MGB & GT Forum

I can't believe that I'm failing at this, but I can not figure out what air filter I have. The car is a 1980 MGB, but the original Zenith carb was replaced with a SINGLE SU HS type (RAY id'ed it as a HS 6, somebody else thought it might be an HIF44). The air filter is clearly labeled NAPA42176 (the 4 is a little hard to read, but I'm pretty sure that's what it says), it is a flat cylinder with two bolts. I've searched around the forum, but have only been finding threads on fitting air filters on dual SUs around a brake booster. Here's a photo of the carb and filter:



I have been to NAPA already, and they have discontinued the part and do not have a replacement. I did find a filter with the same radial dimension, and can cut the old can apart and use it to sandwich the new filter. I think I can make that look pretty OK, but would rather something a little less redneck. I've looked through Moss' catalogue, but don't see the two bolt holes on the filters that look to be similar (are they covered with the nifty MG and SU branded filters?).

Anyhow, I sure appreciate any insight you can give me.

Cheers,
Paul

I'd bet that if you took the measurements of the element and contacted K&N (https://www.knfilters.com/contact.htm) customer service they can tell you which of their elements fit your housing, providing that is what you are looking for.

Paul
Ray is spot on the carburetor you show is a HS type. This is determined by the float chamber being mounted beside the main carburetor body, as yours is.
As to it being a 4 or 6 you will be able to determine this yourself. Measure the choke diameter, (below). These are sized by datum dimension of 1" and then 1/8" increments. So the standard MGB size carburetor is a HS4 or HIF4 being 1.5" or 4 x 1/8" measure increments. If the carburetor is still attached to the engine measure the outboard choke diameter.

Measure your choke dimension and get back to us then we will find you a suitable filter.

B

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Life's most persistent and urgent question is, "What are you doing for others?"

Hmmm....bolt pattern is straight up and down, not angled?

There are two bolts, on the same horizontal plane, symmetrically dispersed.

Thanks so much guys, I'll get the ID measurement tonight.

The filter body itself is 6" diameter.

Cheers

Sorry Gerry, you know what I mean, I was being representative not figurative.
I am showing a H4 however the 4 part is relative .

BUT if you must ............................. and before we ask, the outboard choke dimension of 4 carburetor is 1.375" diameter.

B

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Life's most persistent and urgent question is, "What are you doing for others?"

Bruce, I'm curious-what was the first carb off of? Seems like the Minis used that config but surely not in HS4

Gerry,
These are H4 are fitted to the MGA, other vehicles as well, think, TF, Magnette Z series etc. I prefer the H type versus the HS due to the funky jet tube of the HS. Plus the H type have/had those lovely Brass choke levers.

B

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Life's most persistent and urgent question is, "What are you doing for others?"

Interesting Napa air filters. The 71 I just bought had 2 air filters like that for the SU's with the Napa logo on the cover. Never saw those before. I am not going to use them as I have room for the stock ones.

That looks like an H4 (maybe HS4) but that's definitely a front carb mounted in the back position like they did on a Magnettte. The air filter may be a Kinby - an old disposable brand that came in an orange box - remember those?. The best thing about them was that there is a fitting on the back to hook your crankcase vent so you vent to the air filter without any real vacuum! Basil 707.762.0974 basiladams@yahoo.com

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Basil C. Adams
1956 MGA Coupe (Show Car)
1957 MGA Roadster (Driver)
1958 MGA Coupe (Racecar)
1959 MGA Coupe (unrestored)
1960 MGA Coupe (unrestored)
1960 MGA Roadster (Driver)
MKIII Elva Courier (E1056)
1967 427 Cobra
1972 Alfa Romeo Montreal
A coupla late MGBs
1960 Austin Healy BN7
More Cars than Brains

Paul,
Let's stop this guessing stuff! (H type float chamber have center bolt to float chamber)
You definitely have a HS type carburetor shown in your photo.

Fact!

In the photo is also visible the small triangular tag on the float chamber screw that identifies this carburetor.

So; tell us what is the number on the tag? AUC (D) xxx and again tell us the choke diameter?

The air filter element is as described a NAPA type replacement filer that was used on SU carburetor equipped Volvo cars in the day.

Information below to redeem this filter if you choose to, or tell us the choke diameter there may be other options open to you.

http://www.californiaclassix.com/Bernard/SU_Filters.html

B

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Life's most persistent and urgent question is, "What are you doing for others?"

You guys are fantastic, thank you for all of the leads.

The tag number is AUD 230R
The measurement across the air intake on the carb is 1 5/8"

I have no need to replace with an identical filter, but the dimensions of the current filter are:

6" diameter
1 3/4" (approx) depth
2 7/8" distance between bolts

Cheers,
Paul

OK Paul this is good.

So this is a carburetor originally fitted to a B18B Volvo engine. This is a HS type 1 3/4 or HS6 These Volvo cars were equipped with dual carburetors and the 'R' in the model number indicates you have the rear one.

In the link I posted above shows you how you can 're cycle' the filter. Doesn't look overly daunting to do. You can buy size round elements to replace the old you have.

B

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Life's most persistent and urgent question is, "What are you doing for others?"

According to this:

https://issuu.com/theshadybower/docs/su_reference_catalogue_16_2012/127

It was OEM on my parents 1968 Volvo 144.

If it's an HS6, shouldn't it be mounted to the manifold with four bolts? And if it is an HS6, an air filter for a Triumph TR4 would fit and might be cheaper and easier to find than one for a Volvo.