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Triumph TR6 - SU Carb woes

Trying to put a set of SU's on the TR6...very nice rebuilt carbs with new throttle shafts, bushings etc. Can't seem to get them to run right with the rich/lean without the rpm's going through the roof and thats with the idle screws backed out. When I lean the jets up to get the rpm down she runs poorly. I used the ZS thick gaskets and I'm wondering if I shouldn't have? My top end gasket set only contained 4 normal thickness gaskets for carb to manifold...do you reuse the thick ones or should the SU's run without.
JT White

er, I think the "thick ones" are insulators...anyhoo any help in set-up, tricks etc would be appreciated.
JT White

All I can say JT is that is is a back and forth activity. Time the engine, adjust the carbs, time the engine, adjust the carbs, and again and again. It took me 6 hours over 2 days to get my Strombergs and timing right. But once done, I haven't had to touch them since (10000 plus miles)

Do you have an air flow meter to balance the air flow through the carbs?

Make sure the accelerator linkage is such to allow the throttle plate to be in the right position at idle. (Don't ask me what the right position is but the manual should tell you)

I have no clue about the gasket affect but make sure any vent holes are properly vented.
Michael Petryschuk

I told you so.
A lot of things come to mind, maybe one of them is the problem. Is the throttle disc. centered and fully closed? With the idle screws backed off, there should be very little light showing around the disc. Is there a spring loaded valve in the throttle disc? They were used to limit vac. on over run and are a potential source of grief. Do you have throttle springs that are anchored to a heat shield and do they have enough tension to fully close the throttles? Make sure the air valve move freely and hits the bridge with a loud click. Sounds like you either have a vac. leak or the throttles are fully closing. Check the various vac. hoses for leaks.
A good starting position would be to wind the jets down .050" from the bridge and open the idle screws 1 turn.
Keep us posted.
Berry
BTP Price

JT,
Where did you get the carbs, and what kind of car did they come from? Do you have the Vacuum advance line hooked up? Where is your timing set, and I might have more questions if you can answer those.
Rod
Rod Nichols

Timing, valves, points, set, spot on ...points, condensor, rotor, cap, wires, plugs all within the last two months. Carbs came from NZ off of a TR6...reputable dealer, very nice carbs, very well rebuilt and cleaned, has a good track record of sending carbs to the US for TR6 use...contacted several people who got these from him and they have had no problem putting them on their TR's. I've a serious migrane this AM so if me headache subsides I'll tackle them this afternoon or eve after our Jaguar Club cook out...hopefully the XJS keeps it's head about it!
JT White

JT,
Check the casting numbers on your float bowls. I bought mine from New Zealand also, but bear in mind, the TR6 never came from the factory with SU's. If they came from a 2500 Saloon, they will have different float bowls, to offset the extreme angle the motor is sitting. (nose high) I found out from Joe Curto, and I was having horrible issues not unlike what you described. Check the casting numbers first, as one of the bowls mat be deeper than the other. Hope that helps, and the migraine goes away. BTW...a friend here in Boise went thru the same issues a year after I did, bought his carbs in NZ also! Notice a pattern here? If the vacuum is hooked up plug it off. The SU will not supply vacuum correctly for the retard diaphragm on the TR6 dizzy. It'll just give you another headache ;)
Rod
Rod Nichols

Thanks Rod...I solved my problems...ZS's back on! These SU's are really a nice looking set of carbs BUT I had my ZS's so sorted that I really didn't have the patients for the SU's and really like the look of the ZS's on the TR. I'll put the SU's up on E-bay along with the added new fuel pressure regulator and single choke cable for a great price and then use the monies for a new wood dash.
JT White

JT......
Email me....replace the dot with a .
Rod Nichols

You've got mail
JT White

OK, guys, I have two 175 ZU's. Do I rebuild them, send 'em out to be rebuilt like the alternator, buy something off ebay or one of the usual suspects or what?? What's the consensus? Thanks.
db
Doug Baker

I hope yopu mean ZS's not some ZS/SU Hybrid! They are relativly simple carbs that the average DIY person can do. I alway rebuild my own, thats why I'm back to my ZS's since I took the time to sort them out while the SU's sat on the shelf then I just lost patients for the SU's after fiddleing about with the ZS's foir sp long I just didn't feel like setting up the SU's (hey, I took the easy way out)...I'd rather have stock provided it's working right BUT some do like the ease of maintenance (or lack of adjustments) required on the SU's. My beautious SU's are up for grabs...hint, hint ; )
JT White

JT, please forgive my ignorance. Zenith Strombergs. 175's!! So, a rebuild kit from TRF and just go at it huh? What about Powder Coating, or polishing. Is that reasonably done? Just to clean things up a mite. I understand that various needle are available. How do I go about choosing the best one for my application? Thanks.
db
Doug Baker

Doug,
It's been a few years since we communicated. Email me and I'll give you my experience with my triple stroms.
benji

Mine are on ebay and people do crack me up...it's a BIN non-auction and there are four people "watching" them. You "watch" something on ebay when it's under "bid" auction, when it's BIN only the only thing to watch is someone else getting them!
JT White

Doug,
Check your email.
benji

With the age of our carbs, I think it is a good idea to go Pertronix and high output coil to eliminate slop in the dizzy and to get one more tiny little HP out of her. I have had my Pertronix in for just about 10 years and not one problem.
I took Autosol to the top of mine Doug. I left the bodies OE.
Just out of curiosity, do you still have the 2 brass tags or does my mind think it remembers you saying you did pick 2 up?

Rick
Rick Crawford

No Rick, I need the brass tags. I had one. Sought to clean it up. Damaged it significantly. A generous soul on the BBS did send me two, but for different years. Mine is 3385R. I need 3385L. I now have a pair that are 3337R and 3337L that I'd dearly love to trade to some needy fellow in exchange for a 3385L or a matched pair.

Reminder...I still need the button for the handbrake lever!! The vent rod is back in stock in GB and TRF has it in stock so I no longer need that item.

Thanks.
db
Doug Baker

Rick, do you have an electric Tachometer? See Rod's note on the Distributor thread.
db
Doug Baker

Rick's talking about the el. ignition and Rod was talking about the whole dizzy.
DON KELLY

Well Don, If you put Petronix in the distributor instead of breaker points is that not electronic ignition and can you still use the gear driven tach connection? Need to know cause I'm about to send my distributor to Jeff to rebuild!@!! I don't understand what you mean about el ignition vs the whole distributor???
db
Doug Baker

Yes,You can still run the tach drive.

Rod was talking about Pertronix also sells distributors too.
They are electric tach facilitated.
I have a Mallory dizzy and it doesn't have a tach drive either ,just electric.
DON KELLY

Doug,

You are still running the same distributor if you stick the Pertronix kit in it so the mechanical tach drive is not impacted. The Pertronix kit consists of a Hall effect sensor that attaches to the breaker plate in lieu of the points and condensor and a ring with magnetic rods in in that goes on the distributor shaft below the rotor. Do be aware that rotors other than Lucas (Bosch for example) may not fit when a Pertronix unit is fitted.

If you were to change over over to a Mallory, Pertronix or even other types of Lucas six cylinder distributors that have no provision for a mechanical tach drive, then you would need to convert your existing tach over to an electronic unit or find a substitute tachometer.
SteveP1

Have Jeff send you his rotors, the big guys are now selling his.
DON KELLY

Steve, Don, Thanks guys. I'll call Jeff on Monday. My Distributor is in the mail.
db
Doug Baker

To me??
Got 2 already. I'll send it back
DON KELLY

Don, If it gets to you, please do send it back or better still; on to Jeff!!
db
Doug Baker

I'll keep an eye open for it Doug ;)
DON KELLY

This thread was discussed between 17/07/2010 and 25/07/2010

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