3208T 260HP Engine rattle BAD!

Following a great 200 plus hour tour to North Queensland thru the Whitsundays on our liveaboard Mono Lyscrest 42 from Brisbane we finally got home again after a year with relatively no problems. Even did a complete service on both engines prior to departing Magnetic Island off Townsville. Two weeks after getting home decided to run the engines on the dock when I heard a very load clacking sound coming from Stb engine (and it didn't sound as it was running on all cylinders) on lifting the hatch to determine which engine it was I immediately shut down. Diesel Mechanic was called and he also didn't like what he heard and also shut it down. He thought it maybe water in fuel as there was evidence of this which had effected the genset which would not start. Proceeded to do a fuel clean dialysis, changed all filters and cleaned out injector lines etc (got lots of fine brown crap out) When all done started genset and it ran OK. Started Engine and still had this broken noise. Have since lifted tappet covers and all rods etc seem OK nothing broken or loose. On turning engine over without starting her you can hear a shoosing sound and some knocking noise it appears from further inside. He is about to do a compression test and run a camera down to each cylinder to see what gives, sometime in next couple of weeks. Looks like my insurance and pocket are about to be hit big time....any ideas or words of sympathy for this broke boater old pensioner!

The shoosing sound is probably air going past the rings. Internal noise could be several things. Engines that are running fine and make noise at the next startup usually have a fuel or injector problem. At idle a bad injector can sound remarkably like a broken rod.
One thing you could do is swap the injectors between the two engines.

Firstly, welcome aboard! Always good to add more Aussies to this forum.

With luck it will turn out to be an injector problem. Good luck with getting it sorted!

A partially failed damper plate for the tranny can make many strange noises.

Check your valve clearances, it may be a bent or stuck valve.

The whooshing noise would have my attention, that does not sound like injector. Frequent 3208 weakness is head gaskets. I’d take another look at the valve train and as suggested look for a sticking valve. I pulled off one of my heads myself this past winter, just myself. Ran an I beam through the salon to help with the heavy objects and no helper. This is a simple engine, whatever it is, it can likely be fixed.

You were right

Mechanic did compression test on Stb engine and found no compression on number one cylinder however after tapping down on valves found some compression> Looks like we have a valve problem on number one. Following up with a camera showed nothing wrong with top of piston. All others cylinders shape up OK with good compression. May have dodged a bullet here. Injectors sent off for testing and for clean & repair if required. Head to come off in a week or so, only on the one side as Stb side would be a bugger with no room to work in this engine room. Will update everyone interested as we go. Thanks for your help everyone. Robin

Welcome Aboard! Glad your problem is turning out less serious than it might have been.

Welcome.
Who did you end up getting to work on her if you don't mind me asking?

Sometimes a "valve problem" is just carbon buildup that keeps it from sealing.

An attempt before disassembly cold be to use a "flit" gun ) a pump sprayer for bugs as use 50 years ago) to spray water into the intake.

This causes steam in the cylinders that loosens carbon quite well. Spray rapidly enough to caise missing , but not stalling at about 1100RPM.

Outboards have a chemical they use that might also work.

Pulling the head for a real top overhaul is of course best , but best done in the off season.

FF said:

Pulling the head for a real top overhaul is of course best , but best done in the off season.

Click to expand...

We're in Queensland
There is no off season.
Beautiful one day perfect the next

Hi Mate, We use Franz from Aquasure Marine Victoria Point.

Head Gaskets!

Further to my engine rattle problems we have now lifted the head on inboard starb side of the V8 Cat engine to find that the problem was a blown (after market) head gasket! Although there appears to be a fair amount of carbon build up that seems to be the only damage. Both engines have less than 1600 hrs even though the boat is 1991 model. Have tried to contact previous owner to find out if he had changed this gasket and why, yet to get a response. Question to all the Cat experts out there? Due to costs and us being pensioners, can I get away with having this one head machined and valves done (injectors already be serviced all good) and leave other side alone? compression test show good readings on other head. Engine recon guys say I should do both but my mechanic thinks we should be OK. Block looks OK with head off! We don't intend doing anymore long cruises and will just potter around Moreton Bay here in Qld. Any constructive comments appreciated. Robin

You could just do the one head and see how she runs. If there are any problems, just do the other one.

Absolutely can do one engine at a time.

3208 head gaskets have a "watch out" after 20 years or so. Boatdiesel.com is the place to go with several including Nautidog as guys to listen to. Ski on this site is a solid source of hands on information as well.

The 260 HP version is long lived but does require a careful hand as they age. A coolant drip is usually the first sign.

You can do the one side. The opportunity is that doing both will be cheaper since you already did most of the prep of pulling everything else apart. I did just one side, because we had the other off years ago and I invested in making a gantry crane in the salon so I can do the labor myself. It’s a gamble to only do one side, but not a big gamble.

Often times head bolts get reused. Best practice is to replace. Cat went to a stronger head bolt and increased torque values at some point and that was related to the head gasket issues. At a minimum have your head bolts checked to make sure they are the higher torque variety. They are not cheap, but I’ve always felt it’s not worth the gamble here to not just get new ones.

You can do one head, but preference is to do both as it seems the 3208 head gaskets age rather poorly. Seems you get 20-30 yrs and then they start leaking.

I did one head on one engine and strongly advised the owner to do both heads. He rejected the advice. Six months later the other gasket blew.

But it depends on planned use and difficulty in access. If it is a real pain to access, nothing wrong with taking your chances with the outboard head.