Uprated Oil Pump Spring

[driversdomainuk 8]

Hi

 

As part of my rebuild I am considering getting an Uprated Oil Pump Spring from WMMS. Has anyone used this and would it be recommended to also fit a new Oil Pump in the process.

 

Are there any significant benefits of having this uprated spring for motorsport use?

[Guest ashnicholls]

No point having a new oil pump unless yours is nackered,

 

these people only just give u an old one thy have cleaned up.

 

I have fitted the spring in mine, not knowing what it is doing, but I cant see it hindering the engine.

 

All you need to do is clean your pump up while its apart, and fit the spring.

[saveloy 8]

I never see this as a good idea in a road engine. It only increases pump pressure in a linear fashion. Pressure at idle will be too high and it will also be too high at low rpm.

That in itself will increase the oil temp, and excessive pressure at idle (especially at cold start) will mean less lubrication and more wear.

It's high capacity you want, not high pressure.

[petert 554]

That uprated spring is the same as they use in the XU10 engines anyhow.

[Guest ashnicholls]

I never see this as a good idea in a road engine. It only increases pump pressure in a linear fashion. Pressure at idle will be too high and it will also be too high at low rpm.

That in itself will increase the oil temp, and excessive pressure at idle (especially at cold start) will mean less lubrication and more wear.

It's high capacity you want, not high pressure.

 

If that is the case, then what is the point?

 

Why would Pug Sport make it?????

[petert 554]

Why would Pug Sport make it?????

 

Because ideally you need 10 psi per 1000 rpm.

[saveloy 8]

The spring is available because it's intended for race/rally use, i.e: high revving engines that will be re-built more frequently than road engines.

[JeffR 51]

The modified oil pump spring was one of several changes PSA made in addressing the XU9 oil control issues.

 

As petert mentioned, the XU10 production engines had these fitted along with a windage tray, pump sprocket cover & baffled sump.

 

Personal experience with my GTi6 doing 2 years of track days on Advan rubber shows these changes were successful.

[Guest ashnicholls]

So, what we saying, good or bad mod on a 8v??????

[SPGTi 2]

The spring is available because it's intended for race/rally use, i.e: high revving engines that will be re-built more frequently than road engines.

 

 

Just to add DDUK only uses his car for sprinting so in effect it is a "race" engine.

 

Steve

[JeffR 51]

So, what we saying, good or bad mod on a 8v??????

 

 

I can't think of a reason to run the spring in the 8v engine.

 

The XU10 head (at least J4RS-16v) is divided into seperate zones -inlet & exhaust longditudinally. I think this was part-answer to too much oil being retained in a head with its' smaller volume compared to the XU9. Any condition presented gravitationally on these engines (think-extreme corner G-forces of fast left-handers on track days) presented no problem.

 

I think 8v engines would be no worse off by running the upgraded oil pump spring but I believe this is a 16v issue with oil starvation.

Edited September 28, 2006 by JeffR

[Guest ashnicholls]

So its ok in the 8v???????

 

As a road car?????

 

Dont tell me, I have to take my engine to pieces again, to get it out??????????????

[saveloy 8]

So its ok in the 8v???????

 

As a road car?????

 

Dont tell me, I have to take my engine to pieces again, to get it out??????????????

 

Your rev limit isn't high. And it's about the same as the standard car.

So, you have no need for any extra pressure. Personally I would remove it.

I have a 205 TT and even with the extra oil feed to the turbo, I don't have any issues with pressure or capacity.

[petert 554]

I think it's more important to fit the XU10J4 26T sprocket and chain, so you get more flow.

[Guest ashnicholls]

I dont get how high pressure causes less lubrication??????

 

If its standard in the XU10 whats the problem,

 

I have an XU10 head?

[saveloy 8]

The head won't be the issue. But the crank and shells will be.

Although an increase in pressure will reap an increase in flow, it is by no means linear in it's effect. In other words, you need a large increase in pressure to reap a small increase in flow.

Your increase in pressure would be fine at high revs, say 7K plus. But too much pressure, especially at idle and low revs, will mean that you won't be able to keep it in the right place.

The bearings may spit it out where it is easiest, rather than pass it through as intended, limiting lubrication.

You may also find excessive oil on the cylinder walls, which the rings will struggle to contain. This will result in higher than normal oil consumption and other possible problems in the combustion chamber, i.e: over heating.

[Guest ashnicholls]

Serious???????????

 

Why has this not being mentioned before.

 

I know lots of people that have used it with no problems?????

 

Would it increase breather pressure???????

[Guest ashnicholls]

Anyone else agree with saveloy.

 

Does it need to come out??????????

[saveloy 8]

I tell you what. Why don't you get it to a garage and have them check the pressure at 1000 rpm intervals.

With engine oil warmed, as long as you aren't seeing in figures that are much higher than the standard specified numbers, then you should be fine.

The standard figures are something like: 2 bar at idle and 5 bar at 4500 rpm.

[nick 3]

How does it affect the pressure at idle?

 

I always thought that the spring mechanism was basically a bleed valve, with the higher rate spring allowing a higher maximum oil pressure before it bleeds pressure off.

 

Nick

[C_W 3 1 Cars]

Yea the idle pressure isn't altered as the pump isn't pumping fast enough to affect the relief valve even with the softer spring fitted anyway.

 

The stiffer spring just increases the point/revs (depending on oil temperature/thickess) at which the relief valve opens.

[saveloy 8]

Fair point. Although, talking to Special Tuning many moons ago, they did tell me there would be an increase in pressure from low down in the rev range.

[JeffR 51]

I've fitted this system to my 1.9 Mi engine.

 

XU10 spring, 26 tooth crank sprocket & longer chain, and a mechanical oil pressure gauge.

 

On start-up:100 psi

Engine warm at 3000rpm: 68 psi

" " at idle:22 psi

 

The GTi6 & Raylle site gives similar figures.

[Guest ashnicholls]

I was running fully synthetic 5-40. With the uprated oil pump spring.

 

And the oil pressure warning light would come on at bout 800rpm, with low oil pressure. Was not so bad when cold, but definately had low oil pressure when it got warm.