SUs on a US TR6

[Chris59]

Hello,

 

I will swap the Stromberg carbs on a US CF TR6, for HS6 SUs : the engine and exhaust manifold are standard, the exhaust system is standard but in stainless steel.

Which needles and dampers springs should I use, thinking I will use K&N air filters ?

 

Secondly, I have a pair of SU's on another US TR6, fitted with a 2500 saloon engine ("MG" prefix, I think), again with standard down pipe and exhaust system.

Which needles and dampers springs should I use in this car, again with K&N air filters ?

 

Thanks in advance for sharing your experiences,

 

Cheers,

 

Chris.

[rpurchon]

Hello,

 

I will swap the Stromberg carbs on a US CF TR6, for HS6 SUs : the engine and exhaust manifold are standard, the exhaust system is standard but in stainless steel.

Which needles and dampers springs should I use, thinking I will use K&N air filters ?

 

Secondly, I have a pair of SU's on another US TR6, fitted with a 2500 saloon engine ("MG" prefix, I think), again with standard down pipe and exhaust system.

Which needles and dampers springs should I use in this car, again with K&N air filters ?

 

Thanks in advance for sharing your experiences,

 

Cheers,

 

Chris.

 

i use BAE needles and yellow springs on mine.

richard

[Chris59]

Thanks Richard for your reply !

 

Any other US TR6 owner with SU carbs here ?

 

Cheers,

 

Chris.

[stevefmyers]

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

[Chris59]

Hi Steve,

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

One of these TR6 has already SU carbs, but the needles/springs setting is not correct actually.

Cheers,

Chris.

Edited April 30, 2009 by Chris59

[johnny250]

Hello,

 

I will swap the Stromberg carbs on a US CF TR6, for HS6 SUs : the engine and exhaust manifold are standard, the exhaust system is standard but in stainless steel.

Which needles and dampers springs should I use, thinking I will use K&N air filters ?

 

Secondly, I have a pair of SU's on another US TR6, fitted with a 2500 saloon engine ("MG" prefix, I think), again with standard down pipe and exhaust system.

Which needles and dampers springs should I use in this car, again with K&N air filters ?

 

Thanks in advance for sharing your experiences,

 

Cheers,

 

Chris.

 

Chris, this is an excellent site for seeing the differences that needle swapping makes... http://www.mintylamb.co.uk/suneedle/

 

john

[Chris59]

Brilliant, Johnny, thanks a lot !

 

Chris.

 

PS : I like your avatar, it looks like a "Purple Helmet", or am I wrong ?

[Frans C]

Hi Chris,

 

I drive the BAG needles together with a shaved head en a rebuild and recurved distributer.

 

Regards ,

 

Frans

[TR6 Poor]

Hello,

 

I will swap the Stromberg carbs on a US CF TR6, for HS6 SUs : the engine and exhaust manifold are standard, the exhaust system is standard but in stainless steel.

Which needles and dampers springs should I use, thinking I will use K&N air filters ?

 

Secondly, I have a pair of SU's on another US TR6, fitted with a 2500 saloon engine ("MG" prefix, I think), again with standard down pipe and exhaust system.

Which needles and dampers springs should I use in this car, again with K&N air filters ?

 

Thanks in advance for sharing your experiences,

 

Cheers,

 

Chris.

Well, you should consider swapping the carbs for the Lucas injection. I did, and I am glad I did. Cheers

[stevefmyers]

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

[johnny250]

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

 

 

I don't know if this photo helps you Steve http://i197.photobucket.com/albums/aa55/25...ny/P1030723.jpg

 

I have since routed the rocker box breather to an oil catch tank and blocked off the feeds into the SU's.

 

john

[Chris59]

Hi Steve,

If your carbs came from a TR7, you need a "T" pipe to connect the 2 carbs to the fuel line, as the float lid on a 7 aren't of the same kind as the ones John shown us.

On a TR4, as on John's pict, the front carb float lid as 2 pipes : one inlet, the other is a direct outlet to be connected to the rear carb float lid, who as only one inlet. Both float lid have a small hole under an aluminium cover, just bellow the inlet tube. This hole is here to allow the fuel to get out (and air in) if the needle valve don't do his job properly, allowing overflow.

On a TR7, each float lid as one inlet tube and one "overflow" tube, who replace the small hole on the other model. This system allow the use of a rubber pipe to be connected on each outlet pipe, thus the overflow fuel is not sprayed in the engine compartment, but under the car, as the rubber pipe are routed under the car.

This kind of float lid must be connected to the fuel line via a "T" connector, as write previously (the Stromberg metallic pipe will not do the job)

Hope you understand my English ....

Chris.

[Chris59]

Hoops, forget this detail : the inlet pipe is always the one who is closed by the needle valve, the oulet pipe is the one who is in the middle of the float lid.

Chris.

[stevefmyers]

Hoops, forget this detail : the inlet pipe is always the one who is closed by the needle valve, the oulet pipe is the one who is in the middle of the float lid.

Chris.

 

Hi Chris. I hope you can see from the attached photo that I have fitted the carbs. I've attached the fuel pipe to the float chamber and the vent pipes on the main body to the rocker cover. I'm not sure that you can see there is a second outlet pipe on each float chamber (its been painted silver to match the rest of the float chamber!) which is parallel to the second pipe (which I've attached to the fuel line) but comes from the centre of the float chamber lid. I have no idea which car the carbs came from as I purchased them as reconditioned units on Ebay! I have connected up the second float chamber tubes as I need longer tubing which I'll fetch tomorrow. I also need a "thingy" to hold the choke cable but that's a minor point. I guess if worse comes to worse I can just try and start the car and see what happens! If the fuel and other pipe need to be reversed that shouldn't be too difficult.

Cheers

Steve

[stevefmyers]

I have now connected all the pipes up and it started second time. Needs some minor adjustment but will take her for a spin this afternoon and then check the mixture. I have a feeling she's running a bit on the lean side. It will be interesting to see whether I have cured the occasional but very annoying pinking/misfiring problem. I also took the opportunity to put a bit of oil on the advance/retard mechanism after checking that the vacuum hose was not leaking. Of course, if it's still misfiring, even it is only three or four times in 50km, then I'm back to square one again.

 

Perhaps, someone knows of a rolling road in the vicinity of Ghent, Belglium??

 

Steve

[stevefmyers]

Just thought I'd let those who gave me help over the last week or two that "Charlie" is back on form. She managed to do about 50 miles last night and I almost had to restrain her, so keen was she to exceed the speed limit on the motorway! It did raise a couple of other problems. One is the run-on when switching off the engine. I will adjust the mixture and check the timing but it looks as though I will have to invest in an anti-run-on valve. The other niggle now is a squeak that comes from the bonnet. How picky can you get?

 

We're off on a "rally" tomorrow and will end up doing around 300km - it's not a timed rally but more like a treasure hunt - so it will be interesting to see how she performs.

 

Many thanks to all those who guided me.

Steve

[Chris59]

Hi Steve,

Happy to read that it work for you. I still manage to find the right needles for my TR6, which ones do you use on yours ?

Cheers,

Chris.

Edited May 2, 2009 by Chris59

[Chris59]

Some news about the carb swap : I have tried BDQ needles, but they didn't work at all over 2000rpm.

 

After some damper springs swap, checking the ignition, etc, I ended with a set of standard TR7 needles and springs, ie BDM.

 

You know what ? She now goes far better than with the Strombergs, but the BDM needles seems to be lean at some stages.

 

I may try a set of BAE or BAG needles, but not immediatly. Next step will be to fit polyurethane bushes at the rear left trailing arm, and a new halfshaft, as done on the right hand side last week, but that's another story....

 

Thanks to all contributors,

 

Cheers,

 

Chris.

Edited May 3, 2009 by Chris59

[Chris59]

Hello,

Some news about the carbs swap : the Tr6 now pull strongly, with BAG needles and yellow spring, but (there is always a "but"....), between 2500 and 3000 rpm, when the speed is stabilized in 4th speed (not under acceleration), I can hear some "explosions" in the K&N air filters.

May be an advance curve problem ? Any idea ?

Cheers,

Chris.

Edited May 22, 2009 by Chris59

[Frans C]

Adjust a bit more fuel and/or a few degrees earlyer

[TR6 Poor]

If you didn't have the popping before the needle/spring sway, you are most likely running lean now, pull the choke out slightly to see if the popping stops. You could do this much easier if you purchase an air/fuel meter, or borrow one. Reading plugs is for the pro's. Cheers

[Chris59]

The plugs are reach enough at low rpm, could do with more fuel at full blast, I think; but I haven't check at 2500 to 3000 rpm.

 

Will try to pull the choke slightly next time, if it solve this problem, will try a set of BAE needles.

 

I thought about the advance curve because it didn't match the carbs caracteristics.

 

I will let you know asap the result.

 

Cheers,

 

Chris.