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MG MGB Technical - Strange air filter to carb gasket

I took my K&N air filters off for a clean and re-oil yesterday and was surprised to find the gasket between the carbs and the air filter flared intake plate not to be the 1.5” circular type. See image. The cutout is distinctly not round when placed next to the ones I'm going to fit.

Any clues what these should be used for? they are heading to the bin shortly.

They were probably fitted when I had a rolling road tune up, during which these would not have been in situ during the tune, as the filters were off. Once tuned these were fitted on completion and reduce the effective diameter, and modify the tune a bit. So a 1 & 7/16" carb - HS 3.75!

I’ve drawn round the apertures and compared them with the new ones to show the difference - the big question is will it make the car faster !

The tuner will remain anonymous but is highly regarded in Ferrari circles!

Happy Friday !



Richard Thompson

Richard,
surely they're just misshaped from, er, well, who really knows. Perhaps whilst off the car they were put in or on something that altered their shape. a liquid and/or heat.

Your bottom gasket looks like a generic multifit paper gasket whereas the other two look like they were originally SU type shape gaskets.

If you've got an MGB there's a bloke that advertises on here that's an expert, wrote a book, and in my experience much better value for money as A) he does a better tune up than a couple of other rolling road tuners I've been to, and B) his charge is very good. First time I went to him he was nines times better than the previous A-series tuner I'd been to because his work to me seemed three times better at a third of the price of the previous chap.

Despite what many say I've found with some it's often hard to loose a good reputation even when deserved.

I'm sure the Fezza man and his followers would say they were fine when they left his place, you must have done something to them, caused them to alter whilst on the car, split something(?) - so what do you think might you might have done to them? :)
Nigel Atkins

They are the original style, as on the left here, but very misshapen for some reason. May have been stored and got damp.

The ones on the right are 'Murphy' alternatives which you can't put on the wrong way round. Unless the breather holes are clear from the carb through to the air filter the mixture is rich because the piston can't move as it should. Mind you, that doesn't stop you getting filter base plate on the wrong way round!


paulh4

I've had exactly that happen-
had some dirty gaskets that I needed to use temporarily so gave them a quick wash in the parts washer--the washer has jet fuel in it--
A week later I had to remove the aircleaners to fit the guy's new K&N filters and the old gaskets had gone to that same shrunken distorted shape as in Richard's pic
Must be the combo of some gasket material types and the cleaning fluid --
I wouldn't blame Enzo's man he was probably just trying to do the right thing
I doubt you would notice much/any loss of performance, but on absolute full hook full throttle there may have been a miniscule loss

willy
William Revit

This thread was discussed between 09/07/2021 and 10/07/2021

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