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Re: Late TR6 Weber Manifold

To: RX74EVR@aol.com
Subject: Re: Late TR6 Weber Manifold
From: Bob Lang <LANG@ISIS.MIT.EDU>
Date: Tue, 22 Feb 2000 09:58:55 -0400 (EDT)
Cc: triumphs@autox.team.net
On Fri, 18 Feb 2000 RX74EVR@aol.com wrote:

> Robert,

Hello.

I cc'd the triumphs list just because I think I might make a point or two 
here of general interst... although I do tend to get windy from time to time.

> yes i did find someone who traded me even up for my early manilfold for their 
> later one about 3 weeks ago. 

Kool.

> I did find a place that sold them new with 
> linkage for $365 but was not in a hurry to pay that. 

I hear you there. I now have two early and one late manifold. I guess I'm 
all set if I need another car setup with webers... ;-)

> Now I just have to find 
> a pair of NOS rear bumper wrap arounds 

??? You mean the bumper bar or the "boobs"?? The bumper bars do show up 
from time to time... there were two sets at the VTR auction up in 
Portland, ME last summer... Good luck finding those. They're also called 
AMCO bumper overriders - among other things.

FWIW, my regular TR6 happens to have the bumper bars front and rear... 
had 'em since new.

> and someone who can tell me what 
> distributor i need to use with my triple webers since they dont create enough 
> vacuum to run the advance, then I'll be set to run(hopefully!) 

Okay - two things here (maybe a few more).

1. if you have a stock TR6 distributor, unless you happen to have an 
early TR6 - which from your other posts I presume not - then your 
distributor is set up for a vacuum _retard_. If you want to get that to 
work properly, I offer the following. There is a tap in the Cannon 
manifolds for a vacuum line. Actually, for the TR6, it's normally used 
for a vacuum source for the brake booster. There are fittings that you 
can buy (call the weber guys like Greenfield Imported or Performance 
Warehouse or wherever) that has large tap for the brake booster and a 
smaller tap for the vacuum retard. Get that part... sorry, I don't have a 
part number to offer, but I know these are available.

I ran my DSP TR6 this way for two years, and once I got the vacuum retard 
to work properly, I was able to tune the car to about 10 BTDC with the 
vacuum line connected at idle and with the stock springs in the dizzy, I 
was able to get around 22 degrees BTDC at around 2500 or 2700 RPM's. I 
say "around" because the numbers did bounce around a little. I'm not sure 
why, but I presume it was because of distributor shaft wobble or 
something like that.

With that setup, my car was a little weak on the low end but it ran great 
- especially above 3000 RPM's and 3500 to 4500 was the "sweet spot". This 
was perfect for my use which was mostly autocrossing.

2. If you have a few extra buX$, you should think seriously about getting 
a Mallory dual point dizzy. TRF sells one with the tach drive for around 
$200. If I undertand the part description well enough, this is a 
mechanical advance only dizzy. Anyway, with that unit, your timing will 
be as good as you can get it with a distributor. 

Other points - if you have trouble getting the Webers to work right, keep 
in mind the following treatise - make sure everything in the engine is 
perfect before you start trying to tune the Webers. I know this is 
blatently obvious, but everyone that converts to the DCOE 40's makes this 
mistake. They start trying to make the carbs compensate for other 
problems in the motor... And I really mean make sure everything is perfect.

Case in point - is your timing chain new? If not, slight variations in 
the timing can occur - this will show up as different types of engine 
problems depending on the severity... really _any_ slop in the timing 
domain is bad for the Webers.

Also - make sure your compression is fine and that your valves are 
seating correctly. I had a bad valve guide on my car, and a decell 
"run-on" backfire literally burned the auiliary venturis on both throats 
of one of my carbs. See, the valve didn't seal completely and the flame 
was able to travel out the carb...

Don't be afraid to consult with a "real weber expert". A person is not a 
RWE unless they have a dyno or have access to one. You cannot tune these 
beasts without a dyno. If you don't believe me, give me a call or drop me 
an e-mail when you've spent $500 for idle jets and that sort of stuff. 
With six-of-each things in your DCOE 40's, things add up fast.

Finally - be honest in how you intend to use the car. If its for cruZing, 
then tune it so, if its for racing - then tune it so. You can't have 
both, so when you go to tune the thing be realistic about the usage.

> thanks again 
> for keeping a head up for me!

You're welcome and no problem. I do tend to be months behind on the 
digest, but that's just the way I am.

> Paul Seedoff

regards,
rml

TR6's
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