High performance diesel - Page 3

Jon Fuller · 17-01-2006, 12:00 PM

mine are GM (not AM General) 6.5 TD V-8's, they are the lower compression (18:1) motors, as supplied by Peninsular Marine in Michigan, I bought them as long motors (blocks, heads, cranks, rods, pistons, DB2 Injector pumps etc) then did the marinising & ancilliries myself.

I also bought the Switzer turbochargers from peninsular, and after 3 years of aggro trying to get my exhaust manifolding reliable, I gave up and bought the cast Aluminum manifolding from them also.

They make an estimated 325 hp (educated geustimate based on fuelling, verified by the performance of the boat)

They drive through Mercruiser Bravo1's.

they've done 200 odd hours now, and the engine/drive combo seems ok.

MikeyFIN · 17-01-2006, 12:43 PM

Ok so you´re one of the few who really has a good experience with Peninsulars.
A guy here with a Baja 420ES has similar engines and he´s had some problem with them ( hole in block etc..).
I´m very familiar With Peninsulars as I know the importer here personally.
He stated there were onetime 420 hp Penisular Beasts.

On the other hand GM 6.5´s with AM general pieces has normally aspirated got up to 210hp on a dyno and the Turbocharged run in Vans&Suburbans&Pickups here with up to 270-300.

Me thinks that Scarab would fare even better with 6.5´s but lets see if it gets Duramaxes with Powerglide 2 speeds.

Jon Fuller · 17-01-2006, 12:46 PM

the guy who had trouble, are they genuine peninsular (low compression) motors, or are they marinised 'Automotive units?

MikeyFIN · 17-01-2006, 01:15 PM

Genuine, he got them at least once warrantied thou.

But I remeber a Time when he bought that thing saying that as long as theres gas in pumps he´ll stick to BigBlocks.

Might be something with pouring the power on too soon (cold engines) and the load of a 420 Baja is quite much.

The same importer made also autoengines to marine use with seriously limited in succes....

Jon Fuller · 17-01-2006, 01:28 PM

Oh, well. I doubt it's because he puts the power on too soon, they suffer with quite bad turbo-lag, and as a result (unlike the supercharged 'Marinediesel' version from sweden) it's hard to make it work until the RPM's are up.

I marinised an Automotive 21.3:1 CR GM 6.5, but only to 240 hp, single turbo from a Volvo AQAD41 motor, no intercooler.

Used it in a single engine 26 Extreme (Ring 26). It only did 47 mph, but was very reliable, and VERY economical, using under 3 imp galls/hour average, usually cruising at around 40mph.

That's about £2.50/hour back then, absolutely unheard of at the time. Did 2000 miles in one season, then sold it to a friend who did another 1000 miles or so, without a single problem.
He re-engined the boat with a 315 Yanmar after that, as he wanted more speed, he sold the motor to a Bayliner owner, who continued to use it.

I think the answer is to not be too greedy with the amount of power you try to extract.

Peninsular do indeed make a twin turbo 400hp model, but i'm not sure whether the motor is really strong enough for that.

MikeyFIN · 17-01-2006, 01:52 PM

Well the reason no1 several boaters run into is with Diesels you have to wait to let the temps stabilize before starting to pour on the gas.

Your experiments sound good. when you keep to your senses how much you stress any engine they probably work ok.
Have heard even that Yanmars aluminum exhaust headers then to crack/melt relatively easy.

I´ll really look forward to Duramaxes in the future.
With Surface drives.

Jon Fuller · 17-01-2006, 02:03 PM

I reckon my motors spend most of their running time at 80% or greater, as the boat runs far better when running @ 60 and above. Arse end is too heavy for slow cruising, the ballance is all upset.

i take it you've seen the various vids?

http://media.boatmad.com/gallery/v/m...final.wmv.html

http://media.boatmad.com/gallery/v/m..._8_05.wmv.html

http://media.boatmad.com/gallery/v/m...rtigo.wmv.html

MikeyFIN · 17-01-2006, 02:59 PM

Yes I´ve seen them..just in fact watched the again 15 min´s ago.

Diesels tend to like to run above 80% of full power anyway so at least you´re right on the spot mostly.
You might look into www.northoffshore.com there´s also some boat with diesels...big and small..the biggest being a MasMar 75.

Rockey · 17-01-2006, 05:45 PM

jf what about the tigershark diesel any news on that in the bat boat

jw. · 17-01-2006, 07:30 PM

Quote:

Originally posted by MikeyFIN
You might look into www.northoffshore.com

That aerobatic plane vid is seriously cool. Amazingly sharp to the controls.