[SUs on a US TR6]

Hi Steve,

I am near Valenciennes, and should do the carbs swap next week.

One of these TR3 has already SU carbs, but the needles/springs setting is not correct actually.

Cheers,

Chris.

 

Hi Chris,

Did you manage to complete your carb swap? I started to play with mine last weekend but am confused about the pipe connections. There are two pipes on the float chamber which would correspond with the two that are on the Stromberg but which is the connection from the fuel pump? Any guidance would be most welcome.

Steve

[intermittent engine]

Thanks Ted

It seems to come back to the distributor every time so I'll give that a good going over and check for wear etc. BTW mine is a 1976 TR6 (imported from the USA in 1994 to Belgium) currently carrying twin Strombergs (with SUs still in the box awaiting a spare hour or two). Don't know if that would make a difference to your suggestions.

 

Thanks Ivor

I'll check the vacuum hose but you're right about the fuel filter being non-standard. It was one of the first things I changed when it started misbehaving (having learnt a valuable lesson on the Monte a few years ago when we were stuck at the top of a mountain for 4hours in the middle of the night at -10 degrees!). I just bought one from a local general motor factor so perhaps I should order a real one?

 

Thanks MikeC

It looks like it's back to the distributor again! OK. My job this evening will be to strip it down and prod it about a bit.

 

I'll let you all know how it goes. In the meantime, very many thanks for all your contributions. Seems as though we've all suffered similar problems in the past but not necessarily for all the same reasons. It's better than the usual fault finding charts you get in those manuals!

Steve

[intermittent engine]

You don't seem to have changed the infamous rotor arm Steve?...as electronic ignition made it worse could be breaking down under higher voltage?

 

john

 

Thanks John. I forgot to mention that I also changed the rotor arm (although I am aware that there are some dodgy ones out there so perhaps it could still be that problem). I also changed the coil as well. I did try and take a logical approach to the problem changing one thing at a time to see what effect the changes had. The most pronounced difference was on removing the electronic ignition (as someone suggested in the forum some time ago).

 

Thanks Stuart for the advice re the 123. I'd forgotten you had to convert the tacho. Good point. Not sure whether it is practical to send the distributor for rebuild as I live in Belgium. Perhaps if I can wait until the end of the season. We're off on a rally on the 1st May so we'll see how she behaves on a longer run. Took her out on Sunday and she only misbehaved two or three times on a run of 70 miles or so.

 

I was wondering if it could also have something to do with vapour loss as it doesn't seem to happen until she is warmed up. Would that give an intermittent misfire? Only case against that is she seems to cope with higher speeds (over 80mph) better than cruising at 60 and I would have thought that symptoms of vapour loss would occur at higher rather than lower speeds?

 

Steve

[SUs on a US TR6]

Hi there Chris

I am in the process of swapping the Strombergs on my US TR6 for SUs but can't really offer any advice until I've managed to fit them. But if you happen to have a photo of the set-up to show the connections I would be most grateful. I see you are on the French side of the Belgian border. I live up near Gent so not that far I guess?

Steve

[intermittent engine]

Hi there Mike

It sounds like I too have been suffering the same problem. The misfire happens at around 3,000 revs in top gear but only sometimes. Usually it is when the car is warmed up and has been travelling some time at a constant speed. It just has a hiccup and continues. I've replaced the HT leads, removed the electronic ignition (which did help considerably), points, condenser, plugs and dizzy cap. I also took the car to a friend who has an electronic tune-up set in his garage and re-set the carbs (Strombergs). It is still misfiring but less frequently which makes me think it is not just one problem but several.

 

I keep thinking about the advance/retard mechanism in the distributor but have no idea what I should be looking for. In trying to narrow down the occasions when it misfires I believe that it is most apparent when there is some strain on the engine going up slight inclines. This is what makes me wonder whether it is something to do with the advance not working. I shall take the advice of looking under the points and applying a little WD40. It would be interesting - not to say highly annoying - to think that I have spent all this time, money and energy attempting to fix the problem when it all it needs is a spot of WD40 in the right place! But I remain sceptical that it will work. Perhaps, a possible solution is one of those new distrubutors with the dial-in advance curve function? Anyone have experience of these?

 

In the meantime, I have taken the opportunity of buying a pair of SUs - not necessarily because they are better but the Strombergs are always causing problems especially when it comes to fine adjustment. The rubber grommet in the dashpot doesn't seem to last long. Of course, the SUs are prettier too (in my eyes).

Steve M

[Curing Chronic Misfiring]

Whilst I wouldn't consider any of these nasty modern devices , IF I were, I would buy a spare tacho and have that converted. Spare tachos for TR6s are plentiful and cheap and that way you don't lose the use of the tacho and can also reinstate the original, either when the fancy gizmo fails and you throw it in the skip and revert to the tried and tested ancient technology, or sell the car to another sceptic or originality freak. .

 

Doh! Thanks for the reply. That's so obvious I should have thought of it in the first place!!! I must be getting senile. Any ideas for where I can get the tacho converted and how, exactly, does it connect to the engine?

[Curing Chronic Misfiring]

"Charlie" is a 1976 USA-import TR6 running with Stromberg carbs but her engine was swapped for a recon job about 5 years ago. About the only concession to modern motoring is the Lumenition conversion.

 

Late last year "Charlie" developed a bad cough most noticeable when ascending slight inclines (we don't have hills in this part of Belgium!). It got progressively worse so I started searching the Forum for similar problems and taking the advice given replaced leads, plugs, coil (not realising there was a ballast resistor I ended up having to rewire the new coil - many thanks to another entry on the Forum), dizzy cap, rotor arm. I also took her to a professional mechanic with the old tuning equipment but all we managed to do was shift the problem from misfiring at the top end to failure to start and back again!

 

Having gone through all the options we were left with one possible source of the problem. The distributor. The mechanic suggested I switch back to old-fashioned contact points to try and eliminate the Lumenition as a possible source of failure. He did remark that he thought that with Lumenition it was either it worked or it didn't and there wasn't an in-between. Having changed back to points it works beautifully! It's a different car!

 

It took a long time getting there but with the help of the Forum and my mechanic mate she is sorted for now.

 

My question. I have been looking at fitting the 123 Ignition but realise that it doesn't come with a connection for the tachometer. I remember seeing in one of the Forum logs that you can "send the tachometer" away to be converted to electronic. Does anyone have more information on the conversion please? Remember I live in Belgium so access to UK garages is not always possible and as I am using the car at least 2 or 3 times a week at the moment I don't really want to lose the tacho for too long. Or should I wait until the winter and then send the tacho away to be rebuilt? And how does it work anyway? Sorry for my ignorance on the subject of rev counters.