Water and oil?

I recently purchased a 1973 Delta with a 170hp Volvo Penta I/O. Now I'm hoping it's not as big of a loss as I think it is.

You see I checked the oil when I first bought it. Crystal clear. The guy I bought it from said it hasn't been changed since 2007. I don't know if oil can look fresh out of a bottle if it's been sitting that long. We ran the engine for a minute or so and it ran fine. Didn't get to run water through it because he didn't have one of those hose adapters that cover the water intake.

So I take it home all excited to have a supposedly good running boat I could take to the lake the next day. I went over the engine to make sure it would be able to handle the lake the next day. Got out my stern hose adapter ( or whatever you call it), started the water, and started the engine.

Had it running for a good five minutes when I noticed oil leaking from the oil cooler? I think to myself, "A little leak, no big deal, I'll check it out." I disconnected the water line on the oil cooler and oil/water came pouring out. When I cranked the engine a lot more water/ oil came pouring out. I then removed the oil pressure switch, and volla more water/ oil.

I looked over the engine for cracks and couldn't see any. However I did notice one of the freeze plugs had just been hammered back in place. Then I did a compression test and they read:

Cyl 1 = 130 PSI
Cyl 2 = 128 PSI
Cyl 3 = 140 PSI
Cyl 4 = 100 PSI
Cyl 5 = 115 PSI
Cyl 6 = 130 PSI

I'm not sure how to diagnose this any further without ripping apart the engine. If you notice cylinder 4 and 5 are significantly lower than the others? Could it just be a head gasket? Or is my block cracked on the inside? How would I know if it was asides from ripping the engine out?

Thanks,
Kingtut512

 

what do the spark plugs from 4 & 5 look like. sounds like the gasket or a cracked head. on one of my b30's [170] the water transfer holes in the head had grown larger due to corrosion , it kept blowing the head gasket until i got the holes built up with weld and refaced the head. no problem after that. they are a great engine, simple and strong. the other thing is , it might be your oil cooler that is the problem and not the engine, i had 2 of them pack up . i removed the cooler and cut the threaded stub down and fitted the oil filter straight on without a cooler. never had that problem again. with modern oils it doesn't bother the engine not having it. the compression drop may just be valve seats that need a grind. hope this helps. get it sorted out and you will have a good engine for a long time. get rid of the cooler and run the boat for a few hours then do another comp check , in case the water has frozen the rings. just keep an eye on the oil level while you are doing it in case its not the cooler. i hope you can understand my ramblings.

 

Mixing Oil & Water

Dear Kingtut512,

You observed Oil+Water on the water line.

That means the Oil leakages to the water's circuit because the Oil Pressure level is much more higher (3 to 5 bars or 40 to 70psi)
than the Water Pressure ( never more than 15psi) when the engine runs.

So please check First the Oil Cooler and normally you will find a crack which caused for the observed leakage of Oil through
the core element device (Heat Exchanger)
and Check also the continuity of the O'rings rubbers on the Core faces if are needed to be changed with new.

These O'rings seal and separate the Oil and Water compartments of the Oil Cooler.
Proceed to dismantle the Oil Cooler Body for a Pressure test to the Oil Cooler Core Element (Heat Exchanger).

The differences of the Compression Pressure on Cyl. 4 and 5 should not be related with the observed malfunction.

 

good post, i just re read the thread, definately a cooler problem when oil leaks at cooler it is unrelated to engine. just remove the cooler and you will have no problems. don't worry about testing it .

 

That engine needs to be rebuilt. You have a 30% difference between the cylinder pressures, on the compression test, clearly you have a stuck, cracked or broken something or other, probably a valve. This coupled with your other issues suggests someone was lying to you when you purchased it. That motor is done, tear it down and see what else they were lying about.

 

The service minimum compression is 120 for those engines

 

Cylinder's Compression

Dear All,

The lower measured Compression value maybe based to simply fact that the engine was remained stopped for long time period.
It is obvious that on some of cylinders the valves could be stayed at open position.
If the exhaust muffler or what ever used was not closed-end type, then all this period the water spray and the humidity affected to the Valves' seats.

Normally a maintenance service to the Cylinder Heads should be necessary and of course not so much expensive.

It will be recommended to confirm with ex-owners if the engine was stopped for long period and to ask them the maintenance expenses to be shared.

Go on very carefully gathering the most info regarding the engine's past from the ex-owners with low profile.
When you have a more sufficient image of that you will have to proceed and arrange the maintenance level and the cost sharing with the sellers .....

 

The compression reading wouldn't be off by 30%, even if the engine was stored for years. At least not just one cylinder would be that low. There are several additional checks to be made, squirting motor oil into the spark plug holes, just before pulling another compression check, would have been my next test, but with those numbers, it's probably not worth the bother. A lab test of the motor oil would reveal all that's wrong with the engine, likely telling you what I already suspect.

 

Question

Dear PAR,

Why then Kingtut512 was not complained for smoke on the exhaust?

 

My impression of Kingtut is he's a novice and not especially well versed in marine engine applications (not intended as a personal dig at him). I say this from what I gathered from his post. He started the engine without muffs, which nearly instantly destroyed the impeller. He did note the oil, which hasn't been changed in 4 years was pristine, suggesting to me someone is lying, but he apparently accepted the "sales pitch" anyway. Freshly hammered freeze plugs, the second worse cylinder in the compression test was still nearly 20% off the best, water in the oil, etc., etc., etc.

I don't know the experience of Kingtut, but seeing fresh oil in a 38 year old, filthy sump after 4 years would have have raised a big red flag in my head, how about yours? Coupled with the other obvious signs, the compression test, the lack of other reasonable, simple tests that you and I would have preformed in 15 minutes of checking out this old girl. This all tells me it's an engine that the seller found it necessary to lie about, hence my suggestion it's probably spent. I'm not sure about where or how much in Nevada, but I can get oil tested locally for $20 and have results in a few days. This will tell all about the engine, though again, many of the signs suggest it should be torn down and examined for more lies about it's condition. I wouldn't be surprised if they found banana peels in the crank case. Now, I haven't seen this done in a couple of decades, but . . . An oil test kit can be purchased, postage pre-paid from www.oaitesting.com

 

the fresh oil may have been to hide the fact that the cooler was leaking. hard to sell with white engine oil. i still would be inclined to get rid of the cooler and give it a real good run and then see what the compression is like . these things are built like a brick shithouse, i would not be surprised at all if it came good with a run. if it was an engine that was being used all the time and it suddenly got those comp drops i would agree with par but because it has sat around with water in the oil it may just need a good run to free everything up again. if it does need a rebuild the parts are easy to get and they are the simplest engine i have ever had.

 

Or it may swallow a valve and leave him paddling.

 

i understand what you're saying but do you understand my point. he can run it in the back yard , if it comes good he will know by the next comp test , if not then rip the head off.

 

You and I would be able to sort out this engine/drive and be reasonably confidant about heading out for a few hard pulls. Yes, I understand your point, but mine is we don't know what the abilities and experience levels are with Kingtut, so . . .

 

fair enough.