4000su to 3910 loader switch.

[Gromit]

We've been working on switching our Ford made loader over from our 4000su to a 3910. Everything was bolting up until it came to the crankshaft pulley hub. The hub doesn't line up with the pipe in the bolster. It off by a good 1/4 inch. The bolster castings seem to be identical. Are there different castings? Another thought was that there is a difference in the specs for the crankshaft between the gas and diesel engines. Any incite would be appreciated.

 

[Sean in PA]

The hole in the bolster is for the shaft of a front mount pump, so it should line up with the center of the pulley. Sounds like that 3910 might have run into something at some point in its life so that it's not straight any longer

 

[Ultradog MN]

I read your post yesterday and couldn't quite figure out what the problem is.
Are you saying the hole in the front bolster is not concentric to the crankshaft?
The front pully is identical on gas and diesel engines. Is your pump drive shaft too short?
Could you post some photos?

 

[mhb@ufe]

Are the radius rods bent? The center axle pin and bushing is probably worn and the front axle support could be worn also.

Mark

 

[Gromit]

Nothing appears to bent. And with the heft of the bolter directly bolted to the engine block, I really don't see how anything can get bent. When you look through the bolster hole, you can see that the bolt for the pulley is off center. I'm going to assume then that if engine isn't the problem, maybe a bad casting?

 

[Gromit]

Shaft isn't too short. The pulleys are identical, but are the blocks identical between the gas and diesel?

 

[Gromit]

Rods are not bent and there doesn't seem to be any measurable wear.

 

[RodinNS]

The engines are geometrically identical. That should not be an issue. Bolsters... I suppose it's not impossible for one to bend as IIRC, those are cast steel. Still highly unlikely that it would bend. Most likely... there is a problem with the pivot pin. I think I'd drop the axle down and have a look at the pin and bushings. Sometimes... unless you've jacked it off the ground and dropped the radius rods loose... you won't actually see the slop in the axle pivot. It's also possible that someone has done a half assed repair on it in the past and it's not centered correctly...

Rod

 

[Sean in PA]

(quoted from post at 08:50:07 05/15/14) Shaft isn't too short. The pulleys are identical, but are the blocks identical between the gas and diesel?

The positioning of the crankshaft pulley relative to the bolt holes for the bolster should be identical between a gas and diesel engine. The center of the crankshaft pulley should line up with the hole in the bolster on all models, gas or diesel.

I'm still thinking that the bolster took a hit sometime in its past and is not quite straight. Or possibly the holes in the bolster for the bolts where it mounts to the engine got wallered out and it has shifted position. Have you had the nosecone and radiator off to see if there's anything incorrect in the mounting of the bolster to the engine or if it looks crooked in any way?

 

[Gromit]

Everything looks straight. It seems to me that if
something hit it that hard, the casting would break.