[Fot] TR-4 / TR-6 tranny lay shaft bearing mod?

[Peter Vucinic]

Larry,
That's exactly the bearing I was talking about. I run two of the open cage
bearings. You can simply buy the countershaft already done to accept these
bearings. 

Open cage is used in MANY dog gearboxes instead of bushes in the gears. So I
find them more than adequate for the task.



-----Original Message-----
From: fot-bounces at autox.team.net [mailto:fot-bounces at autox.team.net] On
Behalf Of Larry Young
Sent: Wednesday, 20 November 2013 7:55 AM
To: Tony Drews; FOT at autox.team.net
Subject: Re: [Fot] TR-4 / TR-6 tranny layshaft bearing mod?

I think Peter is talking about the open cage style counter shaft bearings
(see Step 12 of http://www.vtr.org/maintain/TransRebuild/TRTrans01.pdf).  My
experience is that the open style is worse than the closed shell bearings.
For racing, two bearings or a longer bearing would be better than either one
of these. For a street car, I usually recommend the shell type even though
they are a PITA to get out.
- Larry

On 11/19/2013 12:09 PM, Tony Drews wrote:
> The Open bearing you describe - is that the bearing between the input 
> shaft and the main shaft?
>
> Thanks, Tony
>
> At 06:20 AM 11/17/2013, Peter Vucinic wrote:
>> Tony,
>> You can purchase a modified Countershaft Gear Set form Rimmer 
>> Brothers. Moss probably have them as well?
>> It is already machined to accept 2 bearings at one end. All the hard 
>> work has been done.
>>
>> Also, if your gearbox has the needle roller bearings that are captive 
>> in a steel outer. Get rid of this design and use the TR6 style of 
>> 'open'
>> bearing.
>>
>> The early style of bearing with the steel outer will allow wear 
>> material and debris in the oil to locate inside this design bearing 
>> and cause premature failure. Not a good design.
>>
>> All the gear boxes I build I change to the later open style bearing 
>> and haven't had an issue as long as you regularly change the 
>> transmission fluid etc. Especially true if you have an Overdrive 
>> attached where you are now introducing wear material from the lining 
>> in the OD.
>>
>> I just freshened up a friend racing gearbox after 10 years of 
>> competition running with a J type OD attached. Lay shaft only had a 
>> few thousands of an inch wear.
>>
>> Hope that helps?
>>
>> Cheers...
>>
>>
>> "You can Make a Small Fortune From Motor Racing. As long as You 
>> Started With A Lage Fortune!"
>> Kind Regards
>> Peter Vucinic
>> TR-4
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>> -----Original Message-----
>> From: fot-bounces at autox.team.net [mailto:fot-bounces at autox.team.net] 
>> On Behalf Of Tony Drews
>> Sent: Sunday, 17 November 2013 1:46 AM
>> To: fot at autox.team.net
>> Subject: [Fot] TR-4 / TR-6 tranny layshaft bearing mod?
>>
>> Has anyone modified the TR-4 / TR-6 tranny layshaft assembly to 
>> accept larger, higher capacity bearings?  Turns out the root cause of 
>> my transmission failure was the failure of the front needle bearing 
>> in the layshaft assembly.  Before I do the parts search / purchases, 
>> I thought I'd check to see if there's a longevity improvement that 
>> can be made there.
>>
>> It's been a while since the box was apart, and let me tell you - with 
>> a buggered up layshaft shaft the disassembly is challenging.
>>
>> I'll be replacing, input shaft, layshaft and 3rd gear at least. Also 
>> had a weird failure where one of the pins that the spring slides onto 
>> in the overdrive is broken off - may have been an assembly issue.
>>
>> I may have most of the parts needed for the rebuild, we'll see what 
>> uncle jack's tranny parts stash includes.
>>
>> Cheers, Tony Drews
>> _______________________________________________
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