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MG Midget and Sprite Technical - MG Metro inlet manifold and HIF44

Hi All,

Does a standard alloy MG Metro inlet manifold mated to an SU HIF44 carb fit under the bonnet OK on a 1275 midget ?

Ben Brown

I believe it doesn't. Before I obtained a Titan manifold I played around with one. I had to do this to it.


Steve Church

Hi Steve, I wondered about doing that myself, Are you saying it still didn't fit ? How much is the Titan and where do you get it from ? cheers Ben
Ben Brown

Hi Ben, the tests I did indicated that it would fit with this amount of metal removed. I obtained a Titan from ebay before I could fit the modified BL part but I did some careful measurements and reckoned it would clear the bonnet. Titans are like hens teeth. There have been several threads about them and I had heard that there were two types with different 'angles' one of which was for the Mini. Others will no doubt add their two pennyworth. Note that my HIF44 has a low profile cap....not sure where it came from, but it gives another few millimeters of clearance.

Sadly my '71 Sprite has gone to pastures new and I now have a '68 B Roadster.


Steve Church

Hi Steve, Thanks for your input very useful. Dont suppose you still have that modified manifold under the work bench do you ?

Looks like it would be a pig to seal on the head though would need some very inventive washers :-(

I tried a B too last year they do look great and very roomy and comfortable but oh so dull to drive compared to a midget.

cheers

Ben
Ben Brown

Ben, I did my manifold the same as Steve's, just did it carefully with a file and then got it flat with emery on a flat surface. All you need to do for the washers is file the face where the washer sits to the same profile as the manifold face. Then use the thick standard washers and if the inlet is a different thickness to the exhaust manifold just file a step in the washer. Done two like this now and both have had at least a couple of mm clearance (one has about 10mm) with the standard dashpot cap. No problems with manifold sealing either.

John
John Payne

I machined mine with a woodworking router! and a suitable jig to hold the manifold in. The soft metal was not a problem for the HSS router bit. I also finished off on a flat surface (18mm MDF) with emery.

Ben, I may still have it about somewhere. email me steve at rivend dot freeserve dot co dot uk.

The Sprite was getting just a bit too small for my arthritic body to get into!!
Steve Church

The standard Metro inlet will not fit under the bonnet of a Midget. I used a Howley (no longer made)inlet less well known than a Titan often overlooked and go cheaper because of it. I picked one up on ebay 6 months ago for 12. The lower profile damper cap I think comes from an earlier HIF38 but will fit the HIF44. You will need to use a 1500 throttle pedal as the organ type does give enough movement it is also better to use a slightly longer cable - I used a BMX cycle brake cable and re-profiled the nipple - it came with an angled curved end section making for a neat and smoother cable run.This may start a debate but having fitted a 1.75 HIF44 I replaced it with a 1.5 HIF38 which I found gives a far more crisp lower end without effecting top end performance. It makes for much better average road use and also meant I could use a modified MGB back plate inside the air filter which greatly improves the air flow.
P Willoughby

A picture showing the Howley inlet manifold with the HIF38 and low profile cap


P Willoughby

Hi Ben, I have a Oselli Toqrue manifold which I not going to fit.
email me at twiceknightlies@btinternet.com
P C Knightley

I'm interested in what you say about the 1.5" carb being better than the 1.75" for general use. I know on the MGB, fitting the bigger carbs doesn't always give an improvement, particularly at lower revs. It's all down to the speed of the air passing through the venturi. The bigger the choke the slower the air velocity, unless your engine is worked to make it able to move quite a lot more air. With my car (in bits) I was given a 1.75" SU, but am now wondering if I should source the smaller one.
Mike Howlett

Mike,
It will also depend on what cam you are using. The components need to work together. I am using a 44 carb and a 276 cam. If I let the revs drop too much it still pulls OK. But there is a delay before the revs pick up if I just floor the throttle, but if I feather the throttle for a moment to increase gas velocity it then picks up much better
Guy Oneandahalf Sprites

Well sorry to upset the aplecart, but I have a metro set up that fits under of mine. I even put plasticine on it to see if I have any extra clearance - which I have. I had all sorts of issues, so it still sits on the shelf. At 60pence a litre, the weber does not punish too much here.
Shawn

As Shawn suggests, suck it and see. Every Midget is different. The engine bonnet clearance is different for every car. you may be lucky and find it fits ok with no modification needed. The Triumph Dolomite Sprint had HIFs with a shorter dashpot along with various other Leyland models. All getting pretty hard to find.
I do know where there are a few Titans, but the postage from Oz is a bit limiting.
Cheers John
HALL JOHN

Mike, I agree with you, that is interesting, I wonder what a rolling road would say about the two set ups, and why the low end improvement was seen with a '38?


for a 1275 mini, when running a single carb, the 1 3/4"/HIF44 SU is usually considered ideal. A 1 1/2 (HIF38) works fine, but is rather small. They used the smaller one for the 1275 Mini "Sprite" in the early '90s, for MPG. The common swap is to trade it for an HIF44, with a suitably sized manifold. But don't take my word for it, I followed the advice of Keith Calver (he regularly dynos and posts his results at minimania.com / minispares.com).

I bet that the manifold has quite a lot to do with it. When I swapped my (metro based) CI intake with HIF 38 on my mini, for a minispares intake + HIF44, they both are supposed to breathe really well. I wonder if the issue here is regarding what is / is not available for the Midget intake, when P Willoughby tried the same?

Norm
Norm Kerr

Well my 61 inc postage standard alloy metro manifold, HIF6 SU with K&N filter and stub stack arrived this morning care of eBay ... very pleased with that.

Was sold as seen (or not in my case) so with some trepidation I fitted it onto the engine to see how much I would need to mill off the manifold to get it to fit properly.

Well it just went straight on with no clearance problems whatsoever I put a big blob of blue tack on the top and closed the bonnet not even touched it. Maybe my engine mounts are shot or something to do with my 5 speed more likely, anyway no complaints there.

What I am less pleased about is the hole in the side of the plastic float (how do you manage to damage that) some dip stick must have dropped it and stepped on it or something. It also has a weird needle in it ADE what I was hoping for was a BDL.

Anyone out there with a scrap HIF6 or 44 or bits ?

So my DCOE twin 40 weber is now up on eBay so hopefully I will get my money back with some over to buy these bits.

I have a question --- My HIF6 has its vacume take off underneath and it comes out exactly in line the butterfly in its closed position, is that correct as I would have expected it to come out a few mm downstream of the butterfly and be on top of the carb.

There is also another vacume take off on the manifold, a little skinny one in addition to teh brake servo.

The number on the carb is UD 697R there might be a A in front of that.



Ben Brown

according to the Burlen SU site, AUD697R is the righthand half of a pair as fitted to the wedgie Princess 2200 of 1974-1975 and the standard needle for that was BCP. The float is WZX1509 and costs 8.29
David Smith

Hi David, Thats great and great prices too will give them a call tomorrow. Its the right hand carb I have so I need a WZX1510 float. The BDL needle is only a fiver too. cheers Ben
Ben Brown

This thread was discussed between 13/10/2010 and 24/10/2010

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