[xj-s] Timing chain replacement - '85 HE UK

XJ-S
1

Hi there

This is my first posting to this list - although I have gained much useful
information by reading it. I am slowly sorting thru the various “issues”
regarding this car and have reached a point where I need some specific
advice from the list. I hope someone out there can help.

My timing chain is making a slight noise (only audible at idle) indicating
it is stretched.

The timing has had to be advanced 11 degrees (out of specification) to
compensate for this.

I am getting bad economy (22l/100km, 13mpg (Imp), 11mpg (US), city driving),
inconsistent starting (sometimes perfect other times requires 2/3 tries -
maybe unrelated) and very high HC and CO levels in the exhaust.

If the timing is set to specification performance drops and economy worsens
to 24l/100km, 12mpg (Imp), 10mpg (US).

The temp sensor has been replaced - before that economy was about 26l/100km,
11mpg (Imp), 9mpg (US).

This car doesn’t have an oxygen sensor as described in Kirby’s book - US
only apparently.

The job to replace the timing chain involves a bit of disassembly but then
the new chain is just threaded thru - medium expensive.

If the timing chain guide is broken then a much bigger job is required - v
expensive.

Kirby’s book has a page with economy figures - presumably for US spec cars.
He also says that UK spec (B emission) cars operating in the first 15
minutes should get 12mpg (US I assume), 19.5l/100km. As I make mainly short
trips I should presumably be getting about this level (am interested in
modifying this B emission system after the car is corrected).

Is there a way to tell if the guide is broken before commiting to the timing
chain job - either by test/symptons or inspection?

I have heard that the timing chain should give 150,000 mls. As my car reads
107,000 mls does this indicate either another fault causing premature
failure or that the milage has been “adjusted”?

Can you advise what brand of timing chain Jaguar used (assuming Jaguar
didn’t make it themselves)?

I would like to check my B emission timer - but I don’t know where it
is/what it looks like?

Thanks for your assistance

Regards

Julian
'85 XJS HE coupe (UK spec)

2

My timing chain is making a slight noise (only audible at
idle) indicating
it is stretched.

Well, my chain, after 160k had less play (both longitudinally and
transversely) than an aftermarket replacement! So the old chain went
back in.

The timing has had to be advanced 11 degrees (out of specification) to
compensate for this.

Very, very (extemely) unlikely that the chain could possibly cause this
amount of shift. It ain’t made of elastic :slight_smile:

I am getting bad economy (22l/100km, 13mpg (Imp), 11mpg (US),
city driving),
inconsistent starting (sometimes perfect other times requires
2/3 tries -
maybe unrelated) and very high HC and CO levels in the exhaust.

If the timing is set to specification performance drops and
economy worsens
to 24l/100km, 12mpg (Imp), 10mpg (US).

How is your distributor advance mechanism? Both mechanical and vacuum?

The job to replace the timing chain involves a bit of
disassembly but then
the new chain is just threaded thru - medium expensive.

If the timing chain guide is broken then a much bigger job is
required - v
expensive.

The thing this tells you is, check the distributor first. Then check it
again. The advance systems are stuck (mechanical) or inoperative
(vacuum) - a pretty solid working assumption.

Kirby’s book

Kirby’s book says: check the distributor advance mechanisms.

Can you advise what brand of timing chain Jaguar used (assuming Jaguar
didn’t make it themselves)?

Morse. It is continuous and has no link. Aftermarket ones have a link.

Craig

3

Can you advise what brand of timing chain Jaguar used (assuming Jaguar
didn’t make it themselves)?

Morse. It is continuous and has no link. Aftermarket ones have a link.

The Reynolds chain I fitted in My XJ-S in 1987 had a joiner link. When I
went back in 1998 to get a chain for the e-type, the guy (at the local
Reynolds warehouse) looked at the sample, cut off a length of chain and then
re-rivetted it as a continuous loop.

He assured me that it would not come apart at the joint. Time will tell.

regards,
MikeFrom: Craig Sawyers