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Hi All

Following on from my thread about adjusting valve clearances due to valve seat recession, David Marks advised that I would be far better off replacing my cylinder head.

I have bought a secondhand head from a specialist breaker and all of the clearances are in spec and everything looks in excellent shape.

I am after a bit of guidance here as the only manuals I can find are the .pdf versions and none I have found give a really detailed guide to replacing the head. The cam chain tensioner are different on my car too, the cap is one piece, whereas the manuals show on where you can release the tensioner through the centre.

The other grey area for me is the timing gear/chain arrangement. How do you feed it through the head? Take the gears off completely?

Any help would be most welcome

Cheers

Glen.

http://www.jec.org.uk/forums/viewtopic. ... ket#p43513


this link above may help a little

BB

http://www.jec.org.uk/forums/viewtopic. ... ket#p43513


this link above may help a little

BB

Excellent, that was exactly what I needed. Many, many thanks.

Hi all.

I am in the process of removing the head and am struggling to get the cam sprocket bolts out as they are mega tight.

The timing tool is not man enough to stop the cams turning and I don't want to strain the chain.

Any tips?

Cheers

Glen.

Hi Glen.

Have you tried putting a socket and breaker bar on the crankshaft pulley and wedging it against the chassis to stop it moving. Then try and 'crack' each bolt before removing any of them in the normal manner (don't forget their locking tabs have to be pushed back first). I don't think that this would put any undue strain on the chain - unless they're welded on!!

just put the car in gear ( or park , if auto ) this will put the whole weight of the car on the crank , and the chains will take it

make sure your also turning the bolts the right way.......


and as said above, make sure the locking tabs are bent back

BB

Thanks Guys

There are no locking tabs on my car. It's got flanged bolts.

I will try your suggestions tonight.

Cheers

Glen.

Hi All

I successfully removed the bolts using good old leverage. The sprockets on my car are different to those I have seen in the manuals, they do not have a removable centre, but long slots for the bolts. This explains why they were so tight.

My chain tensioner is also different to the manuals in that it does not have a removable centre to gain access to the Allen key drive. If I could work out how to upload a photo, I could show you - photobucket perhaps?

So my next question is, how do I re-tension the chain? Wind back the tensioner, fit it and let the oil pressure do the job?

Cheers

Glen.

Hi All

Well, the good news is that I have changed the cylinder head and the compression on all cylinders is between 11.5 and 12.0 bar. Thanks for everyone's help.

The bad news is that the rough idle and "fluffy" running at higher speeds is still there, so it wasn't poor compression causing it after all. This is a tad annoying to say the least.

You can expect a few more posts while I get tot he bottom of it.

Glen.

have you tried adjusting the electrical timing at the bottom of the distributor

BB

AJ16 = no distributor, BB.

Paul

ok

thought it was an AJ6 , so scrub my previous comment , lol

BB

Hi all

Yes, AJ16 so can't adjust the ignition timing.

Here is what I have tried.

Holding it at a fast idle and disconnecting the coils one at a time points to No1 as being the culprit, no difference when disconnecting the coil.

I swapped the coil with No2 and the fault stayed at No1, I then swapped the plugs and still No1. Took No1 plug out and it's sparking - that's as far as I've got.

Being dual fuel and the fault being the same on both LPG and petrol tends to suggest ignition, but both fuel systems get their injection signal from the same ECU so there could be a dodgy connection or broken wire deep inside the loom - what joy.

Next step is to plug my OBD11 reader in so see if that brings up any codes.

Keen for more advise as always.......

Glen.

I thought I would let you know that I traced the cause of the misfire to a big leak on the inlet manifold caused by me leaving a big chunk of the old gasket there - Ooops.

She now purrs like she should.

Thanks for all the help along the way.

Glen.

I've read through this thread, and I think it has good information. Thanks. I have also been unfortunate to have had to strip and re-build my cylinder head in the passed, due to poor advice from a 'so-called' jaguar specialist! I discovered my problem was an intermittent fault with one of the oxygen sensors, and after speaking with the fabulous David-Marks, he pointed me in the right direction to find this. Still, it gave me an opportunity to acquaint myself with the AJ16 Engine, and I feel more confident knowing that now the Cyl-Head has been completely refurbished by me, I have no-worries about the valves or their clearances. The only negative side was one that could happen to any engineer, I didn't clean one of the cylinder-head-bolt holes out properly, (there was a little coolant managed to get down one of the holes) I got 'hydraulic-lock' and snapped a head-bolt whilst torquing. So, if you do a cylinder-head, make sure you clean the bolts-holes out with a thin screwdriver/rag, and blow-out with compressed air, (making sure the compressor you use is well filtered with no water in it!) Cost me a gasket and a set of bolts extra!!