White smoke, blowby, low oil pressure, but good compression. Thoughts?

[jkaiser77]

Hi guys, I bought a used sailboat this past spring with an Atomic 4 that had been sitting idle for several years. Although the engine works, white smoke comes out the exhaust, oil pressure is low (Cruising 20psi, 5 - 10psi at idle), and smoke comes out the oil intake at higher speeds.

I ran the motor several hours trying to burn off any "winter oil", but the problem persists.

I did a compression check and all four cylinders are right around 100psi. If the compression is good, does that mean the oil rings are fine? Or do all signs point to oil ring damage?

[Peter]

JK,

i looked at your thread on your white spark plug deposit but have no idea there - maybe others do.

oil pressure - the A4 has an oil pressure regulator that you can adjust. Near the back of the engine on the right hand side, under the fuel pump, is a large nut with a smaller machine screw with a slot in it. loosen the large nut and turn the machine screw in clockwise. That should increase your oil pressure.

white smoke and blow by - wiser minds needed there too.

peter

[jkaiser77]

Thanks, Peter. I tried adjusting the oil pressure regulator - not much happened. Next I tried dressing the seat - still nothing. Ordered a new one, but haven't installed it yet.

Hopefully someone will have some insight on the white smoke/blowby.

[Al Schober]

JK,
White smoke from the filler is a sure sign of worn rings - particularly the lower oil control rings. The upper two rings control compression - these can be good while the oil rings can be worn.
I tore down one engine with those symptoms and just for fun checked the end clearance on the oil rings. End clearance is supposed to be about 10 mils or a bit less. The ring set in this engine was running about 100 mils! Those oil rings were just along for the ride - they were doing nothing!
The good news is that the A4 block is a high chrome alloy, which reduces wear and corrosion. Typically, an overhaul doesn't need machining of the bore or even removal of a ridge. Just put new rings on the pistons and reassemble. Of course, your mileage may vary..
As for oil pressure, try adjusting it upward. If you can't get where you want to, or if max pressure is barely adequate, your overhaul will be looking at new bearings. Depending on the condition of the cam and crank journals, this may not be a big deal.
I don't know your capabilities. Do you have a good machine shop you can trust to do the stuff you can't?

[jkaiser77]

Thanks, Al. I was afraid of that. My capabilities are limited at best, as are my finances. Not even sure how I'll get the engine out of the boat. I'll try to figure something out.

[Peter]

There is a pretty recent thread entitled "Best way to extract" that you may find interesting.

I changed my engine on the hard in the boat yard. They charged me $50 to lift the old one out and the new one in. They provided the crane - I helped.

It was very nice to do it with a nice sense of security.

P

[romantic comedy]

You did change the oil, right?
what oil are you using?

[jkaiser77]

Yep, changed the oil - S.A.E. 30 weight

[jkaiser77]

Ok, here's the update...

Pulled the engine last fall, took the engine apart this week. When I got to the rod bearings this is what I found:



Totally shredded. As for the others, one was worn, two were fine.

I'm assuming this accounts for the low oil pressure + smoke pouring out of the oil intake?

[Ken Rockwell]

I'd say you pry want a refurbished crank, and a pair of rods. It's cheaper than a machinist. Plus he could tell you its cracked. It's definitely the cause of the smoke but, you need an oil pump or oil passages cleaned out. You lost presure, bearings don't just ware through like that.

[thatch]

At this point I would say that it's time to do a little math on the project. Since the condition of the block has not yet been determined it would probably be best to wait until all of the cards have been dealt before buying any parts. As Ken stated, you may only need to buy a crank and 2 rods, but if the block is toast, you may need to head this project in another direction. The Moyer folks will be able to guide you in the most sensible direction.
Tom

[jkaiser77]

Thanks, guys. Appreciate the advice.

I'm definitely pausing all purchasing decisions.

Took the block and manifold to the machine shop this morning. They'll let me know the verdict later this week...

[Ken Rockwell]

Good move. Look for used engine prices in the meantime.

[Al Schober]

I'd say that having one (or more) bearings worn like that would definitely account for the low oil pressure, but not the smoke. I still suspect the lower oil control rings. Let us know what your shop finds.