New 1990 VDP Owner

If you call welch call and ask for Dave…they have MNAY MANY engines and complete drivetrains.

And if on the West Coast there is Jaguar Heaven in Stockton California.

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This model of Jaguar engine, the AJ6, does not have a serpentine belt as such but rather more conventional belts to drive alternator, water pump, AC compressor, etc. Loosing one, or all of these belts, would not have an effect on the engine internals UNLESS it was driven to the point of overheating. However if the timing chain jumped over the sprocket(s) that would cause major valve issues.

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I believe the PO drove it with main accessory belt broken until the car likely overheated and died. I’m wonder if I can get by with a head replacement at this point.

Sean, a head off is easier than engine out to start with, if the bores look ok then I would say that you could get it going with a replacement head, I feel sure someone somewhere would have one.
These engine are good for 250-300,xxx kilometres

Robin, they’d better be or it’ll be curtains for my old crate in a couple of months from now!

Robin, did you mean to say 250-300,000 miles? Because there are listers that have clocked that many miles, and my '94 is showing 188,xxx miles (302,xxx kilometers).

Hi Mike, just keeping to local/personal knowledge rather than hearsay (not meaning to say that I disbelieve people saying they have those figure)

After careful consideration, it’s with a heavy heart I’ve decided… to pull that darn cylinder head and pray for a disgusting head gasket! The possibility is slim that is the reason for my no compression, but either way, it’s gotta come off!

I’ll likely start yanking sometime this weekend, seems fairly straightforward. If I find the valves are toast I’ll try to source a used head or maybe have this rebuilt since there is only 145k miles on the old girl. Could get another 100k on rebuilt head you think?

No worries, my daily driver is a ‘16 Ram 2500 with a Cummins, so I’ve got time on my side baby!

Sure. Don’t need to check for water/oil mixes, my gasket failed without a warning and I couldn’t see any blown spots. Let’s hope the cylinders and pistons make a good impression (and that the valves didn’t leave impressions).
Good time to clean things up and hopefully get somewhere.
Good luck!

This is off topic and a bit late, but as a newcomer myself, welcome to the forum . . . I just bought my first Jaguar, the one I always wanted . . . the XJ40 a week earlier. I absolutely love it! I am astounded how inexpensive these cars are, suggesting major under appreciation! So glad that you rescued this kitten rather than let it be parted out.

gtjoey1314 having fun

The old girl has been moved into the garage, ready for bonnet removal to begin operation “cylinder head”

I’ve been busy nursing my grotesque finger back to health and working on the boat. As soon as I can allow time the process will commence.

I never give up.

Good for you! Every XJ40 kept on the road, and in good repair, is a victory for those of us that love them! We Jag-lovers are here for you!

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Mike_Stone, you make me proud to be a fellow XJ40 owner with that comment!!!

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Well, you might have all though I had given up! (and I had), but alas, I WILL pull this Cylinder Head with some spare time that we all have now :slight_smile:
Question, how the heck do I secure the timing chain sprockets? I don’t intend to remove the cams, I really just want to do an inspection of the gasket and valves before I put too much effort into it. My only real hangup is the timing chain and sprockets…is there a quick “how-to” with pictures that someone has already done? I tried to search but the one I found said the page no longer exists :frowning:

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I’m at the hospital at present with the wife but will try to look at my Haynes manual when I get home. Its been a good 10 years since I did the HG on my ‘40 and can’t for the life of me remember what I did with the cam sprockets, it’ll probably be patently clear once you get the cam cover off.
Just a note, the head bolts can be re-used twice before Jaguar recommend replacements so do not go purchasing new ones. Just make sure when you put the engine back together that you centre pop each bolt to indicate it has been out once.
If they are already centre popped it indicates that they have been out (the number of pops indicate re-use. 1 pop + second time in 2 pops = renew them)

Thanks! I have the manual too, I think if just remove the four bolts holding the gears to the cams, and then maybe zip tie the chain so it doesn’t move, I will be alright! I’m still set on TDC, I think a blown head gasket has caused complete compression loss in each cylinder…or the valves ALL got whacked!

Don’t worry too much about the chain - providing you stop it falling down inside the timing cover

Just follow the instructions for valve timing with the #1 piston at TDC

A read of this thread may reassure you -

Thanks Bryan, that’s exactly the answer I was hoping for! Everything else looks pretty strait forward. I have the old girl parked under a big wood beam I plan to attach my hoist to.

Should be off this weekend now!