Pump Wiring Botchery!

[spider]

Earlier manifolds (I think pre 97 possibly 96) will not have any EGR gubbins in most cases. I'd have to check but I'm sure the first 406 TD's did not have any EGR. Other ones will fit (306/405) but you'd not match the downpipe I guess. Very early 406TD did not have a cat either, possibly a manifolds of one of these.

You're correct in that the vacuum pipe actually operates it. As long as the valve is actually closed removing the vacuum will be enough in most cases. The problems that sometimes happen when people block the vacuum are because the valve is either coked up or not 100% jammed shut before.

[evilally]

Cheers Andy. On second thoughts, I'll just refit the one I have and do the vacuum pipe mod. Getting a hold of the right parts could take a while and I need this thing rolling again.

[spider]

If you ensure the valve / manifold is not choked with residue from the EGR system and the valve is free to move and closed, no vacuum = no operation.

Ensure you block the open vac pipes.

Random tip: the fuel pipe leakoff end 'cap' on the injectors seem to make ideal caps for this vacuum port blocking purpose if the pipe is the correct size. I did this on the 106, stuck one on the t-piece on the main pipework for the EGR then did not have a silly pointless thin vac pipe doing nothing.

[evilally]

It was a long fight with the inlet manifold tonight, but finally success. Here's what the EGR has done to my engine:





....anothoer curiosity. There was hardly any of the inlet gasket left, less than half. What was left was very brittle and crumbled easily. What worries me is where did the rest of it go? I have a lot of gunk down the back of the engine. I think the crap generated by the EGR has got past the failed inlet gasket and gone down the back of the engine. I only hope that none of the gasket has gone the other way into the engine

On to valve clearances. I only measured the inlet valve on the cylinder which made 200psi (after which I called it a night and I'm waiting on a delivery from the chip shop ). Specified clearance is 0.15mm, but feeler gauge reckoned it was 0.06mm. Is this a serious problem? Not that it matters as I have a new head arriving tomorrow, but it would be nice to know if this was the source of my issue (and the failed gasket can't have helped).

[CitroJim]

Quite mucky isn't it!

The clearance is very tight Ally and this is the classic happening of the XUD7 engine where the valves hammer into the seats and close up. It's not so often seen on an XUD9 but you just have! I expect you'll find some even tighter ones and that will account for the low compressions. They will be tight enough just to hold off their seats and drop compression significantly when cold and make starting very hard.

As soon as the engine has warmth in it the clearances will open up so in the summer you may not have noticed a starting problem at all...

[evilally]

Cheers Jim, here's the rest of the clearances:

Inlet 1: 0.06mm
Exhaust 1: 0.26mm
Exhaust 2: 0.26mm
Inlet 2: 0.1mm
Inlet 3: 0.08mm
Exhaust 3: 0.28mm
Exhaust 4: 0.28mm
Inlet 4: 0.08mm

......so the cylinder with the tightest inlet has the lowest compression, so that adds up. Exhausts all look good which is consistent with what people say about inlets being the usual problem.

Checking clearances, good times:



....and a slightly used recon head turned up today:

[CitroJim]

Ally, are you going to try to re-shim or going straight for a head change? I ask as you are very likely to find a re-shim to the correct clearances will resolve all your problems...

It just seems worth it to possibly save a whole lot of work...

[evilally]

Hi Jim, probably the sensible thing to do would be to reshim, but I had decided just to go for the head swap. To get the camshaft out I'll need to take the timing belt off. At that point, there are only a few other minor items that will need removed to lift the head. I'm thinking that it would be good way to rejuvenate the engine (along with rebuilt injectors, manifold de-coke and de-EGR). Plus I don't mind a decent bit of spannering. That is assuming the new head is shimmed correctly and ready to go.....

[spider]

I was going to say check the clearances on the other head while its convenient.

If changing them measure shims rather than rely on their number if possible.

Not sure if its worth a recheck when its fitted as well

[evilally]

Might as well, only takes a few minutes!

Another question, is this amount of oil on the turbo acceptable or is something (-expletive removed-)?

[CitroJim]

It is quite oily although I'd hazard a guess that most has come from a leaky rubber coupling on the compressor side and is unlikely to be the oil feed or return line...

[evilally]

Thanks once again Jim.

I have been stopped in my tracks one more time. I measured the clearances on the "recon" head:

Inlet1 0.24
Exhaust1 0.3
Inlet2 0.3
Exhaust2 0.36
Inlet3 0.3
Exhaust3 0.36
Inlet4 0.4
Exhaust4 0.24

They seem comical to me. I purchased this on ebay, I think I'll be sending it back

[CitroJim]

They certainly need resetting Ally but if the rest of the head is good and you got it for a good price just redo the clearances...

However, if you paid top dollar for it as a fully recon head and so on then it's a different story..

I'm tempted to set clearances toward the loose end of the tolerance range given what we know about how they close up over time and how they're tightest when cold...

[evilally]

Cheers Jim, the head was £120 with a new set of Denso plugs, apparantly clearances were set. I'm going to keep it and sort it out. I'll take the cam out of my old head and see how it works etc and maybe I can re-use the shims to make something workable.

I lifted the head last night and it actually looks like I've got a blown gasket, after all that!

[CitroJim]

I lifted the head last night and it actually looks like I've got a blown gasket, after all that!

Ahh well, not wasted work then Ally Good...

This might help you calculate the shims you need. A spreadsheet to take the pain out of the maths...