Hi,

Great day out at Gaydon yesterday. Really interesting looking at some of the XJS cars parked on the hill (plus a beautifully restored pre-HE engine P reg).
My 1978 pre-HE has a problem with the timing chain. I need to find a timing chain tensioner adjuster to get me out of the current issue I have, before I can move on with fixing the engine.
I don't really want to but one just for a few days.

Does anyone have or know of anyone who could lend me one for a few days?
I am based in Malvern, Worcestershire, UK.

Many thanks.

 

Is there such a thing? I've never heard of it.

 

with the amount of labor involved , dont make sense to just borrow one?

 

There is no adjuster - it is on or off - you need a pretty strong tool to lock it into its parked position which has to be done from the top in conjunction with a release tool through the timing chain cover. Are you tearing the engine down ? there aren't many chain problems you can fix up top.

If the tensioner has been in service for a while disturbing it could break it, releasing the tension may be the start of your fun.

This site demonstrates the tensioner pretty well Tensioner Operation but when yours get straightened may be when your troubles really start - and these things are expensive to replace and the engine front has to come off - which essentially means the radiators and such unless you're a real masochist and into self abuse.

 

pic of chain and tensiner,

 

Thanks for the advice. Bernard's site is very interesting. You can buy these tools, latest quote is about £165. However, my 'man in a shed' who has been doing XJS stuff for years made himself one in half a day. He also whipped off the top engine parts to expose the timing chain. He has released the LHS (looking from the front) chain tension (it was very tight and could not be moved with your finger). The RHS is still tight. He says other reasons why engine will not rotate could be sticking pistons rings or frozen crankshaft. He is trying to diagnose as much as he can without taking the engine out.

 

The V12 only uses one cam chain and only one tensioner. Whatever is being looked at (RHS) it is not a tensioner. There are a number of guides and the position of those should be marked before removal.
If in fact you mean the chain is still tight on the other side, it is probably because of the direction of travel and still loaded between crank and cam sprocket.

 

Your mention of a frozen engine, as in failing to rotate, would have very little to do with the chain, and/or its components.

BUT

Behind that chain stuff, is the oil pump, and those I have heard of jamming, with the real early, mainly carby cars, had an issue, and there was a TSB for the "drive adaptor" to be changed only upon complaint from owners.

My suggestion, having been down this path a few times.

Mix up "the brew", AKA 50/50 ATF and Diesel Fuel.
Remove the spark plugs.
Pour an egg cup (rough suggestion I have never measured the pour) of said brew in each plug hole.
GO AWAY, a few days maybe, drink beer is a good time passer.

That "brew" will un-stick rings to liner, EVENTUALLY. Forcing the beast will result in engine OUT, and re-ring at least.

I mention this many times for barn finds, and have "saved" 3 with this method.

Seized crankshaft??, never seen one do that, in ANY engine, unless it was parked up due to running without oil, thus screwing the whole engine, which of course is an unknown.
Of course, the oil pump, mentioned above, will JAM the crank if it has failed internally, but, as said, very rare in any numbers game.

My main ask:

To the best of your knowledge, was it a runner when parked up?? That yes or no is a game changer for assistance in the correct direction.

 

I'd also exercise some care now, if you have released that chain you do not want to turn that engine over with the cams in place and nothing to drive them with, if the brew works and I've also used that on a few things, there's a note about this in the Jaguar service book for pre HE, you also have no idea whether that tensioner cracked or not.

 

Thanks for all.
The car was bought from new in 1978 and regularly driven and serviced, until it was put in the dry garage in 1989 with mileage of 24,135 on the clock. I remember sitting in the back and when it accelerated, it pushed me back in the seat.
It was my father in-law's car who did all sorts of work to it, including completely cleaning underneath and powder coating everything.
I remember helping him take the whole rear suspension and transmission off while he cleaned it all up and then put it back.
AFAIK, the engine has not turned since 1989. It still has the ancient tyres on with loads of tread.
The interior looks like someone just parked it in 1989 and waked away leaving the keys in (looks amazing inside).
He was a mechanical genius who loved tinkering with cars, so he would not have done anything to wreck the engine (apart from leaving it for that amount of time).

My father in-law passed away in 2016 so I decided to see if it would go again in this year (as well as his other Jaguars).

The dipstick shows the engine oil is clean (looked almost new).
We removed the spark plugs and flywheel cover, then took a pry par to try to turn it clockwise only - nothing.
We put diesel down all the bores and left it a few days. Again it would not turn.
We put a endoscope camera down the bores and all looks normal (not like the Mk2 which dropped a valve 2 years ago).
We drained half of the coolant from the block - it was all nice and runny with coloured anti-freeze in there.
We put hot water in the block to try to help expand it a bit - last resort. Again no movement.
Followed by WD40 down the bores - left a few days - nothing.

We then connected a fully charged battery in the boot. Slowly clicking the key around and all expected lights worked and electric windows.
Tried cranking the engine on the starter motor - just a clunk and no movement.

So it has been in storage for the last 6 months. I am now getting my mechanic to see what the cause is, before I decide to sell it for parts or try to get it going again.
The mechanic knows his stuff, he rebuilds XJS engines.
A couple of recent photos.

 

Thanks for the uodate.

I reckon rings rusted to liners.

Time, is all you got I am afraid.

Last PreHE i returned to life had my brew in there for 3 months,with fresh Diesel fuel from time to time.

Eventually it moved, a 3/4 drive breaker bar with a steel pipe over that, and heaved on it, and it moved about 5mm, Beer O'clock.
A week later, we got full rotation.

Another week of nursing it, and then it fired up and ran. Guy still drives it daily, and that was 25 years ago when the rebirth took place.

NOT pretty when it 1st sprang to life, and we were too scared to shut it down, so drank beer and watched it, then it gave a huge "fart" and belched all sorts of stuff out the downpipes (exhaust removed ready for extraction from the body), and settled to a SMOOTH V12 beat.

Your call of course. They are so awesome when right.

Had to be the beer, HAHA.

 

434Mhz,

As mentioned, I wouldn't start by looking at the tensioner. I'm sure with the collected wisdom of "The Brew", you can get it turning over!

If fo whatever reason, you feel you have to sell it for parts (I hope you don't, early ones should be preserved), please let me know where it goes, as there's a few bits that I'm sure could help my own pre-HE.

Good luck

Paul

 

Here here - but I too hope it won't come to that - if the price was right I'd consider taking the car myself as a none runner rather than see it broken up - I hope he gets if fixed, there will never be cars like this again - if electric is the future count me out but that's a debate for a different thread.