I took the damaged layshaft and another from a similar GT6 tranny that had
about 80k miles on it, but with no damage, to a manufacturing and heat
treating company in Dayton, Ohio. They did a Rockwell test which in no way
damages the shaft, yet tells them the hardness. I observed the measurements
and according to the engineer, the old original shaft had a Rockwell number of
62; the new damaged shaft had a number of 64. This means that the new shaft
you sold me was in fact harder than the old one.
I then had them test one of the original and one of the damaged needle
bearings. Both tested equally hard with numbers of 61/62 for the new and
62/63 for the old.
The engineer said that hardness of the components was NOT at fault.
I then had the diameter of the two layshafts and the needle bearings measured
to three decimal points. They were the same. However when I lined up the 43
of the original undamaged needle bearings I still had with 43 of the new
damaged ones, the line of old original needles was one needle longer. I don't
understand this, but it appears that the components SpitBits sold me were NOT
inferior.
Nigel at SpitBits offered to replace the layshaft and needle bearings at no
charge, but I cannot accept. It appears that I must have done something wrong
in the assembly, and take full responsibility for the damage.
I want to publicly thank Nigel for his help and offer and apologize for any
discredit I may have caused him.
Mike http://pages.prodigy.net/mikeross/ updated 4/10/02
'63 Spritfire
'66 Spitfire
'69 GT6 convertible project
'70 GT6+ (maroon)
'70 GT6+ (green)
----- Original Message -----
From: spitbits
To: Mike Ross
Sent: Friday, April 19, 2002 3:12 PM
Subject: Re: Layshaft problem
Dear Mike,
Thank you for your continued interest in the quality of the layshaft.
Although we do not have a problem with you getting it tested yourself, the
manufacturer wants us to stress to you the importance of them receiving the
part as found when removed from the transmission, or they themselves will not
be able to make the accurate tests. They would prefer the product gets sent
directly to them. However if you still prefer to have your mechanic do some
testing, please understand our manufacturer might not still agree to replace
this part. (Spit Bits will continue to honor your replacement part free of
charge.)
Please let us know what you decide to do.
Sincerely,
Nigel Cosh
Owner
Spit Bits
At 07:20 PM 4/17/2002 -0400, you wrote:
***************************************************************************
*******************************
___ORIGINAL POST___________4/15/02
Has anyone heard of inferior layshafts or roller bearings being sold for
Spitfire or GT6 gearboxes?
Here's why I ask. After a couple of Triumph Club members helped me rebuild my
gearbox with components from SpitBits, I found it very hard to shift into 1st
gear from a stop. It was also very difficult to downshift into 3rd from 4th.
We only test drove the car about 5 to 8 miles. We pulled the tranny and
opened it up.
What we found was astounding. See
http://pages.prodigy.net/mikeross/layshaft.html . The layshaft for the
laygear was badly galled or scored by the roller bearings. Some of the roller
bearings had flattened. This was after just a few miles. The layshaft I had
removed originally was over 30 years old and had over 65,000 miles on it, and
it was pristine by comparison. We were lucky to have pulled the tranny when
we did.
The original reason we pulled it back out was because of the tightness and
difficulty in shifting. All the synchro balls and springs were in place, but
it was impossible to move the 1-2 and 3-4 hubs forward and back by hand. We
measured the springs and compared them to the old ones and to a set of synchro
springs I had from Victoria British. The SpitBits springs were .002" longer
than the others. More importantly, when I substituted the original used
springs and the VB springs I was able to move the 1-2 and 3-4 hubs forward and
back by hand. I think that the springs from SpitBits may be too firm. Once I
get a new laygear, I'll either use my old ones or the VB springs. BTW, we
never used the shims that were available.
I can think of a couple of reasons for the scoring of the layshaft:
1. the steel of the layshaft wasn't hardened sufficiently.
2. the roller bearings were defective, perhaps oversized (some were flattened
indicating that they weren't rolling.
Any other ideas?
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