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Waxstat carb jet conversion kit

Here’s where to discuss anything specific about your standard(ish) car or something that applies to the model in general.
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UKPhilTR7
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Waxstat carb jet conversion kit

Postby UKPhilTR7 » 10 Apr 2020 11:34

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Beans
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Re: Waxstat carb jet conversion kit

Postby Beans » 10 Apr 2020 18:56

Some reading in my blog, label SU from july 2017 onwards: https://tr7beans.blogspot.com/search/label/SU
Most important thing to bear in mind is that when you need to fit (new) bushes for the throttle spindels, you need a milling machine.

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1976 TR7 FHC (currently being restored ...)
1980 TR7 DHC (my first car, a.k.a. Kermette)
1981 TR7 FHC (Sprint engined a.k.a. 't Kreng)

http://www.tr7beans.blogspot.com/

UKPhilTR7
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Re: Waxstat carb jet conversion kit

Postby UKPhilTR7 » 11 Apr 2020 15:10

Need a milling machine?
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sonscar
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Re: Waxstat carb jet conversion kit

Postby sonscar » 11 Apr 2020 16:51

Or some way of accurately machining the bush holes the right size,depth and exactly in line.His is possibly not a job for a hand drill.Steve..

UKPhilTR7
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Re: Waxstat carb jet conversion kit

Postby UKPhilTR7 » 11 Apr 2020 23:14

OK so if I am getting this right, if I replace the Waxstat jets to the pre 76 non thermostatic jets, I will need to machine the needle to make it fit? I will not be able to buy the uprated ones that are currently available?
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Beans
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Re: Waxstat carb jet conversion kit

Postby Beans » 12 Apr 2020 00:17

No, you need a milling machine when you have to fit throttle spindle bushes.
Maybe some reading is in order before you start with this job :roll:
Image
1976 TR7 FHC (currently being restored ...)
1980 TR7 DHC (my first car, a.k.a. Kermette)
1981 TR7 FHC (Sprint engined a.k.a. 't Kreng)

http://www.tr7beans.blogspot.com/

Stag76
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Re: Waxstat carb jet conversion kit

Postby Stag76 » 15 Apr 2020 03:35

Hi Phil,
Are you back home?

The conversion to non wax-stats is a straight forward bolt in job...a bit finnicky, but no machining required.

The carbies tend to wear where the brass shafts that carry the butterfly valves pass through the
alloy body. This is equivalent to an air leak and causes idling problems.
If it is bad enough, you have to have bushes fitted, although it's probably easier to throw it away
and find one that hasn't worn.

The other option is to have a groove machined in the shaft and fit an "O" ring to seal it.

Beans
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Re: Waxstat carb jet conversion kit

Postby Beans » 15 Apr 2020 07:44

Another problem with worn spindles is that the throttle disc won't seat properly.
As a result idle speed can become quite random.
Though an extra seal certainly won't harm :wink:
Image
1976 TR7 FHC (currently being restored ...)
1980 TR7 DHC (my first car, a.k.a. Kermette)
1981 TR7 FHC (Sprint engined a.k.a. 't Kreng)

http://www.tr7beans.blogspot.com/

UKPhilTR7
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Posts: 1906
Joined: 24 Mar 2005 12:52
Location: West Midlands, England

Re: Waxstat carb jet conversion kit

Postby UKPhilTR7 » 17 Apr 2020 22:59

Hi Stag76, yes I am back home now (back in the UK) and my girl is back with me after her long holiday in Australia :-)

I think that is my problem, that I need to replace the bushes on the carb near to the bulk head. When I tried to tune them, I could get the carb by the rad down to a low number, but the carb by the bulk head would now go below 5 on the carb tuner.

When I was there, I was thinking it may be worth changing the jets too and getting the whole system. Currently, my idle runs at 850 - 900 when warmed up, but after the electric fan has been the idle runs at 900 - 950.
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