• The Roadster Factory Recovery Fund - Friends, as you may have heard, The Roadster Factory, a respected British Car Parts business in PA, suffered a total loss in a fire on Christmas Day. Read about it, discuss or ask questions >> HERE. The Triumph Register of America is sponsoring a fund raiser to help TRF get back on their feet. If you can help, vist >> their GoFundMe page.
  • Hey there Guest!
    If you enjoy BCF and find our forum a useful resource, if you appreciate not having ads pop up all over the place and you want to ensure we can stay online - Please consider supporting with an "optional" low-cost annual subscription.
    **Upgrade Now**
    (PS: Subscribers don't see this UGLY banner)
Tips
Tips

TR6 1 & 3/4 SU's on a TR6

Share this page

K

karls59tr

Obi Wan
Bronze
Country flag
Offline
What size jet needle is used on a TR6. Asking for a friend who is replacing the Strombergs on his TR6 with SU carbs from a TR3. Wonder if TR3 linkage would work for that application or would something have to be fabricated?
 
steveg

steveg

Yoda
Gold
Country flag
Offline
I'll be working on this same question later when I convert to HD6s. APT Performance in Riverside, CA does a lot of Triumph dyno tuning and sells many needles for SU carbs. I'll be wanting to know what needle is spec'd for the HS6 conversion kits for the TR6, which they sell. Guessing the same needles would work on the H6 TR3 carbs you're mentioning.

https://www.aptfast.com/
 
charleyf

charleyf

Luke Skywalker
Country flag
Offline
Karl,
I believe your biggest problem with using the H6 carbs from a TR3 on a TR6 is going to be the linkage. The H6 carbs use a bell crank located at the front of the carbs and is located on the exhaust manifold. You will have to do a lot of fabricating to establish that. The TR6 uses a bell crank located between the carbs. However the HS6 carbs (used on a few late TR4s) use a bell crank located between the carbs.
 
T

titanic

Jedi Warrior
Country flag
Offline
Also, the SU H6 carbs are "thicker" (flange to flange) than the ZS or SU HS6 carbs. There may not be enough room for the stock air cleaner. What would be gained from the switch?
Berry
 
steveg

steveg

Yoda
Gold
Country flag
Offline
APT got back to me . BAG is the Swing needle used in the HS6 TR6 conversions. Won't fit in earlier carbs - HS6 and HD6 require a fixed 100 needle for the 100 jet. These are comparisons of the jet area with the needle. Note the TR3 is richest of all:

NeedlesTR6_2.jpg


From Ian Hamilton's "Needles.ods" spreadsheet
 
T

titanic

Jedi Warrior
Country flag
Offline
Steve-Just remove the cap on the swinging needle, lightly file the knurls on the shank, and the needle can be used in a fixed needle piston. I have also found that the recommended BAG needle (used with the 8 oz yellow spring) was too lean).
Berry
 
steveg

steveg

Yoda
Gold
Country flag
Offline
titanic said:
Steve-Just remove the cap on the swinging needle, lightly file the knurls on the shank, and the needle can be used in a fixed needle piston. I have also found that the recommended BAG needle (used with the 8 oz yellow spring) was too lean).
Berry
Click to expand...

Berry,

Thank you for the input. Looks like the Healey normal CV might be a good starting point after all.

Edit: Healey BJ7 HS6 normal (BC) added. Healeys run the 12oz Green spring - that would make the BAG run a little richer.

NeedlesTR6_4.jpg
 
T

titanic

Jedi Warrior
Country flag
Offline
The short answer is I am using a KN needle with red springs. It was recommended by a person who had a wide band AF meter and similar mods as my engine, which are an increase in CR to about 9.5, 150 hp PI cam, and the dual outlet exhaust from a later TR6. He found that the lighter (4.5 oz) red springs gave better acceleration. He also gave me a modified profile for this needle for better performance-it is .001"-.002" thinner starting at station 2.
Berry
 
steveg

steveg

Yoda
Gold
Country flag
Offline
titanic said:
The short answer is I am using a KN needle with red springs. It was recommended by a person who had a wide band AF meter and similar mods as my engine, which are an increase in CR to about 9.5, 150 hp PI cam, and the dual outlet exhaust from a later TR6. He found that the lighter (4.5 oz) red springs gave better acceleration. He also gave me a modified profile for this needle for better performance-it is .001"-.002" thinner starting at station 2.
Berry
Click to expand...

Good info, Berry!

Question - if one is going to shave the needle for all positions above idle, couldn't the jet be dropped a few thou instead?
 
T

titanic

Jedi Warrior
Country flag
Offline
Steve-I suppose you could, but the idle would be pretty rich. I think that is what Kastner suggested in his competition prep manual, but he wasn't concerned with anything but the upper range.
Berry
 
Similar threads
Thread starter Title Forum Replies Date
R TR6 Crazy Ignition Failure in TR6 engine… Triumph 7
mctriumph For Sale 69 Tr6 Triumph Classifieds 1
B TR6 TR6 block decking Triumph 2
A TR6 How many fuel filters-TR6 Triumph 25
Got_All_4 General Tech TR6 Transmission Troubles Pops Out of 3rd gear Triumph 2
J TR6 Repadding TR6 frame Triumph 0
S Wanted Need an HVDA conversion kit for 73 TR6 Triumph Classifieds 3
M TR6 Sorting out new TR6 Triumph 10
tr6nitjulius For Sale TR6 Clutch Master Cylinder $40 Triumph Classifieds 0
S TR6 '72 TR6 distributor issues Triumph 3
R TR6 Limit Mechanical Advance on TR6 distributor? Triumph 8
RonC General TR TR3 Shifter on TR6 Triumph 8
B TR6 TR6 convertible top frame Triumph 0
K TR2/3/3A The TR6 gearbox Ist gear.... Triumph 1
tr6nitjulius For Sale TR6 tail light assemby & Resurfaced/New Ring Gear Flywheel Triumph Classifieds 0
tr6nitjulius TR6 TRIUMPH TR6 Triumph 7
S TR6 New tr6 purchase Triumph 31
Jim_Stevens TR6 Barn find of TR6 and many TR3 parts Triumph 9
nichola TR6 Hot spot on cylinder head - 1973 TR6 Triumph 2
R TR6 Heater control bezels TR6 Triumph 2
L For Sale 1974 Tr6 for sale Triumph Classifieds 0
tr6nitjulius TR6 TR6 Parts Visualization Triumph 0
Got_All_4 For Sale 1969 TR6 Driver Seat Triumph Classifieds 0
R TR6 TR6 Choke Cable Triumph 11
Got_All_4 For Sale TR6 TR250 TR4 parts for sale Triumph Classifieds 2
B For Sale TR6 Carburetors Triumph Classifieds 0
R TR6 TR6 Triumph 6
Chrisc9 TR6 TR6 brake light Triumph 6
glemon TR5/TR250 Answering My Own Question Rear Tube Shock Conversion Numbers TR4a-TR6 Triumph 0
tr6nitjulius General TR TRIUMPH TR6 the possibilities! Triumph 12
SherpaPilot TR6 Unidentified fitting on TR6 Engine Triumph 3
Got_All_4 TR6 Need 1969 TR6 Expert Got Questions Triumph 17
tr6nitjulius General TR 6/24/23 TRIUMPH TR6 (5) TR8 (2) Spitfire (1 RHD of 2) TR3A (1) Triumph 0
AngliaGT ANOTHER TR6,& an MGB Spotted 0
A For Sale 1974 TR6 Triumph Classifieds 1
Got_All_4 TR6 Triumph TR6 PDWA Brake Question Triumph 1
EWD For Sale ‘74 TR6 original wheel trim rings Triumph Classifieds 3
EWD For Sale ‘74 TR6 original radio Triumph Classifieds 0
EWD For Sale ‘74 TR6 original starter Triumph Classifieds 0
EWD For Sale ‘74 TR6 original steering wheel Triumph Classifieds 0
JPSmit TR6 at lunch today Spotted 0
E Wanted looking for a tr6 bell housing Triumph Classifieds 12
jfarris For Sale TR6 Yellow Fan - new Triumph Classifieds 0
L Wanted right front turn signal 1975 TR6 Triumph Classifieds 2
charlie74 ‘74 1/2+ TR6 Spotted 0
E TR6 TR6 flip-up bonnet question Triumph 4
Marvin Gruber For Sale 1974 TR6 for sale, $7200 Triumph Classifieds 3
T TR6 TR6 Tire Pressures Triumph 2
B TR6 Triumph tr6 coolant leak Triumph 4
tr6nitjulius General TR Fan Belt Replacement '72 TR6 Triumph 1

Similar threads

Top