Bearing shells.

[Tubal Cain]

Hi,

Brian's article and photos covering the stripdown of Henrietta's engine prompt me to raise this query.

Having stripped a couple of Dexta engines, I was surprised to find that the white metal lining on all the bearing surfaces had dissapeared, but was still evident in the oil grooves and that the journals etc. had been running on the copper backing! In each case the journals, crankpins and thrust faces were in good order and still within tolerance, and there was no indication that the white metal had run.

As I have never experienced this before I wonder if anyone else has come across this, and if so what conclusions have you come to as to the likely cause?

Or considering the age of our tractors can it be put down to normal wear and tear.

Gerald

[Aussie Frank]

Hi Gerald,

When I stripped down my P6 TA engine from my E27N that was how the bearings were as well, but that was how the bearings were made. I checked them and they were not out of tolerance. I still had to get the crank reground because one of the journals had some rust on it and when I got the new bearings I think the big end bearings had white metal surfaces and the mains had copper, or it could have been the other way around I can't remember now. Does anybody else know why copper was used instead of white metal?

Regards, Frank.

[Brian]

That was a pretty normal experience on many engines that I stripped, Major, Perkins, BMC or Dexta. The white metal on the shells was never a thick coating on the copper, more like a spray coat. The bearings on all Rootes and Ford cars were normally a much thicker layer.

[Aussie Frank]

Hi Brian,

For a while I thought I was going mad but now I am sure that the main bearings that were supplied for my P6 were in fact copper on the bearing surfaces just like the ones that were in the engine. I found an eBay auction that shows them clearly. http://cgi.ebay.com.au/Perkins-P6-Main- ... dZViewItem Is it possible that some early Dextas had these bearings fitted too?

Regards, Frank.

[Tubal Cain]

Hi Frank,

I know that the advert claims that they are new bearings, however the photo suggests that there is white metal in the oil grooves and where the horns are washed away. One would therefore expect to find white metal on the bearing surfaces.

Quite a puzzle.

Gerald

[Brian]

Frank,
Like Gerald, I would view those with a little suspicion. They would usually come in a greased package all joined together. They might have been cleaned heavily.

[Mike Kuscher]

Brian, Frank, Gerald,

Something has been 'nagging' at me for the past few days regarding these bearings.

A35 van, A30 car (the Austin rollover) and Reliant Regal (Yes, I had a 'plastic pig' for 12 months) and others. When I put in new big ends and mains I tended to buy Glacier bearings. These, as we all know, have a copper base coat with the 'white metal' deposited onto that, just like chroming.

What's nagging at me though is I had a MK1 1200 Cortina for some years, the 'notorious' 3 bearing crank. When it finally started to give more smoke out of the breather pipe than the exhaust I did an engine rebuild. Reboring and regrind was carried out by a little place called Townsends, in Selly Oak, Birmingham. I'm sure that I was supplied with Vanderville big ends and mains for that and I seem to recall they had introduced a 'new' bearing supposedly designed to reduce the 'running in' time required.
I think they were called 'easy bed' or something like that and the 'novel' idea was that they were composed of the copper 'base coat', the 'white metal' bearing surface and a very thin further deposition of soft copper, on top of the 'white metal' to supposedly ease 'bedding in'.

I'm sure that I'm not 'going round the twist'. Does that make sense to you or is my memory starting to play tricks?

Mike