mk1-forum.net

I remember reading about it somewhere on here...
But I can't seem to locate the post.

If memory serves it was a discussion about the "valve" or ball in the oil line on the front of the engine- under the nut on the left by the wok...

That if it is stuck, or sticking... it can cause high oil pressure readings.

Does this cause oiling issues as well?
Just got my car running semi- steadily today after a carb and coil swap. So now i have to adjust and tune the carb, timing, everything.

But I noticed my oil pressure guage shooting up to 100 psi just cranking the engine over.

It stayed at that level, and never dropped back off.
It's not a stock engine by any means, and close to 20 years since built from what I can tell.

Should I not be running her anymore until I address this?

Aha!
I located the thread i was thinking of, and read up on the discussion of the valve plunger, and use of a ball.

I'm to embark on pulling mine apart this weekend...

Any removal method suggestions if I find a stuck plunger?

I hesitate to say it, but ............... could you crank the engine (no sparks) and use the oil pressure to push it out ?

If it is only a little bit stuck you might be able to release it by sticking your finger in the hole, into the shuttle, twisting it and then pulling it out. If this fails, a bit of wooden dowl tapped into the shuttle then twisted and pulled may work. Easier if you have a spare plunger to check the internal fit of the dowl.

IMHO the cranking method is fraught with danger (oil everywhere .... you did say you were seeing 100 psi while cranking) ...maybe remove the spring and replace the cap before cranking???

100 psi is a bit high .... but not tooooo excessive for a new, cold engine running 20W50 oil. Won't hurt to run this pressure while setting things up.

I'm not a fan of ball valves..... you will need to trim the spring to use one. Keep up the oil changes and the standard bullet works fine. If you find the pressure a bit high (once you get everything set up and operating - say, more than 75 when hot at 3 K+ revs) you can drop the pressure back by fitting one or more copper sump plug washers between the relief valve retaining cap and the block. Some will say 75 is too high but I've run mine like that for 30 + years and find it "reassuring"

Cheers, Ian

Thanks for the replies gents.
Off to work, and will be tearing into it after I get home.
Will update with findings.

Sorry, I'm unsure from your post if you are using the original shuttle or bucket type of valve here or the common modification of swapping that to a ball ?

If you are using a ball, be aware of a few things, firstly, that the stock spring is too long and if fitted without shortening, then yes, you'll see 100 PSI +. The other thing is while using a ball here is ~ OK-ish ~ in a Competition engine, they are a bad idea in street engines;-

https://www.theminiforum.co.uk/forums/t ... e-vs-ball/

On the other hand, if you are using a stock valve and spring, then if you are using a high volume oil pump, I'd suggest swapping that to a stock one. The High Volume Pumps can easily overcome the volume of oil that the relief circuit can pass.

If you have a stock pump, stock valve and stock spring, then I'd say it's likely the Relief Circuit for the 'back side' of the valve is blocked or choked. A common cause of that is when the brass plugs are removed and one that's too long (from the front of the block) has been fitted, blocking the port. When this has occurred, the oil that's on the back side (spring side) of the valve can't vent anywhere, thus hydraulically locking the valve.

BTW Minispares sell the ball and shortened spring as a set

https://www.minispares.com/product/Clas ... 36KIT.aspx

No guesswork involved when it comes to shortening the spring

I'm not advocating you fit one ... just FYI

Spider wrote: ↑Sat Jun 01, 2024 9:22 am https://www.theminiforum.co.uk/forums/t ... e-vs-ball/

Great explanation there

AndyPen wrote: ↑Sat Jun 01, 2024 9:31 am

Spider wrote: ↑Sat Jun 01, 2024 9:22 am https://www.theminiforum.co.uk/forums/t ... e-vs-ball/

Great explanation there

Cheers Andy

Good interesting and thought provoking thread Joel. Good responses too

Well, my daughter needed some help with some yard work today pulling four tree stumps out that had to be cut down. So no progress on the car yet.

I'm unsure as to what's actually in use in my car-
As I've never removed the oil pressure relief valve cap or plunger ever... yet.
I've never wanted to disturb the coating of engine paint on it, without good reason to!

No idea what oil pump was used on her as well.

I recently spent some time chatting with Keith Calver on Facebook a few weeks back about the engine, as Pete Flanagan mentioned to me that he had been the builder of it.

Great guy to talk to, tried very hard for me to see if he had any information or paperwork left on the build... to no avail.

So hopefully, soon enough- it's just a matter of digging in and finding out what's there.

Again, many thanks for the replies and the advice guys!

So many small steps for me... to the point of running properly again!

AndyPen wrote: ↑Sat Jun 01, 2024 9:31 am

Spider wrote: ↑Sat Jun 01, 2024 9:22 am https://www.theminiforum.co.uk/forums/t ... e-vs-ball/

Great explanation there

Great read! Thanks for sharing that.

Spider wrote: ↑Sat Jun 01, 2024 9:22 am Sorry, I'm unsure from your post if you are using the original shuttle or bucket type of valve here or the common modification of swapping that to a ball?

If you are using a ball, be aware of a few things, firstly, that the stock spring is too long and if fitted without shortening, then yes, you'll see 100 PSI +. The other thing is while using a ball here is ~ OK-ish ~ in a Competition engine, they are a bad idea in street engines;-

https://www.theminiforum.co.uk/forums/t ... e-vs-ball/

On the other hand, if you are using a stock valve and spring, then if you are using a high volume oil pump, I'd suggest swapping that to a stock one. The High Volume Pumps can easily overcome the volume of oil that the relief circuit can pass.

If you have a stock pump, stock valve and stock spring, then I'd say it's likely the Relief Circuit for the 'back side' of the valve is blocked or choked. A common cause of that is when the brass plugs are removed and one that's too long (from the front of the block) has been fitted, blocking the port. When this has occurred, the oil that's on the back side (spring side) of the valve can't vent anywhere, thus hydraulically locking the valve.

Wow Beautiful explanation!

Thanks Spider

So, I had a little time today to poke around in the engine bay...

Perusal for the esteemed opinions....

I have no pressure relief valve.

Correct factory cone, ball bearing, spring or otherwise.
There's nothing under the valve cap but the seat area.

As I'm pushing around 100psi in oil pressure WITHOUT a relief valve of any type constricting the flow....

I'm probably good at assuming I have a high performance/pressure oil pump in my engine?

Thoughts?

If some one left out the relief valve they had to have a reason ..... Maybe they just blocked up the relief (and back pressure) vent at the same time.....8-0 100psi without a valve does not suggest an oversight...

Cheers, Ian

A standard pump is well capable of making 100 PSI +.

I'd say here that the Oil Pressure Relief Valve Drain is blocked for what ever reason. Then in an attempt to diagnose or resolve that, the Valve and Spring has been removed.

So much for any further speculation here. The engine will need to come out and be stripped at least off the gearbox to find out why it's like it is.



Please IGNORE the arrows in this pic.

This is No. 3 Main Cap. Just in front of that is the Oil Pressure Dump Port. I'm pretty sure given your descriptions here, this pot is blocked. It should be clear all the way in to the Relief Valve.

One other thing I should probably mention-

I don't know if it's standard or not?
I have an external line going from my pressure relief cap- over to the oil filter housing.

I'm venturing a total guess-
A relief bypass- or something like a full flow system?

We used to do something similiar with aircooled vw engines- off the oil relief to an oil cooler, larger sump, reservoir, or additional electric oil pump.

The picture is not mine- but the line I'm talking about is readily visible.

The pressure relief cap is down here

timmy201 wrote: ↑Wed Jun 12, 2024 4:05 am The pressure relief cap is down here

Ah!
So I'm an idiot then! Lol.
I thought it the top one, and pulled it to check.
Didn't even see the lower. Smh.

Will be double checking soon then.
And the top hole has a very similiar tapered bottom inside- looks just like images I've seen of the relief hole in threads.

Thank you timmy!

Ahhh,,, yeah,,,,, I should hope there was nothing under the Banjo Bolt !

Never mind Joel, we live and we learn !