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HD6 / 8 carbs.

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N

NIB

Senior Member
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Is there some simple way to identify identify if you got HD6 or HD8 carbs mounted on the car, without taking them off and measuring the diameter.
On the top of the square flange bolted to the inlet manifold D2-6 is stamped, i guess it means HD6? But on the float chambers it says AUD124, which is HD8.

Would be nice to know before i order parts. The car is a 1966 BJ8 so they should be HD8, but the D2-6 confuses me.

Greetings
Niels
Denmark
 
Niels,
You probably do have HD8 carbs unless you have some reason to believe that someone has replaced the originals. My 64 BJ8 carbs have A76 stamped on the front carb flange and A86 stamped on the rear carb flange. I have no idea what that number means. My carbs also have the AUD124 on the float bowls. Have a good day!

John
 
When i bought the car from the dealer, I was informed the engine had been totally rebuilt two years ago because the previous owner had run it with no oil pressure. The previous owner had the dealer do the rebuild, and since he was also short of money, he later sold the car to the dealer.
I bought the car form that dealer.

I just got a workshop manual and was looking at all the numbers, and discovered the engine block is a 29D and nok a 29K as its supposed to be. I havent heard from the dealer yet, if he just replaced the block because it was too damaged or how he did the repairs, but im planning on checking all numbers on the parts around the engine to see whats original BJ8 and whats not.

Niels
 
Don't the HD6 carbs have brass tops and the HD8 black plastic?
 
The portion of the dashpot where the dampener screws in is also much shorter on the HD8 than the HD6.

To me, that's the most obvious visual clue.

Unfortunately, I'm severly lacking in pictures of SU carbs, but these are a glimpse of HD8s:

hnr_014.jpg
 
Don't go by the brass cap. Many replace the black plastic with the brass cause the black plastic ones break easily and the brass looks cool when you polish it.
TH
 
IMG_1481.jpg


As usual, Randy has great attention to detail. Here are my HD6 carbs on my 29D engine block and the tops are definitely taller than the HD8.
 
Niels-

Each flange on my pair of HD8's has a "B3 6" stamp. I have owned these SU's and the BJ8 since 1973 and am sure that the carbs are HD8's.

Jerry
 
Randy Forbes said:
The portion of the dashpot where the dampener screws in is also much shorter on the HD8 than the HD6.

To me, that's the most obvious visual clue.
Click to expand...

Didn't the Jaguar HD8s have a different dashpot neck. I seem to recall people sawing them down and rethreading to make a proper dashpot cover for a Healey.
 
I have the short tops, so its HD8.
Had a talk with the dealer, he had sent the engine to an engine workshop to be repaired. He knew the engine block had been replaced because it was too damaged, but he always believed it was the correct type that what used. Bit annoying to know that now, I have to have a look at the parts to see what 29D and whats 29K, is there a list somewhere where you can see the difference?

Niels

engine.jpg
 
You only have to remove an air cleaner to measure the throat diameter, and that of course will tell you for sure what you have. 1 3/4"=HD6 and 2"=HD8.
 
NIB said:
I have the short tops, so its HD8.
Had a talk with the dealer, he had sent the engine to an engine workshop to be repaired. He knew the engine block had been replaced because it was too damaged, but he always believed it was the correct type that what used. Bit annoying to know that now, I have to have a look at the parts to see what 29D and whats 29K, is there a list somewhere where you can see the difference?

Niels

engine.jpg
Click to expand...
About the only real difference, as far as replacements go, is that the dipstick tube is slightly different, and the dipstick itself could possibly be a different part number.

It's really not such a big deal.
 
BobFrisby said:
You only have to remove an air cleaner to measure the throat diameter, and that of course will tell you for sure what you have. 1 3/4"=HD6 and 2"=HD8.
Click to expand...
I'm guessing that you haven't pulled the filters off a BJ8 lately? PITA!

By far and away, I would rather be able to tell at a glance :wink:
 
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