agricola wrote: ↑Sat Jan 23, 2021 6:20 pm
Interestingly if you look at a new replacement oil seat insert,( yes the seats are removable) they have 2 sides which are slightly different the conclusion I came to is one side is for the ball the other is for the valve. So I just wonder whether swopping ball for valve is that straight forward?
I was thinking the same.
OP.. What is the oil cooler you have fitted? From what I have seen the KAD pump shouldn't give lower pressure at slow speed. You can always try adding a flat washer under the spring of the oil pressure relief valve, this shouldn't change the idle pressure, if it does there is an issue relating to the valve.
An ex swiftune engine builder explained me that the race pumps like the KAD one, were supposed to give less pressure to avoid cavitation?
I have another problem, I just did a few starts. Newly reconditioned 1275 s engine, new oil pump,...
As soon as the engine is started, the pressure spikes to full scale.
I don't know if it's the pressure gauge or there is a problem with the ball and spring.
I'll try another gauge first, but if the problem remains, what do you say to look at?
geroch wrote: ↑Mon Jan 25, 2021 5:26 pm
I have another problem, I just did a few starts. Newly reconditioned 1275 s engine, new oil pump,...
As soon as the engine is started, the pressure spikes to full scale.
I don't know if it's the pressure gauge or there is a problem with the ball and spring.
I'll try another gauge first, but if the problem remains, what do you say to look at?
Thanks
Tom
If you use the ball instead of the normal relief valve you have to cut the spring
bwaminispeed wrote: ↑Mon Jan 25, 2021 5:35 pm
That's pretty normal, especially if using 20W-50 oil, when it's cold, it's like pumping molasses through your engine.......
Thanks for the replies, the 20w50 is very thick, but the other rover has the same oil and it doesn't.
geroch wrote: ↑Mon Jan 25, 2021 5:26 pm
I have another problem, I just did a few starts. Newly reconditioned 1275 s engine, new oil pump,...
As soon as the engine is started, the pressure spikes to full scale.
I don't know if it's the pressure gauge or there is a problem with the ball and spring.
I'll try another gauge first, but if the problem remains, what do you say to look at?
Thanks
Tom
If you use the ball instead of the normal relief valve you have to cut the spring
For the spring I took the kit of minispares, do I have to cut anyway?
1) the oil pressure you describe sounds pretty much spot on to me. 70 - 75 running & 20 odd ticking over. I'd be very happy at that.
2) A few folks have referred to the OP seat being for thimble on one side & ball on the other is probably not right. The seats were made by BMC / BL & were designed to go one way round & be used with the normal thimble.
3) Using a ball bearing instead of the standard thimble is simply asking for trouble. They NEVER work as well as the standard factory set up & are one of the VERY WORST modifications anyone can make to an engine.
The seat does have a different shape at either end but the concave end isn't for a ball bearing, it's not even the same diameter as the bearing and has a grooved lathe turned surface rather than the smooth ground surface that the correct 'thimble' end has.
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Ops mind you I have never used the ball so had no idea as to size of ball. At least I got both in the right way round! Strange that of the 2 alternatives one is soft aluminium the other a very hard ball bearing
The ball bearing is an after market thing, Vizard amongst others used to recommend it. The ball bearing seems to be an undesirable modification these days, having said that I've run one since the mid 80's.
Started using one because the standard oil pressure relief valve used to stick open on a regular basis on the knackered 2nd hand engines I had when I was at college.
Rarely had that issue with the ball, but if it did stick a quick 6000rpm would clear it.
I don't think the shuttle is aluminium, I think its steel, sure I used to use a magnet to remove it - or crank the engine with the cap and spring removed if it was stuck!
Have spoken to Tim @ Minimail about this & I can categorically say that the seats he sells are NOT made for the shuttle at one end & the ball at the other. They are a standard BL part & were made to fit the standard shuttle only.
I was always under the impression the ball was a OEM Cooper S thing, so learnt something there.
The only problem I can see with the plunger is that they can stick and the ones I have here, even in green Rover bags are of very poor finish, don’t even look ground. Most other valves I have seen in other engines are hardened, I guess the seat is in the Mini as they are quite tough.
I do have a JE Devolopments Rover V8 tadpole valve to try as I believe sticking on those is a common problem. Seems the same size as a Mini ball.
bwaminispeed wrote: ↑Wed Jan 27, 2021 10:04 pm
Shuttle is plated steel.......
if the plating starts to go on the shuttle (plunger as I called it ) then potentially, that would not seal as well angainst the seat and allow oil to pass, and lower the oil pressure......wouldn`t it ?
mk1 wrote: ↑Thu Jan 28, 2021 7:32 am
Have spoken to Tim @ Minimail about this & I can categorically say that the seats he sells are NOT made for the shuttle at one end & the ball at the other. They are a standard BL part & were made to fit the standard shuttle only.
Nice, luckily I asked for advice!
I'll wait to try the hot mini, to see how the pressure reacts.
Thank you all for the valuable information.
A couple of random points (not capable of rational thought at present)
What I have been selling was original Rover surplus parts. I am now down to 10 so am investigating getting some made
I am allergic to anything inside the engine and gearbox and give it to someone cleverer than me. A clever engineer might know why the valve is the shape it is on the rear.
I have always had an adjustable screw for the oil pressure . The S did seem to run a different spring to other engines , even standard 1275's, so I assume it was always a bit stronger but using it with the ball is asking for trouble - needs cutting down; in which case why not go for the standard set up
I have deep suspicion about the ball and S spring especially when the gauge goes off the end of the scale when its cold
I am aware that the seats do pit but I am not sure what the main engine builders do - I have certainly never sold any to any of them
The cost of a new bullet and spring is tiny . If in doubt change it regularly I would have thought
The other hobbyhorse in oily area is what oil to use. 30 years ago we proved that the top speed on a standard Mayfair was raised by 4-5 mph when using Mobil 1, so i have always used 10/40 in my racer as a compromise. 10/40 was recommended standard oil from the factory from the 80's but i am guessing that half the members on here would think that buying anything other than 20/50 in a metal can is worthy of a fatwa....
) then potentially, that would not seal as well angainst the seat and allow oil to pass, and lower the oil pressure......wouldn`t it ?