I have a 1950 BD that runs poorly when cold. It turns over very easy...too easy. I think it has low compression. It misses terribly. I have had the injectors out and serviced with not much improvement noticed. After its at working temperature it smooths out a lot.
Any thoughts on what to do?
Wes
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Wes, does it smooth out under a load? These engines are known to run like this - miss and stumble around when cold and not under load. The one I have in my OC-12 does it. Smokes white too. But under load she runs just great.
Part of the problem I believe is the Roosa Master fuel pump. Something in them is just not right. They ran like this when new. I've heard the engines with the Bosch pump don't do this.
If you put a muffler on it it will run and sound better too. I'm not sure why, but it does help these engines. I think a lot of the stumbling you hear is just what you "hear" - the engine is not actually running bad.
Good luck,
Blake
Take the exhaust manifold off. Start the engine. See which cylinders white smoke come out of. A trick is to find the missing cylinder(S) and then if you only have one or two, take the fuel injection nozzles out of those cylinders and put then in cylinders that do not miss. If the miss stays with the cylinder no doubdt you have a compression problem. As far as injections pumps go you have either a Bosch ( all the lines out the top or a model A Roose. If you have a Bosch, be carefull as they are timed to number 6 cylinder instead of number one. Also make sure you have oil in the pump and the governor.
Thanks Blake and John.
It does run reasonably well under a load Blake. It is a Bosch pump. I have previously determined which cylinders are missing (the most) by loosening then tightning the injector lines one at a time and listening for a change in the engine. I then swithed injectors with no change in the missing cyl.(s) I have also drained, flushed and put fresh oil in the pump and gov.
I still dont know if it is the pump, the valves or the rings etc. I hope Blake is right, and its just the nature of the beast.
Thanks again
Wes
Are you able to have a dummy injector body made? If so you could pull the rocker arem shaft so the valves can not open. Then the dummy body has to seal in the block and you need to supply air (about 120-150 psi into each cylinder. This is a modified cylinder leak down test.When you pump air in listen for leaks at the intake port, the exhaust port or the oil pan if the rings are bad.
Wes,
A lot of it is the way the manifold is designed. Can't remember the details, but my gramps who was Experimental Engineer told me that these engines sounded like they stumbled under no load. Try the muffler and see what it does.
Does the white smoke go away after it is run a while and gets warm? It could be oil sitting on top of the pistons from sitting.
Let us know how it sounds with the muffler.
Blake
I will let you know how things turned out. Thanks again for the suggestions.
Wes
I haven't been running the BD as the fan belt broke and with the hydraulic pump on the front I couldn't figure out how to get at it.
Life has been getting in the way of my old crawlers and tractor hobby.
I'd get it warmed up good and check the timing. It could be a little slow. My OC18 sounded odd and stumbled and missed more than it should have and it ended up being slow a couple degrees.
The BDs I've been around all seem to spin over easily, and all stumble smoke and miss until they run for a couple minutes, or until they come up to temprature. Even my friend's that was meticulously rebuilt years ago misses for a minute when cold.
Bob
The shaft going to the pump is splined and should be able to unbolt it from the crank and slide it into itself to gain access
Bob