EGT gauge - probe installation on TD5

[Cret]

I know I've mentioned this in my other thread but am guessing most people won't see this as it's generally unrelated to the thread title.

I've just bought an EGT gauge this week. Was thinking it would be a good while before I could spare the money for one but I got this all new for a snip at £25 so it would have been rude not to.

Would like to know from people who already have an EGT gauge fitted where exactly they have the probe fitted, and how much of a ballache it was to fit.

I've already had a couple of comments on this suggesting a certain spot on the manifold, but would love to know from other people who have one fitted how they've done it, even with a pictures if people are feeling extra helpful!

Does the manifold need to be removed to drill it? The reason I ask is because of the concern that swarf will fall in as a matter of course and end up damaging the turbo next time I fire up the engine. Perhaps it's possible to drill it in situ then get any bits out with a magnet or something?!

Also, I'm not sure what exact kind of metal the exhaust manifold is but I'm assuming it's a very hard cast metal & potentially a mass destroyer of drill bits/taps etc? I've got some cobalt bits which are very good but I'd rather not chew them up if I can avoid it.

Appreciate any useful info on the installation of one of these anyway, as it would be a nice think to have fitted so I can keep an eye on things after 'tinkering'- thanks in advance for any good tips.

Cheers

Jim

[western]

http://forums.lr4x4.com/index.php?showtopic=1298

http://forums.lr4x4.com/index.php?showtopic=18350

both on Tdi engines but installation not that different for a Td5.

[Cret]

Thanks for the links - they're interesting reading, and there's a bit of useful info in general terms of fitting.

The EGR takeoff point on the tdi looks perfect, but unfortunately on the TD5 that's at one end of the manifold instead of in the middle like they appear to be.

I doubt it's a suitable spot for accurate readings therefore (unfortunately).

So am still not sure about any of my questions I suppose, ie:

1) Best spot?

2) Do i need to remove the manifold (because of swarf)?

3) Is the manifold a complete bugger to drill?

[David Sparkes]

Until a td5 'white knight' comes along, my thoughts are;

Yes you have to remove the manifold, not because of swarf, but because you don't know the location of any internal webs or bosses. Whether these exist for strength or to guide the gasses is immaterial, it will be embarrassing to hit one off centre and snap the drill bit, or even worse, make an unthreadable oval hole.

I removed the manifold I modified, and discovering the location of an unknown internal web guided me to the absolute best spot for the tip.

Yours may have no internal obstruction, but until you look, if no one will tell you, you won't know.

Swarf; there is a school of thought that it doesn't matter, because the first puffs of exhaust gas will blow it out through the turbine before it gets up to speed. However, removing the manifold to look at the inside puts the question of swarf into touch.

Drilling; before turbos, manifolds were cast steel or iron, and as you say, difficult to drill. With turbos the needs have changed, the manifold has to be strong enough to carry the turbo over bumps, and withstand very high temperatures. On some engines they will get red hot in service, not just on the test bed.

On my BMW the manifold looked like rusty steel on the outside, but drilling it revealed it to have a very high nickel (?) content. Whatever, it drilled easily and took a thread like a dream. Absolutely no problem at all.

However, if no one is giving you direct answers you can trust, you have to display more faith in your own ability to make appropriate decisions on your own. It's a learning curve, and the pleasure of climbing it is enhanced by the fact that no one has told you where to put your feet, but you have got there anyway.

HTH

[Cret]

Thanks for your post David - yes that is helpful.

I do have a reasonable bit of faith in my own abilities as I've been car fettling for something like 18 years now. Way less than many of course, but I've learned a lot of bad ideas and a lot of useful stuff over that time.

I'm certainly not beyond making mistakes though, so I'm a fan of asking what I don't know before trying things that I don't have direct experience of. For instance where a job might be quite time consuming to find out myself (due to wife, kid, house to do up, car to do up and boat to do up etc), or has high potential for causing damage.

Interesting comment about the swarf in terms of it being blown through (not something I'd considered) but it's a little bit hit & miss for my liking, and as you say it becomes irrelevant if I remove the manifold anyway.

The theory about the unknown factor of the inside of the manifold is perfectly sensible and I suppose it would thus be silly to guess as a result. I don't fancy having a manifold riddled with 'test' holes either!

So that brings me to another question then - is it a pain in the backside to remove the exhaust manifold on these engines or relatively easy? I've found some cars in the past to be horrific in terms of things that have to be removed first to provide sufficient clearance etc, so I'm wary of simply ploughing in without seeing if people know first, but if it comes to that then that's what needs doing.

I have a Rave manual somewhere so I'll see if that says & will do some googling etc, and will simply go out and have a bit of a stare at it of course and see how it looks.

Appreciate the reply anyway, thanks.

[cieranc]

I took the turbo off the top of my manifold (Def spec 200TDi) and used a magnet on a stick to collect the swarf.

The manifold itself drilled very easily, and tapped well too. Almost like drilling aluminium.

I also know someone who didn't remove the manifold or turbo, just drilled and tapped it with no problems at all.

[Cret]

Thanks Cieran

I've just had a look at the manifold and it looks like it ought to be quite straightforward to remove with the turbo out of the way, but I know sometimes that in itself can be a chore.

The manifold looks very thin, so it could get interesting in terms of the probe itself as it's rather long!

This could get interesting....

[RedLineMike]

hi,

if you remove the turbo heatshield & have a look at the manifold there is a round dot where the manifold collects & then goes into the turbo, i have fitted 3/4 EGT guages to Td5s & this is where i drill to fit the EGT probe

Mike

[Cret]

Thanks for this Mike

That removes a lot of guesswork from it. I've looked at the bit you described and it looks perfect, BUT....

Unfortunately it turns out the probe that came with the gauge I gotis pretty long, and if I fit it there it would basically be long enough to come out of the bottom of the manifold as well I think!

Real bugger! I suppose it might be doable to drill and tap the hole at an angle.

The other possibility that I've wondered about is bending the probe as I've read a thread (may have been on here - can't recall) where someone did this without any real issue.

Might be possible to buy a shorter probe presumably but if I'm going to have to resort to doing that it might make sense to try the bending option first since there'll be nothing to loose really!