Volvo Penta 3.0 project

xjnmud

Recruit
Joined
Aug 18, 2009
Messages
4
Alright. I?ve been doing my homework on this project for a couple weeks and I think its time to come on here and get some advice.

1998 Four Winns Horizon RX
Volvo Penta 3.0 I4 SX out drive
Open cooling system

Brief history: Bought this boat as an upgrade from my 94 three seat jet boat. The add read ?runs but engine needs work?. Being a shade tree mechanic and feeling it was a good deal no matter what, I got it.

What I got from the previous owner: Had it out about eight times this summer. Last time it was out it got hot. The engine was shut off until cool and then idled backed to dock.

What I have found:
The engine would turn over but would not crank. And by not crank it would fire once or twice and then die and sounded like it was missing.
Compression readings were 140psi, 140psi, 140psi, and 120psi
Spark plugs were wet.
There is water in the oil.

Original prediction: Blown head gasket due to overheating cause by a failure in the cooling system.

Last weekend I took the head off to inspect everything.

Things noted from head removal:
First, I found a 2 inch bolt in the hose that runs from the thermostat to the water pump on the block. (I suspect an idiot has been working on this motor)
Next, I notice quite a bit on mud and crap in the combination manifold.
The head gasket looked pretty good, no obvious signs of failure.
There seemed to be some bolts that were newer than others on the manifold. (again, I don?t think this is the first time this has been taken apart)
Last from what I could see the cylinder walls looked good. Although there is nothing on the crank pulley for me to put a wrench on to turn it over so I?m only looking at the tops of the cylinders)

My feeling are: Priority one, see if the block is cracked, if it is game over. If the block is not cracked how is water getting in the oil. Is the manifold cracked, head warped, what..? once that is determined fine the cause of overheating i.e. bad thermostat, impeller etc.

My budget for this project is $1000 to get it running well and I?d like to get this resolved before the temperature drops below freezing.

My questions as of now:
What is your opinion?
Where do you think I should go from here?
Will I be fine bumping the starter to moved the cylinders for further inspection? Is there another way to turn that fauker over?
Will a visual inspection of the cylinder walls be enough or should I do something more like magnaflux?

Sorry for the long post, hope you guys can enlighten me with some wisdom.
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Re: Volvo Penta 3.0 project

Howdy,


What I got from the previous owner:
You probably should not believe all you hear from the previous owner.


Do you experience freezing temps where you live?


Go with what you know.

You have water in the oil. That is MOST frequently a cracked block from freeze damage.

The best way to check for a cracked block is to pressurize it (before removing the head)

What I have found:
.................Compression readings were 140psi, 140psi, 140psi, and 120psi
Spark plugs were wet.
There is water in the oil.

Original prediction: Blown head gasket due to overheating cause by a failure in the cooling system.

Last weekend I took the head off to inspect everything.
You proved it probably wasn't a "blown headgasket" from the above info.


cause of overheating i.e. bad thermostat, impeller etc.
Almost always the raw water pump, or raw water circuit clogged by previous raw water pump failure, possible water pickup leak (or leak prior to the raw water pump) causing it to suck air which would cause premature impeller failure ......could be a thermostat but not usually.


Will I be fine bumping the starter to moved the cylinders for further inspection?
Won't hurt anything probably......but I don't think you have a huge cyl problem. ......compression was 120 + (maybe 1 weak cyl....)


Water in the cyls could be from a cracked manifold. They also crack from freeze damage.

Wouldn't hurt anything while the engine is running if it's only cracked in the "exhaust area" (the water is "blown" out with the exhaust.)

But when you shut it down, the residual water in the manifold would run back into any open exhaust valves.

If is was cracked in the intake area....well, that wouldn't be good. You could get water "injection" while the engine is running..... THAT could cause a serious hydrolock.......I.E. break things, blow headgaskets etc. (your compression readings probably ruled that out)

The only real easy way to check for a cracked block/head is to bolt the head back on (and hope the head gasket will still seal) and pressurize the cooling system and check for leaks.

It should hold 15-20 psi. If it doesn't you can use soapy water to look for bubbles on the outside. You can also listen for internal hissing.

Sorry about that.....


Welcome to Iboats!!


Rick
 
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