No Oil Pressure

[4129R]

Eureka.

4 hours to take the engine out and take the water pump cover off the front of the engine.

As I suspected, the grub screw blanking the oilway just past the oil pressure flange, where the sprocket for the layshaft is located, was missing, so oil was going straight back into the sump rather than up the oilways in the block.

Quite who took out that grub screw, when, and why, I have no idea.

I must have built this engine over 3 years ago, and if I had taken it out, I would have seen a grub screw lying about when the engine was built. It could have been me or the PO, but hopefully this is all that is wrong, and I have caused no damage running the engine for about 3 x 8 second bursts, with a long gap in between.

It will take me a while to clean it all up and screw it back together again and time the distributor, but it started very easily this morning before I took it out, so I should know fairly soon if it runs properly without any damage to any bearings.

[Kendo]

Well done. It’s always good to have a definite answer to a mystery problem.

[4129R]

It seems that the grub screw is 1/2" Whitworth thread, the same as the gearbox sump plug.

I have to buy a pack of 5 for £5.15.

Cheap fix.

Quite where the original went and when is a complete mystery.

Looking through my box of strange Lotus bits, there is a grub screw, but it is bigger and the wrong thread, so I have no idea where the original is. It is too big to be not noticed if I had taken it out to check an oilway. I did this on another block which was lying around in Louisiana and mud wasps had bunged up holes in everything everywhere so I was checking the oilways, but not on this engine.

[kram350kram]

Is that the only oil gallery that requires a plug? One missing plug may mean another’s could have been overlooked?

[4129R]

Is that the only oil gallery that requires a plug? One missing plug may mean another’s could have been overlooked?

Unless I looked at a bare block closely, I do not know if there are any other oilway plugs. They would have to be visible from underneath, as there is nothing at the top where the cylinder head attaches, and nothing at the flywheel end that I can see.

If anyone has a bare Ford block handy, are there any other oilways plugged other than where the jackshaft sprocket is just past the oil pressure union take off?

[EuropaTC]

Great news !

No matter where the cause of the missing plug lies, it's fixed now and you can get it back in the car & running.

Brian

[S2Zetec54]

Having a quick look at the inter web showed me this

https://www.burtonpower.com/oil-gallery-plug-1-8-bspt-x-1-4-fp503.html

…..there is a line that says one required…. But that the size might be different…..well that’s my reading of it at first glance

[BDA]

I would be surprised if it were Whitworth thread. I would think it is more likely NPT and if not that, BSP.

[4129R]

I would be surprised if it were Whitworth thread. I would think it is more likely NPT and if not that, BSP.

What thread is the gearbox fill plug?

I have a fill plug that screws into the oilway hole easily, so it is the same thread.

Whitworth (1803-1887), also known as British Standard Pipe (BSP) or British Standard Pipe Taper (BSPT), were originally thread forms for pipe fittings. They are still used for pipe installations in Europe today. They are therefore also known as pipe threads.

[BDA]

Interesting. I had never measured a tranny fill plug and had assumed that it is some metric equivalent to NPT being a tapered thread and all. So I checked the thread with my thread gauges. The one that fit the best, but not perfectly, was 20 threads per inch. The 18 TPI gauge also "fit" but not as good. No metric threads fit at all. Maybe something like 1/4" NPT or 3/8" NPT was 20 TPI. Nope, 1/4" NTP and 3/8" NPT have a thread pitch of 18 TPI. I found the specification of JIS and BSPT (both tapered) thread (https://trimantec.com/blogs/t/thread-identification-guide#NPT-Chart) and the 3/8 (-6) size has a thread pitch of 19 TPI. (This is curious to me because I usually associate a dash number designation as an AN designation but clearly that isn't the case here.) The specified diameter for 3/8 BSPT OR JIS is 0.65". Measuring the diameter of a taper is obviously problematic but my plug does measure about 0.65". I don't have a 19TPI thread gauge so I can't verify that it has the correct thread pitch.

So it appears to me that my NG3 (and I assume all Renault trannies likely to be found on a Europa) are likely 3/8 JIS or BSPT. Are there enough weasle words in there for you?

I'm not as familiar with BSPT as I am with NPT or even BSP (which I just found out is also called BSPP) is a straight thread) so I can't say if it is likely that your block is tapped for it but it seems logical.

[4129R]

The oilway plug by the jackshaft sprocket is exactly the same thread as the short union for the oil pressure gauge which screws into the block very close on the same oilway from the pump.

I have bought a G1 1/2" - 11 BSP and a  G 1/2-14 BSP pressure pipe plug allen socket screws off eBay and I am hoping one of those two is the correct thread.

Oh dear, on further research, it seems I need a 1/4" BSP grub screw which is 13.16mm in diameter and 19 turns per inch.

Soon I will have a whole collection of strange sized grub screws, and hopefully, 1 of those will fit.

I was wondering why QED specialist Lotus engine company had 1/4" grub screws on its cylinder block components list. Now I know why.

https://qedmotorsport.co.uk/product/block-oil-way-bung-1-4/

[BDA]

By now you probably have a complete selection of plugs that have any chance of fitting but it just occurred to me that maybe the easiest way to find out the correct size is to make a call Burton Power or Barum Engines (I see them on YouTube) or QED (certainly they mean 1/4 NPT).

[4129R]

By now you probably have a complete selection of plugs that have any chance of fitting but it just occurred to me that maybe the easiest way to find out the correct size is to make a call Burton Power or Barum Engines (I see them on YouTube) or QED (certainly they mean 1/4 NPT).

I will be phoning QED tomorrow to order 2 x 1/4" grub screws. At their price, the postage will be more.

[4129R]

Is that the only oil gallery that requires a plug? One missing plug may mean another’s could have been overlooked?

I now have plenty of oil pressure. A missing oil gallery grub screw was all that was wrong.

There is another grub screw blanking off an oil gallery, but that plug is on the exhaust manifold side of the block, and both easy to see and easy to access with the engine in situ.

[SilverBeast]

Excellent.