Massive thank you to Phil - and more advice please?

[philthehill]

Mark & Rob
I have sent an 'e' mail with drawing attached to Gervase@cam-machine.com requesting without prejudice or commitment a quotation for the manufacture of an individual oil pressure relief valve seat and a max batch of qty 10.
I will await a reply.
Rob - I have mentioned that the name/company was put forward by yourself.
Declan - you have a new PM.
Phil

[Mark Wilson]

Phil, Rob and Declan - many, many thanks for all your efforts, but fingers crossed I've got one on its way - different supplier in the States who has confirmed that he has two in stock. (PM me if you are interested in the other.) Similar price to the Spanish supplier so not worth putting you and your colleagues to a lot of trouble, Declan.

The news about this came after I'd spent an interesting couple of hours this afternoon. Firstly I removed the existing seat with an M10 tap and threaded bar. Not as mangled as I'd expected, in fact quite a neat bit of drilling if I'd wanted holes there

[frame][/frame]


Taupe (another thanks) had sent me some fascinating information about the automatic 1275s, particularly the Austin Americas, having seats which were threaded and had holes in the side (complicated reason, mainly to do with high oil pressures needed for the auto trans). In this was the suggestion that if you had a seat from an auto you could convert it to manual by blocking the holes. Well, I'd unintentionally made my own version of the auto seat - so why not do the same thing? Popped it on a bit of aluminium bar and a bit of welding and filing later -
[frame][/frame]

I would have used this if a new one hadn't become available, but as I've now got north of £800 riding on this engine I'm not about to take chances to save a bob or two.

Hopefully this concludes my entry for this years Great British Bodge Up!

I'll hopefully be finishing the car over winter (not the first year I've said this) and will write up a Resto thread when I'm done, with a report of how I do with the engine. I might just be back needing more help before then, though......

Mark

[philthehill]

Mark
I have received a used oil pressure relief valve seat from Steve Mantom at EngineTech, Hartelbury nr Kidderminster.
I was put in touch with Steve by Peter May of Peter May Engineering. Steve does engine work for Peter May.
Interestingly the used valve seat is modified. The inlet to the relief valve seat and direct from the oil pump is blocked with a grub screw and qty 4 7/32" apertures have been drilled through the reduced centre dia of the valve seat. The outer part of centre tube has been tapped to allow extraction of the valve seat.
The oil pump in normal use serves two oil galleries from a common oil pump outlet, one serving the oil filter directly and the other serving the oil pressure relief valve directly.
The reason I understand is to ensure that only filtered oil is by-passed by the oil pressure relief valve.
The oil pressure relief valve cup is prone to sticking inside the seat/block especially when oil from a shared engine/gearbox (Mini) contains crud.
Oil passing through the 7/32" holes still bears on the oil pressure relief valve cup so the oil pressure release valve works as normal.

Mark
I would suggest that the oil pressure relief valve cup is lapped into the relief valve seat before the seat is fitted - doing so will alleviate the need to clean the lapping paste from the block and oil ways.
If you are using the 5/8" ball bearing and Cooper 'S' relief valve spring http://www.minispares.com/product/Class ... .aspx|Back to
then there is not such a need to lap the cup to the seat but the seat should be in good condition.

Mark & Declan
I still require the additional oil pressure relief valve seats.

As an aside - as EngineTech undertake work for Peter May Engineering (Midget/Sprite tuning) I would suggest that they are a good source for engine re-conditioning and engine modifications.
EngineTech may be already known to the readers of this Forum.

Phil

[panky]

Is there any advantage in using the ball bearing type relief valve?

[philthehill]

The main advantage of using the ball bearing is that there is very little chance of crud jamming the ball open or shut unlike the normal cup fitted by the factory which is known to jam.

[panky]

That's good, no real disadvantages then. Happy with that as I fitted one to my Mini

[philthehill]

Perfect for a Mini with the engine oil also lubricating the gearbox.

[Mark Wilson]

Phil,

Sounds like the used seat you have come across is the auto seat, there's a picture on this mini forum thread

http://www.theminiforum.co.uk/forums/to ... %20%20ball

The grub screw would replicate it's use in an auto, which doesn't have the oilway directly from the valve seat to the oil pump. The pump in an auto apparently delivers a lot more pressure/ volume, so perhaps not safe to assume that this mod would be OK on a manual engine, although the aim of ensuring that only filtered oil is bypassed sounds worthwhile, particularly on a transverse engine.

Mark

[philthehill]

Mark
Thank you for the link.
Unfortunately the photo in the link does not show the inner end of the auto relief valve seat.
The used valve seat supplied to me is a normal oil pressure relief valve seat Pt No: 2A797 which has had the four 7/32" holes drilled in it and a plug (grub screw) fitted into central tube at the oil pump end.
The comment in the link about unfiltered oil going to number three main journal is correct if the holes are drilled and a plug (grub screw) is not fitted into oil pump side of the relief valve seat if and when used on a non auto engine.
I have no concerns relating to the modified valve seat supplied to me being fitted to a non auto engine as the oil will still circulate as designed (except for the non oil transfer direct from oil pump to relief valve) - the only difference will be that the release valve will operate with filtered oil.
There may be a small increase in oil pressure through the oil filter but that can be managed by increasing the size of the filter. Note:- the oil filter fitted to the auto engine is much larger and therefore has increased filter surface area.
For use in a rebuilt engine it may be a bonus as all oil going through the oil pump will have been more effectively filtered and not just the normal circuitry of oil from sump to oil pump to relief valve and dumped back into the sump unfiltered. Long term I can see a distinct benefit as regards longevity of the oil pump which to me is the heart of the engine.
Phil

[Mark Wilson]

This is fascinating stuff. I'm quite amazed how much I've managed to learn from this episode, but I'm now definitely at or beyond the level of my understanding! I'll be happy if I can just get my engine back to the way it was designed. The main long term change I will make is to fit a spin on filter conversion, not for convenience but for the ability to use a better filter. Having seen scoring on my otherwise lightly worn bearings, and also now to the relief valve seat, I will take rebuild cleanliness and efficient filtration very seriously indeed.

[RobThomas]

THINK make an adaptor that screws to the bottom of a screw type filter housing to allow the use of a remote filter, if you want to keep original pipework. The other option is to get one of their unions that screw into the block above the dissy and make a plate with a union that bolts to the block near the front engine mount. I seem to recall that the thread in the block for that long bypass pipe is a funny one. The one near the front can be made with a short section of bar that has been drilled for 2 mounting holes and another hole to take a 1/2 BSP pipe union.

I can get pics if needed.

[philthehill]

Rob
The thread in the block for the oil union that takes oil to the oil filter head via the pipe is 5/8" x 18TPI UNF.
Phil