Crank and clutch workings

RiderRocketman

Supercharged
Joined
Sep 13, 2005
Messages
430
Location
Twin Cities, MN USA
The other day when I dropped off the new clutch parts at the dealer I took a snapshot of my open engine case. Here is my Mistress' innards with some things pointed out for your enjoyment. I've been reading the service manual and trying to figure out how all these parts work, so here's my best interpretation.



When your engine is running, the main crank gear is always turning and in turn run the oil and water pumps, alternator (not pictured - in rear of engine), cam shafts and anything else connected to the crank shaft and gear either directly or via chains.

I'm not sure what that large bearing on the left is for, but I'm thinking it holds the balancer rod, which stabilizes the triple engine. Engines with even numbers of cylinders (2,4,6,etc...) don't need a balancer as the movement of the pistons negate one another, but in a triple we don't have that natural balance so a balancer rod is used to keep things stable. Otherwise the engine would shake itself apart.

That main drive bar is where the clutch assembly sits (below).



You can see in the top photos the entire clutch assembly all together. Those big primary drive and backlash eliminator gears (snapshot 6) you see connected to the outer drum mesh directly with the main crank gear, so the outer drum is also always rotating when the engine is running.

In snapshot 2 you see six big springs. These are not the clutch springs that you'd replace, such as with Barnett clutch springs. These are actually there to dampen the torsional forces when the clutch is engaged.

I don't show the replaceable clutch springs here but in snapshot 3 you can see the 5 bolts which hold those springs in place and in turn hold the clutch plates tight. In snapshot 4 the inner drum is removed and you can see the clutch plates sandwiched inbetween the front pressure plate and back plate. Those sandwiched plates are the ones you'd replace.

Now how the clutch works to engage the transmission...
I think I need some help from a real gearhead as I can't seem to figure out how it really works.

Logically, the inner drum that houses all those plates is the part that connects to the transmission's drive bar. When the clutch is disengaged, the inner drum and plates are pulled out so they don't contact the outer drum and rotate with it. But the plates and inner drum mesh with the outer so I'm wondering how the plates disengage from the outer drum.

It might be that the Backlash Eliminator Gear (the thinner of the two large gears in snapshot 6) also pulls back with the plates and so disengages the transmission. Anyone know how that clutch assembly really work?
 
I think that the water pump would be driven off the end of oil pump sprocket shaft , the chain that you think drives water pump I would have thought that this is the cam chain considering the size of chain and the tensioners . :?:
 
there some cracking pictures by riderrocketman , nice to see a little further into the engine . :D

RiderRocketman , is the bearing that has failed to be seen in picture or is it the othe end of engine. :?:
 
Nice job, thanks! I love this kinda stuff. Don't really want to ever have to mess with it again, but it's fun to look at! :D
 
Send it to Tech, and any other photos you could take as the clutch is installed, please show us. If the mexh won't let you hang around, loan him your camera and a $10 spot to phot everything!!! Great post!
 
I'll see what I can do to work out more pictures.

The failed bearing is not in the photos. It's in the transmission which is behind the case wall where that main drive bar is.
 
I believe you're right Sully. After reviewing the service manual again it does look like that big chain on the left is the cam chain.
I'll change the photo and text. Thanks!
 
RiderRocketman said:
...............................................
When your engine is running, the main crank gear is always turning and in turn run the oil and water pumps, alternator (not pictured - in rear of engine), cam shafts and anything else connected to the crank shaft and gear either directly or via chains.

.............................................................................
Now how the clutch works to engage the transmission...
I think I need some help from a real gearhead as I can't seem to figure out how it really works.

.....................................

This is my answer based on what these excellent pictures show--------somebody correct me if I'm wrong, but this is what I see............











From looking at the top picture of the engine, it looks to me like the oil pump is chain driven only when the clutch is engaged (in neutral or in gear) and the tranny is turning.

To understand how the clutch works, look at figure 2--the outer primary drive gear meshes with the main crank gear and is moving all the while the engine is turning. The smaller circular hub in the center, meshes with the main drive bar of the transmission and the steel plates.

When the clutch is disengaged, the center part does not move (unless the back wheel is jacked up--then you will get some movement due to friction and the wheel will spin)

When you engage the clutch, the outer unit, that's always moving (along with the "keyed-in" friction plates) presses the moving friction plates against the interspersed steel plates that are keyed into the inner hub and both units "lock" together and drive the transmission.

The Barnett springs are made of a shorter overall length (unwound) thus we would expect them to be stiffer. They are also theoretically able to be more compressed that the stock springs, but I don't see that compressability plays a role here. Possibly, if the stock springs are compressed close to their max at engagement, the Barnett's would still have a range of motion left in them possibly adding to a smoother engagement.
 
Interesting. I wonder why they'd want the oil pump to only run with the transmission engaged. I'd think you'd want oil circulating at all times. Though looking at the oil system, there are two oil pumps - a pressure pump to shoot oil from the oil tank under pressure to various parts of the engine and a scavenger pump to get the oil at the bottom of the sumps back up to the oil tank. The service manual is unclear if both pumps run from the same sprocket. It could be that the pressure pump is run only with the transmission while the scavenger pump is always running. That way, when all the components are running hard with the tranny going, the whole system gets shot all over with oil but when the engine is not working hard (transmission not engaged) the scavenger pump keeps the oil moving at a slower pace.

I got a better picture of how the clutch works now, but it's hard to imagine without seeing it work. I wish I could see the components running. It's pretty fascinating stuff.
 
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