Skimming XUD9 diesel cylinder head

BX Tech talk
Dyane425
Confirmed BX'er
Posts: 72
Joined: Mon Sep 10, 2012 11:22 am
x 1

Skimming XUD9 diesel cylinder head

Post by Dyane425 » Sun Jun 24, 2018 4:43 pm

I am considering getting my cylinder head skimmed. Quite a few firms do this, but they advise that on many Diesels, the valves sit proud of the surface of the head, and will need to be removed prior to skimming. Do the valves sit proud of the surface of the head on the XUD 9 (D9B) Diesel engine (1991 J reg Diesel Auto)?

Kaapelimies
BXpert
BXpert
Posts: 189
Joined: Wed Feb 10, 2010 9:01 am
Location: Hollola, Finland
x 6

Re: Skimming XUD9 diesel cylinder head

Post by Kaapelimies » Sun Jun 24, 2018 6:57 pm

Strange question. I've always had the head checked for leaks, which means it has to be totally dismantled. I would never skim a head without checking it's trouble free. It doesn't even cost so much compared to doing all the work and after the first 1000km find out that the head is cracked.
BX 4x4 estate, several BX Van's and some more normal estates in Finland.

rutter123
1K Away
1K Away
Posts: 1990
Joined: Sun Sep 02, 2012 9:54 pm
Location: South Lincs
x 40

Re: Skimming XUD9 diesel cylinder head

Post by rutter123 » Sun Jun 24, 2018 10:31 pm

As Kap says skimming the head just for the sake of it is pretty pointless unless it's warped from over-heating in which case it's most likely the end of your engine. Any decent engineering company should be able to check tolerances and remove components like valves etc before skimming and prob a good idea to lap the valves as well, sounds as though youre having problems.
I'm pretty sure an early pug 306 n,/a head is the same? And easier to source if yours is knackered.
There maybe 2 variations 66hp and 72hp round port and square port if my memory is correct.
90 BX Tzd turbo 294k SORN undergoing major surgery
90 BX Tzd turbo estate 46k awaiting surgery
65 Peugeot Boxer Van the new workhorse
52 Toyota Rav4 180k Bulletproof Jap reliability

User avatar
Vanny
Merseyside resident
Merseyside resident
Posts: 3424
Joined: Tue May 17, 2005 11:48 pm
Location: BX Pub
My Cars: BX 16v Ph2
x 11

Re: Skimming XUD9 diesel cylinder head

Post by Vanny » Fri Aug 03, 2018 6:28 pm

With a cast block and alloy head the rates of expansion and contraction of the two halves will result in warping, within the micrometer range. Obviously this is why you've got a gasket.

I've always been taught with an XUD when the head gasket let's go, the head will have some amount of warp and should be skimmed not needs be to make it seal but to give the next headgasket the longest life. And XUD typically can't be skimmed more than 3 times.

On the bottom of the head there should be a circular depression, this tells you how many times the head has been skimmed (as it gets skimmed the bottom of the depression becomes shallower).

A decent engineering company will tell you if it needs taking apart or not. Most places will strip it down as part of the pre and post cleaning process. I wouldn't bother to do it yourself unless your curious of really tight on money. There are a couple of types of valve spring compressor, make sure you get the right one. My diesel one won't work on the valver head.