MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

TR parts and Triumph parts, TR bits, Triumph Car Spares and accessories are available for TR2, TR3, TR3A, TR4, TR4A, TR5, TR6, TR7, TR8, Spitfire and Stag and other TR models are available from British car spares and parts company LBCarCo.

Triumph TR6 - Carbs....probably

My '76 TR6 sat for about eight years. After the usual trial & error, I got it running...sort of, but now when it "starts", it doesn't want to start in the first place, then when it does catch, barely runs, bucking all over the place and then dying with a puff of blue smoke coming out of the Strombergs. I need a baseline here.....car is completely stock, & I have done the carbs with new diaphragms, float levels, float needle-valves, & cleaned up by-pass and temp. compenstors. Also has new plugs, points, rotor, cap and leads and has been re-timed. Should I give up and get some Webers?
T.G. Lawson

Leave the webers at the store
What did you do with the fuel in the tank and the fuel pump?
DON KELLY

Aha, Don, I real epiphany!!
db
Doug Baker

Changed fuel pump, replaced fuel lines from pump to carbs, replaced fuel filter, added fuel stabilizer to tank, put in a bunch of fresh gas.....that's about it........tried to start car today; same thing....it wants to run, but sneezes out of the carbs and either revs to 3000 or dies outright, after dieseling......
T.G. Lawson

You would be surprised at how much junk is in the bottom of that tank after that long. I bet it'd in the filter,pump and carbs by now.
Don't take much to screw a carb up
DON KELLY


Thanks. The fuel pump is actually brand new....I installed it last week, & the carbs, from what I can see, are clean with little crud in them. I dunno.....I guess the next thing is to take the tank out and/or flush the lines....something I was hoping to avoid.
T.G. Lawson

TG

My opinion is if it is running roughly it isn't gas supply but timing. Not sure how you timed it without it running. Try moving the distributor a bit each way to see if you can get it running smoother. Blue smoke out of the carbs suggests the intake valve is still open when it is firing.

Before removing the tank- try using a can of gas and hook it up to the fuel pump and run it. See if it is any better. If it is, then you have a cruddy tank. If it isn't then the problem lies elsewhere.

This does assume the engine hasn't been taken a part and the timing chain was put out a notch or two or the distributor drive gear is out a notch.

Also check to ensure you have the firing order right and the right plugs are attached to the right distributor cap spot.
Michael Petryschuk

Make sure the pistons in the carbs move freely. If the car has been setting for 8 years the diaphragms will probably need replacing as they become fossilized with age.
Berry
BTP Price

Thanks, guys. Pistons in carbs move OK, & I re-timed engine by bringing #1 cyl to TDC by hand and then turning dist until rotor was aimed at #1 cyl. Have had carbs off three times & checked and re-checked and checked again diaphrams, float level etc. Have also had by-pass and temp. comp off more times than I can remember.I have to admit, after 20-odd years of fooling around with cars, this one has me stumped. webers looking pretty good right about now.......
T.G. Lawson

Hi TG,
I'd be leary setting my timing the way you described..can you borrow a timing light ?
Charlie
Charlie B.

Do you know how to set it by vac. reading?
DON KELLY

I just did it that way to get it running....I figured once it ran, I could fine tune it and get it right. It does run, but, well, you know............will take a shot at it again tonite.....
T.G. Lawson

Have you adjusted the valve clearances to 0.010? If the clearances are out it could be preventing the valves from fully closing or opening.

Check vacuum lines for leaks.

I would be concerned that if you can't get it going OK with the Strombergs, you won't get it going with the Webers much better.

Check the compression on the cylinders if you haven't to see if you are getting good compression.

If you haven't opened up the engine and it has sat for 8 years without being run, the rings could be in bad shape and not sealing well. Mine sat for 20 years withe the head off. All the rings were carbonized in the pistons and I had to chip them out.The pistons were seized in the cylinders as well. It was a mess. I wish I had taken pictures of that.
Michael Petryschuk

I was thinking of vac. leaks too-brake booster or emission hoses. I tried to start my car with the booster disconnected and it would barely run. Also,sticking valves or a broken valve spring. Centrifugal advance sticking?
Lots of possibilities, really just WAG from here.
Good luck
Berry
BTP Price

Did a compression test: 125 to 135 psi in all six cylinders. Replaced brake booster hose and had a hard look at other lines - they seem OK. One thing: when the car does run - if you can call it that - there is absolutely no response when you press the throttle.....no change in revs, no nothing. Eventually, the engine kind of strangles itself & stops running, accompanied by gas sneezing out of the carbs.........
T.G. Lawson

Hi Tg

Did you try to start the engine before you replaced the plugs, leads etc. Could it be possible that the leads are connected in the wrong firing order. I believe some manuals actually published the incorrect firing order.

Colin
C J Norcott

You didn't mention that the condenser was replaced (I presume it was). Also, maybe substitute the coil with a known working or new one. What does the spark at the points look like-nice fat blue one or weakish yellow?
Berry
BTP Price

Spark at points bright blue, replaced condenser - twice - will try coil next. And re: firing order....that's a thought. I have checked mine & it's the same as the illustration in my Haynes manual. Will investigate this further. & once again, thanks to those who have taken the time to respond. The quest continues.......
T.G. Lawson

TG

I think you should get some more RPM if you press the throttle regardless. I seem to remember that it is possible to put the throttle plates on backwards. You may want to check.

How did you adjust the needles in the carbs?

Did you do a rudimentary adjustment on the throttle linkage to get the 2 carbs somewhat synced in air flow?
Michael Petryschuk

Don't think I touched throttle plates.....& re: needles, got the special tool & have adjusted needles by adjusting them from the top of the dashpot to maximum, turning right & then back one turn at a time....nada. Replaced spark plugs / wires, dist. cap, & played with timing @ dist. Have done some carb adjustment w. throttle speed screw, but engine just as f***** up as ever......
T.G. Lawson

I never saw a response regarding proper firing order for the plug wires. Did you confirm that the rotor was at the #1 position around TDC of the timing?

Also, are you sure the choke is engaging correctly? It won't run well at all when cold without choking.
Brent B

OK, the firing order is 1-5-3-6-2-4. The distributor turns CCW.

This sounds like the timing is off. The engine can be timed very close statically. In fact, the TR3 & TR4 engines are timed this way...no timing light necessary.

Here is the way to get the timing close enough to run very well.

The procedure as I do it...Make sure your points are set to spec first. This is always important whenever setting the timing, as a change in in the point specs affects the timing.

1. Bring the engine up to the timing mark on the pulley by turning the engine clockwise as looking from the front. If you go by it, don't back off. Go around again, as you don't want to introduce timing chain slop into this. Now the engine is at the timing that you want. Rotor should be pointing toward either #1 or #6. Don't worry about whether it's ready to fire on #1 or #6 cylinder, it doesn't matter.
3.Loosen the clamp on the dizzy.
4. Hook up a test light or voltmeter to the point side of the coil, and turn on the ignition.
5. If the test light is on, turn the dizzy CCW until the light goes out, and then turn it back (CW) until it just goes on.
If the test light is out, turn the dizzy CW until it just goes on.
6.Tighten the dizzy clamp.


Timing is now set for wherever you lined up the timing marks for.
Arthur A. Liefke

Make sure if the ballast wire is still in place that the coil is that made for an externally ballasted system Big PO mistake (ask me how I know) is to slap any 12Volt coil on the ballasted system. Mine had a standard blue Bosch coil with the ballast still in place...super hot spark at start but not so good after start-up. Switched to a BWD ballast coil from Advance Auto for a whopping $14 and the results were G-R-E-A-T.
JT White

Have an old coil from a Morgan 4/4 I used to own....will try it, but otherwise, the carbs are history. I vowed the next time I take 'em off will be the last time, & I'm going to get some of those weber 45MCHH single choke kits being sold right now for $299, all in. Any carb as fussy as these strombergs can only cause me grief in the future...........
T.G. Lawson

Turned out to be the carbs, after all. Put on set of Weber 45MCHH single chokes, and everything was tickety-boo....well, almost. Troubles with linkage & choke cable & it idles too high, but at least now it's running on all six & doesn't cough and backfire. Again, thanks to all who offered advice.........
T.G. Lawson

This thread was discussed between 23/08/2010 and 07/09/2010

Triumph TR6 index

This thread is from the archive. The Live Triumph TR6 BBS is active now.