• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

SU Carbs and Rebuild.

Share this page

S

Stoney

Freshman Member
Offline
Hi guys,

I am considering changing out my side-drafts for the old SUs. I won a set on e-bay several weeks ago. How much is a general rebuild kit, and how difficult is it to do a general rebuild?

I have never handled the SU style carbs before.

Any hints or words of wisdom?

Thanks /ubbthreads/images/graemlins/cool.gif
 
Oh for all the parts, $ 125 the pair depending what you have. Check Moss they are in the catalog. Can also be professionally done for 350 the set. Which includes polishing plateing and flow balancing.
 
I paid about that for my rebuild kit and then did it myself. It is really no more difficult than anything else and you have the added bonus of really understanding how everything works which helps when it comes time to bolt them on and tune them up.

I did a very thourough job and dipped then polished every piece as I went. Lots of time spent with the Dremel, but that isn't necessary to have them work well. That was just to make them pretty.

This set replaced a Weber DGV and made a convert of me. I was doing the rebuild for my Mom who wanted things stock and when that fresh set of SUs went on they kicked the Weber's butt all over the place!

JACK
 
these have to be some of the easiest carbs to rebuild. You might not even need any parts, you can clean what you've got.

I'd recommend starting disassembly and only replacing anything worn. If it looks fine leave it be.

Some things to look for:

1 - the piston needs to move up and down freely. Clean it really well and then lightly oil the surface of the dome.
2 - check the throttle shafts for wear at the brass bushings. That's the most expensive part to fix (the bushings). Grease the bushings before reinstallation.
3 - ensure that your needle is straight, no wear, and the jet is clear of debris.
4 - clean and set the float level very carefully. This is the most likely point of leakage that can cause poor operation.

These things are super simple, don't be afriad!
 
one more thing - the webber/zs/su carb manual from haynes is very usful the first time you tear into your carb. I think it's worth the $12-15 for peace of mind.
 
Hello Stoney,

Firstly get a manual so that you can set the jet, floats etc to the basic setting, and all other things being equal it (they) will need minimal tuning once re-installed.

"1 - the piston needs to move up and down freely. Clean it really well and then lightly oil the surface of the dome."

to expand on this, the piston and inside the dashpot (dome) should be clean but do not use anything abrasive, just chemical cleaning. The only thing that needs oiling is the steel centre tube of the piston,as the piston skirt does not touch the bore of the dashpot.

The other important thing is to ensure the jet is centralised, and the manual will give instruction on how this should be done.

Alec
 
Yep! Listen to Jack(s)and Rob, they are steering you straight. I would just add, if you do need a kit check out Royze https://www.royze.com/Kitaustin_healey.htm they have kits, needles, and jets, all good quality and far less expensive than specialty vendors. I bought kits for some SU6s that were truly shot, the kits were under USD40 each.
Some people don't like them, but I think the Grosse ball type float valves are a must have, as is a GOOD in line filter (or two). Many times SUs just need a really good cleaning to be 'rebuilt'!
The SU, IMHO, is about the best designed carb ever produced (only the Weber DCOEs are in the running - and they are WAY harder to tune)!
Here is a quick description on my site of how they work https://www.su-filters.com/sucarbs.html

Cheers!
Dave G.
 
Ok, I called Royze and got a lady called Gina, she sold me a pair of H1 rebuild kits for 39 bucks each, 5 bucks shipping + tax all over the phone. # 386 427 7108 nice lady.
 
[ QUOTE ]
...Some people don't like them, but I think the Grosse ball type float valves are a must have, as is a GOOD in line filter (or two). Many times SUs just need a really good cleaning to be 'rebuilt'!
The SU, IMHO, is about the best designed carb ever produced (only the Weber DCOEs are in the running - and they are WAY harder to tune)!

[/ QUOTE ]

DAVE!!! I love ya, man! 'bout the only equivocation is: Weber DCOE's ain't that hard to tune. Not "WAY harder"... just a bit more patience needed. /ubbthreads/images/graemlins/devilgrin.gif
 
Hmmm... ya gotta get OUT more, Rob! /ubbthreads/images/graemlins/smirk.gif
 
Well shucks, but you gotta remember, for some of us 'a bit more patience' constitutes "WAY harder"!
I'll maybe move the DCOEs up a notch as soon as they've had a production run of 70 yrs...Like the SUs did! /ubbthreads/images/graemlins/lol.gif

Cheers!
Dave G.
 
sheesh...plumbers. /ubbthreads/images/graemlins/wink.gif
 
Back
Top