View Full Version : Engine: BMC Commodore 38 Diesel
john j henderson
10-06-2004, 03:00 PM
I have a Newage/BMC Commodore 38 diesel, 65 hp with a bad exhaust manifold. Engine has not been run in 3 years. I found a replacement manifold in Australia for approx. $500 US dollars. Because of the rare supply of parts for this engine, would it be better to scrap the engine and repower, maybe with a Perkins rebuilt 4-108 or similar.
[ 10-06-2004, 04:02 PM: Message edited by: john j henderson ]
10-06-2004, 03:03 PM
I suggest the answer is probably "yes".
Alan D. Hyde
10-06-2004, 03:07 PM
Just how much trouble and expense would be involved in MAKING a new part for it?
I agree with Andrew (I almost always do, unless he supports perfidious Albion) It was not a great engine to start with.
I don't know what kind of boat you have. You could put a dry manifold (from a London taxi) and have a dry exhaust (beloved by Maine lobster boats) or inject the cooling water after the manifold.
[ 10-06-2004, 07:26 PM: Message edited by: Hwyl ]
10-07-2004, 05:01 AM
John ,$500 seems a lot for a manifold...is ther a motor vehicle equivalent ?The London taxi...if you can find that a manifold should be $50 used.
10-07-2004, 09:54 AM
And if you want a Perkins, I have one in my shed that's yours for the taking. It was on a generator, so no gear, and I was told it ran when it came out. Near New Haven, CT
10-07-2004, 07:15 PM
I am side-tracking on the main issue, but need to understand:
1. Why are water-cooled (fresh or raw-water) manifolds standard issue in the majority of marine engines?
2. Why are "dry stacks" (presumably standard, air-cooled manifolds?) standard issue in some work boats ?
john j henderson
10-07-2004, 07:54 PM
wet exhaust not only cools the exhaust, it also help decrease the noise of the exhaust
10-07-2004, 09:54 PM
But if noise is of no concern, could marine engines operate with standard air-cooled exhaust manifolds ?
Or would the latter entail a fire hazard, especially in the smaller engine rooms of recreational boats ?
Before I DIY-marinised my boat engines with fresh-water-cooled manifolds, I had entertained the thought of completely surrounding (encasing ?) the original air-cooled manifolds with a cast piece of copper (or bronze), through which cooling water would circulate.......some people said it would work, others just the opposite.
Lobster boats here in Maine (cold water) usually have a long u shaped pipe in the water (keel cooler) that runs from the regular water pump. The exhaust manifold is just htere. The rest of the exhaust pipe is wrapped with insulation, then there is a big expansion-box/muffler/silencer they tend to be noisy, but it's so simple.
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