14 replies to this topic

[Readers14]

So I have a HIF44 with dia 1.75” inlet aperture.

I’m replacing the inlet manifold with a Minispares item, but noticed that the rubber spacer & abutment plate apertures are around dia 1.5”.

Not a massive difference I know, but surely that is going to cause disruption to the air flow?

 

I’m going to need a new thinner spacer anyway, as the freeflow air filter is a tight squeeze against the bulkhead. 
 

[Readers14]

I’ve read the inlet manifold section of the yellow bible & there is no mention of inlet port matching, other than it doesn’t really matter if you have a smaller carb port than the manifold port.

But mine seems to be the other way round, ie bigger carb port, smaller spacer port & smaller abutment plate port, which to me says there is a restriction in flow.

I’ll check the port size of the Mini Spares inlet manifold when it arrives.

Edited by Readers14, 30 March 2021 - 11:01 AM.

[rock1day]

I would open up the spacers and manifold to match the carb bore. Otherwise they will act as a restrictor.

[Readers14]

I would open up the spacers and manifold to match the carb bore. Otherwise they will act as a restrictor.

Yeah that’s what I’m planning to do.

[GraemeC]

Doesn’t sound like the right spacer or abutment bracket to me. All the ones I’ve used have matched the 44mm carb opening.

[gazza82]

Doesn’t sound like the right spacer or abutment bracket to me. All the ones I’ve used have matched the 44mm carb opening.

Possibly HIF38 parts?

[Readers14]

 

 

Doesn’t sound like the right spacer or abutment bracket to me. All the ones I’ve used have matched the 44mm carb opening.

Possibly HIF38 parts?

 

That’s what I’m thinking.

Car is 1275 Sprite, which originally came with a HIF38 from the factory.

Previous owner fitted HIF44 but without the necessary hardware to go with it.

[gazza82]

I might have a spare HIF44 abutment plate .. but I'll need to check a number of boxes before I can confirm that!

[Readers14]

I might have a spare HIF44 abutment plate .. but I'll need to check a number of boxes before I can confirm that!

Would be great if you have one!

Let me know if you do & how much you want for it.

[rock1day]

 

I would open up the spacers and manifold to match the carb bore. Otherwise they will act as a restrictor.

Yeah that’s what I’m planning to do.

 

The Minispares intake I have has a 1 1/2 bore, but has a design that easily allows it to be opened out to 1 3/4 inches. 

 

I`ve seen carburettors fitted to these manifolds without the spacer - for clearance perhaps? 

Edited by rock1day, 31 March 2021 - 11:12 AM.

[Readers14]

 

 

I would open up the spacers and manifold to match the carb bore. Otherwise they will act as a restrictor.

Yeah that’s what I’m planning to do.

 

The Minispares intake I have has a 1 1/2 bore, but has a design that easily allows it to be opened out to 1 3/4 inches. 

 

I`ve seen carburettors fitted to these manifolds without the spacer - for clearance perhaps? 

 

Yeah, you can get a few different thicknesses too.

Think the purpose of the spacer is to move the carb further away from the hot exhaust manifold.

 

My freeflow MED air filter is up against the bulkhead & is a pain to fit/remove.

Removing the spacer would cure this issue but I don’t want the carb too close to the exhaust manifold.

[GraemeC]

Removing the spacer may also mean the throttle lever fouls the inlet manifold

[richmondclassicsnorthwales]

The phenolic spacer reduces fuel vaporisation, that is why you find most carburettors use them

 

You can buy thinner option of spacer

 

CAM4942 is the abutment plate you need and are £13, 

 

12B561 is a spacer which is 0.5 in thick, and 610849 is 6mm thick, and both are for 1.75 in HIF44

[Readers14]

Current spacer thickness is 9.5mm. So need something a little thinner than that.

[rock1day]

Current spacer thickness is 9.5mm. So need something a little thinner than that.

I had an aluminium spacer machined down once, but I suppose you could stick several gaskets together if the 6mm spacer is too much?