[Diy_efi] [ot] Oil pressure during cranking ?

[Ernest Buckler]

Top reply;
You really need to make sure the oil pump is being driven - some old 
American V-8s had the pump driven by the distributor shaft, was possible to 
NOT index the shaft in the slot, thus have no oil pump.

Basic rule is to find an oil passage somewhere and visibly check that oil is 
coming out of, say, a cam oiler, or wherever, BEFORE firing the engine. 
ALWAYS!!!    No plugs, fresh battery, several 20-30 second crankings, I'd 
say yes, you should be seeing oil throughout the engine, regardless of the 
actual psi reading.   If still no oil, you may have a big internal leak 
somewhere, pump pickup plugged or loose, no drive, maybe a shear-pin failed 
or bolt slipped?? maybe a seal out of place? that's preventing oil from 
getting to the top end OR building up any pressure.

Just my thoughts on the subject.  You are absolutely right to be V. cautious 
here, and to make SURE you've got oil FIRST!   A minor repair of oiling 
system, a MAJOR repair of mains, pistons, everything else, if it oil-psi is 
not there.
Ernie B.




----- Original Message ----- 
From: "Mike" <niche at iinet.net.au>
To: <diy_efi at diy-efi.org>
Sent: Sunday, October 30, 2005 11:18 PM
Subject: [Diy_efi] [ot] Oil pressure during cranking ?


> Sorry guys but I need an opinion on this off topic item asap ?
>
> When cranking an engine over, do most crank driven oil
> pumps generate much pressure or do they have a minimum
> crank speed before they raise oil pressure ?
>
> In my case, I did some bottom end work, put everything back,
> heaps of oil in sump, took out spark plugs, cranked engine
> over for 25 secs and still no oil pressure :( I'm not using a
> sender but a proper oil pressure gauge I have just checked
> on a compressor. Engine is RB30ET 6cyl nissan, had oil
> pressure before (via sender) but discovered oil sender was
> faulty and reading high but there was still pressure...
>
> So hence my question, do I need a min RPMs ?
>
>
>
> Regards from
>
>
> Mike
> Perth, Western Australia
> VL Commodore Fuse Rail that wont warp or melt !
> Twin tyres for most sedans, trikes and motorcycle sidecars
> http://niche.iinet.net.au
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