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[Fot] best gearbox for TR6 more...

Subject: [Fot] best gearbox for TR6 more...
From: britcars at bellsouth.net (barry rosenberg)
Date: Wed, 29 Aug 2018 11:37:47 +0000 (UTC)
References: <42ff946f-80c0-5092-955a-9f5d6f26f6e3@pobox.com> <164b3dfa5f3-c92-cf76@webjas-vac220.srv.aolmail.net> <1229176934.7475844.1532037420166@mail.yahoo.com> <1F58DEDC-E5B8-43E6-870A-6D9659E5296D@icloud.com> <AD4A00FD-BF0B-4065-814F-9BE3BBB2F600@ca.rr.com>
My last TR4A race car ran with a TR6 close ratio box with the J type overdrive. 
It used 90w gear oil and shifted instantaneous. Before the toggle switch had 
completed it's travel, it was in overdrive. The J type is very strong and 
reliable and lighter than the A type. Look up Gearvendors.com. They sell a J 
type overdrive to go behind 3,500 hp dragsters, 30,000 lb motor homes and some 
of their parts will fit the Triumph J type overdrive.
Barry

      From: Randall via Fot <fot at autox.team.net>
 To: Greg Blake <gblake58tr3 at icloud.com>; Greg Blake via Fot <fot at 
autox.team.net>; Jack Wheeler <jwheeler1947 at yahoo.com> 
Cc: "fot at autox.team.net" <fot at autox.team.net>; fubog1 <fubog1 at aol.com>
 Sent: Wednesday, August 29, 2018 4:29 AM
 Subject: Re: [Fot] best gearbox for TR6 more...
   
If you do, be sure to check for coil bind. I shimmed mine just a little too 
much, so the ports would only partially open. Pressure looked fine at low rpm 
on the bench, but went way high in service.
-- Randall

On 19 July 2018 20:59:03 GMT-04:00, Greg Blake via Fot <fot at autox.team.net> 
wrote:
Hit send too soon. What pressure did you run on the large piston A type? ?I?ve 
gotMine set at 370psi and it shifts nearly instantly on the bench. Wondering if 
I should add another shim to get closer to 400psi.?

Sent from my iPhone
On Jul 19, 2018, at 4:57 PM, Jack Wheeler via Fot <fot at autox.team.net> wrote:


 Hi Glen.? I agree with most of your comments.? I raced a TR-4 in SCCA for 24 
years, and used both close ratio, and stock ratio gearboxes with, and without 
overdrive.? I always used the later housings (TR-4A - TR-6) and the "A" Type 
overdrive, and I did all my own maintenance.? Early in my career, I always 
thought a straight 4 speed (without overdrive) would be more efficient for 
racing, due to less parasitic losses.? When close ratio gears became legal 
(about 1980), I thought this would be a big improvement over the overdrive 
option.? I had all 6 gear sets set up for my IRS car, so I could gear to use 
either transmission option at all the tracks I raced at.
However, after years of experimenting at Road Atlanta, during The Runoffs, I 
concluded that using a close ratio overdrive gearbox with the 4.3 rear end gear 
was about 1 second per lap faster than using a straight 4 speed with the 3.7 
rear end gear.? The 4.3 rear gear gave me a more usable second gear for some 
tight turns (like turn 7 at Atlanta) than the 3.7 rear gear.? I also tried the 
4.1 rear gear with the straight 4 Speed, but the overdrive option was still 
faster.
I did less research at other tracks, but long tracks with tight turns (like 
Road America) would certainly favor the overdrive option.? There may not be as 
much difference on short, tighter tracks.? But, numbers don't lie, and a second 
a lap was worth it to me, to learn about building and maintaining overdrives, 
with high pump pressure for quicker shifting.? And, I found them to be very 
reliable mechanically.? The only problems I ever had were electrical.
Take it for what it's worth, but that's my story, and I'm stickin' to it!
Jack

    On Thursday, July 19, 2018, 5:30:21 PM EDT, fubog1 via Fot <fot at 
autox.team.net> wrote:  
 
  In all fairness to the conversion advocates, in spite of the benefit of both 
intermediate gearing & the extra top gear with the O/D unit, there are some 
downsides to the O/D.First, it's getting hard to find good units, a lot of what 
I run into is junk. These have been in high demand since forever, I've bought 
many junk TRs just for the overdrives.As Larry pointed out, there are 
alternatives, ie Volvo, but then you have to mod it to suit.Unless you find a 
guaranteed plug-and-play TR box & O/D assembly, you'll most likely be having to 
go through the gearbox as well, and certainly if you're converting a standard 
gearbox to overdrive cuz' the mainshaft is different.That leads to another 
problem, parts availability for overdrive parts is a bit limited, especially 
some of the early A-type stuff, and as is normal these days, quality is always 
a big concern.Then if you have a rebuildable unit, and all of the parts, it has 
to be properly rebuilt, by the book.It's a fairly labor-intensive job and 
requires some degree of mechanical finesse.
If you have to pay someone to do the entire job, the cost could easily get up 
there to the point where a conversion gets more attractive.

There are also a few other negatives, the TR box & O/D unit may weigh more than 
some alternative units, there is some very slight power loss with the O/D, and 
some replacements may have better ratios available.
Having said (typed) this, for a street car, a later TR-6 box, with the 17 tooth 
laygear, better 1st ratio & much-improved 2nd mainshaft gear, with a J-type on 
the back of it is hard to improve on.For racing, late 6 box with a set of close 
ratio gears & a "big piston" A-type works well.
I see both side of the argument but personally I like the TRs as TRs, iff'n in 
doesn't say Stanpart on it, I'm not interested (grin).

Glen
 
-----Original Message-----
From: Larry Young via Fot <fot at autox.team.net>
To: fot <fot at autox.team.net>
Sent: Thu, Jul 19, 2018 12:32 pm
Subject: Re: [Fot] best gearbox for TR6

 Yeah, Glen is right. I should have shut up. I did a cost comparison a few 
years ago. Someone was making a Ford 5 speed conversion also. The cost was more 
or less the same, but of course, it depends on how much you are going to do 
yourself. I have heard the Toyota boxes are getting scarce also ($550 seems 
like a lot). Quantum Mechanics does (or did) a turnkey A or J type overdrive. 
He has everything you need to convert a Volvo J-type to any of the TR series. 
I've helped a couple of guys do this conversion. Volvo's from the 80's are 
relatively unloved, so a couple years ago I could find the Volvo J-types on 
Ebay for $150. Of course, buying the Volvo overdrive or a Toyota 5 speed is 
just the tip of the iceberg. If you want a turnkey deal that you install, 
you're probably looking at $2500 - $3000 regardless of the route you go. If you 
do everything yourself, you can probably get by for half that.
 
 I've had my TR250 from new and didn't have an overdrive until 5 years ago. I 
did a 7,000 mile road trip in it a couple of years ago and found all 7 speeds 
to be useful. Even 2nd OD was nice when stuck behind an RV going up a mountain 
pass.
 
 Like I said, I should have kept quiet, but my point is that I think you will 
find the cost similar regardless of the direction you go. It really boils down 
to what you prefer.
 ?- Larry
 
 On 7/19/2018 7:43 AM, Bill Tobin via Fot wrote:
  
 I dunno larry, I got my conversion from Eaglegate, who was also from New 
Mexico, and it bolted in. Plug and play. Works great, shifts smoothly, and? (so 
far!) reliable. Me being me, at the time, '13 I think, I picked up two spare 
transmissions. Celica W58. For about $175 each. A friend with a wrecking yard 
looked them? up yesterday: around $550. No, they are not for sale! I believe a 
guy in Kansas City took over Eaglegate. If anyone is interested, I could look 
it up. Cheers, Bill
  
 On 7/18/2018 11:56 PM, Larry Young via Fot wrote:
  
 I'd rather have an A-type (or even a J) overdrive - 7 gears, easier to shift, 
easier to install, probably less expensive - What's not to like? Keep the wife 
definitely.
 ?- Larry
 
 On 7/14/2018 4:13 PM, dustin nicholson via Fot wrote:
  
 Is the HVDA conversion kit for the Toyota 5 speed still available since 
Herman?s passing? 
  Dusty?
 
 Sent from my iPhone 
 On Jul 12, 2018, at 8:05 PM, Bobby Whitehead via Fot <fot at autox.team.net> 
wrote:
 
  
   My wife is trying to convince me to keep our 1971 TR6 we've owned for 26 
years...mhhhh.... I told her if we did I needed an overdrive or 5th 
gear...what's the best conversion? 
  Bobby Whitehead Jester's Racing
    
 
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