BigSilverCat

update:
When we ran the boat a few weeks ago and had an engine problem, we thought from the oil everywhere in the bilge that there was going to be a big hole in the side of the block and when we pulled the engine out it looked like there was nothing wrong. We looked all over the engine and could not figure out where all the oil came out of. The oil came from between the head and valve cover spacer, there was an o-ring missing under it. When I put my clear valve cover on I never lifted the spacer up to look under it. Were lucky the oil did not catch on fire from running down onto the exhaust manifold.

We sent the engine back to the builder and they took it apart, cylinders 3,4,5 all had melted pistons. When it was on the dyno the tune would not let the exhaust gas temp get high enough to melt the pistons so we were not sure what had happened. The oil was sampled and showed good so the mains, ect. were handling the power fine it was just something happened that caused a blowtorch in the cylinder. The other engine checked out fine. After lots of thinking about what could have happened we have decided that the tune did not know what to do when the prop blows out coming on plane. We think the high rpm and boost but not much throttle input was making the tune lean and adding positive timing, which would be bad. The engine that burned up had blown out the prop before the other so it was running at 3500 rpm with boost but no throttle for a minute before the other engine spooled up. They had the tune to where there would be no smoke so it was not giving it any fuel to try to get the turbo to spool so that will need changed. If the air temp and water temp would not have been so cold it would have spooled a lot better. They put there race truck on the dyno and when they were loading the dyno they would let the throttle off to about 30% where we were trying to get on plane and the truck would throw flames out the exhaust till they gave it more throttle so were pretty sure that was the problem.

They are rebuilding the engine and I'm going to haul the boat out to Salt lake city in a few weeks where they are located so it will be easier to have the engine builders, tuners in the boat doing the tuning. Having them fly out to Michigan would make us rush on the tuning so they would not have to be out there so long. And it would be harder to make changes to the engines and if there is another problem there would be weeks wasted in shipping again. By taking it out there we would have the ability to change turbos, ect. if they are not going to work the way we want in the boat.

Is anyone on here from Salt Lake City? Does anyone know of where to boat that is close that would give us lots of room to run? Ramps deep enough to float the boat? Ect? It looks like utah lake is plenty long but may be really shallow. I see where we could have 15-20 miles of straight away but may only be a foot or two deep? It will probably be the middle of December so the lakes out there will start freezing over? After we get some testing done on local lakes we will probably haul it down to Havazu or something else closer that stays warm to do more testing.

Here is a pic of where the o-ring was supposed to be that was missing. And the oil mess we had.

FREEDOM US1

That will be good to get the engine guys onboard to understand the boating world. That will help a lot! Catch you when the boats in Havasu!!!

Skater30

Damn Tyson, sorry to hear that!

999JAY

Rear cylinders on the Cummins are prone to getting hotter than the rest, have you the coolant bypass mod on the rear of the block to help circulation, on a raw water cooled setup this would help elevate hot spots and cavitation keeping the EGT lower on these cylinders.

TopSpin80

Bear Lake is a little far, Jordanelle is the lake our family from Utah says to go to... They are thinking Utah Lake is nasty, gross semi fresh part of the salt lake. It stinks like a sewage plant.

Ernie

dvr4hire

I've held me tongue more than once on this thread, but If you think for one second that a diesel engine can actually run "lean" and that doing so for 30 seconds while the props are blowing out would cause it to melt pistons you need to stop what you are doing immediately. If that opinion was given to you by anyone else I would distance yourself from their company as well. Best of luck, Steve Desmarais

dunnitagain

I was thinking the same thing , he's a master at designing gear trains.

skater40

Stay as far away as you can from Weismann.
I would consider lake Powell or Havasu for your testing.With Havasu you have Vern and his Shop to help you out.Their is a lot of talented people in Havasu .

1 MAIDEN AMERICA

I had a head gasket let water get into the valley once. It pushed the dipstick out and coated the engine bay with oil. It looked like an engine massacre. Insult to injury! I feel your pain. It wasn't diesel oil though....damn!

BigSilverCat

I have had this conversation with people before when they told me they leaned out a diesel and I said it cant be done. A diesel is know as a lean burn engine. That is the whole reason we are using them instead of a gas engine. It is not for the "reliability" of the diesel (so far none of the ones I have had built have lived yet) But the whole reason we are using them is because of them burning lean, getting good fuel mileage. That being said I have thought about it for the last couple of hours and I will change my stance on that you cannot lean out a diesel and I will say that yes you can lean it out too much. I know this will start a **** storm, but after thinking about it for a few hours I'm sure that it is possible to run my engine lean enough to burn up the pistons. I'm not saying that is what caused our problem because were not sure yet, but when its put back together we will find out.

Before people start fighting about that you cant lean out a diesel I will say that 99.99% of the diesels ever made you probably could not lean out enough to cause a problem and that any old time diesel mechanic that has worked on diesels for 100 years would probably fight till there death saying you could not lean out a diesel, but I like to think outside the box and I will say that with today's technology you can lean out a diesel to the point of melting pistons.

I have looked all over the internet on diesel forums and pretty much all of them say you cannot lean out a diesel. I am really going out on a limb here and I'm going to say all those people on all those forums are wrong. I know that in theory if you lean out a diesel you are just pulling throttle back and not making as much power but i will say that you can lean out a diesel and have the temp increase. But who do you "call" to find out? Who do you trust there answer? Just because they have built diesels for 100 years would mean nothing to me on if they are right or wrong. It just means they have lots of experience with what they have done but not that they know about something they have never tried.

So here is the question, who do we call to find out if you can lean out a diesel to the point of melting pistons?