WBX "improved" cams in the pipeline

[silverbullet]

10c has told us what is needed and what works, I defer to his far greater experience!
I have a couple of O-ring modded new 30mm pumps which probably won't be needed now.
There is of course more than one way to skin a cat...

[silverbullet]

Oops! Realized that I may have caused confusion by referring to a non-specific Chris...

CJH that seems to be the pump to which our esteemed colleague from Alberqerque is referring. 3-bolt, pre 1970. Probably also available from other sources.

Re: water pipe clearance, I would invest in a stainless set and give them a gentle squeeze in a vice to make them clear the oil pump and front pulley. The painted ones flake and rust too easily.

PS I might well make an experimental shim plate, just too see what results.

[CJH]

Oops! Realized that I may have caused confusion by referring to a non-specific Chris...

Haha - don't worry, I was under no illusions that your question was aimed at me! I worked out who the other Chris must be.

Is it the water pipe that fouls the cover plate then? I understood it was the cradle that requires the cover plate to be clearanced a fraction.

[silverbullet]

Just being polite to all parties...

The cradles can get close with the 30mm pump from what I have seen, some foul and some clear but its as one with the engine so if it fits, then it fits.

The water pipe already has a crude dent or two as per OEM but this is modified engine terrritory so anything goes. The coolant will get across there no problem.

[tencentlife]

PM sent, Ian.

[silverbullet]

This is the one to use afaics. Backroom conversations conclude that the 30mm pump will almost certainly cause more problems than it will claim to fix

https://www.vwheritage.com/shop/AC11514 ... src=slider" onclick="window.open(this.href);return false;

Note: Fitting a well-designed oil cooler is compulsory, you'd be mad to argue otherwise.

[tencentlife]

Yes, that is the type of pump you need to use with the 3-bolt cams. There's a couple cheaper versions, which are probably just as good, like this (where they even mention the aftermarket cams being all 3-bolt):

https://www.vwheritage.com/shop/karmann ... StartRow=1#" onclick="window.open(this.href);return false;

People latch onto brand names, and without hands-on experience with alternatives that's wise enough, but an oil pump like this isn't any kind of precision-machined piece, it's very simple, easy to machine accurately, and Schadek isn't any better than most lower-priced alternatives, sometimes not even as good. When everyone on the interwebs says a certain brand is "the only one to use", you have to remember that literally 99% of them are simply parroting and have never had the thing in hand and wouldn't know how to make a credible comparison if they did. This also goes for the China-bashing crowd, in that case it's 100% parroting because, although I have no love of China (I've been there), they produce everything from the best to the worst of whatever item it is you're looking for. If you'll be buying the same thing repeatedly (Ian), it's worth getting the cheaper alternatives in hand to see if they measure up, they usually do in the case of oil pumps since there's so little to them.

Details that vary are the inlet/outlet hole size, so you want to make sure they are as large as the galley holes they need to match up with. The wear area in the pump body is the upper bore for the driven gear shaft, so the longer that bored bearing area is, the better. Excluding scoring caused by debris sucked up from the sump, wear of the upper gear housing will only occur with wear in the shaft bearing bore; you will almost never see appreciable wear of the lower gear and pin. I use a cheap pump made in India, $20 each, the machining is just as accurate as Schadek's, but its casting has a longer nose for the shaft bore, so a considerably longer bearing area for the driven gear shaft, and that by itself makes it preferable to a Schadek, besides costing much less.

You're going to blueprint any pump you use anyway, that's a must. Apart from optional mods like o-ring grooves, there isn't a lot to do to an oil pump. Blueprinting includes:
checking that the gears mesh and run true without binding
no excessive clearance within their housings (using feeler gauge not more than .003" radial clearance betw. tooth and housing bore)
the driven gear shaft is a good fit in its bearing bore (no palpable sideplay)
the pump body face and the cover are both flat
and correcting either gear length or the body face so that the gear endplay with the cover fitted is .002-.003".

Where I always see people getting into trouble is believing that there must be a gasket between pump and cover, so they may have a pump with .003" gear endplay when they check with a straightedge or the plain cover, then they put the thin paper gasket in, which is actually .004" thick, ending up with .007" effective gear endplay, and watch their oil pressure go south as soon as the oil gets to temp. Some of the gasket sets have cover gaskets that are over .012" thick (OMG!!), to use that the gears would have to be .009" proud of the housing! Obviously you would not use such a gasket. Whether you use a gasket or not depends on what the effective endplay will be when assembled, use your brain to come up with the right combination.

Too much endplay or too much free radial clearance between gear teeth and housing results in excessive "slip", or oil escaping back thru those clearances from the pressure side to the suction side. Since oil viscosity falls with higher temperature, the rate of slip increases with heat and this can radically reduce pump efficiency. You can't do anything about tooth-to-housing clearance, that's fixed in the sizing of the gears and boring of the gear housings, but you can fix the gear endplay to control slip between the gear ends and the cover, which is where almost half of slip occurs.

If you look it up, a spur-gear pump like this is classed as a positive-displacement pump, but I say any pump that depends on the viscosity of the fluid it is handling to effect a seal between moving elements, and that thereby loses pumping efficiency when the fluid viscosity decreases, is not positive-displacement. I deal with a lot of pumps, not just engine components, and in my book to be positive displacement, a pump has to move the same volume of fluid on every cycle, regardless of fluid viscosity; that leaves only piston and diaphragm pumps as positive displacement. Why am I going on about this? Because it helps to understand pump dynamics and the role of slip in a non-PD pump so you can do things to minimise it in order to retain pump efficiency when the oil gets hot.

[CJH]

That's a very useful post, thank you Chris (I'm assuming you're the other Chris that Ian was referring to).

Backroom conversations conclude that the 30mm pump will almost certainly cause more problems than it will claim to fix

Note: Fitting a well-designed oil cooler is compulsory, you'd be mad to argue otherwise.

What's the issue with the 30mm pumps? I am indeed planning to fit an oil cooler when the 2.1 goes in, but since my '83 van has the early cooling system without the pipework for the stock 2.1 cooler/warmer I'm going for a Mocal sandwich plate and the oil cooler below. So it'll have long pipes. Somebody advised me to fit a heavy duty oil pump to cope with this, so what are the reasons not to do this? Is the standard pump size going to cope?

[silverbullet]

I will paraphrase what I was told and what I already know to be true:
In breif, you can have too much of a good thing. A bigger "displacement" pump is trying to push a greater volume of oil through the same journal clearances, so the oil will heat up faster and you can guess the rest. The oil degrades faster, viscosity falls and it costs you hp in the process.
If you had additional outlets for the oil i.e. piston crown cooling jets coming out of the main bearing housings in a turbo engine, then the 30mm has some practical application.
Add in all the clearance issues when using a 3-bolt cam in a wbx, then consider that an oil cooler and 26mm pump is proven to be more than adequate on what is a low-geared/high revving engine in a T3.
Why fit a bigger pump?
I have already ordered a couple of the pre-70 26mm units to get things moving here.

[CJH]

Thanks Ian. But what about if I have an additional 8m of hydraulic hose and a bigger cooler to pass the oil round. I don't think the original pump was intended to do that. Isn't there a benefit in having a bigger pump in this case?

[silverbullet]

Not really. Any given pump will still move the same volume of oil at the same rate before it gets to the bearings, the restriction of which gives the engine oil gauge pressure.
Your oil will be cooler and a bit thicker but there wont be any more of it.
An oversize pump just means hotter oil going to the cooler because it has bee overworked. A front mounted cooler means more oil to get up to working temperature and it takes longer to cool down once overheated.
I am going to build mine with a rear mounted cooler, remote filter head and automatic fan; its lighter and cheaper!
Baz did a similar cooler in his syncro if you want to search it out.

PS I recommend the works of A.Graham Bell as further reading.

[silverbullet]

To put it another way: the first engine I built from scratch was a +040 overbored 1500TC Triumph, complete with fast road cam and big valve fully ported head, all balanced etc plus a high volume oil pump and stronger oil pressure releif valve spring, but no cooler.
The result was an engine that overheated its oil within minutes and had 90psi oil pressure when cold. If it was a chilly day then it could blow the sealing ring out of the oil filter!
Too much of a good thing.

[silverbullet]

For the sake of completeness (but not necessarily recommended or endorsed) I had a little play around with some dead wbx oil pumps, just to finish the thought as it were.
The OEM pumps seem to all measure around 70.05mm diameter for a nominal 70mm bore in the case. The Schadek pumps are more like 69.95, which isnt a huge undersize but the difference between needing a puller/loosening the case halves and simply drawing out by hand, hence the need to O -ring them when blueprinting.
So it would kind of make sense to use genuine new wbx pumps over aftermarket, but its really 50:50 for cost vs. effort, or facilities vs. simplicity.
I bandsawed the flange off one and faced it off to make a spacer, which basically turned a wbx oil pump into a pre-70 one that would be compatible with an aftermarket cam, as previously discussed:

(The hacked about one is on the right, it just about cleared the 3-bolt but its really not worth the effort)

Not sure what it proves, other than anything is possible with a little time and thought?

[CJH]

Not sure what it proves, other than anything is possible with a little time and thought?

....and a well stocked machine shop

Ian - I take on board your earlier comments about a bigger pump, but I'm still in two minds. I don't currently have the left side of my engine case in my possession, so I can't see what route the pumped oil takes, and I can't find a diagram.

If the first place the oil goes after the pump is the filter, then because my sandwich plate is fed from there then it means my extra oil cooler would be the first thing in the circuit. What I can't decide is whether the pressure before (on entry into) all that extra pipework will be the same as the pressure after it. Given that the pipework and the matrix will offer some resistance I would have thought the pressure on return to the engine must be reduced a bit, but hydraulics was never my best subject.

So on that basis I'm still inclined to fit a 30mm pump.

Does that make sense?

[silverbullet]

Without getting into Navier-Stokes equations (HarryMann required, I am not qualified) the matter at hand is that a bigger pump will do more "work" on the oil, so the temp will go up more than with a smaller one.
Doing work requires energy so an oversized pump is basically costing you fuel just to dump the extra heat generated via the cooler.
A sandwich plate diverts the oil immediately from the pump discharge out to the cooler and then returns to be filtered before feeding the bearings, a thermostatic one diverts straight to the filter when cold, as if there were no cooler fitted.
(This is also why you never re-use a cooler after a blow up or fit a used one: they handle unfiltered oil and are impossible to clean out. Fact.)