Stromberg set up - any golden rules?

[dasadrew]

Just started on the mixture setting. After enrichening the needle by 0.5 of a turn and not really noticing any difference using the "lift the piston" method, I thought I'd just whip the top of the carbs off to see where the needles are. Do these jet and needle positions look right? The carbs came "ready to fit and run" for a Stag. Everything looks to be pretty well sunk into the respective housing (needle and jet)
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[edd]

I found lifting the piston method to be very hit and miss. Only the very expierienced who will even go and have a sniff of the fumes. I used a snap on co meter and it really helped.
Just ensure to copy and mixture adjustment to both carbs. I will recheck mine next year but after two years have not had a alter anything. Have you added a regulator. I'm a big fan of a constant feul pressure. ( when I have fuel in my tank that is )

[dasadrew]

No regulator Edd. I got an SU fuel pump which have a bit less pressure than the other replacements about; more like the original Stag pressure.

I get enough constant fool pressure from my boss.

[milothedog]

IIRC the main jets should be 2mm down (0.080") measured on the edge or 2.5mm (0.100") if measured from the centre. It has been know for them needing to be moved up a little to allow the needle to give you the C/O range your aiming for.


I agree with Edd about lifting the pistons, if you don't have access to a C/O meter then a colour tune on a cylinder on each bank is another way of doing it. Obviously you need to make sure the cylinders you use are not both supplied by the same side of the inlet manifold / same carb.

Ian.

[Phil Stag]

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I need to find a carb adjusting tool and i will be all set

[dasadrew]

IIRC the main jets should be 2mm down (0.080") measured on the edge or 2.5mm (0.100") if measured from the centre. It has been know for them needing to be moved up a little to allow the needle to give you the C/O range your aiming for.


I agree with Edd about lifting the pistons, if you don't have access to a C/O meter then a colour tune on a cylinder on each bank is another way of doing it. Obviously you need to make sure the cylinders you use are not both supplied by the same side of the inlet manifold / same carb.

Ian.

Good grief - I'd completely forgotten that I have a couple of colortunes in the tool chest!

Thanks for the comforting news on the jets.

Drew

[Lingen]

Drew. Those needles look a bit far into the piston to me. I.e too rich. To set a basic starting point, unscrew the adjuster key until the brass base of each needle assembly is flush with the base of its piston. Then screw it clockwise 1 1/2 turns. If the jets have been correctly positioned in the carburettor body, the engine should run reasonably well with them in this position.
I have to disagree with Ed as "Piston lifting" is a reasonably simple and accurate way to set the mixture until you can set it perfectly with a CO meter.
Get the engine and carbs up to working temperature and then set the tick over as slow as possible. (I will assume that you have by now set the throttles equally.)
With the elbows out of the way, just lift each piston in turn abut 1/8" with a small screwdriver. If the engine starts to stall, then the mixture is too weak. If it speeds up, it is too rich. Correctly set, it will make little difference. (Key Anti clockwise = weaker).
Give it a try.
Mike.

[dasadrew]

Well, thanks to all the tips and moral support it looks like Ive got a set-up which should get me to the first MoT and re-registration!

It was far too rich and I wrongly thought that it was stalling as it was too lean. Lingen's observation and the Colortune reminder showed a bright orange flame in the cylinders. Not able to get "bunsen blue" (don't think I ever have managed that over the years!) but it's a subdued yellowish-violetish tinge now and runs smoother than ever. Won't be able to balance a coin on it though.

Everything is more or less brand new so I need to do some running in first methinks. A few oil drops on the floor too which seem to be coming from the clutch bell-housing. Hoping that the oil seals might improve with a bit of use as they've been fitted and static for about 4 years now!

Cheers

Drew

[Klaus Schlueter]

.....and runs smoother than ever".

That sounds promising Drew! If it's not raining do we meet at the "Jesenwang Oldtimer Treffen" on Sunday, 3rd of Oct.?

BTW. when you go to the TÜV don't forget the carb adjusting tool. Over the last 24 years I always was allowed to fine tune the carbs with their high tech CO meter.

Jet hight: I have already posted the jet hight info here before which I got from Burlen years ago:

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Klaus

[dasadrew]

Yes Klaus - Jesenwang is on my list. Might need to go to UK though .

I'll take the Stromberg tool to the TÜV but one of the testers is very enthusiastic and managed to completely mess up my Escort Webers in an attempt to get the emissions down. To be honest, I don't get this emissions stuff - it's only at idle so how much does that contribute to pollution?

Jet height seems ok then.

Time on the Stag is limited at the moment since I try and do a 8 - 10 mile walk each day following the Op and that takes a few hours!

Cheers

Drew

[Tdm]

Drew - when my Stag is due it's ITV (MOT), I always get a local garage to take it in, not me personally.
They seem more amenable to having a qualified mechanic bringing the car to be tested, and if there any faults you have so many days grace to bring it back (at no extra cost) to be re-tested.

I give the garage taking the Stag in my carb adjusting tool, as it has previously failed on emissions, and to pass last time they weakened the mixture as far as they could with the car still able to run. Once the pass was obtained I richened the carbs again to the way I like them, and I have 5 years between tests now over here - my next one being due 2019.

[Staggard]

Drew - when my Stag is due it's ITV (MOT), I always get a local garage to take it in, not me personally.
They seem more amenable to having a qualified mechanic bringing the car to be tested, and if there any faults you have so many days grace to bring it back (at no extra cost) to be re-tested.

I give the garage taking the Stag in my carb adjusting tool, as it has previously failed on emissions, and to pass last time they weakened the mixture as far as they could with the car still able to run. Once the pass was obtained I richened the carbs again to the way I like them, and I have 5 years between tests now over here - my next one being due 2019.

I would keep quiet about that if I were you Terry because the ITV station have made a mistake not unless your car was tested before the new resolution DGI 226 4/4/2011



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[steve.n]

I found using the lift the piston method a pain having to remove the carb elbows but found after removing the damper rods, the piston can be lifted using the long allen key from the adjusting tool. May help somebody.

Steve.