Plenum heating vacuum leak, drilled hole??

[haaren]

After a smoke test I found a vacuum leak


So now I took the plenum of again to seal the plenum heating, but to my surprise it's not the plenum heating which is leak but a small drilled hole in the plenum itself.....


Can anyone explain why this hole is there and if I need to seal it?
i will loosen the heating anyway to give it a fresh seal, or can you delete the hole heating without any down effects (it's not connected anyway).
Main question is the small hole as that's my vacuum leak, thank you!

Picture with dismounted heating

So it's the small hole on the right side under the tps

Edited by haaren on Saturday 23 August 12:44

[haaren]

Edit
The mounting points reaches to the inlet, to delete the heating it will need to close these. Not impossible but easier to put it back.
Why is there a extra hole to the side of the throttle valve? Can not see it from te other side, do not know if it's open or closed

[Belle427]

I believe its a drain hole but am not sure if its just for the tps chamber to stop moisture build up etc in there.

[haaren]

Hi belle, bit shout it be "leaking" or should it seal?
If you do a smoke test, will it leak on each engine or should it be sealed on tps or whatsoever?

[blaze_away]

haaren said:

Hi belle, bit shout it be "leaking" or should it seal?
If you do a smoke test, will it leak on each engine or should it be sealed on tps or whatsoever?

Over the last year that hole u der the tps has come under scrutiny. That said it is believed to be intentionally there to allow throttletokeep clean.

The holes from the threads to the plenum should not have gone that deep and need blocking off. This is what mine had too.
Seeing you photos jogged my memory I blocked then off with silicon filled hose tails on the spigots

[Belle427]

I don`t know for sure but would think it should not let the smoke out.
Maybe the throttle spindle seals are worn a bit too letting some smoke through, you could take off the tps and have a closer look but this will require setting up afterwards. Not difficult though if you match the setting on Rovergauge.

[haaren]

Hi blaze & belle,
Thank you for your replies, I will seal the little hole with some liquid gasket. There was no leaking via bolts or the pipes of the heating, so they are not connected to the inside of plenum. Nevertheless I will seal off the bolts with liquid gasket as well to be sure there is no vacuum leak there either. Hopefully it will have no disadvantages over time, but for now probably the best thing to, correct?
It was not a small leak, quite a lot of smoke was coming out of the tiny hole.

To close the tappets of the heater I can also use gas / Teflon tape to seal the bolts and still delete the heating case.

Edited by haaren on Saturday 23 August 21:34

Edited by haaren on Saturday 23 August 21:42

[Belle427]

Cant see too much of an issue blanking it off, just check the throttle plate area now and again for cleanliness.
Looks a bit oily in the photos.

[ChazUwe]

The hole beneath the TPS is their by design. I don't see a reason to blank it off as it is original so obviously meant to be there. If you remove the heater plate thing permanently (with the two pipes) you will need to seal some of the remaining holes. Some people say there are two that need blanking, but in my case there were three. You can shorten the existing bolts and reuse them and the original gasket. Some thread seal can be used for good measure too!

Edited by ChazUwe on Sunday 24th August 11:37

[haaren]

The hole is indeed in direct contact with the tps camber, probably to loose the pressure if you have some leak through the shaft. For now I sealed it to proceed with the vacuum leak test, which it passes now. In future I need to replace both seals of the throttle axel, is there somewhere a guidance to do this?

I did demount the pipes of the heater housing and mount it back, I think this will be better. By deleting the pipes you have a bit more space in the area if you need to do something. That was my view to delete it.

[mk1fan]

I used shorter bolts to seal the mounting holes of the redundant heater plate. In hindsight / if I need to do it again, I would use grub screws. I also used some threadlock to seal the threads.

[scottliv]

What you need for the spindle seal is this. There are 2 fitted. Easy to replace. My spindles were both leaking and thought is maybe how air is getting to the drilling. My old ones were all hard - they were (as far as I know) 30 years old.
https://rimmerbros.com/Item--i-AUD3577L

[haaren]

scottliv said:

What you need for the spindle seal is this. There are 2 fitted. Easy to replace. My spindles were both leaking and thought is maybe how air is getting to the drilling. My old ones were all hard - they were (as far as I know) 30 years old.
https://rimmerbros.com/Item--i-AUD3577L

Hi Scott,
Could you describe how to replace them, are the sales clamped and can you remove all throttle valve parts without any special tools?
In near future I want to replace both as well, the other side leaks a little but when the pressure of the smoke machine gets higher.