to pull the plugs today and see if I can find out which cylinder is problematic, but the thing that has me scratching my head is that it actually runs well and has quite good power and doesn’t smoke out the tailpipe Even taking into account that this car is somewhat stripped , and is thus a bit lighter, the engine feels really healthy and strong even with the single Weber. So with all that in mind here is the question that I was hoping to get some thoughts on-I think it’s one that’s relevant to the knowledge base here in general which is also why am asking - how can this thing be making good power if the problem is with the rings? I would have thought that if the rings are letting this much blow by happen that it would also be impacting compression to a point where the engine would be off song. For education purposes other than rings, what internal to the engine would cause excessive crank case pressure? |
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