23 replies to this topic

[mattyglover16]

Hi, I'm after a oil pump for my 1293cc build does anybody recommend any particular ones or just to purchase one off mini spares ?

 

Thanks

[Spider]

The Steel Backed ones are very good and if the funds will stretch, an 'EVO' type, though they are not always available in all drive types.

[mattyglover16]

Okay thanks for your reply, I'm guessing I won't know what drive type it is until I take it off

[AndyR]

The most important is the tolerances of the pump, to ensure efficient flow.  As mentioned the steel backed pumps will be fine, but i would suggest measuring them up to make sure it is what it should be.  I have had an EVO type from minispares, and they are nice, however even they were slightly out of tolerance, but nothing that couldnt be easily fixed.  If you are going to get very technical you may need a few steel backed pumps to mix and match components to get the perfect tolerances.

 

Andy

[Spider]

I have to say that I've fitted well over 30 steel backed pumps over the past few years, never had an issue with any of them right out of the box. I can't say I've ever bothered to get in there with a feeler gauge and check the tolerances etc, but I do take them apart for cleaning (though they have all been good) and a 'feel' after reassembly. I then squirt a bit of oil in to them and make sure they pump and feel right. Later in the engine build, just before the gearbox goes on, I turn them over basically by hand and make sure that the pump (and everything else) will make Oil Pressure, usually don't see more than about 5 PSI, but that's enough to tell me it's looking right so far,,,,,,,

[AndyR]

I would get your feeler gauge and micrometers out MokeSpider!  Just because it looks right and comes in a box, doesnt mean it is.  Like i said, i bought an EVO pump which is supposed to be perfect and within tolerance - but it wasnt.  Of course all pumps will "work" out the box, but they could all be better!

[peter-b]

I tend to agree with spider. Sure you can check and 'adjust' them about but why? They pump oil.

[mini13]

somthing that has come to light in recent months is that there have been a lot of pumps on the market that have an issue with gasket support between the oil pump inlet&outlet holes, and the cam bearing hole.

 

I belive Minispares have pulled any problem pumps from sale, but no idea about other sellers, so do check anything just to be sure!

 

 

Below is a thread from another forum about it.

 

http://www.turbomini...tid=581351&fr=0

[Spider]

I would get your feeler gauge and micrometers out MokeSpider!  Just because it looks right and comes in a box, doesnt mean it is.  Like i said, i bought an EVO pump which is supposed to be perfect and within tolerance - but it wasnt.  Of course all pumps will "work" out the box, but they could all be better!

 

I agree with you that because it comes in a Box it doesn't remotely mean it's right!  In fact, in my view, it's an untested part and therefore, in general, I tend to treat them with a higher level of 'suspicion' than a used (and therefore 'tested') part. I also don't doubt you in the slightest that any out of the box are - strictly speaking - out of spec. I would never open the box and fit one without checking it first, while not what I would blanket recommend, I go by feel, but only because I would say I know what I am feeling for, but I wouldn't bother getting carried away. I've fitted used and somewhat worn pumps on occasion with no adverse effects..

 

I'll add too, that any excess oil flow is mearly dumped to the sump via the relief valve in any case, so going to the world's end to ensure that the pump is at it's dead set peak operating capacity when fitted IMO, isn't warranted. Apart from dumping excess capacity to the sump, it also only heats the oil. Keep in mind too that all Oil going through the Pump, while strained, is not filtered, so the fine clearances that you may try to achieve are very quickly lost after some of the baulk ring material (from the gearbox, you know, all that fury stuff that ends up on the Sump Plug Magnet) goes through the pump a few times.

 

Just to add some controversy to the whole issue of Oil Pressure, with respect, it is largely misunderstood. To some degree, measuring pressure is relevant and again, to a degree does hold some importance, however, what far outweighs the running any Pressure is the Flow Volume and Rate, however it is considerably more difficult and much more expensive to measure this, so the makers take an easy and cheap way out by measuring the pressure. Theory being, if there's pressure, then there's flow, however, we can also have flow without pressure (or very little).

 

If I remember tomorrow (our time), I'll post up some Polar Load Plots I have of a 998 Cooper Engine, they are VERY revealing and telling. What they do show is that the pressure developed on the Big End Bearing at full noise is a whisker under 5000 PSI (from memory) and yet we are trying to pump Oil in that at what 78 PSI at best - which do you think at a wild guess would win out?   The Bearing Lubrication works not because of any pressure what so ever that we are pumping the Oil in to the Bearing, but where exactly we are Pumping it in, nothing more, nothing less.

 

Until I got my head around this, I used to run a Oil Pressure Gauge and worry about what it was reading, these days, I only run a light and a buzzer. What the actual pressure is I couldn't care less and is almost meaningless, as long as it's flowing, that's all I do care about!

 

I have built a few engines where I thinned the pump to half their thickness and cut some coils off the relief valve to reduce the running pressure to 28 PSI and when idling, the Oil Light would in fact come on. None of these suffered in any way from reduced pressure, but they did go noticeably better and got way better fuel consumption.

Edited by Moke Spider, 04 September 2015 - 09:09 AM.

[Vipernoir]

There is also an issue with the drive spade on A+ pumps being a smidge too long and locking the cam solid.

[mini13]

good insight there by Spider,

 

 

too an extent high pressures are actually undesirable, as we know preasure = heat... not sure how much compressing the oil 50 or so psi heats it up, it would be interesting to have a figure.

 

on the subject of heat, its no good having tight clearances, and thick oil, this = low flow, so the oil cant take the heat away from the bearing, etc,

 

the main reason I always run a pressure guauge is, its a good indication of if somthing has changed,

 

in terms of oil pressure, i like so see 15-20 psi hot at idle, and 45-50 psi by about 3k, pretty much what you would see from a factory engine. another point, Turbo's really dont like high PSI, it'll push oil past the seals and cause smoke.

[Spider]

the main reason I always run a pressure guauge is, its a good indication of if somthing has changed,

 

 

 

Yes, Gauges are excellent for that.

[nicklouse]

 

 

I belive Minispares have pulled any problem pumps from sale, but no idea about other sellers, so do check anything just to be sure!

 

 

Below is a thread from another forum about it.

 

http://www.turbomini...tid=581351&fr=0

interesting read.

 

but no info from MiniSpares?

[AndyR]

Indeed, all good points.  I have a turbo pump that is very well scoured (i did not fit it myself) so am sympathetic to that idea of too tight tolerances.  I simply check and double check to improve initial uptake and effective flow - its a matter of my engineering pride to make sure i am happy with each component before fitting it.

 

Andy

[jaydee]

All this talk about optimizing the pump lately but the secret is in the oil galleries.

You need flow, and the obstructions in the flow can be clearly seen and fixed in a couple of galleries.