Comet 40 outboard alignment

Status
Not open for further replies.

JPGraphX

New member
Messages
118
Reaction score
0
Location
Quebec
Hi !

I have a question about comet 40. With reverse spring spring. (Yellow) how am I suppose to align it.. My belt is not aligned on idle or on top speed. Do I need to reverse the driver when using outboard driven?

Thanks,
JP
 

itsid

Moderator
Staff member
Messages
11,564
Reaction score
107
Location
Ruhrpott [Germany]
nope, keep the driver as it supposed to be (that's why you have the reverse wound spring)

with the engine of align the driven in such a way, that the belt runs perfectly straight and in a 90° angle from both shafts (PTO on driver and jackshaft on driven)

that's the case when the centerline of the driver
(center as in the center of the sheaves, without taking the bell into account)
and the centerline of the driven (again, just sheaves, not the cam-spring-thing)
are offset by ~3/8" (driver is further IN- as in towards the engine on inboard setups)

I think, -someone may correct me if I'm wrong- with a reverse spring and an outboard driven, it's safe to assume that you can run the TC with the fixed sheaves (inboard sheaves on both) aligned.

As long as the belt is perfectly straight on a non running engine, it will stay perfectly straight while shifting through gears.

'sid
 

JPGraphX

New member
Messages
118
Reaction score
0
Location
Quebec
Hello,

I finaly installed the red spring and reversed my driven. But I would like to figure how it works.. may be it will help someone in future.

Here is a picture that show reverse(right) and standard driven(left). In yellow is belt at low torque(speed) or idle and in blue is belt at high speed. I can't see how it is possible to align a belt when they travel on opposite side.

On low torque/speed, the belt should run off axis when using a reverse spring?


JP
 

itsid

Moderator
Staff member
Messages
11,564
Reaction score
107
Location
Ruhrpott [Germany]
You're right.. the belt has a lateral movement of 3/8" on both pulleys, the driver and the driven,
inboard mounted in the same and outboard in the opposite direction, making it a total of 3/4" offset
nearly one width of the belt itself.

I guess I was misinterpreting the pdf .. now it starts to make more sense.
the offset in the pdf wasn't the driver/driven but the non depicted belt ;)

Anywhoo, you could allow the driven to float so that it has a lateral movement of one belt-width, (the 3/4" you need plus 1/8" wiggle room ;) and you can use the belt to determine the space you need)

it should align itself rather nicely and the pdf states the DRIVER must not float..
so.. if the driven mustn't either it would have been said, right?

'sid
 

Badot

New member
Messages
677
Reaction score
0
Any reason you can't flip the driver around on the shaft? I see it mentioned but don't see any reason not to. But the belt can have a fair amount of lateral play so long as at idle it's relatively straight for the driver to grab on smoothly.
 

JPGraphX

New member
Messages
118
Reaction score
0
Location
Quebec
Indeed, I don't see any reason why I shouldn't flip the driver on the shaft. It doesn't look good, but would work.
 

tazmannusa

New member
Messages
213
Reaction score
0
Location
Yettem, California
The only thing about flipping the driver around is the belt will be way out past the end of crankshaft when in high gear range causing more stress and possibly crank flex .
When I first got my 40 series I could not figure how it would run the belt straight with the driven outboard so I just made the mounts so it would mount inboard like it should be
 
Status
Not open for further replies.
Top