tank delamination

Justinf89 · Post by **Justinf89** » Wed Jun 17, 2009 6:07 am

Well I think the plague has hit. About three weeks ago, I ran both of my motors and the stbd one had a slight ticking when it was cold but the went away, although I never left the dock with it. I try to run them at least once a week but this time, I couldn't get down there for three weeks. So yesterday, when I went to start up the motors, the starboard motor made an loud clanging and then constant, very loud popping. I took off the intake and what I find is four bent/broke in half rods and lots of black goop on the valves. The only two things I can think of is the timing chain and fiberglass delamination. I just switched out the carb on my port motor and I didn't see any black stuff down the intake which hopefully means it's the timing chain and just buildup of carbon or something on the valves. Does anybody have any more information on how I can be for sure that this was caused by tank delamination? Maybe even some pictures? I can post plenty of pics if anybody wants. Thanks guys.

Post by **dougl33** » Wed Jun 17, 2009 9:48 am

Black goop on the valves certainly sounds like an ethanol issue, but it doesn't explain why it would only happen to one motor. I would definitely post any pics that you have. Good luck.

h2ojst · Post by **h2ojst** » Wed Jun 17, 2009 12:53 pm

Doesn't sound like a timing chain to me. Probably just a stuck valve or two. Big Block Chevy's are very prone to bend push rods from stuck valves. Once they bend, breaking is not very far behind. Joe Tomaini 1988 Sportfish Attitude Adjustment II Fort Lauderdale, FL

Justinf89 · Post by **Justinf89** » Wed Jun 17, 2009 4:42 pm

Ill hopefully get some pics up along with the heads off by tomorrow night.

otf · Post by **otf** » Thu Jun 18, 2009 3:43 am

You took off the intake, or the valve covers? Black goop sounds like oil sludge from age on the topside of the valves/rocker arms. What you will see from ethanol/the tank is a black resin like material that is hard (like plastic) and coated on the inside (combustion side) of the valves, intake, etc. Maybe this starts like a sludge and then hardens, that I am not sure of but would tend to think not. I couldn't notice it (although there was a little on the carb - I didn't realize what I was looking at) until I pulled the intake manifold off. Sounds like you didn't run it too hard from the ticking to the real stuck valve, so there shouldn't be much damage other than the rods, maybe a valve or two to replace and heads to clean.

Justinf89 · Post by **Justinf89** » Sat Jun 20, 2009 6:53 pm

I took one of the heads off and the piston that the pushrods broke, it turned out to be a leaking manifold which rusted the valves and rusted stuck. I haven't gotten to the other head yet but a set of pushrods are also broken on that side. I think it's kind of weird that I could have two leaking manifolds but well see. I'm still working on the pictures.

Rick · Post by **Rick** » Sun Jun 21, 2009 3:58 am

I can identify Justin, had same problem. But you definitely want to get that head back on REALLY soon. If there's rust in there, it'll certainly spread to the rings quickly. Fill those cylinders with oil while you're waiting for the head but do not delay getting it back on there or you'll be pulling the whole engine. Rick Ticket 85 SF Merc 454 MPI's Falmouth, MA

otf · Post by **otf** » Sun Jun 21, 2009 4:48 am

A leaking exhaust manifold? On the 454 they are connected across the intake in the center to provide heat for the automatic choke. Perhaps one leak ran across the two sides? It does seem strange that both sides would leak/break at the same time.