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> Jensen Healey & Jensen GT Tech > Engine & Transmission > Oil pressure slow to come up on start

 Moderated by: Greg Fletcher
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Oil pressure slow to come up on start  Rate Topic 
 Posted: 02-08-2010 08:07 pm
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1st Post

Joined: 12-17-2009
Location: Hailey, Idaho USA
Posts: 83
The oil pressure on my 1973 JH Mk 1 (12827) seems to take about 10 seconds to come up. It could be my imagination, but warm starts seem to be a bit longer still. Is that 'normal'?

I believe that oil pressure is one if the things Jensen and Lotus fixed on the Mk 2 cars. If that is correct, is there a reasonable way to retrofit my Mk 1 with the same changes.

Thanks in advance for any insight.


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 Posted: 02-09-2010 05:13 am
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2nd Post

Joined: 04-01-2008
Location: Sandefjord, Norway
Posts: 583
That the oil pump takes a long time to prime is a warning sign of imminent failure, but I think I have heard anything up to 30 seconds from cold is "ok". The old worn out engine in Ms Jensen takes on the order of 30 seconds to prime in cold weather, but that engine is done in most respects.

The 907 oil pump has to suck the oil quite high to pump it, so it needs every help it can get in retaining prime. A good oil filter with a proper anti-drainback valve will help considerably. Don't buy the cheapest filter you can find, buy the good one. Just a few bucks more, and helluva lot cheaper than an engine rebuild.


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 Posted: 02-14-2010 02:25 pm
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Judson Manning

Joined: 03-14-2005
Location: Atlanta, Georgia USA
Posts: 406
In realative terms 10sec is not all that uncommon.  A running modification was made to the accessory housing in mid 1974 (oil bleed hole) to speed the priming process.  Your MkI may not have gotten this update.

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