Opp's, help. Identification needed

[FoxTVR430]

So I am rebuilding the oil pump and cleaning painting the sump pan etc.. on my 1993 (pre-serp) engine.

I have found an (extra) screw!!
The dreaded scenario

The question is, if someone could help me identify this little screw!






Cheers
Simon

[Steve_D]

I can identify it (Knurled cup point grub screw).
Where it belongs is another matter.

So did you just find it in the engine or was it in your tray of parts you dismantled?

Steve

[FoxTVR430]

Hi Steve,

It was with the parts I dismantled.
I actually took a picture at the time when taking the oil pump apart, see below.
But I cannot remember where came from. I have looked inside the oil pump housing and there is just no place that I can see that it could come from.
Maybe, has it something to do with the oil pressure relief valve?

[phazed]

Steve_D said:

I can identify it (Knurled cup point grub screw).

Why has the grub screw got that finish on its underside?

It hasn't fallen out the crankshaft? One of those oil gallery close off grub screws?

[Steve_D]

That style of grub screw is designed to lock something like a pulley onto a shaft. The cup and knurl bite into the shaft to give a good lock.
Can't think where this would live on a pre serp oil pump.

OP were you stripping anything else at the same time? like bottom of dizzy etc.

Steve

[TwinKam]

The knurled end is its self lock device, so it wouldnt used to blank a drilling (the knurled end would be in fresh air/oil etc), those usually lock by being tapered.
This one would be used to lock against solid metal so, for example, a pulley to a shaft.

[TwinKam]

...beaten to it!

[phazed]

Thanks Steve, too late Rik! Interesting all the same.

[N7GTX]

Check the upper timing chain sprocket. If it is the vernier type there should be 4 locking grub screws.

https://rimmerbros.com/Item--i-610289V

[FoxTVR430]

Steve_D said:

That style of grub screw is designed to lock something like a pulley onto a shaft. The cup and knurl bite into the shaft to give a good lock.
Can't think where this would live on a pre serp oil pump.

OP were you stripping anything else at the same time? like bottom of dizzy etc.

Steve

Hi Steve,
To answer your question. No I was not. The Dizzy I took out some time ago and is safely stored.
Thinking about this again. I do not remember using my allen keys for the last a week or so.
This is a puzzle.
Simon

[FoxTVR430]

N7GTX said:

Check the upper timing chain sprocket. If it is the vernier type there should be 4 locking grub screws.

https://rimmerbros.com/Item--i-610289V

That could be an idea. But I would have to take the timing cover off, wouldn't I?
That would be a right pain.

[Steve_D]

Timing sprockets use cap head set screws not grub screws.

Steve

[phazed]

Still possibly a grub screw from the crank.

Maybe it was in the sump?

Maybe from a 1973 Raleigh Chopper?

[Boosted LS1]

If the crank's been cross drilled it will have grub screws in it. There would be a big pressure drop if a screw came a drift and usually I'd expect them to be loctited in. Tiz a mystery for sure.

[Belle427]

Strange that, not used as a blanking plug was it?

[N7GTX]

It hasn't been used as a 'spacer' inside the oil pressure relief valve? You can pack the spring to increase the tension when they become weak.

[mickh32]

It looks very new as if it has never been screwed into anything, so maybe it was used as a packer.

[Boosted LS1]

I've used a metal tyre valve to preload a pre serp relief valve.

[Sardonicus]

Wasnt used as someones crude/horrible method of packing the oil pressure relief spring was it? it would certainly explain you not remembering removing it cant see any reason to have this style of grub screw in the RV8 tbh

[N7GTX]

Sardonicus said:

Wasnt used as someones crude/horrible method of packing the oil pressure relief spring was it? it would certainly explain you not remembering removing it cant see any reason to have this style of grub screw in the RV8 tbh

Come on grandad, do try to keep up. See 10.36am yesterday.......