Engine seems to be blocked

or the bottom part of the tensioner broken?

Yves,

Your chain is loose… clearly evident from your earlier photos.
You will not be able to draw a conclusion until you remove the front engine cover.

There is pretty much no space whatsoever under the crank sprocket and the only thing that could fall into there is a chunk of chewed up chain guide from the Bbank side. It isn’t going to be a piece of chain tensioner or anything from the Abank because that would always be moving away from the crank on the A side when the engine rotates.

If you can make the chain tensioner flex in and out with your hand, then your likely obstruction is as Dick said. If you look down all of the spark plug holes then look for a piston crown with indentations in its top or a valve head too low down.

kind regards
Marek

Take a look at Help Anybody know how to manipulate the chain and chain tensioner on a V12 HE - #28 by MarekH

This shows where a “stretched” chain sits and where a brand new chain sits. If your chain is loose and the tensioner broken, then it is “front timing cover off” time. You should be able to slip your hand down the Abank side and verify this. The chain should be strongly tensioned, not just lightly pushed across to the middle of the engine block. Note in the pictures how a brand new tensioner is strong enough to push the old
(oily) chain all of the way across and keep it tight even though that means it is rubbing on the engine block bolts. The new (clean) chain being “shorter”, is under more tension than that and sits more outboard.

kind regards
Marek

Marek, have looked allready at your video on the tensioner and it is perfect. Thanks for your comments. I will do the test pushing the tensioner by hand.

Aristides, I agree it is sure now i’ll have to remove the front engine cover!!! Not pleasant!!

Today waiting for the endoscope, soo removing distributor.


Everything looks good, surprinsingly one screw with spring was missing!!!
Small weights were stuck on the bottom and not moving a lot. Nylon screws seems ok.
I will look at Kirby’s documentation to lubricate method before putting back.

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Removing and cleaning and verify throttle pedestal. Everything ok

i’m looking for the small screw with a spring attach coming from the vernier adjustment inside the distributor. not in the parts list from jaguar. Do you know where to find one?

Any old screw, and maybe a spacer or a tab of Loctite to keep it in place, with any spring similar to the original will do the job Yves.
No high science there, don’t remember though if it’s metric or imperial.

Thanks Aristides
Removed the oil pressure sender, leaking oil, to be replaced.
Painting pedestal and throttle parts.

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Since the throttle pedestal is out it’s a good time to check your throttle potentiometer.
Also have a look at the throttle bushings.

yes i just received bushing and seal between throttle and manifold i will rebuild soon.
For the potentiometer I allready check it some month ago it is good.I had to clean betwen the copper tracks because a lot of copper particles there and short circuit.

unfortunately bad diameter for the outside 7/16=11mm instead of 1/2=12.7mm
I wrote to SNG, waiting the answer

If you’re talking about the bushings for throttle linkage, I bought these on Amazon.
They fit perfectly and work great. Will last a looonnnng time.

Not available, but with details you may find elsewhere?

Thanks but no more available, I will try with a french company THN.

You can always just get a piece of delrin (or brass) and turn it in a lathe to the size you need. Very simple. Very effective.
kind regards
Marek

Thanks marek but i have’t any tool foor turning parts.
After all this cleaning I went back to my chain problem with a big light ( still waiting for the endoscope)
What is very surprising is that the tensioner is giving a very big force to the chain, i can see from above the A Bank because it is bend hard like it has to be ( broken or not???). But looking from above the B bank the chain between sprocket and crank is loose, i can move easily this part of the chain by hand but can’t pull it out.( broken or not??)
Look like the crank is blocked by something else.
Do you think removing the tension on the tensioner will help?
Because at this time i can’t move anything to accesse the 4 bolts of each camshaft.
Thanks for your help

There are many things that could have happened there Yves…
You have to bite the bullet and take the front cover off.

Never done it, but in order to do anything you should first retract the tensioner, and I would be very sceptical fiddling with the old tensioner, it’s known to break if you try to move it one way or an other.
And I would put a new one in there regardless.

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Look at the bigger picture. It is likely that the crank and camshafts aren’t in the right places relative to one another if the chain is loose on the Bside but tight on the Aside. The chain should never be loose on the Bside because the Bside is the first to be pulled by the crank. You sound as though you have turned the engine backwards quite a lot at the crank.

I’d get the camshafts off so you let the valve springs pull the valves back up and then at least there might be some hope of turning the crank without causing more damage.

kind regards
Marek

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