[deluxe72]

Hi. I'm building a '67 TR6 650 engine. The cases are together and the primary and transmission are wide open, nothing installed. I'm replacing the 18 tooth trans sprocket with a 21 tooth sprocket. I just installed a new mainshaft transmission seal and it sticks out beyond the case about an 8th of an inch when fully pressed in. Before I installed the seal I could just barely slide the 21 tooth sprocket in and out between the cases. The 21 tooth sprocket wont fit through the primary door. Since my trans is out i can fit the sprocket between the cases then slide the mainshaft through the sprocket. With the seal in place, though, I can't slide the sprocket between the cases. the seal is sticking out about 1/8th inch. No seal - sprocket barely squeezes in. Is there a better fitted seal that isnt as thick and that won't hog the space needed to slide the sprocket between the cases?

Thanks in advance.

 

[750Devo]

Lots of people will notch the trap door opening to allow the 21 to get through. If you dont you will have to take the transmission apart too replace the sprocket.

 

[96dragginsdime]

Before:

After:

 

[96dragginsdime]

courtesy of dan supercrouton..... also I looked at mine and it looks that the seal sticks out as well. I am only running a 20 tooth though. are your old and new sprocket the same thickness?

 

[deluxe72]

Thanks for your replies. I have thought for months that since my primary and trans are completely out that I could slide the sprocket between the two joined case halves. I can without the seal, but can't with the seal. I guess what I read in more than a couple places is incorrect, or a different seal is being used, or no seal is used. If anyone knows if the seal is supposed to stick out beyond the metal then I would like to know. Or if there is a different seal that can be used then I would like to know that too. Thanks again.

 

[deluxe72]

I just checked the thickness (side to side, like when installed) of the new larger sprocket compared to the old smaller sprocket. They are exactly the same.

 

[lit67]

The seal will always stick out beyond the flange. At least it has on all the motors that I have built. Without tearing your motor back apart, the only was to get the 21 tooth sprocket in is to notch the case as shown above.

 

[deluxe72]

Okay. I guess the information I found is incorrect. The cases have to be apart or loose to get a large sprocket between the cases, or if the cases are together than one will have to notch the primary opening to get the sprocket through the opening. I read at least a couple posts stating if the transmission mainshaft is out then a large sprocket can be slid between the cases. Not so with the seal installed. I'm not going to loosen my cases. Guess I'll be doing some notching.

Thanks!

 

[deluxe72]

I ground / notched the opening today. I used a Dremel with cylindrical grinding bits and a chainsaw blade sharpening file. The file is also cylindrical shaped, about 3/16" diameter. The sprocket is a 21 tooth. Probably took an hour or maybe a little more to grind the notches.

Thanks again for your feedback.

( tags: sprocket gear teeth )

 

[96dragginsdime]

looks good, I am really unsure but I have read thats how people do it as well. I guess once you get the mainshaft in make sure everything fits without issues. seems strange it wouldnt fit in

 

[deluxe72]

This image shows an 18 tooth and a 21 tooth sprocket sitting next to one-another.