The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Signboy on 13.03. 2016 15:49

Title: oil pump problem
Post by: Signboy on 13.03. 2016 15:49

Guys, HELP !
just fitted my new refurbished oil pump today and started her up to find oil cascading from BEHIND the oil pump, is this normal and the oil is somehow scavenged back into the engine or has a seal blown somewhere ????
Its not just spitting but its as if someone is pouring it over the top of the pump
thank you
Signboy

Title: Re: oil pump problem
Post by: Greybeard on 13.03. 2016 16:06

Are you saying that you are running the engine with the timing cover off?

Title: Re: oil pump problem
Post by: Signboy on 13.03. 2016 16:18

yes, thats why im unsure if its ok or not, never noticed this before !

Title: Re: oil pump problem
Post by: Greybeard on 13.03. 2016 16:35

I await other opinions but I feel that the timing chest is unlikely to be oil-tight

Title: Re: oil pump problem
Post by: Billybream on 13.03. 2016 17:03

Have you checked the pump sealing face for damage, needs to be clean and flat, and ensure you use a gasket, together with fibre seal on one of the mounting studs. I personally would not run without outer timing cover fitted.

Title: Re: oil pump problem
Post by: chaterlea25 on 13.03. 2016 17:06

Hi,
Is the oil coming from between the pump and crankcase or from the main bearing/bush?
Have you checked for up and down play on the end of the crank?
Why was it necessary to refurb the pump?

John

Title: Re: oil pump problem
Post by: Signboy on 13.03. 2016 17:12

pump had seized but now sorted.. face is flat and has new gaskets and fibre washer    oil is coming over the top of the pump from behind, just asking if this is normal as you wont notice this once the cover is replaced !

Title: Re: oil pump problem
Post by: bsa-bill on 13.03. 2016 19:14

Quote

fibre washer

?

is this the washer that came with the rest of the gasket for the pump, just thinking that as far as I can remember this is more of a paper washer, little bit thicker than the pump gasket but not by much, could be stopping the pump sitting level to the crankcase face

Title: Re: oil pump problem
Post by: KiwiGF on 13.03. 2016 19:20

Any chance of a video? It almost sounds like oil has filled the crank cases, which would mean the oil is not being returned to the tank, is that possible?

You probably know this but oil is scavenged from one place only, the return pipe situated in the sump plate, all oil pumped into and around the engine has to drain back to that pipe, that pipe returns the oil to the tank, albeit some is "diverted" to the rocker box.

The bottom of the timing chest is always (unless the timing cover is off  *smile* *pull hair out* ) filled with oil up to the level of the drain hole in the inner case, which is above the bottom of the plain bearing bush, so it actually runs in oil even when the oil pump is not pumping.

Title: Re: oil pump problem
Post by: Signboy on 13.03. 2016 19:53

ahh so, thats what im probably seeing,( the oil starting to fill the timing chest ! *smile*)   the oil seems to have good pressure and is returning to the oil tank and rockers    so its ok to just button it up then ?????
i need to understand these a7s as the bike in question is a 1962 model, i liked it so much ive just bought a 1953 a7 star twin plunger!!!

Title: Re: oil pump problem
Post by: kiwipom on 13.03. 2016 20:20

hi guys, yes the oil is coming from the main bearing bush and fills to submerge most of the oil pump before exiting into the crank case where it is scavenged and pumped back to the oil tank,cheers

Title: Re: oil pump problem
Post by: kiwipom on 13.03. 2016 20:30

hi signboy, i posted some experimental pics in 'Wet Sumping`topic awhile ago here's one of them, cheers

Title: Re: oil pump problem
Post by: Signboy on 13.03. 2016 20:44

Thanks kiwipom, just the news i wanted to hear !   and thanks to all the knowledgable members on this forum for your imput *smile*