Carbs HS6 vs HIF6

Dave3066

Dave3066

Well-Known Member
Gents

I was just looking at the nicely cleaned carbs in the 4 cylinder section and it started me thinking about my own carbs. My V8S has HIF6 carbs fitted, but I have a pair of HS6 carbs in the shed that I bought off eBay a while ago. My intention was to buy a couple of cheap carbs to practice stripping and reassembling prior to tackling the ones on the car. I didn't realise at the time I bought them that there were different types :oops:

Anyway, Can someone perhaps give me a rundown on what the main differences are between the HIF and HS types and which, if any, is better?

Cheers

Dave
 
I think the main difference Dave is the float chamber.

If you look at the HS8's in my posting in the 4 cyl section, you'll see the fuel float chamber sitting to the side of the main carburettor body. The jet incorporates a flexible pipe that connects to the bottom of the float chamber.

If you look at the HIF6, they are rather chunky at the base, this is because the fuel/float chamber is incorporated within the body of the carburettor.

HIF = Horizontal Integral Float-chamber.

Apart from that, I'm ignorant to any other differences :D

Bri.
 
The other main difference is that HIF series carbs have a needle that is allowed spring loaded sideways movement.

Personally i much prefer the HS series as being simpler and easier to get at the float chamber needle and float. I've heard opinions expressed both ways as to which type gives better performance / mixture control. My view is that the HS is easier to set up and is therefore more likely to be spot on.

Chris
 
Thanks Gents

That's a start. There must be something else in it though as I found this post from Harvey:

harveyp6 said:
Personally if you remove the AED I'd take the opportunity to remove the HS6 carbs and manifold at the same time and replace with the later HIF6 carbs and manifold, all of which have manual chokes.
Click to expand...

Does that mean the inlet manifold is different for HIF and HS carbs?

Dave
 
chrisyork said:
My view is that the HS is easier to set up and is therefore more likely to be spot on.

Chris
Click to expand...

I can't see that the HS6 can be easier to set up other than doing the float height, and in practice the HS6 linkage is always worn and is over complicated, and the carbs wear badly and go out of tune very quickly. I'd always get rid of the HS6's in favour of HIF6's.
 
The air flow rates between the two designs are not equal either, with the HS6 delivering a maximum of 210 cfm (cubic feet per minute) while the HIF6 delivers an increase of 30 cfm to see a peak of 240cfm.

There are differences also between the two inlet manifolds, with Rover improving upon the flow and mixture distribution characteristics of the latter manifolds which carried the HIF6 carburettors as standard.

Ron.
 
I seem to have sparked a bit of debate here....good, just what I was after.

I think I'll still strip the HS carbs that I have and clean them anyway but stick with the HIFs. At least I have a couple of spare dashpots towards a matching pair. I presume they're compatible?

Dave
 
There are no compatible parts between the HS and HIF ranges as far as i know. For example, in the dashpot/piston assembly that you mention, a plain bearing is used for the piston rod on the HS, while there is some kind of ball bearing on the HIF carbs.
 
Demetris said:
There are no compatible parts between the HS and HIF ranges as far as i know. For example, in the dashpot/piston assembly that you mention, a plain bearing is used for the piston rod on the HS, while there is some kind of ball bearing on the HIF carbs.
Click to expand...

:roll: Bugger! :roll:

Anyone need a pair of HS6s :)

Dave
 
Research and find out what other classic cars use the HS6. then use this information in your ebay listing to sell them.

It makes a huge difference, I've seen HS8 pairs (for the 2000TC) when advertised as also a Jaguar part fetch double the price as those advertised as only Rover P6!

Bri.
 
Brian-Northampton said:
Research and find out what other classic cars use the HS6. then use this information in your ebay listing to sell them.

It makes a huge difference, I've seen HS8 pairs (for the 2000TC) when advertised as also a Jaguar part fetch double the price as those advertised as only Rover P6!

Bri.
Click to expand...

I'll give them a bit of a polish to make them look good too :)
 
Dave3066 said:
Thanks Gents

That's a start. There must be something else in it though as I found this post from Harvey:

harveyp6 said:
Personally if you remove the AED I'd take the opportunity to remove the HS6 carbs and manifold at the same time and replace with the later HIF6 carbs and manifold, all of which have manual chokes.
Click to expand...

Does that mean the inlet manifold is different for HIF and HS carbs?

Dave
Click to expand...

Yes, the HS6 & HIF6 manifolds are different.

(Sorry for the late reply, I missed your post somehow.)
 
Demetris said:
There are no compatible parts between the HS and HIF ranges as far as i know. For example, in the dashpot/piston assembly that you mention, a plain bearing is used for the piston rod on the HS, while there is some kind of ball bearing on the HIF carbs.
Click to expand...

AFAIK the ball-bearing suction chambers were introduced on later HIF's? Mine don't have this arrangement...good job too - I can just picture them rolling off the back of my workbench! :)
 
vaultsman said:
Demetris said:
There are no compatible parts between the HS and HIF ranges as far as i know. For example, in the dashpot/piston assembly that you mention, a plain bearing is used for the piston rod on the HS, while there is some kind of ball bearing on the HIF carbs.
Click to expand...

AFAIK the ball-bearing suction chambers were introduced on later HIF's? Mine don't have this arrangement...good job too - I can just picture them rolling off the back of my workbench! :)
Click to expand...


Sorry if i sounded misleading, i am not terribly familiar with early HIFs.
 
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