1975 302

[woody66912]

I have been a marine service tech service for 23 years now, and I'M STUMPED. This engine has a the style of oil fill cap that is vented and the cap has steel wool in it for a filter. Hears the deal, only at WOT does it happen, It's dumping white smoke out of the cap i have moved the PCV valve from the starboard side valve cover to the port on a side where the fill cap is, note there is no build up of oil running down or around the valve cover or cap. It's so bad that it comes out of the front air intake, It does use some oil but not enough to what i would think of as excessive, Yes It's 38 years old. And time for a rebuild but it doesn't miss a lick anywhere in the RPM range. I will try to upload a pic of the boat style.

 

[Mbrgr1]

Re: 1975 302

I have been a marine service tech service for 23 years now, and I'M STUMPED. This engine has a the style of oil fill cap that is vented and the cap has steel wool in it for a filter. Hears the deal, only at WOT does it happen, It's dumping white smoke out of the cap i have moved the PCV valve from the starboard side valve cover to the port on a side where the fill cap is, note there is no build up of oil running down or around the valve cover or cap. It's so bad that it comes out of the front air intake, It does use some oil but not enough to what i would think of as excessive, Yes It's 38 years old. And time for a rebuild but it doesn't miss a lick anywhere in the RPM range. I will try to upload a pic of the boat style.View attachment 210766

Cool boat! It's got to be blow by into the crankcase and out the oil filler, but white smoke as you know is typically antifreeze, but would not apply in a boat. I'm thinking you do need a rebuild, you could have great compression rings and bad oil rings. MK

 

[achris]

Re: 1975 302

I have been a marine service tech service for 23 years now, and I'M STUMPED. This engine has a the style of oil fill cap that is vented and the cap has steel wool in it for a filter. Hears the deal, only at WOT does it happen, It's dumping white smoke out of the cap i have moved the PCV valve from the starboard side valve cover to the port on a side where the fill cap is, note there is no build up of oil running down or around the valve cover or cap. It's so bad that it comes out of the front air intake, It does use some oil but not enough to what i would think of as excessive, Yes It's 38 years old. And time for a rebuild but it doesn't miss a lick anywhere in the RPM range. I will try to upload a pic of the boat style.

A few questions.

1. Is this a Mercruiser (or a car engine dropped into a boat)? I ask because Mercruiser didn't use PCV valves. If it has the valves (not just vents/breathers) it's not a proper marine engine. And if it is a Mercruiser, which particular 302? Mercruiser used both 2 bbl and 4bbl, called them 888 and 225...
2. White smoke is usually water. How are the exhaust elbows/manifolds/gaskets?
3. What front air intake? On the engine should only be a flame arrestor on the top of the carburetor...

Chris........
P.S. Don't need any more photos of the boat, how about a few of the engine?

 

[haulnazz15]

Re: 1975 302

A few questions.

1. Is this a Mercruiser (or a car engine dropped into a boat)? I ask because Mercruiser didn't use PCV valves. If it has the valves (not just vents/breathers) it's not a proper marine engine. And if it is a Mercruiser, which particular 302? Mercruiser used both 2 bbl and 4bbl, called them 888 and 225...
2. White smoke is usually water. How are the exhaust elbows/manifolds/gaskets?
3. What front air intake? On the engine should only be a flame arrestor on the top of the carburetor...

Chris........
P.S. Don't need any more photos of the boat, how about a few of the engine?

My 351w (Merc 233) had a PCV valve on the starboard valve cover, and the breather on the port-side. I do assume it's a valve, and not just a metal fitting, both have hoses, but the one connected to the PCV valve went to the base of the carburetor while the breather went to the flame arrestor. It may have been unique to the Ford engines.

Here is a pic of the hose/valve/fitting as seen on the rear of my engine. However, on my new engine pictured, I went with a dual-fitting flame arrestor and just took both hoses there as the 4bbl carb I switched to didn't have the barbed fitting on the base.

 

[haulnazz15]

Re: 1975 302

I have been a marine service tech service for 23 years now, and I'M STUMPED. This engine has a the style of oil fill cap that is vented and the cap has steel wool in it for a filter.

I switched my breather out because that steel wool in mine had pretty much disintegrated. My current breather has no filter element in it. It puts a little bit of oil residue on the flame arrestor, but nothing major.

 

[woody66912]

Re: 1975 302

The intake i speak of is on the engine cover. The engine setup i have is the same as in post # 4, but i have a merc carb 2 jet, the only thing i can see that would cause this is the crank case is getting more positive pressure than the PCV can handle, and i thinking the only thing that would cause this is ring blow by but it doesn't burn oil?.

 

[haulnazz15]

Re: 1975 302

I would be concerned about having enough "white smoke" that it comes out of the engine cover. Are you sure it's from the oil fill/breather? I don't see how anything could escape the flame arrestor at WOT as the air intake should be pulling in tons of air.

 

[woody66912]

Re: 1975 302

Yes it's coming out of the fill cap, at WOT i can look in the front hood vent and see it.