20,000 comedians out of work.... and you're makin jokes
Cheers Mates?26A GT6+, 28 TR6Brian Schirano
585-305-0349 Cell?
BSchirano at yahoo.com
From: Duncan Charlton <duncan.charlton54 at gmail.com>
To: Brian Schirano <bschirano at yahoo.com>
Cc: Scott Janzen <sjanzen at me.com>; "kkjjk at aol.com" <kkjjk at aol.com>;
'Friends of Triumph' Triumph <fot at autox.team.net>
Sent: Friday, June 9, 2017 5:59 PM
Subject: Re: [Fot] vibration
Mmmm ? sounds like an excuse to swap the two engines to see which car ends up
with the vibration!
Duncan Charlton
1121 Lower Elgin RdElgin, Texas 78621USA
On Jun 9, 2017, at 1:00 PM, Brian Schirano via Fot <fot at autox.team.net>
wrote:
echoed problem here w/my GT... still
motor was completely balanced, alum flywheel balanced and the pressure plate
balanced indexed to the flywheel, decent damper. Driveshaft re balanced and
phase corrected like Scott. I run different axle so only have inboard u joints,
no phasing there. rebuilt the diff last year, bearings good, still have rubber
mounts, but newer, and the pressed rubber mounts in the diff new neo. I will
have to study driveline angles, I've read about this but have not addressed as
such. I remember it's counter intuitive, they should not be completely
straight.
This year when I finally get to my only event, VRG at the Glen, I will be
running last years tires on TR7 steels vs my old alloy BWAs and see if that
makes a difference. My buddy that mounts and balances took extra care and saw
no runout or flat spots.
Interesting, we also run a TR6 w/completely stock motor, and do not have any
vibration there. Given the care of the GT motor build and none in the TR and
it's longer stroke, make me wonder. (although the GT does run sometimes up to
1000 more RPM on periodic long passing straight occasion
welcome more commentary here
Thx
Brian?26A GT6+, 28 TR6Brian Schirano
585-305-0349 Cell?
BSchirano at yahoo.com
From: Scott Janzen via Fot <fot at autox.team.net>
To: kkjjk at aol.com
Cc: 'Friends of Triumph' Triumph <fot at autox.team.net>
Sent: Friday, June 9, 2017 10:58 AM
Subject: Re: [Fot] vibration
I used to have the exact same problem with my GT6, also noted in the same spot
at Summit Point. ?I?m still not convinced it is not related to RPM - in lower
gears, you run through this range much more quickly, and I think it?s the RPM
combined with the speed and the longer time you spend in this RPM range.
Anyway, I found that both my driveshaft u-joints were slightly out of phase, as
were the u-joints on the rear axle half-shafts. ?I don?t know what your
half-shafts are made with - cv joints, u-joints? ?Mine are Spicer splined
sliding half-shafts with inner and outer u-joints. ?A good driveshaft shop
corrected both of these issues, balanced everything, made sure all the u-joints
fit tightly in the yokes, etc.
The other thing I spent some time with was the alignment and mounting of the
differential. ?The GT6 has far from optimum alignment of the differential
relative to the transmission - poke around on this subject but here?s one
article http://www.markwilliams.com/driveshafttech.aspx??
Anyway, the best I could achieve was to get the nose of the differential as
high as possible and the rear as low as possible, if I remember correctly.
?Also, look at the mounts themselves - are they in good shape, tight? ?My diff
is mounted with all aluminum spacers front and rear, no rubber, and i had the
rear ones made eccentrically so that I could adjust the rear up and down a bit.
?
It seemed that a combination of these things worked. No one item was the silver
bullet. ?Not sure if this is a new problem for the car - if it is, I?d ?suspect
the diff mounts or poor balancing of one of the rotating components.
Of course, we are assuming this is not suspension or engine vibration related -
good to eliminate all of those as well, but also relatively easy to check at
speed and you can usually feel it if it?s out at a wheel.
Scott
On Jun 9, 2017, at 7:35 AM, kkjjk--- via Fot <fot at autox.team.net> wrote:
?I have a significant vibration with my GT6 which occurs only at speed, in 4th
gear starting about 300-400 before redline (approx 6600 RPM).? In any other
gear to redline there is no problem, so it is related only to speed.? I had the
driveshaft universal joints replaced and balanced with no change in the
vibration.? The tires are brand new and balanced as well, although I did have a
bit of shaking of the car, so I will have them re balanced again.? But I need
to know what I should look at next to find the solution to the problem.? The
diff?? Rear axles? And what items specifically?? I have to back off a bit near
the end of the straight at Summit Point due to this problem, which sucks.? A
longer straight at another track would be even worse! Any help would be
appreciated!? Thanks- Jay De Pol
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