23 replies to this topic

[Matt's Dad]

Sorry, not to undermine your handy work, but just checking that you have replace the seat on the conversion?  The Auto and Manual ones are different and leaving the Auto one in, while it will work, it also sends unfiltered Oil down to No, 3 Main Bearing.

Yep, I changed the seat. Luckily the cross-drilled auto one was threaded down the middle, and using an old short head stud I rigged up a simple puller to extract it.

After weeks of searching, Minispares eventually ran to ground a replacement 'manual' seat, luckily just before I was ready to splash out on having one made...

The slim magnet is obvious now it's been pointed out..!

[Matt's Dad]

Without too much of a "Holy thread resurrection, Batman!", prompted by Moke Spider's check question on the oil pressure relief valve seat, I thought I'd show what he means and add a few notes about converting an auto block to use in a manual at the same time...

 

This is the oil pressure relief valve seat used in the automatic and you can see what Moke Spider is referring to. The cross drilling does indeed feed unfiltered oil to number 3 main and is why it needs replacing with this http://goo.gl/3yQrFf

 

 

The automatic transmission pump is substantially different to the manual transmission version, the block is bored deeper to take it, so this material needs putting back in. An adapter plate imported from Australia does the trick. http://goo.gl/osZIbD

 

 

Then it's necessary to machine the pressure feed gallery from the manual pump to the main oil gallery. A 3/8" end mill cutting 1/4" deep into the rear face of the block creates the cavity. Note the A+ distributor clamp helping to hold down the drill stand and a piece of rag stuffed into the cam bearing to keep swarf out. A hoover was used during boring too, to help lift the iron dust.

 

 

Next the cross drilling from the newly bored cavity to the main oil gallery is put in (before knocking in the 'manual' oil relief valve seat). With the adapter plate firmly held down with screws, a 5/16" long series drill through the oil relief valve seat cavity makes the connection, effectively cutting a 'half moon' in the block and the same in the adapter.

 

 

Once this is done, it's necessary to make up a gasket to go between the adapter plate and the block, using some Loctite gasket goo in addition, to make sure that the plate seals and there's no oil leakage path around the drilling or outside edge. On some blocks it's also necessary to drill the dipstick hole and even on some export blocks, the oil filter head mounting too I believe. This wasn't necessary in our case.

 

We only ended up doing this work because we'd sent the block to Oselli for boring and facing and only when we came to fit a nice new MED oil pump, did we realise the block was from an MG Metro Automatic...

 

 

[limby2000]

I never knew they done an mg metro auto! That,s was a rare beast.

[ACDodd]

I use a ball in every engine I have ever built. Cut 1.25 coils off the stock spring. Oil pressure will ne where it should.

Ac

[andyt]

Ac, I have the minispares ball and spring could I use this without cutting it or should I just cut the standard spring, I started this thread a few weeks ago as I had read several articles about changing from the bullet type of valve, is the ball better?

 

Andy. 

[gazza82]

Minispares spring should be shorter for the ball anyway.

 

I have both in the garage and the new ball-spring is visibly shorter.

[Matt's Dad]

With the Minispares 'shorter' spring and ball kit http://goo.gl/tyCvld I got 120psi...

Comparing the two springs, the shorter 'Cooper S' type spring seems to have a much higher spring rate, which may compensate for its shorter free length(?)

Minispares suggest that the 'standard' spring used together with the ball should give 75psi. I haven't tried that combination, just gone back to the plunger type.

Edited by Matt's Dad, 26 November 2015 - 01:07 PM.

[Spider]

 I had read several articles about changing from the bullet type of valve, is the ball better?

 

Andy. 

 

The Ball is supposedly less likely to Jam than the original bucket type, but from my own experience, the balls bring on many more problems than they solve. I've only ever found one jammed bucket in all the engines I've stripped and IMO, statistically, based on that, I wouldn't remotely say the original bucket is a problem.

[ACDodd]

I just use the stock spring with theball and cut off 1.25 coils its easy as that.

Ac