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Oil pressure

Posted: Sun Mar 01, 2009 11:28 pm
by xvivalve
I'm starting to recall my various observations from when bringing the quicksprint home 18 months ago, now that it is road legal . One of great significance is it is running at 80psi at cold idle! going easily onto three figures at chat. Good...or bad? ...and this is nearly three years after buying it...my second journey!!

Re: Oil pressure

Posted: Sun Mar 01, 2009 11:39 pm
by triple tango
mine does too,
80psi cold idle, 60psi hot idle, 80 -90psi hot & above 1300rpm
I believe its a combination of a well put together engine & an uprated pressure relief valve spring

Re: Oil pressure

Posted: Sun Mar 01, 2009 11:41 pm
by trackerjack
Well I am one who is not impressed with high oil pressure springs as it loads the jackshaft and is not required.
More is not always better.

Re: Oil pressure

Posted: Mon Mar 02, 2009 11:25 am
by xvivalve
More is not always better
This is what I thought. Therefore replace PRV spring with standard and it should return to 'normal'? A job for the post running in oil change methinks.

[typo on first post; should read two not three years]

Re: Oil pressure

Posted: Mon Mar 02, 2009 1:33 pm
by Dolly racer 33
Much too high. 33 runs at 60 psi on full chat, that is 8,000 rev/min. Why load up your jackshaft & rob yourself of power to have unnecessarily high oil pressure :?:

Re: Oil pressure

Posted: Mon Mar 02, 2009 4:56 pm
by xvivalve
Thanks guys, will get it altered.

Re: Oil pressure

Posted: Mon Mar 02, 2009 6:57 pm
by triple tango
guess I should refit the standard spring in mine too then...

So recomended standard pressure is fine ?

Re: Oil pressure

Posted: Mon Mar 02, 2009 7:17 pm
by Mad Mart
Yep, 60psi here at full whack!

Re: Oil pressure

Posted: Mon Mar 02, 2009 10:26 pm
by Hans ten Broeke
If you really wane do something to get enough oil to the bearings etc, have a good look to the pictures in the next link.

Every one knows that for example an not matching intake manifold onto the head can rob's loads of power, even a step further people have there (engine) had flown.
All done to create as much flow as possible.

The same also happen if you take a good look to your oil system.
Most of the oil pumps do not match the block at all.
I always make the in and out port of the pump matching as much as possible.
Measured on our Superflow flow bench up to 40% extra flow at the same pressure.
The same at the take of plate for the oil cooler, also important to make the entry's to the hoses as big as possible.
Every little step will help, so also all the oil channels I can reach are made as smooth as possible by using several diameter flex hones.

http://sprint.smugmug.com/gallery/4523497_6t3iq#P-1-12

One picture, the rest is in the link

Image

Re: Oil pressure

Posted: Tue Mar 03, 2009 8:42 am
by mbellinger
Thank you Hans - the pictures tell their own story.

I used to do exactly the same thing when preparing my Hillman Imp engines years ago, though the differences between block and pump were nowhere as bad as in Hans' pictures. Its amazing really when you look at the crap workmanship all over the Sprint engine that it ever ran sweetly at all. That oil pump to block joint is actually acting as a restrictor.

And yes Alun, your pressure is miles to high. When you have run in and start ahem, extending it a bit, you will have oil p155ing out everywhere under pressure. It will go for the gasket of least resistance first.....

Re: Oil pressure

Posted: Tue Mar 03, 2009 8:57 am
by Dolly racer 33
It is not only the oil pump that needs modifying. The main block oil galleryfrom the transfer housing also has a step in it which needs removing.

Re: Oil pressure

Posted: Sat Mar 07, 2009 5:16 pm
by triple tango
changed back to standard, 40psi hot idle, rising to 55psi above 2500rpm. Engine is a bit quicker now! Does that sound ok chaps?

Compare the springs;
Image

Re: Oil pressure

Posted: Sat Mar 07, 2009 5:17 pm
by Mad Mart
That sounds about right Roy.

Re: Oil pressure

Posted: Wed Mar 11, 2009 10:50 am
by xvivalve
Did you achieve that task with everything in situ Roy?

Re: Oil pressure

Posted: Wed Mar 11, 2009 8:47 pm
by triple tango
yes, nothing needs removing.
Jack front of car, pull split pin from pump, loose about a teaspoon of oil, & refit new spring.