Ok wow. I have been looking on how to set those needles and that seams all soo simple!, I will definitely have a look into that tomorrow!, though these needles arent the fixed type, they are spring loaded. i hope this still works for them!
budgel,
Mar 14, 8:00am
Why didnt you read the links I posted!
socram,
Mar 14, 8:03am
Agree.The key to a lot of what you have said might be that you can't get the car to run leaner. It might well be that the jets/needles are worn. Remember that on an SU, as the needle lifts, it lets more fuel in.They are extremely sensitive and on my own car (Strombergs), as a temporary fix when no alternative correct needles were available locally after a full engine rebuild, the original needles were set slightly higher to mimic richening the mix, but that is not a good permanent fix.
That was in 1994 and I still don't have the correct needles fitted!
Also agree that the condenser is a cheap component that you might as well replace.
ginga4lyfe,
Mar 14, 10:58am
I did, and a picture with barley any description as to what i was looking at on the needles kinda confused me
pdc1,
Mar 14, 7:05pm
I think you made an thread about anything good about Triumph 2500. I realise now that there is, they have SU carbs. Not really giving you much help I know, but they are marvellous carbs. Might pay to pull them back to pieces again and study them, and get your head round how they work, however the problems that you have been describing could be electrical too. Actually Jazz posted a picture a while back of a carbie balancer that can be simply made out of some tubes filled with oil on a board. I thought it was quite good at the time. It might pay to yell out to him to send the pictures again.
tractor9,
Mar 14, 8:51pm
I'd be interested in Jazz's pics too.
ginga4lyfe,
Mar 18, 1:52pm
ok MAYBE this is a "tadaaa! I found the problem" moment, but i have found that my vacuum advance is not working, it moves ( which i tested) but i didnty test to see if the diaphragm leaked, in which. it does, so IM looking for Swift Automotive ( Christ Church ) Email address which on an internet search doesnt show anything, So does anyone on here know the blokes and have their email! also. maybe some one may have a spare Lucas 45D6 dizzy and vac advance! but yeah, she now back fires a LOAD less, but driving her is almost like jumping on an old tiger, you expect to be thrown off, but it just lays over and gives up ( bad analogy i know ) , ie it pulls away nice then loses power and starts spitting through the carbs , so most likley a Timing issue!
saki,
Mar 18, 3:18pm
Swift no email in classic car but try www.qualityrebuilds.combang heaps of advance on it before you get the unit repaired and give ti a try, about 20 deg for starters.
ginga4lyfe,
Mar 18, 3:52pm
Cheers, they are just down the road, so i may as well visit them in person
ginga4lyfe,
Mar 24, 3:06pm
ok, well i managed to get a new vacuum advance and the problem hasnt gone away, so. i think iv most likey burnt a valve, so I have ordered in a head-set that comes with head gasket and valve seats, im gunna pull the head off and have a good ol look right now!
pdc1,
Mar 24, 3:26pm
Hope it isn't too late. You're probably upto your elbows in oil and shit right now I guess! I think you are rushing getting the head off at this stage. I would be reluctant and do it only as a last resort. You could open up a larger can of worms in the process. If it has good compression I would be having a good look again at everything else. Check that you have the needles in carbies properly set, that pistons are free moving and fall with a nice click, that choke is properly off and not interferring with the mixture screws etc etc, and also that your ignition system is excellent. p.s. I've never had any trouble using atf in the dampers either. Too many times I've pulled a head in an old unknown engine has resulted in a total rebuild, or I've put the head back on and it ends up burning oil shortly after.
skin1235,
Mar 24, 3:58pm
whoa up, why pull the head, you've got good and even compressions, back it up and start thinking of other causes
skin1235,
Mar 24, 4:07pm
you say it pulls away even, then as the revs get up it starts backfiring It is not compression related then is it, thus not valve related, and if you have static spark set correct as you claim it is not spark related either, that is a vac advance unit, more vac more advance, less vac more retard, retard doesn't backfire it just has less power So back to the carbs, take them off and do them again, this time make absolutely sure that gaskets are on right, diaphrams are in right, needles are in right, springs are in the right place, etc ( a gasket back to front on the mount will block or partially block the vac to above diaphram, and they get more sulky than a 15yr old virgin ata stag do if they cannot breath right
it was running okay before you did the carbs!, so why have you been pissin about with non carb issues to fix a carb issue, you remind me of the carpenter who cut the door frame the wrong size then fixes it with a fkin big 'amma rather than recut the frame to correct size
ginga4lyfe,
Mar 24, 4:12pm
ok well, to head right back to the beginning of the story, it's original compression test showed quite varied results, the second one was done by my uncle, and i dont trust his eye sight as much as he does, and now, its consistently back firing, lean or rich, so the only other reason as to why its back firing is the valves, as the ign is now working 100% properly, and eh, im only spending 90 bucks for head gasket, crank seals, valve seats, and intake and exhaust gasket, and a bunch of other stuff, so why not! the most harm i can do now is further ruin an already not working properly engine , and a replacement "known good" triumph GT6 engine is only 250 bucks, or i can spend the same for a rover 3500 V8 , or i can spend slightly less over hauling the engine, atm its a second car in the works, not a daily (yet! ) so im not really loosing out, Oh and is there any way of finding out if the new valve seats are ok for unleaded fuels! Im guessing because i didnt run leaded additive the engine burnt its valves because of this , though the previous owner told me " oh nah i drove it for months on this burnt clutch and unleaded!" I guess you cant trust people as far as you can throw them! haha, oh well!
skin1235,
Mar 24, 4:13pm
if I remember rightly the 2.5 twin carbs bolted onto plastic blocks, and those blocks had gaskets both sides, the blocks are drilled to suit the carb and can easily be put back on the wrong side out thus the drillings no longer match, thay can also be right finackyfemales about air leaks on the mounts too, the diaphrams were a prick to re-use too, they tend to swell and don't always sit back in the register as you'd expect
skin1235,
Mar 24, 4:17pm
IU must have missed the bit about the uncle - to get proper reading they maust be taken properly, and if the uncle is a mechanic I'd suspect he'd know that and how to take them
If it is valves you'd find it in 2 minutes, pop the plugs and check compression, then a teaspoon of oil down each and do them again
I get that it is not a huge expense nor of the utmost importance, but I hate to see a potentially good engine reduced to bits never to go again for the wrong reasons
ginga4lyfe,
Mar 24, 4:20pm
I see were you are comming on with that conclusion, I have pulled the carbs off 3 times now, stripped down and rebuilt them twice, SU HF6 Carbs are pretty straight forward, and they are definatly not sticking at all, I have checked and double checked for vacuum leaks, and found zero, the car is runningquite nice at idle, only back fires on acceleration and at midd Rpm's ( Id say around 3-4k rpm's )
skin1235,
Mar 24, 4:21pm
magic additives to stop valve seat recession and or valve burning are for idiots with too much money and no logic, how many older cars are on the road, how many use the additives, how many who have the older cars and don't use the additives have suffered head and valve issues
ginga4lyfe,
Mar 24, 4:21pm
Nope it has the heat shield card, then a thin gasketthen the carbs, there is literally stuff all space for those plastic type spacers
skin1235,
Mar 24, 4:29pm
matt, I wish I were in your area, I'd have the problem sort toot sweet, and without pulling the head too, it will be on the induction side, inlet side, incorrect adjustment or air leaks in and or around the carbs, (diaphrams had a habit of leakingespecially after you've had the out and washed them) I just don't get that it is of another source, you say it pull s away smooth then mid range starts popping so it won't be a lead wrong but it could be a plug dropping under load, although you'd expect it to drop just above idle as load comes on rather than at mid revs, hey you've got 6 of them drop one off and go for a drive, if no change, change to drop another, eventually you'll find which one is doing the mischief, then you'll be closer to finding the cause, it will at least tell you which carb it is too
ginga4lyfe,
Mar 24, 4:47pm
so buy a few more plugs and try see if the plugs i may have maybe defective! though whats weird is that it doesnt back fire throught he exhaust anymore, its poping through the inlet and sometimes pops the plunger out the top, foot flat to the floor just makes it feel quite poppy and very flat and low on power, kinda like bogging down, so maybe i should just pull the inlet manifold off,and replace thegaskets through out! and I keep going through it in my head, but i honestly dont know what diaphragm you keep mentioning
skin1235,
Mar 24, 4:55pm
pop a photo up of the carbs, I've probably got my SU's and strombergs mixed up - it's been near 25 years since I worked in the trade
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