Airhead question: 77 tranny with 82 flywheel - Page 2

supershaft · 01-29-2013, 03:41 PM

Quote:

Originally Posted by disston

The 17.5 gears are supposed to have an X on them. I have heard the same thing SS mentions that there are a few with no X but are X gears. You usually can't see the X until the gear is off the shaft.

I didn't know before that the angle is a reference to the sharpness of the teeth and not the slant of the teeth. I thought it was the slant.

A lot of people think that. That's how the gears get mixed in some cases. That's why some people talk about the changed PFA effecting end play and axial load. It doesn't. What it effects is where each individual tooth along the height of the tooth contacts the next tooth and transfers the load.

Kai Ju · 01-29-2013, 03:45 PM

so if you were to engage an X and a non X gear the teeth will not mesh properly while matching gears will ?
In other words, matching gear teeth will engage fully, down to the root of the tooth, while non matching gears won't.

supershaft · 01-29-2013, 03:51 PM

Quote:

Originally Posted by Kai Ju

so if you were to engage an X and a non X gear the teeth will not mesh properly while matching gears will ?

I have seen it done numerous times working hear and there. They fit together just fine. They do make a bit more noise from the get go. From what I have seen, it takes 5 or 10k miles for them to eat themselves. That they will do! Very unfortunately, I have seen some pure unobtainium close ratio intermediate shafts F'ed up for it. Man I wish I had those F'ed up shafts now that I know you can swap those gears!

Kai Ju · 01-29-2013, 04:43 PM

I would have thought that if the tooth angle is different that non matching gears would not engage the same depth as matching ones. What I'm getting is that You have a couple of shafts in your hand and you're trying to figure out whether you can replace one with the other by engaging the two gears and looking at how deeply they engage. I'll probably be doing that on Saturday since I have to replace the gear on an input shaft and will be looking at some used shafts to source the parts from.

boxerotto · 01-29-2013, 05:30 PM

Quote:

Originally Posted by boxerotto

has anyone actually shortened the shaft?

anyone ?

supershaft · 01-29-2013, 05:46 PM

Quote:

Originally Posted by Kai Ju

I would have thought that if the tooth angle is different that non matching gears would not engage the same depth as matching ones. What I'm getting is that You have a couple of shafts in your hand and you're trying to figure out whether you can replace one with the other by engaging the two gears and looking at how deeply they engage. I'll probably be doing that on Saturday since I have to replace the gear on an input shaft and will be looking at some used shafts to source the parts from.

That isn't it at all. Non matching gears engage the exact same depth. They just touch each other at a different height on the teeth. You can't see it the way you are describing it.

Kai Ju · 01-29-2013, 06:29 PM

Quote:

Originally Posted by supershaft

That isn't it at all. Non matching gears engage the exact same depth. They just touch each other at a different height on the teeth. You can't see it the way you are describing it.

Then I best be looking for that X, don't I ?

supershaft · 01-29-2013, 06:53 PM

yup

disston · 01-30-2013, 07:36 AM

Quote:

Originally Posted by boxerotto

has anyone actually shortened the shaft?

Yes it has been done this way. It is mentioned on Snowbum's site but I don't think he talks about what happens with the push rod length. Does it also get chopped? I'd have to compare myself to be sure. I think the push rod stays as is. But I'm not sure.

Do use some kind of an air powered rotory tool with a fresh cutting wheel. Or I guess make do with what ever you got. Also bevel the edge of the cut.

Big advantage of course is this can be done with the trans assembled.

chasbmw · 01-30-2013, 09:03 AM

You probably need to use the later pushrod. The tip is hardened

disston · 01-30-2013, 10:03 AM

I don't think so Charles. My understanding is the push rods are different lengths, they go with the cover, bearing set up, so I don't think you can use a later push rod unless you use a later cover. I might be wrong though.

Mr Bum makes no mention of the push rod. I guess I should think this means it works as is. I don't think he ever passes up an opportunity to add a couple extra paragraphs to his web pages, does he?

chasbmw · 01-30-2013, 10:27 AM

Dissiton,

I have a feeling that you are right.

supershaft · 01-30-2013, 12:08 PM

Like a lot things on mr. bum's site, going on and on about something does not necessarily mean that it has been done at all and if it has been done it certainly does not mean it will work as well as other methods if it works at all.

It sounds like it would work. In practice? I bet cutting that shaft is easier said that done. Especially without ruining the temper on those splines.

disston · 01-30-2013, 12:19 PM

01-30-2013, 09:03 AM	#25
chasbmw Studly Adventurer Joined: Feb 2006 Location: Bath Uk Oddometer: 997	You probably need to use the later pushrod. The tip is hardened __________________ Charles http://i46.photobucket.com/albums/f1...ps6e61ae2e.jpg R90s 1070 replica, R90/6 1971 Commando Fastback

01-30-2013, 10:03 AM	#26
disston ShadeTreeExpert Joined: Mar 2011 Location: Silver Spring, Md Oddometer: 4,980	I don't think so Charles. My understanding is the push rods are different lengths, they go with the cover, bearing set up, so I don't think you can use a later push rod unless you use a later cover. I might be wrong though. Mr Bum makes no mention of the push rod. I guess I should think this means it works as is. I don't think he ever passes up an opportunity to add a couple extra paragraphs to his web pages, does he? __________________ Never memorize something you can look up. ---Albert Einstein

01-30-2013, 10:27 AM	#27
chasbmw Studly Adventurer Joined: Feb 2006 Location: Bath Uk Oddometer: 997	Dissiton, I have a feeling that you are right. __________________ Charles http://i46.photobucket.com/albums/f1...ps6e61ae2e.jpg R90s 1070 replica, R90/6 1971 Commando Fastback

01-30-2013, 12:19 PM	#29
disston ShadeTreeExpert Joined: Mar 2011 Location: Silver Spring, Md Oddometer: 4,980	__________________ Never memorize something you can look up. ---Albert Einstein

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01-29-2013, 03:45 PM	#17
Kai Ju Beastly Adventurer Joined: Jul 2009 Location: So Cal Oddometer: 1,025	so if you were to engage an X and a non X gear the teeth will not mesh properly while matching gears will ? In other words, matching gear teeth will engage fully, down to the root of the tooth, while non matching gears won't.

01-29-2013, 04:43 PM	#19
Kai Ju Beastly Adventurer Joined: Jul 2009 Location: So Cal Oddometer: 1,025	I would have thought that if the tooth angle is different that non matching gears would not engage the same depth as matching ones. What I'm getting is that You have a couple of shafts in your hand and you're trying to figure out whether you can replace one with the other by engaging the two gears and looking at how deeply they engage. I'll probably be doing that on Saturday since I have to replace the gear on an input shaft and will be looking at some used shafts to source the parts from.

01-29-2013, 06:53 PM	#23
supershaft because I can Joined: Sep 2010 Location: San Francisco Bay area Oddometer: 6,046	yup

01-30-2013, 12:08 PM	#28
supershaft because I can Joined: Sep 2010 Location: San Francisco Bay area Oddometer: 6,046	Like a lot things on mr. bum's site, going on and on about something does not necessarily mean that it has been done at all and if it has been done it certainly does not mean it will work as well as other methods if it works at all. It sounds like it would work. In practice? I bet cutting that shaft is easier said that done. Especially without ruining the temper on those splines.