You see British SU used on lots of hot rods, but I know very little about them. Which ones are used? Which ones aren't? Which ones are desirable? Any books or websites for them? What did they come on? Point me in the right direction so I can learn something about them
I'm certain there are books available, just GOOGLE it. I had a 1965 Jaguar MkII saloon with a 3.8L engine and twin SUs for 20 years. They are simple to tune and gave me no trouble whatsoever in 50,000 miles of driving that car. A UNI-SYN device synchs them up nicely. In fact, 20 years after selling the Jag I still use the UNI-SYN to tune my 97s on my flathead-powered woodie!
Depending on engine displacement, they came in several sizes, named for the throat size in inches. Like 1, 1.5, 1.75, 2, etc. Generally run in pairs on inline fours like MG or Triumph or three-up on a six like a Healy or Jag. They are very simple and reliable, easy to tune. The throttle shafts have to be tight or it will give vacuum leaks, like any carburetor. Any of the Brit car webs have info on them. I think the local (US) guy for parts and fixing is Joe Curto out of somewhere in New York. That said, any old sports car machinist worth his salt has experience with them and can help rebuild and tune. Also, there are books at Motorbooks on them I have a pair on my old MG and work fine.
What are you going to put them on? A simple search on Google will give you the answers you are looking for.... http://en.wikipedia.org/wiki/SU_carburetor http://www.sw-em.com/su_carbs.htm There have even been SU type fuel injection throttle bodies made: www.twminduction.com Here's a pair of HD8 SU's on my Daimler hemi:
The SU carbs were used an many of the British cars. Roll Royce, Bentley, MG etc, They are very good reliable carbs. They have a dash pot that you have to keep topped up with oil. They come in several different sizes.
Old Turbo mini coopers used a blow thru style SU Ive seen VW guys use them for drag racing And datsun made their own style of an SU carb i think they used them on z cars with low hood lines
SUs are a very good carb and easy to tune as said before. In the past I've run into poeple that say they are junk just because they don't understand them, but they are one of the most simple carbs ever built. Just make sure the thottle shafts aren't loose that makes them very hard to sync at idle. I have an MGB with two 1 1/2" a Triumph Herald with two 1 1/4" and a TR-6 with one HD8 2" drawn trough into a supercharger, they run very well indeed!
They can still be bought new from Burlens Fuel Systems and they sell everything you would ever need. http://www.sucarb.co.uk/ The newest SU is the HIF series and they were fitted to many, many British cars in the 70's and 80's. Haynes do an excellent manual and there several good tuning manuals. HIF's suitable for a rebuild can be picked up here for around £15 and rebuilt for about the same. Almost any engine will run sweeter and get better mileage on SU's - it probably won't make better horsepower but probably won't make much less. I see it as a good trade off. Remember it is a side draft carb but I've converted cars to run on SU's with their original downdraft manifold by simply making up a couple of adapter flanges and welding them to a 90 degree pipe bend. Because of the design of the SU, virtually any engine will idle smoothly on any SU. Tuning to a specific engine is a matter of finding a needle with the set of right profiles. There are computer programmes to help you find this from the hundreds available off the shelf, but you can also make your own profiles using a fairly simple process. I fitted a big 44 SU to the Citroen 2CV (602cc) engine (see below) - normally this would be WAY over carburrated but I put a divider into the intake manifold plenum and effectively made a twin choke 22 SU. Very forgiving carb and much under-rated. I'd like to convert my 347 Pontiac to run on a pair of 2" SUs.
The blower is an Eaton M62 and the carb is pretty much a stock HD8 of a tripple E-type set up with a change in needle and jet, I also run a little thicker oil in the dash-pot so it wont slam open on take-off. Here's a video of the install. http://www.youtube.com/watch?v=fUT8c7uBmTE
Biggest issue in my experience has been wear on the throttle shafts. Once air starts leaking in past the shafts, tuning gets harder. They are easily bushed and repaired, however.
Volvo used them to approx to 1980 on some non fuel injections cars The were twin su on some amazon and 140 and pv sport The other carbs volvo used were stromberg and pierburg
Had alot of Volvo's and loved em,,very easy carb to work with HD6 is a good one,,The old 240 Z's ran SU's also
Datsun also came out with their version on the 240Z, personally found them easier to keep in tune that the British versions(maybe they weren't as worn out). The US market never got their smaller versions used on the home market 510s,etc... but many made their way here in the used engine market. Stay away from the smog era "hitachis" found in the 280Zs.
6INAROW...school me to! and weasel that HEMI look's like something in the road warrer movie, BUT IN A NICE WAY. this british carb. thing is getting creepy. man come in from the dark side and get holly or edelbrock equipment. or send for your LIMY card! HA!...POP.
I ran an SU carb on a Harley back in the 70's. It worked a lot better than the Bendix pos that came on it. It came off a 3.8 Jag.
MCtim Wow I just started this week to install a Eaton M series on my AJ6 jag engine for my new rail. As you can imagine i find your project very interesting. As a former BMC/ British Leyland mechanic I found the SUs to be very reliable. In 1970 i saw a 230 chev sixpowed FED with three on it at Cayuga Drag strip in Ontario. I took pics of it (Old polaroids) I think i can find them since it happened to be on my Honeymoon. (Yeah i was that dumb. Took my wife to the drags on our honeymoon.
As others have mentioned, very easy to sync and adjust IF you have a set tuned to your engine. Biggest reliability issues are throttle wear and warpage of the piston enclosure. Biggest liability from a hotrod standpoint would be size. How many can you bolt onto the engine? Remember that the hot Jaguars used 3 of the larger ones on a 255 CID six. Jon.
this is what I'm running,but with no smog, my set is one of the rare sets from the japanese market datsun 510 sss, the only emissions is the pcv valve on the manifold, and you want to keep that anyway to keep your oil nice and clean. the domestic Hitachi SU setup has a shuttle valve and some other crap that can't be removed or bypassed. I think if my memory serves me correctly, the very early datsun 240 z cars didn''t have all that garbage, mine is a combination of the original manifold and a domestic japanese manifold and lots of work. I love the carbs, but i need to send them off to have some work done, if you have the japanese hitachi ones, Z therapy will put sealed roller throttle shaft bearings in, this solves the throttle bushing wear issue permanently. They also have a minor "choke" issue, not really a choke of course, but you get the idea, they also can fix that issue. There is also no substitute for how cool an engine looks with a pair of SU's vs a standard holley like 90 percent of whats out there.
is that an aircraft engine oil cooler up there at the top? I thought I was the only other person with one. Very cool setup.
I used Skinners Union carbureators on a panhead Harley. I got the carbs offa junk Volvo. They are easy to tune but I had fuel starvation problem at top end as the inlets were undersized. I drilled the inlets a bit and raised the floats. Aside from the lean on top the SU's performed much better then the Linkarts.
I have a frend that used a su on his triumpf chopper before but he replaced it of some reason i belve that i was need to repair
here is my set up that i went with for my chevy 292 , its not finished yet and i also wanted to make something a little different from everyone else but from what every one has said and read on line the datsun su are way better then the british one, so i went with 3 240 z su which are 1 3/4 , i took a clifford webber manifold and adpated the front parts off of the z ,
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