Thanks for the quick replies.
I was on the boat during the sea trial, and the engine did not start quickly at all-- it seemed somewhat cold blooded to me. The air temp was mid 30s and the engine hadn't been run in a couple of days. Engine has 1300ish hours, and seemed to run ok, though there was quite a bit of steam for a short while. Guy doing the survey couldn't pinpoint where it was coming from, but it was mostly concentrated around the exhaust riser. By the time we completed the trial, the steam had stopped. The boat topped out at 20+ knots @2900 RPM. There were three of us on board, and 100 gallons of fuel-- not a heavy load. Unfortunately the boat is pretty far away, and most likely out of the water by now, so follow up sea trials probably aren't going to happen.
Unfortunately my knowledge of diesels is nill, I've owned an outboard Sisu 22 for the last 32 years. I built the boat as a kit in 1980.
The H&H has a couple other issues, most troubling to me is the lifting rails, which seem to have allowed some water into the divinycell core. Not impossible to fix, but definitely a pain in the butt. I never installed the spray rails and bilge guards on the Sisu for that exact reason.
Anyway, thanks and keep the comments coming.
Quick update: I talked to the broker this morning, and the owner is having Cummins Northest check the filter (cut it open and check for metal), test compression and run a bore scope into the cylinders. My question is: if there is damage to a piston or pistons, would the bore scope pick that up?
Borescope should be able to see excessive wear to liners, valves or piston crown. A lot of times piston skirt wear/ or damage shows up in the liners.
FWIW, a borescope is a lighted optical eyepiece viewer. It has a long flexible "sight" that fits in small openings.
They will probably pull the injector nozzles (tips) for the borescope and compression check which might also show any issues. Just remember, Cummins 6B's are a dry liner which means they can't be changed easily.
When you said "steam" from the riser, sounds like you are talking inside the engine space? Like an exhaust leak?
did the boat have a vibration in it did you notice. And didn't the 5.9 have some type of frt cover problem where they drilled a standard hole and put metric guide pins in.
A few comments and a suggestion or two..
1. As far as the 6BTA 370 seeming "cold blooded" when starting in 30ishF weather that is kinda normal with no pre heater or block heater. I can see in the picture you posted the air intake pre heater is not hooked up. (that is fine, I don't use the circuit either but I have block heaters). So yes a "cold 30F start" will result in initial stumbling/blue/white smoke that will clear. All normal.
2. The white smoke or vapor around the exhaust manifold could be a leak @ the exhaust/turbo flange. Hard to say without seeing it in person and simple enough to resolve. First thing I'd do is take the Cummins elbow off and check to see if the exhaust side of the turbo has "seen any salt water".
3. The owner can cut the oil filter open and have the filter media that examined for metal etc. Right now I'd hold off on the compression test. Kinda meaningless. A better way is to fire up the engine and while @ idle feel for any pulsations with your hand @ the breather tube (hidden unless you know where it is) or the oil fill hole on valve cover #1 and see with your eyes what you have for blowby fumes if any. Remember some blowby is normal with an engine that has 1300 hrs.
4. Of concern to me is the WOT of only "2900 rpms". IF, and it's only an if with analog gauges, the rpms are accurate on the gauge, then a WOT of 2900 =s an overloaded engine. If in fact the engine has some tired piston rings, running the engine overloaded over time would explain the aluminum if the oil sample "means anything". That engine needs to see minimum 3100 @ WOT with the boat loaded as you'll use it. BTW, did the surveyor measure WOT rpm with a photo tach ?? or use the gauge?
5. The Cummins 5.9 has a parent bore engine block. No liners!
To replace rings or a piston or clean up a cylinder the best way is to hone, over bore to next size piston. One jug, two jugs or all six. Not expenive for parts. NO LINERS !!
6. I'm not sure what is meant by the "vibration up front" comment. The Cummins 5.9 is a super smooth six cylinder. There is a bit of "gear noise" up front under the timing chain cover but the engine itself is super smooth.
7. A word of warning on hiring a "marine diesel engine" surveyor. I hired a highly referred "Cummins ONLY engine surveyor" in S. FL to "survey" ($1000) the Cummins 370s in my Blackfin back in 2008.
Running and learning the 1995 6BTA 370s that came with the boat and then repowering a year later with new REMAN 370s......let's just say for a highly referred Cummins marine engine specialist he did not survey the engine the way it needs to be done.
Finally, if you really like that 32 H&H, I would not walk away from the boat because of the Cummins 370 in the boat. You need more hands on assessment of the motor and information to make an informed decision. If I had to bet, that 370 has a ton more reliable hours left in her. After that, pop it out, bolt a new REMAN in.
Lots more to go over with you on assessing this 6BTA.
For what it's worth,
Bill D
