Shims.

[AlanS]

Well, as we delve further into the bowels of the sons BX TZi engine (DKZ) the more I keep convincing myself I need to do.
Popped a valve out yesterday and now discover they'll all have to come out and be faced and the seats cut as well as getting the flywheel skimmed and the baby of them all, trying to get the head stud out that broke as I stripped it down. What a **** of a job that is!
Question is, when I get the valves done and refit the camshaft and buckets, what's the score with setting the tappets?
Is it standard practice to grind down the existing shims used for adjusting tappets on these or are the shims something the engine rebuilder is likely to have due to them being a reasonably standard part on other engines apart from a PSA engine or what else is standard practice as I've never had to do a shimmed engine for many years. Last one I was involved in was a Honda I raced years ago and I had a team mechanic to do that.
As I have the only BXs in a town where there's only about half a dozen Citroens (and we own most of them) and the engine rebuilder has a good reputation but talks waiting times in weeks I feel a bit titanic
If it's a case of having to "buy a boxful" and using what we need, anybody got any clues on cost?


Alan S

[Brian]

Hi Alan,

I think this question has come up before on previous forums.

Well on diesels, I have always carried out a measure, then some shims can be re-used.

Then I have successfully ground one face of a shim placing the ground face to the bucket.

I use a suitable nut so that the shim fits into it, place the nut and shim on a grinding wheel, hold the nut with a Mole wrench, then apply gentle pressure on the shim with a rod or bolt to suit the nut, start the wheel, measure shim at regular intervals so as not to remove too much metal.

Easy does it, don't rush...






.

[DavidRutherford]

are the shims something the engine rebuilder is likely to have due to them being a reasonably standard part on other engines apart from a PSA engine

Yes.

AFAIK, all XU series engines, (be they Chevroned or Lioned) use the same shims. Amusingly, although they are sold as metric, they are quite clearly imperial, and available in steps of 1 thou, which indicates to me that they are a standard part, rather than a PSA specific part.

The standard range of shims is from something like 2.3mm to about 3.5mm (IIRC) if you need thinner shims than this (As I often have done) then it's better to grind a bit off the end of the valve... it's also a hell of a lot easier to make the end of the valve stem square than it is to grind the shim square.

[mnde]

Are they still available in a multi-pack from Citroen, do you know?

Regards,

Mark.

[Geoffrey Gould]

Hello when I needed some thinner shims and the shops were closed etc. then I found it was a simple matter of holding the shim/s and grinding them on an angle grinder. I didnt have a bench grinder available at the time.
Engineers and that had better look away now.
Obtain a 1/2" square drive socket and a long extension bar. The socket needs to have the internal diameter just big enough to fit the shim into (from memory 14 mm). Pack the socket with nuts/washers so that the face of the shim to be ground stands proud of the socket by a small amount. Rest the socket/shim against the face of the disc/grindstone supported firmly.The long extension bar gives you something to hold, press lightly onto the stone, you may find it helps if you rotate the bar ,this I found helped to grind the shim accurately.
Remove, measure,repeat etc.
The shims are IIRC the same size as used on the Hillman Imp engine.
It does work quite well. Obviously be careful dont take any chances if you have any doubts at all.
Cheers.
Geoff.

[tom]

Thanks Geoff. That looks like a workable way of doing it.

[AlanS]

I'm still carefully wrestling with trying to get this snapped off stud out without drilling a hole through the side of the block; brother those headbolts are made of tough stuff. This one snapped right at the top of the actual thread so it's 2" down inside the hole.
We've made up a couple of sleeves to act as guides, heated, penetrened and tried once to drill it, but not a move.
I have been lent some fairly expensive gear to try to do it with, so that's the current hold up.
Thanks for the ideas on the shims, I'm certain it will all be used when we reach that stage which at present seems to be getting further away instead of closer.


Alan S