OS Giken GTA Close ratio gear set - Page 3 - Alfa Romeo Bulletin Board & Forums
 1Likes
Reply
 
LinkBack Thread Tools Display Modes
post #31 of 63 (permalink) Old 12-11-2011, 08:08 PM
Moderator
Platinum SubscriberSuper Moderator
 
Gordon Raymond's Avatar
 
Join Date: Jul 2006
Location: Northfield, Illinois
Posts: 11,160
Don't know if he's reading this Larry, but Richard Jemison probably has done that.
At Ausca we ran the Colatti gear-set without synchronizer hardware as a crash box. At that time, we were distorting the cases in longer races, and used the Colotti set, lightened, and made to run without synchronizers. This worked pretty well as I remember, and the GTA cases shaft bores remained round. This was a loud transmission in use, but on the track it didn't matter.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Gordon Raymond
Illinois SNO Alfa Chapter Director
Illinois SNO Ferrari Chapter Director
and sometimes, CONFUSED AND INCORRECT, but Larry helps me out.
Now:
Illinois Chapter Director AND Charter Member of THE CONFUSED AND INCORRECT
Gordon Raymond is offline  
Sponsored Links
Advertisement
 
post #32 of 63 (permalink) Old 12-11-2011, 08:41 PM Thread Starter
Registered User
 
Join Date: Mar 2008
Location: Austin Texas via So. Calif.
Posts: 274
Quote:
Originally Posted by Gordon Raymond View Post
Don't know if he's reading this Larry, but Richard Jemison probably has done that.
At Ausca we ran the Colatti gear-set without synchronizer hardware as a crash box. At that time, we were distorting the cases in longer races, and used the Colotti set, lightened, and made to run without synchronizers. This worked pretty well as I remember, and the GTA cases shaft bores remained round. This was a loud transmission in use, but on the track it didn't matter.
Regarding 9310: I'm not sure that you need to harden this material. I believe they make heat treatable grades however. Can't get any information about secondary operations on the gears from OSG... Had the get the material info from a second source.

I believe Gordon is correct: Richard Jemison would be the guy for gears.
awesomeBLT is offline  
post #33 of 63 (permalink) Old 12-11-2011, 09:52 PM
Registered User
 
Join Date: Nov 2002
Location: Pleasanton CA
Posts: 652
We sell Richard tons of core trans axles, LSD carriers, cams, spindles, LSD clutch plates, etc. etc. Back many years ago I told him how to stop burning up transaxles, by keeping track of/ checking the pinion shim stack. I will ask him next time I talk to him.
The gear teeth are hardened, including OS, and that is the issue, the welding after the fact, creates a very hard to relatively soft transition between the two parts and it fatigues. The only one out of the Colotti sets that has not broken is one done differently as far as how the old carrier was removed in that the original welded area was left alone and just the outer ring of teeth were cut off, thus the new weld was only between the two parts of a carrier, which is softer than the gear, avoiding the extreme range in hardness.

I have succesfully put needle bearings in stock alfa gears (1st, 2nd, 3rd)and Hybrid ratio sets, I run a set behind my 235 hp V-6 GT on the street and track.

APE

Larry
larry is offline  
Sponsored Links
Advertisement
 
post #34 of 63 (permalink) Old 12-12-2011, 06:14 AM
Richard Jemison
Platinum Subscriber
 
Alfar7's Avatar
 
Join Date: Apr 2005
Location: Pensacola, Fl. U.S.A.
Posts: 7,049
Welding on / in gears

Yes, Larry is a great source for Alfa parts and we are very lucky to have such a source.

Unless gears are protected from heat they are going to be annealed from welding. All of my modified gearsets are welded, but I have built "fixtures" (I used to call them "jigs" but they are far too useful to have them correlated with our president) that allow them to be immersed in a solution while being tig welded together. This keeps the gear teeth well below critical temps.
The only gear that gets the syncro welded is the 1.69 2nd gear for the 105/115 CR boxes. This is a 4th gearset that is reversed and the layshaft gear bored for roller bearings on the mainshaft, and syncro assembly welded to it.

I do this because I have the time(retired) and capacity. It is far easier to buy the gearsets than do this foolishness.
With less than great new replacement parts that are out there, you have to be far more attentive to building these things than just buying parts and assembling them together. See the thread on Syncro issues on the BB.

Richard Jemison
RJR Racing

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"When you are dead you don`t know it.
Only those around you are distressed.
Same with stupid"

Last edited by Alfar7; 12-12-2011 at 06:18 AM.
Alfar7 is offline  
post #35 of 63 (permalink) Old 12-12-2011, 08:53 AM
Registered User
 
Join Date: Nov 2002
Location: Pleasanton CA
Posts: 652
I do agree that for a quick and easy solution buying the gear set is the way to go. I was only commenting on the original theme of feedback about the OS gears, and I wish they did not weld them.

APE

Larry
larry is offline  
post #36 of 63 (permalink) Old 12-12-2011, 08:53 AM
Moderator
Platinum SubscriberSuper Moderator
 
Gordon Raymond's Avatar
 
Join Date: Jul 2006
Location: Northfield, Illinois
Posts: 11,160
Thanks RJ. I also feel better that I'm not the only "retired" guy that participates in "foolishness" for the sake of a job well done. Having the time to think about this stuff, and how to do it correctly is good for us.
Just my opinion. Same with "fixtures". I've lots of those now as well.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Gordon Raymond
Illinois SNO Alfa Chapter Director
Illinois SNO Ferrari Chapter Director
and sometimes, CONFUSED AND INCORRECT, but Larry helps me out.
Now:
Illinois Chapter Director AND Charter Member of THE CONFUSED AND INCORRECT
Gordon Raymond is offline  
post #37 of 63 (permalink) Old 12-12-2011, 09:34 AM Thread Starter
Registered User
 
Join Date: Mar 2008
Location: Austin Texas via So. Calif.
Posts: 274
Just scrolled thru the synchro thread and saw the OSG gear sets that now have Nissan synchro sub assemblies... Assuming the Nissan parts are pretty much proven new technology, as is the gear material, method of fabrication and secondary operations, appears there is a path to update alfa GB's to modern technology and live happily ever after.
awesomeBLT is offline  
post #38 of 63 (permalink) Old 12-12-2011, 09:46 AM
Registered User
 
iachella's Avatar
 
Join Date: Sep 2005
Location: Concord, CA
Posts: 2,167
Thanks Larry for chiming in. I was hoping Merrit wasn't the only one displeased with the design. His feeling might be a bit strong, but at least another expert concurs. I have not been back to talk to him more about it yet but did confirm from two other bay area experts that is was indeed an OS 1st gear that blew the synco teeth and OS has replaced the 1st gear at no charge.

This is good for OS reputation as they stand behind their product, but I wonder if the supplier of that box is aware of this particular failure and if it's the only one ever. I wanted to also ask him if he was sent the replacement gear or if the box was returned to the supplier for repair. There remains at least one supplier that cannot claim no issues with the boxes they have sold. Maybe it's moot since the gear was replaced at no charge. Was there a charge for the labor, I wonder?

Stefano
Concord, CA
iachella [at] gmail [dot] com
iachella is offline  
post #39 of 63 (permalink) Old 12-12-2011, 02:59 PM
Richard Jemison
Platinum Subscriber
 
Alfar7's Avatar
 
Join Date: Apr 2005
Location: Pensacola, Fl. U.S.A.
Posts: 7,049
Nothing New Under the Sun

An old Datsun racer told me over the weekend, that not only did these cars (Alfa 1600 & Datsun 510) share cam drive chains, they used Alfa syncro parts in their transmissions to improve shifting.......
It`s all metal...

Richard Jemison
RJR Racing

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"When you are dead you don`t know it.
Only those around you are distressed.
Same with stupid"
Alfar7 is offline  
post #40 of 63 (permalink) Old 12-13-2011, 08:53 AM
Registered User
 
Join Date: Mar 2007
Location: San Antonio, Texas
Posts: 4,120
Quote:
Quote:
Originally Posted by Alfar7 View Post
An old Datsun racer told me over the weekend, that not only did these cars (Alfa 1600 & Datsun 510) share cam drive chains, they used Alfa syncro parts in their transmissions to improve shifting....... It`s all metal...
Now that's an interesting piece of information, Richard. What if OSG discovered a parts interchangability that nobody knew about?

Jim . . . '72 Super 1300, '70, 1750GTV, 2nd series,
'62, Lancia Flaminia Zagato3c, 2nd series
180OUT is offline  
post #41 of 63 (permalink) Old 12-13-2011, 01:40 PM Thread Starter
Registered User
 
Join Date: Mar 2008
Location: Austin Texas via So. Calif.
Posts: 274
Quote:
Originally Posted by 180OUT View Post
Now that's an interesting piece of information, Richard. What if OSG discovered a parts interchangability that nobody knew about?
Stove, If you look at the gearbox photo on the Synchro thread it appears OSG took creative license with the dogs, best I can see.
awesomeBLT is offline  
post #42 of 63 (permalink) Old 12-13-2011, 02:36 PM
Registered User
 
Join Date: Mar 2007
Location: San Antonio, Texas
Posts: 4,120
I wonder how hard it would be to make an adaptor kit for Alfa gearboxes?

Jim . . . '72 Super 1300, '70, 1750GTV, 2nd series,
'62, Lancia Flaminia Zagato3c, 2nd series
180OUT is offline  
post #43 of 63 (permalink) Old 12-13-2011, 03:07 PM Thread Starter
Registered User
 
Join Date: Mar 2008
Location: Austin Texas via So. Calif.
Posts: 274
Quote:
Originally Posted by 180OUT View Post
I wonder how hard it would be to make an adaptor kit for Alfa gearboxes?
I suppose if you don't want to buy the gear set inclusive you will have to wait until one turns up to see how OSG did it. Am assuming from the synchro thread photo that the gears are specially machined to accept the Nissan parts.
awesomeBLT is offline  
post #44 of 63 (permalink) Old 12-13-2011, 05:20 PM
Richard Jemison
Platinum Subscriber
 
Alfar7's Avatar
 
Join Date: Apr 2005
Location: Pensacola, Fl. U.S.A.
Posts: 7,049
Syncros

It`s too easy to take the time to fit the syncros we have available to get into parts swaping modifications.

Richard Jemison
RJR Racing

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

"When you are dead you don`t know it.
Only those around you are distressed.
Same with stupid"
Alfar7 is offline  
post #45 of 63 (permalink) Old 12-13-2011, 07:10 PM Thread Starter
Registered User
 
Join Date: Mar 2008
Location: Austin Texas via So. Calif.
Posts: 274
Quote:
Originally Posted by Alfar7 View Post
It`s too easy to take the time to fit the syncros we have available to get into parts swaping modifications.
So you don't think it's an improvement using Nissan synchro assemblies...
awesomeBLT is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Alfa Romeo Bulletin Board & Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 
For the best viewing experience please update your browser to Google Chrome