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MG MGB Technical - Larger oil filter

I currently use a K&N HP2004 filter. is there a larger (taller) replacement with more filtering capacity?
Dan Hiltz

Dan
K&N's are pretty good filters, what you've got should be fine, but if you want a taller one, I guess it'll flow better cold so not a bad idea--

K&N
HP-3001 K&N Oil Filter-

Same as what you've go only half as long again

willy
William Revit

Dan, I've use K&N filters in the past, which seemed to work well, but were a bit on the small side. I changed some years ago to MANN W 916/1 filters, which are bigger and they did give a slightly better oil pressure.

They are available on Amazon in the UK: https://www.amazon.co.uk/gp/product/B001CUG71I/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Andy
Andy Robinson

After trying several filters over the years I now use the Mann W916/1. Very good value in the UK at least, about a quarter of the price of a K&N Gold with no difference in gauge indication. The same filter spec is used for the V8, if the size is good enough for that then it's certainly good enough for the 4-cylinder.
paulh4

I'd endorse the Mann w916/1 filter.
Richard Thompson

Dan-
Avoid using oil filter cartridges that are taller than necessary, otherwise when the engine is switched 'Off' any oil above the anti-drain standpipe will drain out of the oil filter cartridge into the engine, leaving an air pocket that must be filled before oil pressure can be achieved, an event that can occur only after the then-displaced air enters the system of oil supply passageways, an event that is never a good thing!
Stephen Strange

The opposite is also true, if too short it can close off the end of that pipe. I've seen a video of someone - AFTER he had discovered it by running his engine with no oil pressure, then proceeded to make a video showing it with no oil pressure!
paulh4

Dan-
As Paul pointed out, , you are wise to beware of short oil filter cartridges that are roughly the same height as the length of the anti-drain standpipe. These are commonly found in parts listings as "MG, all, 1971-1980". This filter screws on to the 1275cc A Series engine of an MG midget and may in fact be correct for that application, but it certainly is not appropriate for the BMC B-Series engine of an MGB. A difference of 1/8" (3.18mm) in the height of the internal construction from what is correct could give normal performance at low engine speeds, inadequate oil flow causing a drop in oil pressure as engine speed increases, thereby producing total disaster at full-throttle. Because the oil pressure sensor is before the oil filter, the oil pressure gauge will not warn you of this defect. These short oil filter cartridges can cause the anti-drain standpipe to come into contact with an internal support that is inside of the oil filter cartridge, causing it to bend. This is sure to damage the combination anti-drain-back and bypass valve. Consequently, any oil filter cartridge should be examined to be certain that all of the internal components of the oil filter cartridge should be, at a minimum, a full diameter of the anti-drain standpipe away from the anti-drain standpipe when the oil filter cartridge is completely tightened. Do not attempt to avoid this by shortening the anti-drain standpipe by 1/2" (0.500" / 12.7mm). This will allow more oil to drain out of the oil filter cartridge, thereby requiring it to be refilled before proper oil pressure can be achieved, the same as if an oil filter cartridge has been installed that is taller than is necessary.
Stephen Strange

Whilst the oil pump and oil gauge galleries are cross-drilled the cooler hose block adapter 1H922 projects through the gauge gallery into the oil pump gallery separating the two to give full-flow filtering. Not always the case on early versions of the B-series but should be on the MGB. Hence the video showing the gauge at zero when a short filter had blocked the anti-drain pipe.
paulh4

Discussions about the oil filter standpipe makes me remember that my '71 car doesn't have one. It has an upside down cartridge filter and has never had any problem with almost instant oil pressure build up on cold starting. What is the function of the pipe?
Mike Howlett

It's supposed to stop oil draining from the outlet similar to the valve round the edge of the filter which stops it draining back through the inlet. For me whilst overnight it rises instantly it does take longer the longer the car stands, but no more than three or four seconds after several weeks.

That's the roadster, the V8 is completely different!
paulh4

This thread was discussed between 05/02/2023 and 27/02/2023

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