help with my 1986 3.0 litre gm

[john barba]

i just got finished rebuilding my 1986 3.0 litre, i put new piston rings, had to replace one piston, i got a used head in good shape off a 1999 mercruser 3.0 litre,got it running put it in the water and oil started to come out of the valve cover vent tube, can anyone tell me what can cause this? help me please

 

[chiefalen]

oil and water ?

 

[wbc1957]

i just got finished rebuilding my 1986 3.0 litre, i put new piston rings, had to replace one piston, i got a used head in good shape off a 1999 mercruser 3.0 litre,got it running put it in the water and oil started to come out of the valve cover vent tube, can anyone tell me what can cause this? help me please

It sounds like there's blow by pressure from the lower end of the engine. This could be the rings installed incorrectly or a bad piston. It sounds like a compression check is in order....

 

[Docksidemarineservices]

How long did you run the engine for? How much oil came out of the valve cover?

 

[wbc1957]

How long did you run the engine for? How much oil came out of the valve cover?

Oil came out the vent tube, not the valve cover.

 

[hystat]

your vent tube doesn't vent the valve cover?

 

[wbc1957]

your vent tube doesn't vent the valve cover?

hystat, you need to read his first comment. It says he has oil coming out of the valve cover breather tube. THE TUBE. This means there is high pressure blow by issues.

 

[john barba]

i am going to check that on monday afternoon, thanks

It sounds like there's blow by pressure from the lower end of the engine. This could be the rings installed incorrectly or a bad piston. It sounds like a compression check is in order....

 

[john barba]

for about an hour maybe 1/4 of a quart. put it under a load in a turn when it started, before that just a little smoke

 

[john barba]

thanks all i,ll update tomorrow night

 

[john barba]

How long did you run the engine for? How much oil came out of the valve cover?

for about an hour, lost probablly around a 1/4 of a quart of oil, put it under a load in a turn when it started before that just a little smokewas comung out of breather tube

 

[chiefalen]

no water ? Was it milky.

How many quarts did you put in.

You saw the dipstick after you filled it?

Is it overly full now, milky on the stick.

If you don't want to reply to me it's ok with me cause i won't ask any more questions without some reply back.

 

[Docksidemarineservices]

Did you run it long enough to seat the rings is why I asked.

 

[john barba]

how should it run to seat rings

Did you run it long enough to seat the rings is why I asked.

 

[john barba]

how long should it run to seat rings

 

[john barba]

no water in oil, put 4 1/2 quarts in, dip stick looked good not over full about 1/4 quart low now

no water ? Was it milky.

How many quarts did you put in.

You saw the dipstick after you filled it?

Is it overly full now, milky on the stick.

If you don't want to reply to me it's ok with me cause i won't ask any more questions without some reply back.

 

[chiefalen]

stock pan hold 4 quarts new filter you overfilled it.

 

[chiefalen]

another question what else did you do to the motor.

New oil pump? Just asking .

 

[Docksidemarineservices]

I would make sure the pan is not over filled and run the engine up to temp for a few hours and see what happens.

 

[chiefalen]

the motor is level ? I have this exact motor the stock pan holds 4 quarts of oil with a new filter.

If you put 4 and 1/2 quarts you put in 1/2 quart to much.

Where did you read you need 4 and 1/2 quarts.

A merc 86' 3.0 would take 5 quarts with new filter.

Not 5 and 1/2 .

This is not my opinion this is fact. What your doing is aerating the oil.