Timing chain tensioner

[peters3103]

Hi Gents,
My engine has been removed for the purpose of addressing a lower timing chain rattle and oil leaks. After removal of the timing cover it was revealed that the hydraulic timing chain tensioner had never had the spring tension released, ie it was still in the locked position. I bought the car with 10,000 miles on a rebuilt engine (receipt) and I’ve subsequently put another 15,000 on it over 12 years. My engine builder (45 years Jaguar experience) was surprised it wasn’t noisier. Chains/sprockets are serviceable so a new (quality) tensioner and chain guides will be fitted along with a new water pump bearing/seal, crankshaft damper, machined flywheel and new clutch. Tappet clearances have also been checked. Here’s hoping for a quiet, oil-tight engine

[abowie]

That's just laughable.

[peters3103]

Yeah hysterical

[abowie]

I feel your pain. It's impressive that it ran so well for so long.

[mtnjag]

I had a similar experience. The PO had parked the car in his garage for 8 years after having noisy chain/valve train noise work done which did not solve the problem. Disgusted, he parked it and didn’t look back. Sold it to me and in the course of checking things out and bringing it back up, surprise, the tensioner wasn’t released!

[peters3103]

Too bad the tensioner isn’t accessible without removal of the timing cover. It’d save a lot of blood, sweat & tears, not to mention $$

[peters3103]

Hi gents,
I have picked up my repaired engine. Now for some painting to the block and head and front suspension overhaul/paint before engine is installed.
I have an update on the inoperative timing chain tensioner. Apparently when the mounting bolts were tightened up the plunger/rubber pad assembly jammed against the timing cover so it was barely providing tension on the chain. Obviously missed by the installer!
So, tensioner and guides sorted (chains & sprockets all serviceable), replacement XJ S3 camshafts fitted and valve clearances done, water pump and crankshaft damper refurbished and flywheel machined and balanced. Hopefully all is quiet and oil tight upon restart

Cheers,
Pete

[PeterCrespin]

How did the chain tensioner touch the timing cover? Did you use the flat plate behind the pad to stop it rotating?

Pete

[peters3103]

Pete, this was an engine rebuild that was done in 2005 before I bought the car in 2007. Presumably the flat plate wasn’t fitted if that is what has allowed the plunger to jam against the cover. My repairer did show me a new tensioner and flat plate to explain the problem he found so I’d reckon that’s what he meant. I was still a bit shaky from handing over the cash!