AJ16 Cam timing

Hello I’m Kyle I’m a new member here but have been around this site/forum for a while. Not sure if there is a better spot to post this but here goes I have a 1995 xj6 that I think the cam timing is off. It was my daily driver till a couple weeks ago, I started it and it ran for a half second and shut off (it was really cold out) I cranked agian and the engine sounded weird like there was no compression, ran a test and its got about 90 on all cylinders. Reomved cam cover, set #1 on tdc timing mark in the little window and the missing tooth on the crank sensor are all in the proper spot. Now I need the camshaft alignment tool 18G1433 (I think this is the right number) to reset the cams. I was reading on here that there is a template available but the link does not work. [x300] Template for a Camshaft Timing Tool - X300 - Jag-lovers Forums (jag-lovers.com) I found one on ebay for $40 but If I could print/ make a template would be preferred. Please help its been a good car!

Hi Kyle, its strange that it was running fine then with no change wasn’t, so would be surprised if the timing is all of a sudden out. You haven’t said if you had to adjust the timing when you checked it? I’d be more inclined to think the sensor had gone. Although you mention figures of 90 for compression - I assume this is psi? seems a little low, would expect 150 psi (there abouts) if my maths is correct and compression is 10.1:1. Have you added a few drops of oil into the cylinder and run the compression test again to see if it makes a difference? I assume that you have done all the usual checks…plugs, spark, fuel pressure, fuel regulator etc?

The earliest X300s had the flatter AJ6 tensioner as I recall? I think the redesign (which can be retrofitted) was to stop the tensioner from falling out after high mileage. Have you got a picture showing the tensioner?

Jaguar issued a few TSBs for the AJ16 engine cams.
03-1-04 Poor Idle Quality.pdf (284.4 KB)
03-1-06 Camshaft Timing.pdf (113.3 KB)
03-1-09 Rattle After Start.pdf (130.1 KB)

I have had AJ16 engines ‘cough/pop’ and then go to low compression cranking.
Seems like the engine over-fueled or something and I had to crank it a long time to get it started again. Very rare but it has happened to me a few times with different customer cars. (maybe bore-wash’?)

!

That’s the newer style fitted to all but the early AJ16s AFAIK. Bob Gauff’s TSB info would be the definitive source. If you still have 90 psi you haven’t bent any valves.

That seems like good news. I’ll add a little oil to the cylinders and try the compression test again.

I’m very much not an expert at these things but, having twice done the same thing before, i.e. running the engine for only a very short time, I’d say it’s flooded.

The way around that is tried and tested but you need a really good battery: floor the throtte and crank. Keep cranking…keep cranking…keep cranking and be ready for her to fire into life.

What do you have to lose?

After that, make a mental note to NEVER run these engines for less than 2 or 3 minutes.

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IIRC with wash down if you use WOT the ECU cuts off the fuel supply so after 30 seconds or so of cranking lift the throttle to about 25% open to get the injectors firing again. If the oil pressure can’t build to regain compression a small amount of oil in all 6 bores is the answer. PITA!

Had a chance to work on it today, added a little oil to each cylinder and cranked it a bit then did a compression test and had around 150, put it back together and it fired right up! Very happy did not expect this to work!

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Way back it took me quite a while to persuade some J-L members that this actually can happen and that oil in the bores was the cure!
I’ve experienced it on my XJ40, X300 & X308.