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MG Midget and Sprite Technical - Cutting an HIF 44 down to size

My Datsun conversion is holding the engine a bit higher and I'm now getting the top of my HIF44 hitting the bonnet.

As I understand it there are two ways to shorteren it.

- Remove material from the top of the damper
- Remove material from the top of the dashpot such that the damper can screw down further

I'd appreicate guidance as to how much of each I can get away with.

Longer term I'll get the carb face of the manifold machined.
Jeremy Cogman

fit the damper off an HS6 instead

HIF dampers are quite significantly taller than the simple flat damper the HS6 supplies. Geoff used one of these from a certain carb specialist who had a stall at the NEC a couple of years ago

(I cant remember his name but it may have been Andrew something)

The dampers share the same sized thread
Bill

I also used a hs6 top on my 1970 midget, and I also took one off a spitfire 1500 carbs as this also screwed into the hif44 and gave me loads of clearence on a 67 sprite that I owned.

hope that this gives a few more options?

John
John Collins

With my HS6, I found the dashpot would move much higher than necessary, i.e. it could disappear from view if pushed up by hand (with the dashpot housing in place. So I chopped ~3mm of the threaded part, found there was still excess travel, and chopped another 1.5mm off to give clearance.

HTH

A
Anthony

Regret I can't find the details for the guy who sent me the HS6 cap. However, I expect it won't be too difficult to track one down from a SU supplier.
I cut down the piston to a length of 74mm ( that is measured from the top to where it is joined to the cylindrical part of the carb. Hope you understand. You will of course lose the circlip retaining format at the top of the piston, but - so what !
I cut the damper rod down as well - externally from where it enters the cap to the tip of the damper it is 61mm. Obviously you cut it longer to go inside the cap. You lose most of the "grip", so I super glued it in. That seems to hold it ok. I think that you may get away making the piston slightly longer than 74mm. It is a matter of trial and error. Mine works ok, but of course I have to top up the piston with oil more often !!
Sorry about the out of focus photo, but it may help.


Geoff Mears (1970 Midget)

Geoff and everybody, many thanks for that.

I've never really seen the point in that circlip!

So the damper rod is just a push fit in the cap is it?
Jeremy Cogman

Yes. A standard one has grooves which bite into the plastic and hold it in place. You will cut this area away - that is why a blob of super glue helps keep it in place.
Geoff Mears (1970 Midget)

The damper push rod is a crimped end pushed into the cap, when Geoff took off the crimping he glued the cap onto it and it seems pretty good

The rod is hard steel but if you want to make a grippy surface on it you could try an old toolmaking tip

take a flat file, fairly rough but not quite bastard

place the cut off end on a steel block where it is free to roll along and using the "side" of the file, where the cut is a row of sharp straight lines and roll the file against the tip of the rod

keep it straight and press down hard so the straight lines off the file edge are scored into the rod surface

the raised profile you induce will enlarge the diameter of the rod fairly significantly as long as the rod has enough "softness" to take the impressions

If you can hacksaw it easily you should also be able to Impress it!

HTH
Bill

Thanks for your input everyone.

I'm off work from tomorrow so I can play with this then.

Just ordered one of these:

http://www.burlen.co.uk/partDetail.aspx?partID=44303

Expensive bit of brass but time not on my side.
Jeremy Cogman

Which in the end wasn't needed.

I've found enought clearance by removing as much as I dare from the damper cap and also removing one of my two carb spacers which not only slightly drops the carb but more importantly brings it nearer the centre of the bonnet.

Cheers again for your input.
Jeremy Cogman

I found this worked quite well for me - see image, and maybe would distract the concours judge away from the fact that I have fitted an incorrect radiator grill (cos I wanted to).

Stops all that banging and crashing which sounded like a 5 year old playing the dustbin lids. Fitting bonnet bumpers is also high on my agenda.

When the weather gets grotty I will pull everything apart and re-profile may manifold again.

Roly



Roly

Jeremy, that cap would look nice with the SU logo engraved on it.
Cheers John
JOHN HALL & JULIE ROBERTS

Looks like a typical Racal fix, Roly.
Nick


> Looks like a typical Racal fix, Roly.

How did you know, I was involved with Racal?

Racal was very experienced at recovering from disasters - usually every day.

Roly
Roly

This thread was discussed between 19/05/2008 and 22/05/2008

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.