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MG MGB Technical - New SU's vs the rebuild? What makes sense?

My 67 needs a set of carbs for the fresh rebuilt stock engine with a mild road cam. I have a set of unknown quality carbs of correct vintage and they look complete but tattered up a bit. This car was not running when I saved it. Any thoughts on the purchase of a new set vs a professional (University Motors, Joe Curto etc) rebuild? Are the new carbs any good? I imagine the cost difference is fairly large but have not done any research yet. Anybody use the Moss supplied new carbs?
R Stegs

I, too, have a '67 but have converted it to a supercharged single carb system. My original carbs had worn throttle shafts and when I was using it as a daily driver opted for the new Moss supplied SU carbs from Burlen who now own the tooling and rights. I was surprised at the defferences between old and new. The new carbs were not made to the same exacting standards and were overall substandard for the hefty cost. I would have your old set professionally rebuilt by either of the two gentlemen that you have referred to. RAY
RAY

Provided your abilities to work on, rebuilt carbs might be worth it. The cheapest way to get them back in proper use overall if you know of their history. Chicago MGOC webb site shows out all relevant details to rebuilding stage, and all spares available by BURLEN.
Best regards.

Renou

Rebuild your existing ones, a very nice MGA at our natter had a new pair of the burlen SUs fitted and they do not compare with the OE fit. How about a jammed dashpot that needed lapping before it would move up and down? No wonder the owner complained it lacked driveabilty. I believe that new fuel valves would have fixed all the problems the original carbs were showing.
Stan Best

My recommendation is a rebuild by Jimmy Hilton of Texas.

Top notch professional. Below are before and after pics of the HS6 sets from my 1968 and 1969 MGCs.

http://britcarfun.com/images/RickIngram68C/

http://britcarfun.com/images/RickIngram69C/
Rick Ingram

R-
If you take your time and do the work with care, you should be able to do a reasonable rebuild job yourself. You'll need a copy of the SU Workshop Manual, plus a copy of the SU Carb Rebuild Video will be invaluable (both available from Moss Motors). Burlen Fuel Systems, the makers of the SU Carburetors, has a website at http://www.burlen.co.uk/ where you can view exploded diagrams and order the parts. The crucial question is: which camshaft have you chosen? That will dictate which fuel-metering needle you will need to install.

Rick-
Those are very impressive images. Can you give us all a means of contacting Jimmy Hilton?
Steve S.

Jimmy Hilton is located in Carrollton, TX.

He can be reached at:

jimmy@batterypowered.com

I am just one of many satisfied customers.
Rick Ingram

There are threads in the archives on the new SU's vs rebuilds. The posts from owners of new SU's were positive to glowing. Problems generally centered around the all plastic floats needing molding flash cleared up to prevent flooding and the fact that the casting finishing was not as good original.

These carbs seem to all have the biased needles but not the overrun throttle valves. Not all the parts are interchangeable with the older units so you'd have to order spares from Burlen rather than through Moss and others.

These are especially pricey through Moss. You can get a better deal direct from Burlen now that the pound is down vs the dollar. That said you can generally get these rebuilt cheaper. The debate is whether the rebuilds can be as good a new ones given the age and abuse many of these have suffered.

I have an archived thread that asked about service from Burlen. The reports were positive. They ship promptly and will work with you. The web site is not the easiest. I would suggest a telephone call if you're serious.

Let's be thankful someone is still making SU parts and carbs.
Robert McCoy

One of the new Burlen made carbs that I purchased just would not adjust correctly no matter how much I fiddled with it. It turned out that when someone was assembling it they dropped the piston leaving behind a large ding in the outer circumfrince of the piston sealing area. It took a lot of fine lapping to finally get it to perform correctly. Caveat Emptor, let the buyer beware! RAY
RAY

I have HS6s on my GT. I priced up a rebuild versus new carbs. The carbs are about £270.

The rebuild kit is £50 but you don't get new springs, needles or floats. The kit includes throttle shafts, but does not include the tabwashers that you'll need to refit them. If you're going to take the whole lot apart for cleaning and painting (like in the pictures) then you're going to need other bits and pieces like springs (which are not available) and washers (such as the one between the float chamber and the main body) which are only available as part of a kit. So your pushing towards, maybe past £100. And then you need to buy a reamer and/or get the bushes pressed in at a workshop. It's got to be an hour per carb to do it properly, way longer if you are going to blast and paint too. At £50 an hour labour, it'll only take a minor problem or two to push the price up past £270... and you still have a 40 year old set of carburretors.

I bought new ones. They were good quality, none of the issues mentioned here. Car runs great.

Sorry to be a nerd, but would I be right in thinking the float lids are 120 degrees out? In the last but one picture of the second set, the float chamber on the carb shown on the left (which is the left hand carb) needs the lid moved a third of a turn counterclockwise as you look at the photo - and the other car needs it turned one third of a turn clockwise.

Now I'm off to get a life...

Neil

Neil

I used Joe Curto to rebuild my SUs, at less than half the price of new carbs from Moss. He had to install new shafts, changed butterflies to the older style and installed the correct needles for use with open K&N filters for around $375. That was 2 years ago and they have run well since. Joe gets my vote!
Joe

R,

within the years, i did a lot of rebuilts on HS 4, HS 6 and HIF versions too.
I found out that allways the spindles had worn but not the bodies, so it was easy and straight foreward to rebuilt the carbs with a kit, needles and new butterflies without the pop up valves they were fitted with on most B's.

I would take the butterflies out first and pull the spindels for an examination. If the bushings in the body are worn out, have them overhauled, otherwise it is a simple diy job and you can download the necessary manual at MGExp. No special tools are needed.

Ralph
Ralph

Joe,

I don't know the price of HS4s, but HS6s are £275 a pair ie $385 (at £1=$1.4) direct from Burlen. I'm guessing that HS4s are a similar price.

Neil
Neil

Neil,

HIF-4s in my '72B are currently selling for $999.95 @ Moss, the resellers like the Little British Car Co. sell them for about $900, so for me $375 was a bargain. I was not aware of pricing from Burlen.
Joe

This thread was discussed between 25/11/2008 and 26/11/2008

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.