GM 90 Diesel

[Crofter]

This engine has been around for a while I guess but there does not seem to have been a lot of discussion about how it stacks up against the generic Listeroids. If there is information somewhere that I have missed, please post a link. There dont seem to be any horror stories about it anyway!

Aside from the Satyajeet web site there does not seem to be a lot of history about its development. It appears to be be on a different enough platform that all dimensions have had to be developed and hopefully a lot of the common problems with the listeroid have been left behind.

Does anyone have extended hours of operation experience. I have not seen any picture or descriptive articles on internal mechanicals. From being made more compact I expect connecting rod and piston length have been shortened a bit with some effect on rod angularity and balance. Is the liner bore chromed? The oil pump arrangement is a much more positive lubrication system than the listeroid. Fuel consumption should be down 5% or so but how friendly is it to alternate fuels. Does the injector stay cleaner?

Sure would like to take one apart to see what makes it tick!

[veggie]

Hi Crofter,

I can't comment on the long run hours but there are a few guys on the LEF that have been running them for a long time. I have these engines in stock and one of them is slated as an R&D engine.
When I tear it down, I can report back with photos.
The 30% size reduction seems to have been achieved by constructing a shallow oil sump and lowering the crank. The standard 6/1 roids have a very deep sump chamber and a large cavity under the engine.

veggie

[veggie]

*** Follow up ***

For anyone interested, here's a video of the GM90 engine.
I found it to be surprisingly smooth for a big single. The base is sitting free on the floor. Rubber pads on each corner.
Biggest complaint was the fuel petcock which leaked right out of the box.   (anyone surprised ?)
I changed the valve and the fuel lines. Everything else seems fine.

http://www.youtube.com/watch?v=IbpiYeCJbNs

veggie

[LowGear]

Nice looking engine. 

Don't the have an oil pump so a remote oil sump would be possible? 

Aluminum piston?

Is that Pex tubing for the cooling system?

Casey

[veggie]

Hi Casey,

The engine has an oil pump submerged in the sump and driven from the crank. Gives positive feed to the big end through a rifle drilled crank.
Yes, the piston is aluminum with 4 rings. 3 above the pin and one below.
Cooling hose is just standard automotive heater hose connected to a remote rad and circ. pump.

cheers,
veggie

[veggie]

No more cycling issues once a load is on ?

No. For safety reasons, I turned down the engine speed for first smoke.
I think I turned it down too far and the governor could not accurately control the speed at 450 rpm.
Spring and weights are tuned for 750-900 rpm operation. Holds speed nicely now.
I fluctuated the load and the revs held steady. I won't go near full load until I get a  bit more run time.

veggie

[Crofter]

Looks like balance is good. What horsepower? Is bolt pattern for cylinder same as ID injection "roids"? Wish I wasnt 3 loooong days drive away!

[Henry W]

No more cycling issues once a load is on ?

No. For safety reasons, I turned down the engine speed for first smoke.
I think I turned it down too far and the governor could not accurately control the speed at 450 rpm.
Spring and weights are tuned for 750-900 rpm operation. Holds speed nicely now.
I fluctuated the load and the revs held steady. I won't go near full load until I get a  bit more run time.

veggie

Hi Vegge,

That is exactly what happened. The spring ran out of travel.

Very nice running setup. I see the engine runs just like my GM-90 ran. As you see, you don't need 2,000 lbs of concrete to prevent it from hopping around.

Henry

[veggie]

Looks like balance is good. What horsepower? Is bolt pattern for cylinder same as ID injection "roids"? Wish I wasnt 3 loooong days drive away!

Engine is 6hp @ 750 rpm and 8hp @ 900 rpm.
Hmmmm...bolt pattern....good question. I was told by the factory that the engine is not available in IDI format.

3 days drive!.... that's nothin !....when I was a kid, I used to walk 6 hrs in knee deep snow to get to school. Left me just enough time to turn around and get back in time for dinner. Never did get an education.

veggie

[mobile_bob]

comeon veggie, you only got it part right!

"when i was a kid, i walked 10 miles to school, barefooted, in 3ft of snow, uphill, both ways..."

"and i liked it!"



thats what i used to tell my girls, of course they rolled their eyes



bob g

ps. as the old saying goes

"the first liar doesn't stand a chance"