1275 Air filter

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alawrence10360
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1275 Air filter

Postby alawrence10360 » Fri Feb 01, 2019 7:22 pm

first post so be gentle..
I'm looking for an air filter assembly that will fit a 1275 but looks like a 1098
I was told by the guy who sold me the car that the original wouldn't fit and it's got a pancake filter now which looks a bit boy racer
its a single SU fitted currently

Monty-4
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Re: 1275 Air filter

Postby Monty-4 » Fri Feb 01, 2019 11:22 pm

What size SU? 1.5" given it's a 1275?
68' 4-door Saloon, another 'Monty'.

alawrence10360
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Re: 1275 Air filter

Postby alawrence10360 » Sat Feb 02, 2019 7:40 am

I believe so
he said it was an HIF ???
I may have that wrong
Every days a school day

IslipMinor
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Re: 1275 Air filter

Postby IslipMinor » Sat Feb 02, 2019 11:00 am

An HIF has the float chamber integral with, and underneath, the body of the carb itself. If carburettor body has 2 mounting studs from the inlet manifold, it is a 1 1/2" (HIF 4/HIF 38), and if it has 4 studs, then it is a 1 3/4" (HIF 6/HIF 44). A 1275 should have an HIF 6/HIF 44, particularly if it is modified at all.

Fitting a flat case air filter from a 1275 Mini/Allegro etc. looks the nearest to 'standard' for a Minor, and is good for a standard (ish) 1275 engine - there is one on eBay at the moment (your will also need to get the elbow that fits in between the manifold and the carburettor):

https://www.ebay.co.uk/itm/Mini-1275-GT ... SwRcZcA8k8

If the engine is modified, then a similar air box from the MG Metro is good up to ~90bhp. Whatever you fit, also fit a K&N element into the box to give better air flow.

We had an MG Metro air filter box, with K&N filter element, and it seemed to work very well, with no obvious air noise. That was until we did a back-to-back rolling road test and found that just removing air filter box and elbow released 6bhp! This was despite cleaning up the filter case and flowing the elbow, so the MG Metro case really does limit the power to ~100bhp.

We now have a complete K&N filter + stub stack in the housing, but have not been back to the rolling road (yet).
Richard



alawrence10360
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Re: 1275 Air filter

Postby alawrence10360 » Sun Feb 03, 2019 5:26 pm

im not sure what size carb it is...
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paul 300358
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Re: 1275 Air filter

Postby paul 300358 » Sun Feb 03, 2019 5:32 pm

Remove the air filter and measure the hole leading into the carburettor , it will be 38mm (1.5 inch) or 44mm (1.75 inch).

alawrence10360
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Re: 1275 Air filter

Postby alawrence10360 » Sun Feb 03, 2019 5:43 pm

Will do
cheers

callyspoy
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Re: 1275 Air filter

Postby callyspoy » Mon Feb 04, 2019 8:13 am

Judging by the filter mounting holes, i would say HIF44.

Chipper
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Re: 1275 Air filter

Postby Chipper » Mon Feb 04, 2019 9:44 am

Yes, definitely a HIF, similar to the one on my 1275. I have seen some folk use the conical 1098cc air filter housing with one of those K&N cone type filters like the one you have, fitted into the housing, which is a neat solution.
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IslipMinor
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Re: 1275 Air filter

Postby IslipMinor » Mon Feb 04, 2019 12:39 pm

The nominal carburettor size, 1 1/2", 1 3/4" etc. is measured at the throttle side of the carburettor, which means taking it off - much easier to count the number of mounting studs! The inlet or filter side hole pattern is very similar for both HIF 4/38 and HIF 6/44.

How many studs/nuts secure the carburettor to the inlet manifold?

2 = HIF 4/38 (1 1/2")

4 = HIF 6/44 (1 3/4")
Richard



alawrence10360
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Re: 1275 Air filter

Postby alawrence10360 » Mon Feb 04, 2019 1:45 pm

looks like 4 to me from this pic
i will have a proper look tonight
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IslipMinor
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Re: 1275 Air filter

Postby IslipMinor » Mon Feb 04, 2019 2:06 pm

Definitely 4, so it is an HIF 44, which is the best one for a 1275 engine.

Do you know what the spec of the engine is? The LCB exhaust is certainly not standard, but what else has been done?

The idea of encasing the K&N cone inside a late type 1098 case will certainly look nice, but depending on the 1275 spec, the case may not have a large enough intake aperture to allow the engine to breathe well.

Some comments:

The distributor advance/retard connection looks 'open'? This should be connected to the vacuum unit on the distributor. Does it has a vacuum unit?

The crankcase breathing connection has been blanked off - what are the crankcase breathing arrangements on the engine?

The bolts holding the front damper to the bulkhead have their locktabs in place, but not bent over. I would suggest that you check the tightness of these bolts, but do not over-tighten, and then bend over the tabs to secure the bolts.
Richard



alawrence10360
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Re: 1275 Air filter

Postby alawrence10360 » Mon Feb 04, 2019 3:48 pm

ok
Its an Ivor Searle engine and when i approached them with the engine seial number the confirmed it was standard.
The vacume connection was off and in fact had melted on the nice shiny LCB manifold... its back on now
The crancase breather has its own filter systen an vents to atmosphere ( see pic )
The dampers fotted are telescopic and i belive what you can see is redundant but i will check
Many thanks for the info
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paul 300358
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Re: 1275 Air filter

Postby paul 300358 » Mon Feb 04, 2019 4:04 pm

Sorry, but my hif38 has 4 studs!! you need to measure the throttle body.

IslipMinor
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Re: 1275 Air filter

Postby IslipMinor » Mon Feb 04, 2019 5:00 pm

A-Series in-line engines are not designed to run with 'open' crankcase ventilation systems, and never did during production. They need a partial vacuum within the crankcase to help keep the oil the right side of the rear crankcase scroll - there is no conventional 'seal' there.

The first version of a crankcase ventilation system used a 'draft tube' running down from the front tappet cover to suck out the fumes when the vehicle is moving, with fresh, filtered air coming in via the air filter into the top of the rocker cover. The oil filler cap is 'non-vented'.

The later version used two versions of a 'closed circuit' system - the first used a PCV valve on the inlet manifold to create a partial vacuum, connected to a canister on the front timing cover, with the fresh air now entering via the 'vented' and 'filtered' oil filler cap.

The final version uses the port on the side of the carburettor(s) connected to the canister on the timing cover, with the fresh air again coming in via the vented/filtered oil filler cap.

The in-line 1275 engine has no side tappet covers, so always had the canister as part of the timing cover - it was either connected to the PCV valve or the port on the carburettor(s).

The HIF 44 has the correct side port, which should be connected directly to the timing cover canister, and also make sure that the oil filler cap is the vented/filtered version.

The original dampers are still the suspension top link, so the lock tabs are still important!

2 or 4 studs? There seem to be pictures of both for the HIF 38, and also some with 2 of the 4 holes elongated? The only sure way is to remove the carburettor, and measure the diameter of the bore where it meets the inlet manifold, as suggested previously.
Richard



philthehill
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Re: 1275 Air filter

Postby philthehill » Mon Feb 04, 2019 5:25 pm

Re the lever damper mounting bolts.

Even with tele dampers the bolts and lever damper are not redundant.

The damper changes its role from damper/top link to just being the top link when tele dampers are fitted unless you have the lever dampers and tele dampers working in tandem.

The lever damper bolts must be tightened (no torque specified) and the tab washers turned over to lock the bolts.

I would advise that the lever damper bolts are checked for tightness every 12 months.
The alloy body of the damper in the area of the mounting bolts is easily compressed and eventually the bolt even though it has not turned can become loose.

Phil


alawrence10360
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Re: 1275 Air filter

Postby alawrence10360 » Mon Feb 04, 2019 5:52 pm

I will sort the suspension bolts ASAP.
Re the crancase breather should the pipe connected to the small filter be connected to the manifold where its plugged off ?
Cheers

alawrence10360
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Re: 1275 Air filter

Postby alawrence10360 » Mon Feb 04, 2019 5:52 pm

I will sort the suspension bolts ASAP.
Re the crancase breather should the pipe connected to the small filter be connected to the manifold where its plugged off ?
Cheers

paul 300358
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Re: 1275 Air filter

Postby paul 300358 » Mon Feb 04, 2019 5:59 pm

Yes, the filter need removing and this pipe fitted http://www.minispares.com/product/Classic/12A1735.aspx

alawrence10360
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Re: 1275 Air filter

Postby alawrence10360 » Mon Feb 04, 2019 6:06 pm

l have an oil leak and i thought it was coming out of the dip stick tube.
This might explain it...


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