Light Aircraft Association

Can anyone explain the difference between oil filters for the VW that are described as "High Pressure"? I assume that some (all?) oilways in the VW run at a higher unregulated pressure than other oilways. If using the ACRO cast alloy adaptor to fit an oil cooler/filter, do I need a special type of filter canister?

Thanks

Rob

My view on this is that "high pressure" filters could be better described as "full flow" where all the circulating oil is pumped through the filter. Some older vehicles had a "by pass" filter where a percentage of the circulating oil was filtered. One of these by pass types would not be suitable to fit where all the oil is filtered. I can't think of an example apart from the old Morris Minor series 2. Rob, you, I know are familiar with the BMC "A" series engines. The first of these had a tin screw- on by pass filter, secured with a large hose clip.
Most modern applications are I think on trucks, I did some filters on a 12 litre Volvo yesterday, this has two full flow and a by-pass all in a row.
I would say more or less any modern car filter, that screws on will do the job.
A vw based engine that I sourced filters for, had an unusual size thread, eventually found that a Mahle oc315 for Lancia/Alfa fitted, also a Saab 9144445. Later found a small filter which would screw off without removing the exhaust, this was a Ford efl500. None of these may fit yours, it depends on the threaded spigot.

Rob, If you're using the Acro adapter Barry Smith should be able to tell you the best filter.

Filters come with different threads. There are also filters with male or female threads and PSP and metric threads - so you need to get the right one. There is 3/4" BSP filter - the Champion C103, which is a small full flow filter (with no bypass valve to open if the filter gets blocked). More complex filters have this feature and also non-return valves. I use a C103 on my VW engine. A more readily available filter is the Fram PH966B, which costs about £5.00. As I change the filter at every oil change at six month intervals the oil remains clean and there is no risk of the filter becoming blocked. In any case any impending blockage would be indicated by falling oil pressure. It should be possible to cut an old filter canister open with a cutter sold by LAS enabled examination of the filter element for foreign material.

Noel.

I'm using a 3/4 threaded adaptor (aka remote filter head) so the champion 103 fits. Same as the BMC A-series.
I'd read somewhere that some of the bolt-on mods for the VW use a filter that takes full pressure oil straight from the pump and BEFORE the pressure reduction valves. Is this right? Sounds a little odd.
Presumably the oil cooler on the VW lives with a lower pressure difference and is thus downstream of the pressure reduction valves.
I've also been told by the local VW camper people that they like to see about 25psi when the engine is running but I am getting about 60. Since the A-series runs at 70+ psi then it ought to be satisfactory.
Thanks, chaps.

Dito everything by Noel. If you can't get a C103 I think C104 fit as well but are a bit taller.

Formation posting. Cool. I regularly used to get 60 PSI on start up but this would soon drop to around 30psi once warm with about 9 PSI at idle warm.

Just had a thought. Is it one of those pumps with the filter on a cast arm that hangs off to one side of the front pulley/prop hub? Would that be what they are talking about?

The Champion C138 filter has a 3/4" female thread (I think the 'C' refers to the thread size/type) and it includes a blocked filter bypass and an anti-drain back valve - approx 3" dia and 3" long. Works well. Hrs of research opening oil filter (non-sealed) boxes in Halfords paid off!