Author Topic: Oil pump assembly.  (Read 184 times)

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Seipgam

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on: December 24, 2019, 03:56:49 am
I'm sure I read somewhere that the oil pump can be assembled the wrong way around, is this correct?
If so what would happen? - I suspect a fair bit of smoking like it has wet sumped as the scavange pump would then have less volume than the feed pump. 
I haven't inspected mine yet but I ask because I seem to be getting excessive smoking after replacing the quill seal. 
Yes I have oil feed to the rockers and everywhere else, and yes the new seal is intact, in one piece and a firm fit in the crank.
The old quill seal was a loose fit in the crank end and had fairly large cracks through it which could (I presume) leach oil back through it.
All this is theory of course.
Any thoughts on the pump assembly though, and what do I need to see to confirm it is assembled correctly?

Merry Christmas, Geoff.
« Last Edit: December 24, 2019, 04:00:20 am by Seipgam »
1954 Francis Barnett, Kestrel 66 122cc
1984 Yamaha SRX250
1995 Royal Enfield Bullet 500


ace.cafe

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Reply #1 on: December 24, 2019, 01:01:56 pm
I'm sure I read somewhere that the oil pump can be assembled the wrong way around, is this correct?
If so what would happen? - I suspect a fair bit of smoking like it has wet sumped as the scavange pump would then have less volume than the feed pump. 
I haven't inspected mine yet but I ask because I seem to be getting excessive smoking after replacing the quill seal. 
Yes I have oil feed to the rockers and everywhere else, and yes the new seal is intact, in one piece and a firm fit in the crank.
The old quill seal was a loose fit in the crank end and had fairly large cracks through it which could (I presume) leach oil back through it.
All this is theory of course.
Any thoughts on the pump assembly though, and what do I need to see to confirm it is assembled correctly?

Merry Christmas, Geoff.
If the oil pumps were installed with feed at front and scavenge at rear, yes it would have wet sump issues.
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Adrian II

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Reply #2 on: December 24, 2019, 08:37:59 pm
The pump with the bigger diameter plunger/piston goes at the front. Easy. The scavenge pump should always have a greater volume than the feed pump, as you know.

Yes, a failed oil seal behind the timing pinion will allow oil from the timing chest to seep past the crank into the bottom of the crankcase, which is when wet sumping occurs, and this can happen even with the pumps fitted correctly.

Does the new seal (30 x 20 x 7mm) sit properly over the relevant section of the timing side crankshaft? If not try fitting a narrower seal (30 x 20 x 5mm) so that the working edge of the seal sits in a bit further. Make sure that the sprung side of the seal is facing OUTWARDS when you fit it.

A.
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Seipgam

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Reply #3 on: January 10, 2020, 02:29:37 am
Just an update on this.

Adrian, I haven't replaced the rubber pinion seal you mention, only the cork quill seal.

The oils pumps were assembled correctly and the smoking seems to have settled down with a bit longer running.  Probably ended up with more oil in the crank case than usual during the oil change and quill replacement.

If I have need to take the timing cover off I will probably replace the pinion seal while I'm in there.

Geoff.
1954 Francis Barnett, Kestrel 66 122cc
1984 Yamaha SRX250
1995 Royal Enfield Bullet 500