1985 Volvo Penta AQ260 (Chevy 350) blowing smoke/oil starboard side valve cover-gctid819400

[btom]

Bayliner 2850 Contessa with a Volvo Penta AQ260 5.7L V8 Blown Overheated Engine

[2850Bounty]

check back in the AM.

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[kevinv123]

Nice to see you made it over to the dark side. Bunch of judgmental guys over on THE other site. You'll get much more help from a lot of very nice people here.

[Download_Complete]

I am not sure the engine CAN be recovered at this point. I am with Rick (as usual) - you will spend a ton of time and money correcting someone's half-ass mistake.

This was all things you could have avoided by sea trialling before you bought. But what's done is done - you have a boat that, in good condition and with a running engine, is worth $9,000 or so. That's a lot of scratch, and the boat is one of the most popular Bayliner cruisers made...ever. This is not a 1983 Capri (with respect to those who have them)....you could, with quite a bit of justification, throw a massive amount of money at this boat.

My suggestion is this: Compression test the engine. This is not going to cost you a lot of money, if any if you are handy. Then I would find a way to put a marine-built 383 in there. Or, if the compression test is OK, rebuild the AQ260 for now and put it back in.

[alanmoor]

I was in your position, more or less twice with the same boat. I got an old boat at a good price without checking it out. Spent a long time trying to troubleshoot the engine without a leakdown/compression test and eventually was told it was a bad engine (when I finally took it to a mechanic and he did a compression test).

I paid someone to replace the engine and rebuild the outdrive for way more than the boat was worth. I ran that one for a bit, and had similar problems. Again i spent a season trying to diagnose it without a compression test, and took it to an auto mechanic that I trust. He did a compression test and told me I had bad compression. I tore the heads off and found that the intake valves had overheated because the intake had been put on improperly.

I rebuilt the heads (without taking the engine out). My engine compartment is roomy, but I still wonder if it wouldn't have been quicker and easier to remove the engine to rebuild the heads. I now have this https://www.amazon.com/gp/product/B0030EVL60/ I tried to use it after I rebuilt the engine, but the engine needs oil in the cylinders to seal properly. The time to use it is when the engine is in the condition yours is now. A leak down test will tell you more, but a compression test is pretty quick and easy.

Things I've learned:

I should have done a leak down (or at least a compression) test early. I spent a long time (2-3 seasons) messing around with plugs, carburetor, and fuel supply. If I were you that would be my first step, as others have suggested.

Paying someone to do the work doesn't guarantee it will be done right. By doing a lot of the work myself (the 2nd time around) I feel more confident in my boat. I was fortunate to have a place inside to work on it.

Make sure there aren't other things on the boat that are going to make it a bigger money pit than it already is (like the outdrive).

I can't tell you if you'd be better off cutting your losses and moving on, rebuilding what you have, or replacing your engine. I will say that I know what I have now and if I had cut my losses I would either not have a boat, or have another unknown (well, maybe not... maybe the 2nd time around I'd have had a survey done).

[alanmoor]

Your results are similar to what mine were. I fixed it by just pulling the heads and rebuilding them. The intake valves had overheated and cupped. A leak down test will supposedly tell you if that is the case - if air is escaping into the crank case it leaking past the pistons, if into the valve cover, it's a valve issue. I will say that when I did the leak down after I put everything back together it was hard to tell where the air was escaping to.

[builderdude]

Is this engine raw water cooled or closed cooled??

if you perform a leak down test on the port side: For each cylinder being tested the piston needs to be at TDC on the compression stroke you'll likely have/hear leakage in the exhaust manifold while performing the test do to water ingress up the exhaust. A cylinder head rebuild/replacement could get you running fairly good again and if you determine the bottom end (rings) needs a rebuild you'll have new heads ready to bolt on when it's complete. In other words you'll want to do the heads regardless.

[2850Bounty]

BTOM, please go back to post #4 and re-read the three paragraphs where I have under-scored your words.

I started working with the SBC in the mid 60s. While I've not seen it all...... I've seen many situations similar to yours.

Damage often occurs from over-heating and it is seldom minor damage.

Given the duration of your over-heating, and knowing that this was a Raw Water Cooled SBC, I will predict that if you spend one once of your energy, and/or one dollar of your money on forensic work....... you will soon learn that it was futile.

My suggestion........ take that $600 that you were considering throwing at replacement cylinder heads, and put it towards a freshly but correctly built SBC engine for this boat.

This means..... single valve relief Flat Top pistons and 76cc chamber cylinder heads with a .038" quench dimension........ or..... a Q/E style piston and the 65cc chamber cylinder heads with a .038" quench dimension.



.

[Tundra_rat]

If you decide to go the route of engine replacement, Michigan Motorz offers a great drop in plug and play at a decent price.

I have been running one for the past 6 years with 648hrzon it. Never a problem, and I just I purchased a Volvo penta 5.7 based engine to install into a trophy.

Sounds to me like you may have a head gasket problem, but that's just my limited knowledge.. a borescope would be a great tool that is less intrusive than a head removal.

[2850Bounty]

"btom" post=820261 wrote:
Bounty, the temp gauge never showed any indication of overheating, nor did I mention overheating in the post. Are you suggesting it was over heating since it was loosing oil? I never ran it without enough oil to have sufficient oil pressure.

[color]blue wrote:
My apologies..... I stand corrected.

Even so...... with a raw water cooled engine and with this issue, I would start fresh. [/color]

When we ran it on the water (at time of purchase) it was cold started and did not have any white smoke coming out whatsoever. It warmed up and ran fine with no white smoke or oil leak for 20 minutes. Now when I start it (will start right up), it immediately blows white smoke out of the valve covers.

[color]blue wrote:
If you are still Hell Bent on trying to save this engine, this is exactly why you will want to perform a cylinder "leak-down" test before you remove the cylinder heads.[/color]

It still seems strange to me that it seemed to run fine with no oil leak or white smoke whatsoever, then 20 minutes later it is blowing smoke and oil, and the compression test comes back with good compression on one side of the engine, and bad compression on 3 cylinders on the other side. Just seems strange to me,

[color]blue wrote:
People are the same way....... for years we feel great, then one day we notice that we don't!

One more thing..... if you do buy or over-haul an engine for this 2850 Contessa, say NO to these!

[/color]

[attachment]39901 wrote:
full dished piston SBC 3.jpg[/attachment]

Attached files

[builderdude]

Both heads were replaced with remanufactured heads (assuming the seller is honest) but the port side exhaust was not "worked on" but it had to come off to replace the head on that side, perhaps they didn't break it apart to examine its condition. It is possible the port side exhaust manifold, spacer, or elbow failed during your run causing water contact with the exhaust valves or worse. That could explain the low compression numbers on the port side. To verify this you'll need to perform the leakdown test, my guess is you'll hear air pressure escaping through the exhaust.

The excessive blow by from the crankcase via the valve covers could be a piston or ring issue.

[2850Bounty]

Here is an exhaust manifold and elbow for the AQ series GM SBC V-8 engines.

Please note the flat surfaces where the two components mate.

Also note the seawater transfer ports.

Father Time takes his tole on the areas between the main exhaust chamber and transfer ports.

When these small flat sealing areas become compromised, water can enter the main chamber.

When/If it does, "exhaust gas reversion" will cause the water to enter a cylinder.

Seawater coming into contact with a hot exhaust valve is not a good thing!


Attached files

[Guest]

I did a compression test today. Here are the results:

Starboard Side:

2: 130PSI

4: 130PSI

6: 130PSI

8: 130PSI

Port Side:

1: 70PSI

3: 70PSI

5: 80PSI

7: 130PSI

The mixing of the oil and poor compression readings could very well indicate a blown head gasket. What do you have to loose by removing and inspecting the head/block for warping and/or bad valves and blown head gasket? Perhaps whoever installed the head just didn't torque it correctly....there are a world of possibilities.

Go from cheap to expensive. If you have a few tools and can youtube how to change a head on a 350, try it out!!

Chay