motor started 2 weeks ago. went to start, wont fire, checked fuel ,spark all ok, found inlet manifould had being letting in water ,only being in salt water app 2 hrs since reconditioned. always run app every 2 weeks at home.to day had a compression test .found low to nothing on most cilinders.mecanic reckcons rings are ceased, for most of the cylinders to cease like this seems major.i reckon it could be valves arnt seating as the valve stems are rusty. dont want to pull motor if i only have to reseat valves.any thoughts.
muzz67,
Jul 2, 3:40am
heads have gotta come off anyway.
m16d,
Jul 2, 4:02am
Nar. you've got some valves stuck open. take the rocker covers off. you'll soon see the ones not closing properly. CRC and a hammer I'll fix it.
frank1,
Jul 2, 4:04am
Suggest you do a compression test with oil down the spark plug holes,will tell you if rings are seized,if compressions come up. Guess inlet manifold is water cooled--yeah course it is--intake manifold gasket or not sealing on heads because of maybe over machining of heads over time If water is getting in thru inlet manifold,the problem is there. You dont say if motor has a heat exchanger.
snoopy221,
Jul 2, 7:32am
.to day had a compression test .found low to nothing on most cilinders.mecanic reckcons rings are cease
Shhesh continuing saga ain't it.
Well at least ya found a ? able to compression test it. NOW you need a MECHANIC-capable of doing a cyl leakage test-tappin valves and re compression testing. Then. pressure testing cooling system. AND-YA STILL-AIN'T STATED HEAT EXCHANGER-OR RAW SALT WATER COOLING.
muffycaz,
Jul 2, 3:59pm
raw salt water cooled. found inlet man cracked. put on new one before compresson test.could it be rust stopping valves seating
pdc1,
Jul 2, 7:50pm
Quite likely to be valves stuck. Take the tappet covers off and check that valves are opening and closing as they should. You will find lots of play / looseness in the rockers if they aren??
petermcg,
Jul 2, 11:42pm
I dont know what sort of cooling system you have on this motor but there is a good chance it has just got to hot in the last run and the rings have gone soft. The rings dont normally seize. Also what about timing is it possible that the timing chain could jump or stretch,, just a thought.
muffycaz,
Jul 3, 3:45am
did a pressure test myself . air was leaking out of exaust valves mainly. took of heads, removed 2 valves seats were pitted so have sent heads to have valves reseated,hopefully this cures the problem,should of thought to put a new manifold on,its only $260 expensive lesson learnt. thanks for all advice,cheers grant.
skin1235,
Jul 3, 6:08am
burning valves in a hyd tappet motor?, ( 350's weren't usually solids, although she may have had solids slipped in her) I'd say the whole engine needs some careful attention, and proper attention
starting with a full flush of oil ( 2 filters), a proper oil rated for boats to fill with new filter,(3rd filter) the hydra's need pulling , dismantling, cleaning, checking and refitting ( do this between the twin flushes and the last filter change) then the breather valve needs the same and check where it is fitted on the air cleaner, make sure it is in the vortex area, not way out alongside the cartridge, make sure there are breathers from both covers, personally I'd chuck the valves away
yep the wet manifold won't have helped but it would appear the whole engine has been drowned recently, all the good care in the world won't negate the proper procs for when that happens
you say raw water cooling - so where is the sacrificial element, did you use a sacrificial element - even one built into the water filter unit - - you do use a filter, not just run whatever crap gets sucked up pumped through the engine blocking head galleys etc right?
skin1235,
Jul 3, 6:13am
raw SALT water?, through an ali valley manifold? oh dear
it maybe too late already for this one
and I'll bet the thermostat is missing as well as the temp gauge, and the temp tap on the outlet if you're serious about this boat and the engine, and the safety of anyone who goes in it - you need to take a long listen to someone about why you do things a particular way with engines in boats
skin1235,
Jul 3, 6:18am
be interested to know what sort of cooling you offered to this engine when it fired up 2 weeks ago, please tell me it was more than the garden hose jammed in a pipe and lots of steam out the other end
elect70,
Jul 3, 8:27pm
Excuse my ignorance but why have salt water circulating around a V8 inlet manifold ? Thought only water cooled the exhaust manifold .
ceebee2,
Mar 27, 8:20pm
Yes IF there is a separate heat exchanger fitted!
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