Oil pressure valve

[k. rogers]

This is one for all you 7hp experts! The oil pressure valve fits over 2 holes at the bottom rear of the crankcase, secured with a stud going through its centre. My question is this: should there be a short pipe on both ends of the valve to fit into their respective holes in the crankcase? I am in the process of transferring bits from the engine which was in the car onto the newly rebuilt unit and the valve I removed only had a short pipe on its nearside just a fibre washer making the seal on the offside end! Thinking mine had one pipe broken off, I found another in my spares only to find it was exactly the same. Are they both broken or is this as Jowett intended?

[AlanBartlett]

As far as i can recall when I took mine off a couple of months ago, there is only one short piece of pipe on one of the holes, , like a locator pipe as it were which sits inside the crankcase, and the other does have a fibre washer, the one directly on the end of the shaft with adjuster screw is the one with the fibrewasher and the other one on the other end of the U pipe sits inside the crankcase( Tony Fearn has a diagram of this on the forum somewhere I think)

Alternatively look in the spares listing, it should have a diagram/picture of what it should look like

[k. rogers]

Alan, just at the moment I pressed the button to post the query I thought " perhaps I should look in the parts book " ! And there is a perfect diagram showing exactly what I've got, so they are not broken - thats a relief (no pun intended). Therefore, I suppose my next question would be why is it designed this way, not that it is now so important.

[AlanBartlett]

Have you taken it apart to see if the piston and spring are intact and free? I can think in my head how it works, but have trouble explaining it, perhaps george can shed some light

[Tony Fearn]

Hello Ken,

There's a bit about the pressure relief valve further down the listing in the Pre-war section as Alan mentions. It's worth having a look at.

See 'Oil pressure on a 1935 Jowett 7hp' from Martin Raine - Sat. August 20th 2011.

The proper gasket is an elongated one-piece type which has three holes in it, two for the oil ways at each side, and a smaller one in the centre to go over the fixing stud.

I think that the protrubing tube you mention just stops he whole thing revolving around the central fixing bolt when tightening up.

Use a bit of gasket-goo as there is a propensity for leakage onto the garage floor from this area.

Another thing that is of interest is that after loosening the locking nut before adjusting the screw to alter the oil pressure (in for more, out for less), when the desired pressure is realised, tighten the lock nut enough, but don't over do it. The adjuster screw seems to be made of a rather harder metal than the lock nut, and if you tighten the locking nut too much it might just crack the adjusting screw.

How do I know this? ...it's happened to me.

Hope this helps,

Tony.

[k. rogers]

Thanks for that, Tony, at least I now know what I should be doing!