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MG TD TF 1500 - What is this bit?

Have a look at the image below

I found this underneath the car this morning and I cant for the life of me work out what it is.

Its clearly some kind of sealing or adjustment screw as opposed to a screw that holds things together.

I had recently just put new seals on the front suspension so the car was jacked up on one side. I cant think such a small thing could be part of the suspension though.

Car appears to run fine...so far

Ray Coyte

Ray,
Check electrical connections at your brake switch?
Just a guess.
Good luck.
David Sheward

It may not be electrical especially with the oil on the thread. I think there may be a similar screw in the gearbox casing that blanks a hole drilled from the upper rear side for the locking balls for the selector rods.I checked the Moss catalogue and WSM but they don't seem to show that grub screw but I am pretty sure it does exist.
Max Irvine

Too big for a grub screw for electrical, and I don't recall anything like that on the gearbox.

Do you own a floor jack? Check the jack.
Dave Braun

Plug off your grease gun.
L E D LaVerne

I hope it is a screw from your grease gun, as there is a screw as in your photo at the rear end of the main oilway drilling in the block, and there may be one at the front end - my spare block has the support plate bolted in position so I cannot check. Rather a lot of dismantling to check if they are both (if 2) there !!
R A WILSON

Had another look at the plug I can see in my spare block, and it is brass. The one in the photo appears to be steel. I also think you might have noticed some oil on the floor !!
R A WILSON

Ray,

There are three places that I know of where there is this type of screw is used. In all cases they are used to plug a drilling.
The Gearbox detent balls ,the rear of the head and the oil pump.
Hard to imagine how any of these can just fall out onto your floor.


John


J Scragg

Thanks for your help everyone.

I had a good look at my jack and greese gun - its not from either of them unfortunately.

The grub screw is steel and hand finished and has some fresh oil residue on it - so its definitely off the car.

I am going to spend an hour or so looking for a hole on either the engine or gearbox tomorrow.

Odd that it has dropped out onto the garage floor and not shaken out when driving. Maybe its an old grub screw and rolled out of somewhere when I jacked one side of the car up...although that doesnt explain its clean apperance and oil film.

I have a horrible feeling this little screw is going to end up costing me a lot of money unless I can find where it came from.
Ray Coyte

Good day all:

Just an uneducated guess, but it looks quite similar to the blanking plug, fitted into the gearbox rear extension casing, filling the opening provided for the fitting of a reversing lamp switch.

If that is the bit, why it would have come loose is another question.

Cheers for now then; respectfully:
Jack Emdall, TD 3191, Halfmoon Bay, British Columbia, Canada
kernow

Ray. What kind of car do you have or engine
TD TF Xpag >Xpeg?
Thoralf. Norway TD4490
Thoralf Sorensen (TD4490)

Ray, did you adjusted the valve's lately ? let me explain here the screw size looks close to a plug from a rocker shaft. It could be the plug loosened itself and it fell on the engine or floor while working on it. Check it out.

hope I am right ,

respectfully Gerard
Gerard Hengeveld

Thoralf sorry I should have said its a TD XPAG

And Gerard yes I did do the valves this morning ! I will pull the rocker box off tommorow and have a look ...where is the plug located on the rocker shaft?

Thank you everyone....you have been very supportive
Ray Coyte

Ray, there are two ends on the shaft ( front and rear )
The shaft is hollow and the plugs block the open ends.

Cheers,

Gerard
Gerard Hengeveld


Mystery solved.

It was one of the grub screws at the end of the rocker shaft. Both of them were missing :-(

The rocker box itself covers the end of the rocker shaft quite closely so I think its pretty difficult for the grub screws to fall out when the cover is on.

I suppose when I took the rocker cover off one must have fallen out - I have no idea where the other went to - if it was ever there.

See enclosed picture.

I have replaced the grub screw and made up another for the other end of the rocker shaft so both ends are plugged now.

Forgive the simple question...but does this mean that my rockers were probably not getting a lot of oil to them?

and...

could the missing grub screw get down to the sump? - I truly hope so as only last week I epoxied a powerful earth magnet inside the sump plug cavity so hopefully that might grab it as it goes past.

Thank you everyone for your input - amazing this forum. Have a good week

Ray

ps Gerard I owe you a pint

Ray Coyte

Ray, it'll be interesting to see if you detect an increase in your oil pressure when you get the screws installed. Bud
Bud Krueger

Just come back from a nice fast run in the Autumn sunshine to Stratford Upon Avon

You are dead right Bud....it has given me an extra 10psi. Hot engine at about 3000 revs now gives me 55 psi....it was about 45psi before.

I am guessing that one of the plugs has been out for some time and the other has only recently decided to unscrew itself.

One more thing to check when I recheck the valve clearances next year
Ray Coyte

Glad to be of help Ray, and that pint ?? I'll take a rain cheque lol.

Have a nice weekend,

Gerard
Gerard Hengeveld

Had this happen to me once while racing. Same deal, about a 10 psi drop. Found the errant plug in one of the casting oil "pockets" down in the lifter valley. You might want to pull the side cover off and take a good look in there. Stick a magnet down into all the oil filled recesses.

Clean everything well and loctite those plugs in place. Won't have to think about it again!

Frank
F Filangeri

Ray, you are correct, your rockers would have reduced oil flow...perhaps no oil flow through the bushings as there would be no resistance to flow out the rocker shaft ends. Regards, tom
tom peterson

This thread was discussed between 28/09/2013 and 30/09/2013

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