Yes the green arrow is it, use a socket or ring spanner.
1-1/16" or 27mm.
Valve is in there behind the spring.
If valve is stuck (probably) go to hardware store and buy a 10mm (hole size) dynabolt. Do it up gently, then you can use it as a handle to pull the offending valve out.

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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.

Thanks doc... i'm just about to go to the hardware store to buy a 27mm socket (dad uses a lot of metric and since it's so close to 1 1/16" metric will do in this case) so i'll pick up a dynabolt at the same time.

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- Simon -

I heard of someone turning the engine over on the starter to allow the oil pressure to blow it out. Might work now that the spring has gone.

Sounds messy though.....

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Mick, my mate suggested that but i told him i didn't want to get everything covered in oil. Plus if it shot it out and it got lost then i'd probably crack it and kill someone.

Anyhow... I'm back home again with my mini. The damn thing ran beautifully after i removed and replaced the cap and spring. I tried to remove the sleeve thingo with the dynabolt but all it did was pull out all the time. I couldn't get it to bite enough to pull the sleeve out. I didn't have time to go and buy a bigger dynabolt so i just put it all back together.

Anyhow i took the Commodore home and got my mate to give me a lift back to get my mini. I drove it out of the carpark and left it idling... oil pressure drops to 10psi on idle now. I don't know how low to let it get before i bail and turn the engine off. But all the time i was driving it i had it up at 2500-3000rpm to keep the oil pressure up above 30psi.

I don't know what to do, can i drive it still? I asked dad if he had a 12mm dynabolt that i could try but all he could offer me was a bunch of Ramset Chemset capsules. Should i try them?

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- Simon -

A dynabolt should do it, if there is a valve in there. Is there one, or does it have a 9/16" ball instead?
If a ball, there is nothing behind it but the valve seat, which stays there.

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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.

I can't really see what is in there... i can't see a ball. It looks like a shiny silver flat disc. But that doesn't sound like what you desribe. I think that there may be some confusion coming from differences in the way things are described and interpretted.

Can anyone show me what the thing i should be removing looks like? That may help.

BTW... i was joking about the Chemset idea. If you know what Chemset Capsules are you'll realise that's a VERY bad idea. They are used in the same places as dynabolts but are a glass tube filled with sand, epoxy and glass.

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- Simon -

Pointy bit is inside block, that spring goes into LH end.
You are looking at the inside of it, by your description.

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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.

So is that what it looks like with a ballbearing or is that the valve and seat type? I'm thinking i probably don't have a ball bearing.

I'm also considering just taking it to a mechanic to get fixed since i clearly don't know what i'm doing nor do i have the parts or time to fix it easily.

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- Simon -

Pic above is the standard valve. A 9/16" or 14,0mm ball bearing can be used instead, but read my posts above to fit it properly.

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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.

I've just browsed through the Mini repair manual that i just remembered i had (the guy across the road gave me it but because it was for Clubmans i threw it in the corner where i throw all my junk) and understand the oil pressure relief valve a little more now.

I was thinking that the bit pictured above in doc's post was not the bit that moved but instead was the bit that housed the valve. I'm now curious as to why it's so hard to remove because surely it's supposed to slide in and out smoothly.

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- Simon -

The motor gets its oil from the gearbox. There is thus potential for metal particles of various types to get sucked up by the pump. These bits can get beside that valve so it jams in the bore.
The filter stops them getting into the bearings, but this valve is before that.
The ball type cannot jam, it's a worthwhile mod, IMO.

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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.

So if i can remove the valve i shouldn't be replacing it with the same thing i should be putting a 8mm dia. 40mm long rod in there with a ball bearing instead? I have a mate who can get me a ball and some rod from his work tomorrow if that's the case.

Obviously replacing it with stock items will work but the ball bearing type is superior?

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- Simon -

Yes and yes.
Ball diameter is 9/16" or 14.0mm. Bearing places sell them.
As I said above cut 3 or 4mm off the spring. Put cut end of spring outwards against hex plug, leaving the nicely wound end against the ball.
And please do fit the 5/16 x 40mm rod, or you will get WTF? weird pressure sometimes..

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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.

Hmmm... i don't like the idea of cutting my spring. I'll give it a shot but what are the specs on it if i need to buy another when i fiddle sticks it up.

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- Simon -

Well go get a s/h Mini spring from someone and cut that...
Cooper or Cooper S spring was a little stronger but it would need to be cut too.
If you don't cut it you will have 100psi- too much.

Hey if you want to keep the old valve instead, just polish all the burrs off and refit it. It must slip in there easy.

Maybe the oil in this motor should have got changed more often...

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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.