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MG Midget and Sprite Technical - HIF44 help required

At long last I am fitting my HIF44. I have a Maniflow inlet with the 'correct' angle but its closer to the bonnet than I would like. It is fitted with a 'top hat' style damper [part LZX 1505]. What type of damper do others use? Can the piston and suction chamber be shortened to give more clearance?

I want to try and sort this before it goes to the rolling road for setting up.
Doug Plumb

Do you know what clearance you actually have?

The curvature of the bonnet (assuming a post Frogeye model) is very deceptive and a lot higher over the carbs than it would appear. Try putting a large blob of plasticene or soft linseed oil putty on top of the daper cap and closing the bonnet gently on to that to check the clearance.
Guy W

Got one on a 1275 in a Frogeye and it is a tight fit. I used a Howley Racing inlet but had the face wedged to give more clearance (there was none originally) but I still had to shave a couple of mm off the plastic dashpot top. It seems ok though, no sign of knocking at all.
I believe the SU used on the V8 engine had shorter dashpots. Not sure by how much though.

Rob
Rob aka MG Moneypit

I put in my 'power pimple' to make room for the cap but I know Geoff Mears has a flat top damper cap from a 1¾ SU
Bill sdgpM

Good Q Doug.

I just had a happy hour trawling through the SU manual Santa brought me.

So far as I can tell from the book the MGBGT V8 used a pair of HIF6's but the Rover P5 and P6 V8s used a variety of HS6 and HIF6 types, depending on spec and market.

I understand the HIF44 is just a metric bore version of the HIF6 (inch and three-quarter) unit - is this correct? That might tie in with Rob's comment about the V8 carbs.

There are two types of HIF44 so far as I can see. One is manual choke and the other electronically controlled (HIF44E). They are different dimensionally, but I don't know the difference. And I don't know if the dashpots and pistons are compatible, but they are different shapes so I doubt it. I imagine you will have a manual type.

Since the manual type has a "tower" at the top of the case I speculate it would be possible to remachine this and shorten the piston by the same amount to reduce the overall height, but I've never heard of it being done.

The man in the know for SU carbs is Peter Burgess. I'd be tempted to ask for his advice.

Anyway - thanks for the pretext to go and read the manual - it was fun!

Good luck.
Greybeard

I vaguely recall being told that my HIF44 had had a Rover V8 dashpot fitted. It is 95mm high from the base of the pot to the top of the plastic cap. I don't know how that compares with the "standard" but with the appropriate Titan manifold it hasn't hit.... yet!
Graeme Williams

this Q comes up quite often and has been answered in some detail previously. I'm sure a well-targeted archive search will turn up the info you need.
David Smith

Apparently there is an SU carburettor that is fitted to a Harley-Davidson motorcycle.
The dashpot fits the HIF and due to its reduced height solves the bonnet clearance problem.
Perhaps Greybeard can locate the part in the SU catalogue otherwise enquiry should be made at Burlen.
Alan
www.masckent.org
Alan Anstead

As a last resort, you could chamfer the mating faces of either the head/manifold or possibly the carb/manifold to suit, or possibly install a suitably chamfered thick gasket/spacer (PTFE perhaps) twixt the latter to angle the HIF downwards.
Mark O

I have had a look at this and yes you can get an hif44 which is shorter.. As far as I can tell this was used on certain rover v8 applications and the dolomite sprint. It is easy to tell because it has a flat damper lid. Had to do this to fit the carb under my speedwell Monza bonnet.
Cheers
Tim
T Dafforn

In fact if you search for hif44 on eBay there are a couple listed.
Tim
T Dafforn

Further to Bill's comment ref damper cap, I also cut down the damper tube and pushrod thingy that the cap fits onto.

Geoff Mears

Are you sure maniflow have sent the correct manifold? They do two A' series HIF 44 manifolds but one is for minis. here's mine with the top hat dashpot filler and there's loads of room between it and the bonnet....

graeme jackson

Tim is correct that HIF44 was used on Rovers, but the book suggests that it was only the 2.6 litre SD1 between '82 and '84. Spec codes were FZX1390F and R or FZX 1406 F and R (Switzerland only)

The only Triumph I can see listed with HIF is the '84 Acclaim which seems to have worn HIF44E, spec code FZX 1460.

Other Triumphs and Rovers on the list, V8 included, appear to have been fitted with assorted HS types.

There is no HD motorcycle listed, but it wouldn't surprise me a bit.

There was a type HD carb used by Austin Healey, Bentley, Daimler, Jaguar and others up to about '69 or '70 which seems to have been superseded in later years by assorted HS types for the most part.

Other engines to use the HIF44 were Itals in 1980, Sherpa vans '80 to '82 and Vanden Plas Ambassador, Princess and Metro models '82 - '83.

There's a huge range of spec codes, which mostly cover variations in jets, needles and springs, but might easily mean shorter dashpots too for all I know. The book doesn't mention it. The SD1 version above may well have had a shortened housing for example, but I can't tell from this book.

Of course there's nothing to say the application list is exhaustive, but it appears to be reasonably comprehensive.

Alan is right that Burlen would know better and Graeme's comment re: manifolds is good. I didn't know there was a difference.
Greybeard

Found it. Tim's right - Rover V8 SDi from '86 on used HIF44s. As they sat in the valley between the cylinders I would bet they were shortened. Spec code seems to be FZX1473.

(My book covers up to '85 only. B**ger).
Greybeard

Alternately you could buy some front engine mounts from MOSS and they will lower the engine by a good half inch. I did the reverse and fitted OE mounts to my new engine and ended up with a dent in the bonnet. When I refitted the old mounts clearance was restored!
Chris Hasluck

This thread was discussed between 27/01/2016 and 28/01/2016

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