no compression 150hpp V6 Mariner

[stocky]

Last time I took the boat out for a spin it overheated. Have just completed a compression test and 5 of the cylinders read >120psi and No. 2 cylinder has Zero. Looks like an expensive fix. Is there a chance of it being a head gasket or being realistic do you think No. 2 cylinder will require either honing, sleaving and new rings. How difficult is pulling down and reassembly of this engine. I have rebuilt car engines in the past so I do have some mechanical knowledge. In addition what sort of money are we looking at to have these jobs done. I'm in Australia so I will just multiply the dollars by 2.

 

[Hooty]

Re: no compression 150hpp V6 Mariner

Yo Stocky,<br />With zero compression, I think I would pull the head and have a look. It could be several things, from head gasket to severly scored cylinder wall. Removing the head shouldn't be much of a job on that engine. Lettus know what ya find.<br /><br />Best dog I ever had was a Queensland Blueheeler named Belle. She was some dog.<br /><br />c/6<br /><br />Hooty

 

[hondon]

Re: no compression 150hpp V6 Mariner

Remember, those are torque to yield heads, and the bolts need to be backed off at the same rate that they were torqued on or you run the risk of warpage.Check that spec.I've been burned by this before.

 

[stocky]

Re: no compression 150hpp V6 Mariner

G'day Hooty,<br /><br />Just took the head off and its pretty ugly in there. The ring on No. 2 cylinder has snapped and the remnants has chewed the crown of the piston, scored the cylinder wall and the top of the cylinder head is chewed. It looks as though I require at least a replacement piston, rings, either a rebore or sleeving and I hope the circumference of the combustion chamber can be repaired. Sounds like big dollars.

 

[mattyc]

Re: no compression 150hpp V6 Mariner

I'm kinda late on this reply, but those mid-80's mariner V6s have a BAD tendency... That is, the oil pump is driven by a gear attached to the camshaft. It is a plastic gear with metalized teeth. The gear wears down over time, and all the metal shards from the teeth wind up in your 2 hole and blow you up. You end up needing a new powerhead or a rebore and rebuild.