Oil pressure

[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!!

[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

[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.

[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]

[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

[xvivalve]

Thanks guys, will get it altered.

[triple tango]

guess I should refit the standard spring in mine too then...

So recomended standard pressure is fine ?

[Mad Mart]

Yep, 60psi here at full whack!

[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

[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.....

[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.

[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;

[Mad Mart]

That sounds about right Roy.

[xvivalve]

Did you achieve that task with everything in situ Roy?

[triple tango]

yes, nothing needs removing.
Jack front of car, pull split pin from pump, loose about a teaspoon of oil, & refit new spring.