Marinette Boat Forum

As posted a couple of weeks ago, had a dead miss and found that I had low compression on a couple of cylinders. My mechanic pulled the heads and after leaving them at the machine shop find that a total rework is necessary. Machine shop priced parts and labor at "about" $ 700.00 which, though I really didn't want to spend the money, I can handle it. Mechanic said he could try to find some used heads but probably cost what the repair is costing. My thinking is that if this doesn't solve my problem, at least I've got a good set of heads to stick on a rebuilt short block. Had good oil pressure and 6 of the 8 cylinders had real good compression. Any suggestions as to whether my reasoning is good or bad. Regards to all, I sure enjoy the help you guys offer.
Rockxx

If the $700 is just for rebuilding the heads, that is way too much. My last 318 was just shy of $700, but that was rebuilding heads, boring block, cam bearings, and all new brass core plugs. I think you could buy two brand new heads for around that price.

He should have done a leak down test before pulling the heads. That would have told you where the problem was. Now it is just a guess.

^^^^^^^ Completely agree on the leak down test. If it were me, I would waste a set of head gaskets and bolt the heads back on for the test.

The leak down test will indicate valve leakage. If the valves don't leak, then you likely have a cylinder ring problem. When I did mine two yeara ago, it showed intake valve leakage. I could hear the hiss through the intake track.

$700 is too much. I just had a set of heads ported, decked and rebuilt for $600. That included half the valves and springs. It was a mild port job that basically knocked off the rough edges. Still. The shop had two hours of machine time into the heads.

For what you need, $300 - $400 sounds more reasonable.

I just had a set done for my starbord engine. Machine shop bill was $294. Valve job w/new valves, magaflux and weld crack, Dover cylindler head service. Chattanooga & Atlanta.

wayne