Excessive smoke from breather tubes

[Stuski]

Chrysler LM 318 engine lots of smoke from breather and dipstick tubes. Compression check revealed good numbers. Motor has tubes from valve covers to flame arrestor no PCV system that I can see. Edelbrock 1409 carbs. Can't understand why I have good compression but a lot of blow by. Port side normal. Motor had valve job some time ago but was run very little until lately. Took it out twice and last time noticed smoke when back at dock. Thought I heard pinging when trying to wind it up. Wouldn't get above 290o rpm. Port side 3500+. Seems like a lot of smoke to be feeding into the carb. Perhaps that causes the pinging?
Also seems to be pushing water out of the cap. I see bubbles in exp. tank with cap off. Could head gasket leak have anything to do with blow by?
At this point thought I may try and torque the head a bit more. Was done to 85 ft. lbs. but I see addendum in manual that says 105 ft. lbs. Can torqueing head more cause more problems with the gasket. I feel I have nothing to lose as I may be yanking the engines for a couple of new long blocks soon if my rings have problems anyway.


Any thought or suggestions would be appreciated.

Best, Stu

 

[Walt T]

Re: Excessive smoke from breather tubes

Oil control rings going / gone bad can cause that without compression numbers being too bad. Doesnt take a much compression blow by to make it look like a lot. No it wont ping on the smoke. No do not retorque the heads. You most likely will cause a problem. This coupled with cap getting pushed open can point to a head gasket allowing combustion into the coolant. A crack can do that too. I would probably advise the customer to seriously consider new engines if keeping the boat a long time. I personally would not want to pull heads looking for head gasket problems when the blow by will still be there, and may even find a bad cylinder and end up yanking them anyway. Sometimes a cheap bore scope from Harbor Freight can let you see a cylinder with ring problems as the walls will have streaks or grooves.

When doing a compression test, the first pop is the most indicative of cylinder condition. Most guys simply spin it and wait to see how high it goes and only go by that number. You can miss a low cylinder that takes longer to build pressure and has blow by.
A cylinder should reach full compression in 4 'pops' if it's in good shape. Older tired motors can still get it up but takes more spins. Kinda like us older guys.

 

[Stuski]

Re: Excessive smoke from breather tubes

Thanks for the info Walt. I was thinking along the same lines, I think I will look to get a couple of long blocks for her. She is a solid old boat and is worth the repower.

Best, Stu