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Rebuilding the SU HD8 carbs

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Donovan2001

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Hello,

I just ordered the rebuild carb kits for SU HD8 carbs. Does anyone any advice on rebuilding these? Does anyone have any videos are links to appropriate websites that might be helpful?

Thank you for the help

65 AH 3000 MKIII
 
Donovan2001 said:
Hello,

I just ordered the rebuild carb kits for SU HD8 carbs. Does anyone any advice on rebuilding these? Does anyone have any videos are links to appropriate websites that might be helpful?

Thank you for the help

65 AH 3000 MKIII
Click to expand...

Resist the temptation to take an emery cloth or fine sandpaper to the vacuum piston or chamber to 'clean up' a fine scratch or some gunk. These are finely machined and matched together--keep the piston and chamber for each carb together (for that matter, keep all the parts for each carb together). Use a soft toothbrush and carb cleaner to clean the gunk (I use the carb cleaner that comes in a gallon can with a dunk basket).

I don't know how you can tell for sure--later kits should be OK--but the rubber part of the jet diaphragm should be resistant to the mystery gas we get these days. I think the green and blue ones are OK, but I'm not sure.

Make sure the jets are centered to the needle (if you don't know what this means do some homework). There are two types of needles: those with a 'shoulder,' and those with a groove to set the depth in the vacuum piston. Make sure you know how to set needle depth.

Best to study these carbs first so you understand their principal of operation. They are 'variable choke/venturi' carbs, as opposed to 'American-style' fixed choke. They are a very elegant and effective design.
 
Can I soak them in mineral spirits? I heard that work too. Also, Is the front carb towards the front of the car or is it closest to the firewall?
Thank you
 
Carb cleaner is much quicker and more effective. The black stuff is mostly carbon, not oily. The front carb is toward the front of the car, the back to the firewall.
 
Donovan2001 said:
Can I soak them in mineral spirits? I heard that work too. Also, Is the front carb towards the front of the car or is it closest to the firewall?
Thank you
Click to expand...

Won't hurt, but carb cleaner, lacquer thinner or acetone would probably be more effective. The carbs are mostly aluminum with some brass and steel--anything that's safe on those metals would be OK.
 
There is a cork washer that goes somewhere on bottom of jet assembly, it is a real bugaboo on rebuilding these things without a gas leak. Some say soak in coffee grounds, lots of mythology and "sure thing" solutions. Mine is the Ace Hardware plumbing drawers have a rubber o-ring that seems to do the trick, now about 15 years since rebuild and no leaks.
Jay, 65 3000
 
The HD carb jets have a flexible diaphragm--nitrile probably--hence the 'D.' There is no cork washer, like in the older carbs.
 
howdy,
just did mine, came out fine after...
returned,replaced flawed jets [diaphrams dammaged]c/o moss mtrs
replaced all tapper pins with split pins
with respect 59er
 
I've taken the front carb apart and it seems as though I'm stuck. I can't get the rod out that hold the flap in place. Is this normal? I removed the screws from the flap and I'm trying to remove rod to clean but it won't budge. Any tricks?

Thank you
 
Donovan2001 said:
I've taken the front carb apart and it seems as though I'm stuck. I can't get the rod out that hold the flap in place. Is this normal? I removed the screws from the flap and I'm trying to remove rod to clean but it won't budge. Any tricks?

Thank you
Click to expand...

If you're referring to the throttle shaft and throttle plate, turn the throttle to the wide-open position--i.e. plate sideways--and gently push or pull the throttle plate out. Then, you should be able to pull the throttle shaft through.
 
OK, I rebuilt the carbs :smile:. I think correctly. Before I install them to the engine, what do I do with the damper oil? Do I pour it down the top? I'm a little confused.

Thank you
 
Put in 20 wt. oil but don't fill to top. You need to be able to insert the piston without oil coming out.
 
Donovan2001 said:
OK, I rebuilt the carbs :smile:. I think correctly. Before I install them to the engine,

what do I do with the damper oil?

Nothing yet.

Install the carbs then fill the piston's tube inside the bell after you remove the little piston to 1/2" below the top of the piston shaft.


Do I pour it down the top?---Yeah like i said above---Keoke- :laugh:

I'm a little confused.

Thank you
Click to expand...
 
Another Question,

Does the arm that connects the throttle to the carb shaft suppose to be perpendicular to the shaft? I don't think the flaps are fully closing. Would this cause the car Not to start?

I'm getting fuel to carbs and I tested the spark plugs and I see sparks.

Thank you
 
Donovan2001 said:
Another Question,

Does the arm that connects the throttle to the carb shaft suppose to be perpendicular to the shaft?--------?????


I don't think the flaps are fully closing. :frown:

Would this cause the car Not to start?-------- :yesnod:

I'm getting fuel to carbs and I tested the spark plugs and I see sparks.

Thank you
Click to expand...
 
fixed the throttle control. The car still will not start. Could it be the firing order? If so, what is the firing order for a 65 AH 3000 MKIII? I might have the plugs wrong. I have an electronic distributor (Flamethrower). If not, what else could it be?

I'm getting fuel to the carbs and I'm getting spark from the distributor.

:frown:

Thank you
 
Austin Healey 3000 MKIII BJ8: The firing order is 1-5-3-6-2-4

Is your choke working correctly? Pull out choke and turn knob to the right to lock it on.
 
Hi Donovan
You seem to be spending plenty on parts for the car but don't seem to have any , even basic, information. You need a service manual, it should be your next purchase.

Ian
 
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