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350 Mag Tournament Ski Big Problems


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I have talked to multiple mechanics and have gotten all kinds of answers. Want to know what yall think

94 350 Mag Tournament Ski

Oil coming through vent tubes on valve covers going into air cleaner.

Oil coming out of dipstick. 

Did a compression test all cylindes are good except #5, which has no compression. 

Does anyone know what the PCV system is on the engine and could that be causing my issues, most likely the dead cylinder I'm thinking??

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If you have a dead hole and oil shooting out of the top end then it is time to just tear the engine down. Your compression from that dead hole seems to be pressurizing the block, so best guess is an issue at the head in the valve train.

If you want to make a mess, pull the valve cover, start the engine and see what happens over the bad cylinder.  If nothing then maybe just bad rings.

Edited by oldjeep
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17 minutes ago, 94bu said:

I have talked to multiple mechanics and have gotten all kinds of answers. Want to know what yall think

94 350 Mag Tournament Ski

Oil coming through vent tubes on valve covers going into air cleaner.

Oil coming out of dipstick. 

Did a compression test all cylindes are good except #5, which has no compression. 

Does anyone know what the PCV system is on the engine and could that be causing my issues, most likely the dead cylinder I'm thinking??

I think you are on the right track here.  The PCV valve can't keep up with all the air you are pumping into the block.

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Tell us a little history. Was it running fine prior to now? Oil changes recently? Any chance the engine froze due to cold?

Steve B.

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Well I had just purchased the boat the middle of last summer. It seemed to be well taken care of as far as cleanliness goes and engine ran flawless on test run. I was told by the previous owner the boat was winterized, along with oil change at the beginning last season. Oil was clean so I had no reason to suspect otherwise.  Obviously he was not honest. There was no way he didn't know about this problem. Like I said the boat runs great for the first hour or two, then steam and oil out the vent tubes and oil out the dipstick starts, but doesn't seem to affect the power or idle of the engine.

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2 hours ago, justgary said:

I think you are on the right track here.  The PCV valve can't keep up with all the air you are pumping into the block.

Well here's the thing, where is the PCV located, or does this engine have a pump? The vents, one on right valve cover and one on the left, where I thought the PCV valve goes are just hollow pieces  plastic with lines running to the air cleaner.

 

 

2 hours ago, justgary said:

I think you are on the right track here.  The PCV valve can't keep up with all the air you are pumping into the block.

 

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4 minutes ago, oldjeep said:

What does the oil look like?  Still oil or mayonnaise?

Still oil.

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2 hours ago, oldjeep said:

If you have a dead hole and oil shooting out of the top end then it is time to just tear the engine down. Your compression from that dead hole seems to be pressurizing the block, so best guess is an issue at the head in the valve train.

If you want to make a mess, pull the valve cover, start the engine and see what happens over the bad cylinder.  If nothing then maybe just bad rings.

Could it be as simple as a stuck valve?

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29 minutes ago, 94bu said:

Could it be as simple as a stuck valve?

Stuck valve wouldn't  pressurize the crank case.  Big crack near the valve could.  Honestly you are going to need to pull the head at a minimum 

 

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How many hours on the motor?

Got the boat last summer - ran fine till now or has this been ongoing for several months?

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Hmm,

If there is a cylinder with no compression that engine is going to run awful. No compression needs verified. A broken spring, valve, lifter, pushrod could cause that. But that wouldn't solve the oil issue. Are you sure how much oil is in the engine? Way too much oil could cause an attempt by the engine to get rid of it.

I'm thinkin' you have two issues to deal with. Any good boat mechanics close by?

Steve B.

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4 hours ago, Rednucleus said:

How many hours on the motor?

Got the boat last summer - ran fine till now or has this been ongoing for several months?

1200...on going. Started right away.

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3 hours ago, Steve B. said:

Hmm,

If there is a cylinder with no compression that engine is going to run awful. No compression needs verified. A broken spring, valve, lifter, pushrod could cause that. But that wouldn't solve the oil issue. Are you sure how much oil is in the engine? Way too much oil could cause an attempt by the engine to get rid of it.

I'm thinkin' you have two issues to deal with. Any good boat mechanics close by?

Steve B.

Well it runs smooth. I did the compression test myself. Multiple times on #5 and came up with the same result...0. There's is the correct amount of oil in the engine. As a matter of fact it will run the oil low enough it will drop oil pressure to zip. I'm trying to find a good mechanic but everyone is telling me the engine is toast and needs to be replaced. Just trying to get a 15th opinion lol.

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As @oldjeep suggested, pulling that one head should be a fairly straightforward process.  You can then take it to an automotive machine shop and ask them if they see anything wrong with it (assuming you don't immediately see the problem when you pull it).  No harm in getting an opinion, and maybe it will help zip up your spine for further work if you need to do it.  Putting the head back on is just as simple.  Just buy new gaskets and use a torque wrench.  Harbor Freight has decent enough ones on sale all the time.

If something is wrong with the head, you'll get off pretty cheaply, so go for it before you spend a big wad on a new engine.

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A leak down will give you a good chance to know why you have no compression without a tare down. one other quick check is a camera into the cylinder. I am thinking you may have a hole in the piston ( top) . Likely detonation.  With zero compression you are more then likely going to be pulling the engine regardless. But it is always good to know what you are looking at before you get into that much work. So if the oil looks good it sounds like the cooling system is good.. I am guessing the head gasket is good. You could try a easy check since you know you have zero compression. your not as concerned about the performance of the cylinder. So put your compression setup back into #5. add  air flow and start listening for air. Pull the dipstick can you tell if air is flowing into the crank area and oil pan?  If I expected the cooling system you could check the cooling system for air but that does not sound like your issue. Check in the valve cover. listen to the exhaust system. Check or listen down the carb or throttle body. If you found that issue you know Intake valve. The oil issue makes me think you have a large leak into the crank and pan area. As I said its always good to have a good scope of what the issue is before a tare down .  Good luck.

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1 hour ago, oldjeep said:

How are you going to do a leak down with no compression?

You would do what is good. Then just use the air to chase what is going on in #5. Just nice to know all you can before ripping everything apart.

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6 hours ago, Sixball said:

You would do what is good. Then just use the air to chase what is going on in #5. Just nice to know all you can before ripping everything apart.

Ah.  I'm in the camp of - if I am pulling the head off a 26 year old motor, it is for curiosity sake before I completely rebuild or replace it.

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10 hours ago, Sixball said:

A leak down will give you a good chance to know why you have no compression without a tare down. one other quick check is a camera into the cylinder. I am thinking you may have a hole in the piston ( top) . Likely detonation.  With zero compression you are more then likely going to be pulling the engine regardless. But it is always good to know what you are looking at before you get into that much work. So if the oil looks good it sounds like the cooling system is good.. I am guessing the head gasket is good. You could try a easy check since you know you have zero compression. your not as concerned about the performance of the cylinder. So put your compression setup back into #5. add  air flow and start listening for air. Pull the dipstick can you tell if air is flowing into the crank area and oil pan?  If I expected the cooling system you could check the cooling system for air but that does not sound like your issue. Check in the valve cover. listen to the exhaust system. Check or listen down the carb or throttle body. If you found that issue you know Intake valve. The oil issue makes me think you have a large leak into the crank and pan area. As I said its always good to have a good scope of what the issue is before a tare down .  Good luck.

If I have a hole in the piston wouldn't the engine run or idle rough?

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26 minutes ago, 94bu said:

If I have a hole in the piston wouldn't the engine run or idle rough?

Oddly - not a lot.  A hole with 0 compression is just along for the ride, unless it is grabbing on the cylinder walls.  Conversely a cylinder with good compression but no spark will really make an engine vibrate.

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Michigan boarder

Here's what I would do:

1) remove the valve cover.  It's easy to do, and will rule out some things, and you might find the problem.  Post pics on here for advice.  If all still looks good, then move to step 2

2) buy an camera that will go inside the spark plug hole (an endoscope).  You can get them for like $50 on Amazon and they are useful for a ton of things.  Put that in the cylinder and see what it looks like.  If all looks good still, them go to step 3

3) remove the head.  I would plan on removing them both, and have them gone thru.  You can usually drop them off at a local auto parts store and they'll send them out for resurfacing, magnafluxing, and putting new seals and everything in.  OR, at this point and since you are this far into it, you can put a new set of Vortec heads in that will help your air flow in and out and bring up your horsepower and recycle your old heads.

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2 hours ago, 94bu said:

If I have a hole in the piston wouldn't the engine run or idle rough?

As oldjeep said its not as bad as a miss or dead cylinder. No big resistance.  You may have had smoke in your exhaust.  The other thing is if you do try to find the issue you will need the #5 cylinder in the firing position. Valves closed. I should have said that but thinking if you do compression or leak down you would be in that mode.  

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4 hours ago, oldjeep said:

Ah.  I'm in the camp of - if I am pulling the head off a 26 year old motor, it is for curiosity sake before I completely rebuild or replace it.

Yeper at 26 years old if it was coming out it would get a complete rebuild if its me. 

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