North American SMD vs Super BMD engine parts?

tractorsam · Jan 2, 2010

Hello all, I was sat down this evening (we're having absolutely filthy weather, snow/rain/snow/rain) and was looking through one of my books and the British built direct start diesels of the Super BMD / B450 appear to use the same block as the North American SMD / 450. I got to wondering if any of the engine parts (pistons, sleeves, bearings etc) are interchangeable? If so are any of these items available (possibly more cheaply) from suppliers (aftermarket?) in the UK. I currently have two of these gas start diesel in need of very serious attention and I'm just trying to find any way to reduce the nearly prohibitive cost. Thanks, Sam

D Slater · Jan 2, 2010

Blocks, heads and most engine parts are different. 3 main bearings in the british diesel blocks and 5 in the US diesel blocks.

tractorsam · Jan 2, 2010

Interesting, they look so similar. I wonder what was the purpose in engineering two very similar yet seemingly totally different engines. I'm surprised that they only had three main bearings, I know the NA one had five and would have assumed the British ones were the same. I had figured on the heads being different. Learn something new every day. Thanks, Sam

Larry B 1486 · Jan 2, 2010

Back in the mid 1970's I had a B450 and a SMD both at the same time. No engine parts are the same. The pistons are the same bore but the wrist pins are in a different location, from the top of the piston. The blocks are not even close. Nothing about the motors are alike. Even the transmission used different size gears and shafts. The B450 also had a differental lock. About the only thing that would interchance was the front and rear wheels, grill, front boster and steering. I think that was about it. Starters will fit each other but won't work, different ring gear. The B450 did have more power than my SMD.

tractorsam · Jan 2, 2010

Thanks for the info. Yet another good idea (or was it?) solidly sunk. Thanks, Sam

mkirsch · Jan 2, 2010

Did patents (or lack of patents overseas) have something to do with the reason the American Super MD had the archaic start-on-gas engine while the Super BMD had a modern glow-plug direct-start diesel?

IH was not known to pay licensing fees on patents, hence the reason for the Fast Hitch in the US, while British Farmalls had 3pt.

tractorsam · Jan 3, 2010

I don't know about the patents but I believe the the reason for the start on gas diesels is that's what they were set up to make in North America. Production in the UK didn't start until about 1950 by which time battery and starter technology would have improved sufficiently. That said, having seen a couple of B450's start up in the summer, you could almost be glad of the gas start diesel. Sam

John M · Jan 3, 2010

Having mechanically restored a B450 quite a few years ago, I can tell you this. I was able to cross the bearings to something made here, dont recall what it was now, and I had the pistons reworked with pins from something else, and the sleeves I had to have made. It wasnt cheap by no means, but find a good engine machineshop, take them your old parts, and have them search for something to cross to. Its out there. I think it might have been cheaper for me to fly overseas and get the parts!!!!!

North American SMD vs Super BMD engine parts?

tractorsam

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D Slater

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tractorsam

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Larry B 1486

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tractorsam

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mkirsch

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tractorsam

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John M

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