When I put the twinky motor together I shouted it a new Mini Spares UK oil pressure relief valve, which consisted of a spring and ball (AEA536kit). I have since gone back to the site and read the spiel again. It says it for a Cooper S or can be retro fitted to increase oil pressure.

My problem was that when I oiled up the engine and gave it a prime. On the starter only, still not wired up. Well the oil pressure came up, up to 100psi, which is sort of max on the gauge. Also didn't appear to be sending much oil to the head. Backed off the nut holding the relief spring and tryed it again and pressure came down.

Took the spring and ball out to measure it and found the length ok, but it was, (guesting) twice as hard too compress. Put the standard spring and plunger in and turned it over again and the gauge sat between 70-75psi and oil was flowing to the head.

Has anyone had a similar problem with relief spring tension?? or this particular kit??

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Dalmeny

I bought the same kit for my race engine and had the same problem, way to much pressure. Instead of playing around with it i just put an old spring and valve in and it's fine now with 60-70 or so psi.

Thanks

At least someone can learn from our misfortune. Just needed to make sure it wasn't just me.

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Dalmeny

They tell you that kit is for a Cooper S.
I have never found a ball in an original S motor. (but it may be a competition part).
As said the pressure is too high unless you cut the spring by a coil or so.
A bigger problem is the spring bends and can flick the ball sideways off the seat. A fix I used is to put a bit of 5/16" steel rod 40mm long inside the spring.
At the end of the day though, all the ball does is give you a bit more pressure at idle, because it seals better on the seat.
The plunger is more reliable.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.