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MG TD TF 1500 - diameter bore in screw inside oil pipe banjo bolt

Inside the upper banjo bolt of the oil pipe is a screw with a hole. This M6 screw is not listed in any part list. What diameter is correct?
W_Mueller

Are you referring to the adapter for the oil pressure line? It goes under one end of the oil pipe that runs from head to block. Sandy
smb brainsky

yes - the upper adapter of the oil pressure line from the block to the head. In my case inside at the head side is a M6 thread with a screw. This screw has a bore hole and it seems someone has drilled out that hole.
W_Mueller

Correct me if I'm wrong but I believe the banjo bolt with the oil pressure gauge fitting is supposed to be at the bottom of the pipe into the block to read the correct engine oil pressure--might pay to check up on that if you're going to run the gauge from there
I seem to remember that there is a popular parts catalogue with it incorrectly fitted to the top-----------------?
William Revit


Look at Archive about "oil Line Restrictor"

https://mg-cars.org.uk/cgi-bin/or17
Richard Cameron

1) I believe the M6 screw was added by a DPO, perhaps to seal an inadvertent hole.

2) Early TDs have the oil pressure take-off at the head. Later cars at the bottom, perhaps to give the impression of higher oil pressure, as in reality one way or the other does nothing to increase actual engine oil pressure - only the INDICATED pressure.
Lew Palmer

@ William
yes the gauge shall be fitted to the buttom

@ Lew

May be it was the DPO - but the new banjobolt I bought comes with a M6 thread inside (at the head end). The old bolt has that thread too and a M6 screw with a bore was inserted. There is a lot of oil in the rocker compartment.

@ Richard

thanks for the link but it comes up with an error. Searching the archiv too many threads poped up.

What is the headline of the thread?
W_Mueller


Search the web archive on this BBS Forum.------"oil line restrictor" and use "All of these Words" checked.
Richard Cameron

I have an early TD (TD3042) with the oil pressure fitting at the head. There is simply no such M6 screw anywhere to be found near or on the pipe, banjo fitting or banjo bolt.

I'd love to see a photo of the screw and surrounding area.
Lew Palmer

The bore of the bolt is .317

Butch
R Taras

@ Lew

I'll try to make a picture but it will last.

@ Richard

I found some minor threads but a restrictor seems to be with some discussions - but I found a bore size of 0,05".


W_Mueller

Don't forget the threads on the EXPAG engine are metric but not as we know them. Their pitch is finer than current ones. If you screw a modern M6 into any tapped hole in the engine you will strip the thread. One of the first things I bought years ago when I had a TD was a set of correct taps and dies which I used to clean all the engine threads. I think they came from Tracy Tools.

Jan T
J Targosz

I have an early TD (TD3042) with the oil pressure fitting at the head. There is simply no such M6 screw anywhere to be found near or on the pipe, banjo fitting or banjo bolt.
Lew Palmer

Banjo bolt with restricting orifice and male fitting out to pressure gauge. In this case, the bolt location is to the head.

JIM N

Phone would not focus on the brass jet, but you get the picture. This orifice measures 0.040".



JIM N

AHH Ha--
reading back through this, the first few posts ---------------------
--------------
""
Inside the upper banjo bolt of the oil pipe is a screw with a hole. This M6 screw is not listed in any part list. What diameter is correct?

smb brainsky
Connecticut
USA

Posted 16 July 2019 at 21:37:03 UK time

Are you referring to the adapter for the oil pressure line? It goes under one end of the oil pipe that runs from head to block. Sandy

W_Mueller
Germany

Posted 16 July 2019 at 22:55:28 UK time

yes - the upper adapter of the oil pressure line from the block to the head. In my case inside at the head side is a M6 thread with a screw. This screw has a bore hole and it seems someone has drilled out that hole."""
-----------------------------

Exactly the same as Jim's pictures

This is the oil restrictor to the rocker gear that has been talked about here---
If the restrictor is in the oilpressure gauge banjo bolt like this one in the pics then this banjo bolt needs to be fitted in the top(cyl.head) position so that the gauge will read correct engine oil pressure frome the engine (oil pump) side of the restrictor

If this bolt were to be fitted to the bottom of the pipe then the incorrect restricted oil pressure would show on the gauge




William Revit

My confusion came from the engines I have seen with a restrictor have had it fitted to the blank banjo bolt and in the top position and the gauge at the bottom for full oil pressure--
With the restrictor in the gauge banjo bolt as you have it and in Jim's pic it will need to be in the top position for the gauge to read engine oil pressure correctly

willy
William Revit

Yes - it is in the top position and it shows to the rockers.

Is that screw with the bore an addition or is it it standard?

Can anyone else confirm 0,04"? Mine is 0,1" and it looks as drilled out.


W_Mueller

We can confirm that this is NOT original. The part shown in Jim's photo looks like a jet from some fixed jet carburetor.

John
J Scragg

Had a look around the internet and found a reference to the restrictor size--
Hope this helps----
"
Factory manual quote:" Commencing at Engine No.31943, the banjo coupling on the oil pipe (gallery to head) has had the internal diameter reduced to .055in. (1.39mm) "
----

There was a fair bit of discussion about this here a while back---

Some people say that the restrictor is there to reduce oil flow in the cylinder head which is a valid reason as there is more than enough oil flowing up there if you run one with the rocker cover off--

Others say the restrictor goes in the bottom position and was put there to stop the oil pressure gauge needle flicking and making a knocking noise at low speed, but, in this position the gauge reads low

Personally I would prefer to know the exact oil pressure so top hole for me-

If the gauge happens to be noisy/flicking a damper in the gauge line would sort that out but I doubt you'll need it

willy
William Revit

Thanks to all


I guess you have sorted it for me.
W_Mueller

This thread was discussed between 16/07/2019 and 19/07/2019

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