Alternative Oil filter/VW Speedshop exhaust question....

[wasserleaker]

Recently bought but haven't yet fitted, a VW Speedshop stainless exhaust.
as some will know, due to one of the pipes being closer to the engine than a std exh, the standard long oil filter would not fit, and a much smaller filter, as fitted to some polo's, and Seat cars needs to be used
(apparently this clearance problem only occurs if the oil/coolant heat exchanger/oil cooler, is fitted, which mine, a 2.1, has)
spoke to the guy at VW Speed shop who reckons the smaller one is fine, but i have doubts about fitting such a tiny filter when the standard one is so much bigger, a filter from a 2.0 Aircooled will fit with the new st/st exhaust on, same thread size and seal diameter, and though quite short, is much bigger in diameter so prob a similar filter area to the original, however the bypass valve in the original std filter is not fitted in a 2.0 Aircooled filter, would this cause problems with cold/thick oil not being able to bypass the filter element? or would the engines own bypass valve take care of it until the engine oil warms up enough, and the one in the filter is just a secondary one? someone told me some brands of filters dont have the valve in anyway as a rule, or am i misunderstanding what this valve in the filter is for? is it mainly a failsafe incase the engines own bypass valve fails? or is it mainly there to allow oil past the filter element when its seriously clogged and no oil can pass thru? i always change oil and filter at around every 6000 miles so this shouldn't happen.
really need to get the new exhaust on soon, but this filter issue is puzzling me
any help or advice would be great, anyone using the small filters or the 2.0 Aircooled filters on a DJ with no probs?
many thanks for any help!

[Red Westie]

You are getting confused....let me enlighten you grasshopper.
The one in the oil filter is called an oil by-pass valve and is there just in case the oil filter gets blocked (this would happen usually through lack of oil changes ie: leaving your oil too long between changes) in these circumstances, rather than allowing the engine to starve of lubricant, the by-pass valve will open (due to the high pressure caused by the blocked filter) and allow the dirty oil to lubricate. Not ideal by better than oil starvation.

The 'Pressure reliief valve' is all together different. It is there to limit maximum oil pressure in the system (too high an oil pressure will blow seals and gaskets) it works in a similar way to a by-pass valve (oil pressure overcoming spring tension which opens a valve) but where as one is there to allow oil to by-pass the filter, the other is there to limit maximum oil pressure....too different things grasshopper.

So....the smaller filter you need to fit will just need changing more regularly as it is likely to become saturated with dirt and block sooner. You will have no problems with the smaller filter..just change it every 5,000miles which most people with these old vans do anyway.
Martin

[toomanytoys]

IMHO its quite daft to design something that doesnt fit with the standard filter... they must have done it on a 1.9 and didnt think to check the 2.1

The bypass valve int he filter is there to prevent to great a pressure differentioal across the filter media.. now this usually only happens on cold start up and if the filter is blocked... I am going to assume (as I dont know for sure) that the type 4 engine doesnt have a bypass in the case for this (the pressure relief in the case is on the output to the bearings seals etc etc and prevents too much oil pressure for those components)

So one "could" assume that the type 4 oil filter is designed to cope with this over pressure... Surface area is prob ok (air cooleds are quite hard on the oil so would prob generate a fair bit more carbonised particals...) and you would prob change it more often than "design" in any case....

I cant say its fine... Anyone running the "short" filter out there????


I must have started typing just as you posted Martin....

[Ian Hulley]

Fritz has a stainless L.A. Performance exhaust fitted ... the 'designer' (i.e. copier of the early 1.9 system) states to use a Golf oil filter ... let's see what Fritz is using

We have a stainless J.P. system, that is the late styleee and you can fit the standard oil filter with 2.1 oil cooler/warmer.

Ian.

[lloyd]

TMT is right about filter bypass valve.

VW Speedshop stainless exhaust / L.A. Performance stainless exhaust... same / same

Make sure you have all the bolts/nuts, gaskets, sensor plugs for sensor holes, etc before fitting. I didn't receive all parts with exhaust kit, two extra shipments before install, and still don't have missing sensor plug over 6 month later (have a make-shift plug).

And exhaust is street racer loud!!

[wasserleaker]

Many thanks for the quick replies, folks! appreciated
Toomanytoys, i agree it is a daft design/oversight if it fits the 1.9 without the oil cooler, (which i can only assume the prototype was modelled on) but not the 2.1 with the added few inches of the cooler, wouldn't have needed much more tubing to just make that one pipe clear the oil filter for both models.
having seen the pic which Fritz put up a while back, his engine doesn't have the oil cooler and can run a std long filter with no clearance probs, and yes, from seeing pics of both the LA Perf. and VW Speedshop systems, they do indeed look identical.
Red Westie... thanks for clarifying what the valve in the filter does and what the pressure relief valve in the engine does!
so hopefully, the 2.0 Aircooled filter should do the job with no ill effects, assuming regular, timely oil changes, which the engine will get, but what would happen on a cold start up, with a filter with no bypass valve in it? assuming it wasn't clogged would the oil pass thru it ok, or could it damage the filter, or worse blow a seal somewhere? wouldnt the oil breather prevent this occuring?
is the smaller filter which has a bypass valve, the lesser of two evils compared to a larger surface area filter which has no valve? as Red westie hints at, as long as its changed regularly the oil shouldn't be dirty enough even if made to bypass the filter element, to do any damage when using the stubby filter.
as you say, Toomanytoys, if the 2.0 A/C engine is quite hard on the oil system and the filters seem able to cope, i think that filter is prob up to the job too, but it would be good to hear from anyone who runs the small valved filters with no ill effects.
thanks again.

[Red Westie]

I quote some extracts from the bible: Hilliers (fundumentals of motor vehicle technology)
Two basic filter types:
Full flow type (all the oil from the pump goes through the filter, these types incorarate a by-pass valve for safety)
By-pass type (where only a proportion of the oil from the oil pump goes through the filter at any one time)

The modern replaceable oil filter consists of about four metres of resin-inpregnated paper that is pleated to expose a large external surface area to the oil. The porosity of the paper is designed to trap nearly all particles over 25 microns (0.025mm)

Full flow types (we can assume the T25 is this type) incorporates a by-pass valve that opens when the pressure drop across the filter exceeds about 1 bar (15Ibf inch squared). This valve opens when the filter is clogged, or when the oil is cold (I stand corrected Toomanytoys) to avoid starvation of the bearings.

I'm not entirely sure if this helps any but a few things are answered as in:

Will the smaller filter be adequate: I think we can say yes as long as it is changed regularly
Will fitting the small filter be safe: again yes, it has a lot of filter paper in it so should cope but if it gets to a point where it can't cope with the flow the by-pass valve will open safe gaurding your bearings.
Will fitting a Type 4 filter be better: well now there is the debate, yes it's bigger so is less likely to clog but it hasn't got a by-pass valve so if it does get clogged or the pressure drop across the filter is too high (we now know this can happen when cold) there is a chance the crank bearings may be temporarily starved of oil.
Next question then: was the type 4 lubrication system the by-pass type (where only a proportion of the oil was fed through the oil filter at any one time?) I know historically many filters fitted to early vehicles did not have a by-pass valve incorporated into them and i also know that the trend in engine design has generally gone from By-Pass type to Full Flow type filtration as this is considered to offer a better solution.
Martin

[toomanytoys]

Yeah, for me the cold start issue is the key factor...
I wouldnt think that the bearings would be starved of oil as pressure will be at its highest.. what concerns me slightly is the differential pressure accross the filter media... where you have the bypass valve.. it opens at 1 bar... allowing the filter media to only "see" 1 bar differential... without the valve... the filter media sees "X bar" (2,3,4,????) but as the type 4 doesnt have a "bypass system" for the filter (I am pretty sure) then the filter should have been designed to cope with this...

Of course... you could send the system back and fit a standard type....

[Red Westie]

I don't think I'd be loosing to much sleep over this, I believe there are several companies producing aftermarket systems where a smaller oil filter is needed and this has been going on for several years now without any real reports of problems. I guess the customers should be making a point of 'expressing their concerns' and if enough do this and even walk away from the purchase having made their concerns heard these manufactures will be forced to make changes to the design.
Martin