Tandem oil pump

[timbo]

Hi everyone, my tandem pump has started to leak due to corrosion of the cover, just wondering if anyone has come up with a solution other than buying a new pump. Thanks.

 

Edited November 15, 2016 by timbo

[Captain Lockheed]

Tim,

 

There are companies that supply just a cover in stainless, but there have been issues with stainless galling. There was a company doing plastic covers but they went quiet. Where about's on Dorset? I am in Bristol.

[timbo]

Captain, I'm in North Dorset near Blandford. Ninemeister used to do the stainless ones but have ceased production, I have found a company who do a billet aluminum one but are out of stock. NB its a replacement for the original cover I'm after, not a protective cover.Seems ridiculous that you need to buy a whole new pump just for a mild steel cover. What is stainless galling?

[Captain Lockheed]

The stainless covers galled (wear between sliding surfaces) and wore away. Which is why ninemeister stopped I believe.

Have you spoken to Brauntons?

There was a company doing a replacement not protective cover, in plastic, can't remember the details though, who does the ally one?

Edited November 16, 2016 by Captain Lockheed
Spelling

[Captain Lockheed]

Alternative car parts????

This rings a bell.

[timbo]

On 16/11/2016 at 7:11 PM, Captain Lockheed said:

The stainless covers galled (wear between sliding surfaces) and wore away. Which is why ninemeister stopped I believe.

Have you spoken to Brauntons?

There was a company doing a replacement not protective cover, in plastic, can't remember the details though, who does the ally one?

 

Interesting, what parts slide with the cover,, or didn't they manufacture them properly? they told me it was because people weren't fitting them correctly, difficult to see how that is possible. Yes ACP manufacture a billet aluminium one, my name is on the list for when the next batch come in. I heard that the plastic one were too expensive to manufacture due to the type of plastic required. I'll search Brauntons, thanks.

[Captain Lockheed]

http://www.brauntonengineering.co.uk

 

[timbo]

2 hours ago, Captain Lockheed said:

http://www.brauntonengineering.co.uk

 

Hi, thanks, but it looks like they replace the whole pump.

 

[Captain Lockheed]

14 hours ago, timbo said:

 

Interesting, what parts slide with the cover,, or didn't they manufacture them properly? they told me it was because people weren't fitting them correctly, difficult to see how that is possible. Yes ACP manufacture a billet aluminium one, my name is on the list for when the next batch come in. I heard that the plastic one were too expensive to manufacture due to the type of plastic required. I'll search Brauntons, thanks.

The pumps rotating vanes are under the cover.

The pump is a combined oil scavenge and vacuum pump, it needs tight tolerances between the rotating vanes and the cover and the shape (elliptical) to do the job, the trouble is if you go for a different material to combat one issue - corrosion, then you may have to deal with others, in the case of SS in this application galling.

They probably manufactured them as a replica of the existing cover, to a high tolerance.

Fitting, I don't know.

The engineering is all about compromise. It will be interesting to see how the ally cover fairs as it will need redesign because of the different material properties. They will probably keep the same design in Ally and hard anodise, it will be interesting to see how the design copes with the differing thermal expansion of the ally cover and the rest of the pump.

Sent you a PM

[Captain Lockheed]

Aluminium is prone to galling too, hence me thinking that they will probably hard anodise.

 

[timbo]

http://alternativecarparts.co.uk/shop/997-porsche/porsche-997-turbo-aircraft-grade-aluminium-replacement-pump-cover/

 

what do you think ! opinions gratefully appreciated.

[Captain Lockheed]

I think ACP are doing a great job of developing some useful bits. 

Aluminium is prone to galling in similar applications, they say that it is aircraft grade but don't give the actual grade which is a 4 digit code, eg 6061 is great for aircraft structures but too soft for this application.

They say - Special hardening process and then coloured, this could be hard anodising.

Without further details, eg grade and hardening process, evidence of testing etc; it's difficult to comment.

 

Did you look at the link that I PM'd to you?

[timbo]

Yes thanks, I pm'd you back, not sure about the suffix, some seem to be 01, others 02 and others 04, does it mean they are different batches of production or modified versions.

[Captain Lockheed]

2 hours ago, timbo said:

Yes thanks, I pm'd you back, not sure about the suffix, some seem to be 01, others 02 and others 04, does it mean they are different batches of production or modified versions.

01, 02 are earlier versions 04 is the latest version, Loren has already covered this, see below,