Layshaft Steel Gear

Gunzel · 10-25-2010, 12:00 PM

I have what appears to be a new Racing steel Layshaft and gear, non straight cut gears. 48 teeth on the gear, has large holes drilled in the gear face, and the whole thing is one piece. The unot is not marked with a Zero, or a One.The books show wear limits and such, but not the Diameter of a new Zero or One gear. Anyone have these measurements

tadd · 10-25-2010, 01:21 PM

Its not straight cut, so if I had to guess its a 964/993 piece and not an early race piece. Nice.

t

Gunzel · 10-25-2010, 06:55 PM

I have been told that a 964 gear has 35/60 teeth, this has 28/48, so it is an early style. Its in the Anderson book. The question is what is the diameter of a new Zero gear, an a new ONE gear. using the proper measuring method with the two 4.5mm rollers.

Quote:

Originally Posted by tadd

Its not straight cut, so if I had to guess its a 964/993 piece and not an early race piece. Nice.

t

Walt Fricke · 10-25-2010, 11:36 PM

I think you might be better off putting it in a case half with a crank with its gear on, and measuring backlash. With both a 0 and a 1 crank gear, as those are your only choices.

The factory changes something here - only sell replacement 0s? Smaller diameter? Wayne's book mention this?

A one off piece like this isn't going to have a stamping, is it? Interesting to go to all that trouble and not make it straight cut, if for an early engine.

What holds the gear against rotation on the shaft? A woodruff key? I guess the chain gears are good enough to hold it axially, since there is no bolting flange.

MBEngineering · 10-26-2010, 01:31 AM

HI Gunzel
the gear is prob' out of a GT3, looks like this one

and you might find the group No' on the bottom side, where the flanged bearing is, it will be etched on and not stamped.

has it a Made in Germany on it??

if not it could be a early GT3?

regards mike

Gunzel · 10-26-2010, 06:57 AM

Walt & MBEngineering

Thanks for the imput, however

I have had this piece for somewhere between 20 to 30 years, so it cannot be from a GT3. Also the pictures I have seen of the 964 part shows it has a bolt on gear? Also one thread says it has a 60 tooth gear vs. a 48 on my gear. In Andersons book he shows a side view of a Layshaft and says its a competition piece, and its a one piece forging. My part has no markings at all, I have been all over it with an optical magnafining glass and there are no marks. So the question is still the same -- has anyone ever measured a new gear, steel or aluminum that is marked with a Zero or One using the proscribed method? What is the diameter of the gear? I will eventually check the backlash also.

BURN-BROS · 10-26-2010, 08:35 AM

If it's 20 years I'd guess that is was from a 959

Gunzel · 10-26-2010, 09:47 AM

A side question is did the 1973 to 1975 RSR use Steel Gears on their Layshaft? But the actual question is what is the diameter?

BURN-BROS · 10-26-2010, 10:17 AM

The competition cars would have used a one-piece that had a straight cut gear. The one you have suggests a production type application. The GT-3's used the 959 part number for quite some time untill it was superceded by a newer part number.

tadd · 10-26-2010, 11:55 AM

Isnt this avoiding the actual question? Regardless of tooth count, if it is to fit the case it still has to have the same outside diameter. In the back of Waynes book (in the most useful pages) there is a list of gear combos. Both a 0 and 1 with a 0 crank gear are acceptable, IIRC. Duplicate for a 1 crank gear.

t

blue72s · 10-26-2010, 01:52 PM

Subscribed. (where's the popcorn smiley?)

BURN-BROS · 10-26-2010, 03:20 PM

Quote:

Originally Posted by tadd

Isnt this avoiding the actual question? Regardless of tooth count, if it is to fit the case it still has to have the same outside diameter. In the back of Waynes book (in the most useful pages) there is a list of gear combos. Both a 0 and 1 with a 0 crank gear are acceptable, IIRC. Duplicate for a 1 crank gear.

t

Correct...0's and 1's. This applied to the competition shafts ans well as the 959 shaft.

My parts book does not show the shaft and the crank gear as seperate items, so I cannot verify if the crank gear is the same as all other production gears.

Gunzel · 10-26-2010, 03:26 PM

What does suscribed mean?

Quote:

Originally Posted by blue72s

Subscribed. (where's the popcorn smiley?)

Gunzel · 10-26-2010, 03:30 PM

GENTLEMEN

You are all missing the question.

What is the diameter of a new countershaft gear #1 and #0 when measured with the two 4.5mm rollers.If you do not know then don't reply.

tadd · 10-26-2010, 03:49 PM

Aluminum gears are 136.50 and 136.55 for 0 and 1 respectively, the pins at 180*.

One would assume these #s will be the same for the steel gears since it has to fit in the same case.

With that, I will shut the heck up.

tadd

Gunzel · 05:49 PM

Tadd

I did not mean to brush off anyone. However your figures are in all of the Porsche Spec books, Anderson, Pelican, etc and they are wear limits, not the Diameter of a new gear. I guess I will have to purchase a new Zero Gear, and a new One Gear and measure them. My new steel gear for instance measures 137.16mm but I do not know if its a One or a Zero. I also think you are correct in that both the steel and aluminum gears have the same deminsions. Thanks for the effort

Quote:

Originally Posted by tadd

Aluminum gears are 136.50 and 136.55 for 0 and 1 respectively, the pins at 180*.

One would assume these #s will be the same for the steel gears since it has to fit in the same case.

With that, I will shut the heck up.

tadd

tadd · 10-26-2010, 06:56 PM

I can measure a brand new strait cut steel gear (both). Would that help?

It's a 48/28 combo. I'd just need to chase up the correct Sized pins at work tomorrow.

Tadd

Gunzel · 10-26-2010, 07:45 PM

Todd

That would be super.I don't know if you measure straight cut gears the same way as the other type but if you can do it without going to very much trouble I would really appreciate it. Are you using straight cut gears in your engine?

Mike

Quote:

Originally Posted by tadd

I can measure a brand new strait cut steel gear (both). Would that help?

It's a 48/28 combo. I'd just need to chase up the correct Sized pins at work tomorrow.

Tadd

tadd · 10-26-2010, 08:08 PM

Yes.

Between the GT3 oil pump and the 3.8 rsr cams (102 LC) I'd worry too much about the aluminum gear. Seen them shear teeth almost all the way around.

If I can't chase up the correct sized pin I'd be happy to bring you the gears to measure. IIRC, I was going to pester you about some 906 fan measurements so I think you were local to me. I'd still like to pester you about that at some point. Life just got in the way

.

tadd

tongkude · 10-27-2010, 02:18 AM

The one you have suggests a production type application.