Blowby through vent tube? Mercruiser 3.7

[Dubed]

No pcv. Shop owner was familiar with the motor. Knew all about it.
And Uncle Bucks car was awesome!

 

[Scott Danforth]

should just be open vent elbow

 

[Dubed]

should just be open vent elbow

Yes just an open bung on the valve cover. Hose runs from it to the carb

 

[Scott06]

Agreed. My question is.... would all that oil coming out of the vent tube and being pumped through the carb cause that? After all, it isn't a 2 stroke

Not enough oil comes out the vent and into the carb. take plugs withyou to the machine shop, they are going to say it was lean , but your plugs are not lean at all… in fact oil and rich…

the plugs look like the ones out of my 65 gto. I did a backyard hone re ring, bearing, new cam, valve job… in 1992, still runs as bad as it ever did, when i nail the throttle dipstick gets popped out..

 

[Dubed]

Not enough oil comes out the vent and into the carb. take plugs withyou to the machine shop, they are going to say it was lean , but your plugs are not lean at all… in fact oil and rich…

Yes I took pictures and put plugs back in. Lean would be ultra clean looking wouldn't it?

 

[Scott06]

Yes I took pictures and put plugs back in. Lean would be ultra clean looking wouldn't it?

Yes yours are the opprosite of lean and detonation…here is a plug reading guide http://wallaceracing.com/plug-reading-lm.html

 

[nola mike]

Yes yours are the opprosite of lean and detonation…here is a plug reading guide http://wallaceracing.com/plug-reading-lm.html

I think that's oil rather than a rich condition. But oil is getting in all 4 cylinders, so running lean -->tuliping a valve doesn't seem likely. But don't see why oil past the rings would cause low compression in one cylinder.

 

[dubs283]

.....oil is getting in all 4 cylinders, so running lean -->tuliping a valve doesn't seem likely. But don't see why oil past the rings would cause low compression in one cylinder.

Yes, plugs are oil fouled. Not wet fouled, OP says plugs are dry with oil cooked/hard on the plugs. Look close at #2 plug, same cylinder with low compression. Plug tang has debris flaked off with the likelihood of excess heat being the culprit.

Oil blowing past the rings into the combustion chamber can cause excess heat, enough to tulip a valve, cause gasket failure, piston damage, etc.

 

[76SeaRay]

You need to be at the shop when they pull it apart to see for yourself what was going on. With all of them oil fouled, my guess is they put the rings in wrong (didn't offset the ring gaps, maybe a compression ring in upside down). Any shop can make a mistake and you want them to own up to a mistake if they made one.

 

[j cat]

No pcv. Shop owner was familiar with the motor. Knew all about it.
And Uncle Bucks car was awesome!

the engine has to put a additive

Lucas Oil 10063 Engine Break in Oil Additive - TB Zinc Plus​

when the engine does the first start up in the engine oil .. 95% great ...look it up .

 

[Rick Stephens]

the engine has to put a additive

Lucas Oil 10063 Engine Break in Oil Additive - TB Zinc Plus​

when the engine does the first start up in the engine oil .. 95% great ...look it up .

I wish you would stop with the irrelevant stuff.

 

[Dubed]

Trolls everywhere no matter what you do

 

[j cat]

I wish you would stop with the irrelevant stuff.

I did that additive and many over 90% rebuilt the engines people use it .
back in the old days eng oil has a high amount of zinc ,,,, old engines have to use a zinc plus for old engines .
my 470 does not loose engine oil .. the spark plugs look like new .I take out the plugs every year .inspect it .. over 30 yrs .
you have to look it up on the zinc plus for older engines and do a rebuild on engines.
you did not say any issue !!!!!!!!!

 

[dubs283]

I did that additive and many over 90% rebuilt the engines people use it .
back in the old days eng oil has a high amount of zinc ,,,, old engines have to use a zinc plus for old engines .
my 470 does not loose engine oil .. the spark plugs look like new .I take out the plugs every year .inspect it .. over 30 yrs .
you have to look it up on the zinc plus for older engines and do a rebuild on engines.
you did not say any issue !!!!!!!!!

This is the second time you've posted in this thread what OP should have done. That time has passed and now OP has an issue and is seeking RELEVANT information regarding the issue.

It's great you have a good running engine, have done all kinds of maintenance and are proud of it, good job. It seems as though in this and other threads you have posted in you are merely taking the opportunity to brag about your engine/drive, how great it is and how you've managed to keep it that way. Again, that is awesome but really it's time to stop with the useless self promotion and clogging threads with posts that frankly read like incoherent shorthand without any merit.

/end rant

 

[Lou C]

Right now the issue is how to deal with the shop so that you have a good outcome. My thought would be to ask them to do a leak down test so they themselves can see where the problem lies. While the solution is not an easy one that is what needs to be done….

 

[Scott06]

This is the second time you've posted in this thread what OP should have done. That time has passed and now OP has an issue and is seeking RELEVANT information regarding the issue.

It's great you have a good running engine, have done all kinds of maintenance and are proud of it, good job. It seems as though in this and other threads you have posted in you are merely taking the opportunity to brag about your engine/drive, how great it is and how you've managed to keep it that way. Again, that is awesome but really it's time to stop with the useless self promotion and clogging threads with posts that frankly read like incoherent shorthand without any merit.

/end rant

X 2 on this and in post 1 OP states he used break in oil and followed a reasonably proper break in regime.

 

[Scott Danforth]

I did that additive and many over 90% rebuilt the engines people use it .
back in the old days eng oil has a high amount of zinc ,,,, old engines have to use a zinc plus for old engines .
my 470 does not loose engine oil .. the spark plugs look like new .I take out the plugs every year .inspect it .. over 30 yrs .
you have to look it up on the zinc plus for older engines and do a rebuild on engines.
you did not say any issue !!!!!!!!!

j-cat, we are sure you mean well, however most of your posts are 180 degrees off, or against the processes outlined in the manuals.

Please read all the posts/replies and contemplate the answer prior to answering. make sure you read the details. the OP indicated he used break-in oil (which contains zinc)

as stated above, the OP has done everything by the book, has become frustrated and has come here.

sometimes things happen. sometimes the machine shop screws up, sometimes rings break, sometimes an overheat causes the bores to go wonky.

the OP is following all the correct steps.

how your engine runs or what you did 25 years ago is of no value to the thread.

 

[kenny nunez]

One other thing to check, remove the breaker plate in the distributor to make sure that the centrifugal advance weights,springs and support pins are tight. If they should become loose then there will be an over advance condition that can cause damage.
Delco inline distributor bodies are prone to this kind of internal wear.

 

[Dubed]

So here's the damage. Very bizarre

 

[Lou C]

wow it makes you wonder what could have caused that! stuck rings? bad installation? rings installed wrong?