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My current carburettor spindles appear worn as the idle speed changes when you wiggle them and it is difficult to set it up correctly so I thought I would rebuild my spare set of carbs and fit them over Xmas.

I will have a go myself but I would like some tips please. Can spindles be replaced and how do you go about it, I will also replace the jets and I have a recently purchased set of BAL needles to fit.

Anything else needed (I have gaskets and carburettor mountings) and any tips appreciated.

Ta in advance.


1980 Persian Aqua DHC

I think Burlen do a rebuild kit for SU's which includes the spindles and bushes in the full kit.

http://burlen.co.uk/

http://sucarb.co.uk/carburettor-kits/rebuild-kits.html

Alan
Saab 9-5 2.3t Vector Auto Estate
'81 TR7 DHC

I shall be reading this thread with interest since I am embarking on the same job shortly!

Andy the spindles can certainly be replaced, I have stripped down one of my spare carbs & once the throttle plate is removed the spindle can be extracted. I had a great deal of trouble getting the throttle plate screws undone - I will be needing a new throttle plate!

If the carb body is worn then you need to either get the body rebushed to eliminate air leaks when you reassemble, or I did find on eBay someone selling modified spindles with O rings which apparently will stop the air leak. I'll try to post a link.

Tony

<font size="1">1981 TR7 FHC Cavalry Blue
1980 TR7V8 DHC Jaguar Regency Red - sadly sold!
1977 TR8 FHC EFI Factory development car Inca Yellow</font id="size1">

The way our carb guy does them is he drills out the bushings on a drill press with the right size drill bit and presses in the new bushings. Although I've seen his set up during a club gathering to see a members TR7 regular to Sprint engine conversion I've never actually seen it being done so don't know what's involved in lining up the carb to bore out the bushing which I'm thinking is critical. Also when pressing in the bushing proper support on the inside of carb is needed I'm thinking. I didn't get a lot of details from him at the time as we were there to look at the engine not carb rebuild procedures.

- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

I made some caps from nylon rod for a friend to get better running from the CD 150's on his Vitesse. We originally intended to bore and re-bush, but felt that the tolerances would be too hard to maintain. If we were a couple of thou. out, the butterfly could bind or not close properly. These work well. They are press fit.




TR7 Convertible
Sprint Motor
MegaSquirt EFI

At the risk of ridicule I think that SU spindle wear causing problems is part fokelore and part urban myth.There are so many other potential wear /maladjustment incorrect needle profile,oval jet,damper wear ,piston rod wear,dashpot wear etc etc,that a small amount of air bypassing the spindle is only significant at idle.As soon as you open the throttle the percentage of air compared to the open butterflies is insignificant and is accounted for by the metering anyway.Just my experience with SU equipped vehicles over 40 years.Expecting the backlash,Steve..

It's idle where most people struggle, uneven idle, high idle speeds that can't be lowered.



- - -TR7 Spider - - - 1978 Spitfire- - - - 1976 Spitfire - - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra - Yellow TCT

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by sonscar</i>

At the risk of ridicule I think that SU spindle wear causing problems is part fokelore and part urban myth.There are so many other potential wear /maladjustment incorrect needle profile,oval jet,damper wear ,piston rod wear,dashpot wear etc etc,that a small amount of air bypassing the spindle is only significant at idle.<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">When the spindle wears, it is hard to get the tick-over correct as un-metered air is involved. Also, the butterflies are no longer centralised and so may not close correctly - more tick-over problems. I have replaced the spindles before, I also fitted butterflies without the weird valves - again try Burlen for parts.

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">At the risk of ridicule I think that SU spindle wear causing problems is part fokelore and part urban myth<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
I think you are correct...if it caused as much trouble as it's credited with, the company would have done something during the many years of manufacture, similar to the seals that Mikuni installed when they bought the rights to the Solex Sidedraught along with the worn out manufacturing plant.

Having said that, some manufacturers do have a tendancy to ignore problems...Herald/Spitfire rear end, 2000/2500 sliding-spline axles, TR7/Stag Water pump, Morris Marina just to name a few.


TR7 Convertible
Sprint Motor
MegaSquirt EFI

How dare you tell us that SUs don't wear out Steve!

Strangely enough, that is my experience too. I've owned some pretty old, high mileage SU carbs, & never had spindle wear cause a tuning problem.

On that, I love Stags solution. Much less mucking around than spindle rebushing, & probably as effective.

On the sticking, not fully closing problem, --- dirt. Stop oiling the spindle area, clean it up to remove the dust stuck in the oil gumming the things up, & the problem is usually cured.

In my poorer days, I would solder up jeffremj's weird valves. Just leaving them there, solid, doesn't seem to effect performance at all.

The main problem I've had with SUs themselves is flooding. Fixing the fuel pressure, [2 PSI is best, but no more than 2.2 PSI], will usually tame a recalcitrant SU. Check the floats, & replace the float bowl needle & seats if it doesn't.

Getting them to idle is a different matter.

Balance is all important here, but remember it is mainly needed for that idle. A little variations in suction or butterfly opening are not really that important above about quarter throttle, but at idle, critical.

Most balance problems, with older engines like ours often have nothing to do with the carb, but the engine & it's attendant accessories.

First throw out all that anti pollution garbage, or make it inoperative with suitable ball bearings in all hoses & lines. Stick a solid plate under the EGR valve, throw out that fool air pump, & make the exhaust airtight. Oh, & stick another solid plate under the EGR, just to make sure.

If local law makes this impossible, you have my sympathy. Come back in a week to read the rest of this, after you have all that garbage working properly.

Now fix the vacuum of all the accessories you do need, distributor, brake booster, & engine breather. You can not tune a carb if it is sucking air from a split hose or diaphragm.

Check the plugs are clean.

Included in this is fixing any suction leaks in the inlet system, particularly those rubber mounts.

At last, now you can check the suction on each carb. I still use the hose in the ear method, but have switched from rubber to plastic hose, just to be more modern.

If it is a long way out, have a quick try at balance, but if it resists, don't waste too much time, go to the engine itself.

I presume you have done a compression test. If not do one now, it will revel any major valve or piston problem.

I have found it very hard to tune our engines to idle, if the valve clearances are more than a couple of thou out. If they are more than this, fix them before blaming that poor SU for the problem.

Now the SUs. Clean the dashpots, check the needles are straight & installed correctly, not touching the jet, & that the pistons rise & fall smoothly, easily & COMPLETELY. While the pistons are out, check the choke action, & that the jet slides fully up the jet tube, when the choke is off. Adjust the jets to level with the top of the bridge in the carb throats, then wind them down 8 flats of the jet adjusting nuts as a starting point.

Confirm there is no flooding.

You have now almost completed tuning your SUs by actually doing normal servicing. The rest is simple.

Disconnect the throttles of the carbs. Start the car, roughly adjust the idle, & run until warm. Blip the throttle about every minute & a half during the tuning & hold above 2000 RPM for a few seconds to clear the plugs.

With the plastic tube in your ear & the carb throat, adjust the throttle stops until the suction is equal on each, & the idle is about where you want it.

Now gently lift each piston a small amount. The revs rise a little, & then fall as you do.

If they stay higher, it is too rich, so adjust the jet up a flat of the adjusting nut.

If they fall immediately it is lean, so adjust the jet down one flat.

Continue with this until you get that slight rise, followed by a fall on each carb.

You may have to readjust the idle during this procedure, if so be sure to keep the suction equal.

Now your 7 should idle as well as the next car at the lights, even if it can't beat them away from them.

Hasbeen

I know that this company used to rebuild ZS carbs for TR7s at one time:

http://www.paltech1.com/index.html

Clay

[url="http://www.jclay.me/"]My Triumph Site[/url], [url="http://www.triumphtechnical.me"]Technical Stuff[/url], [url="https://docs.google.com/folder/d/0B8MWEvqOpX3udEF4SmFQUW9RS09hbU5uNW5Wd0xrUQ/edit"]My Public Folder[/url],

I`m not taking them all the way to Ohio from the UK, Clay [;)]


1980 Persian Aqua DHC

I am not saying that the carbs do not wear,I am suggesting that it is not the showstopping problem it has been made out.Although not a vehicle technician by trade I have had lots of experience running crappy old SU equipped cars on no budget and I have been lucky enough to never have had to do anything with the spindles.I was always told DO NOT adjust the carb/s,It is almost always something else,or with an older vehicle a combination of things.I have always had other things to fix before spending on the carbs.I am not saying do not have them rebushed,I am saying look elsewhere before doing it.This seems to have livened up the forum.Steve..

Sorry Steve, that was meant as a joke, but I forgot the smiley.

I agree with you completely.

Hasbeen

All this delightful roaring and not one word about verifying the ignition is firing first time and all the time because you replaced the defective ignition cables with new ones, and cleaned the rotor & distributor cap contacts, and cleaned/regapped or replaced the spark plugs.

This is why our Sonscar was told to leave the carburetors alone. It's because 95% of all carburetor problems will be fixed in the ignition system.

But, watch out for that other 5%, it'll sneak up on you.

Mildred Hargis