Hey guys,

It wasn't even a month and I had to park my XK8 at the service shop as the engine broke something We still haven't checked what exactly, as the shop is pretty busy at the moment. I'm hoping for a broken tensioner, the shop are more inclined at something broken inside the block (rod or smth... not sure about the correct translation). I noticed a knocking sound in high revs (3000+) at first while the car was driving perfectly fine. I managed to get to the shop and the car started stalling right when I was parking, after which it was unable to start as if the engine was locked (not sure about the correct term). The shop managed to start it and was still knocking, but this time on idle too (previously you couldn't hear it on idle). The knocking is heard from cylinder 2 (I think... the one closest to the right headlight) and where the upper tensioner is. I'll post a video at the end of the post.

So I'm already getting ready for all the option and trying to familiarize myself with the specifics around Jaguar engines, compatibility, naming conventions, etc. Ideally I would want to keep my AJ26 engine and repair it, but if it proves too costly I might consider other options. The cheapest one (around me) actually is to get a working 2000-2002 S-Type and source the engine from it. This way I can test and check the engine before buying the car, not that that helped a lot with the XK8 . Still such cars here are between 1000 and 2500 euro. But through my research I saw all option for swapping with AJ27 or 4.2 engines, but I couldn't find info about AJ28 which seems to be the one in the S-Type. Obviously AJ28 requires some other stuff with it, similar to AJ27 when swapping an AJ26, which will be ok, I think when I'm getting a whole donor car Would it be okay, or there is some crucial incompatibility

Note: Yes I considered LS swap, but here it is not that easy to source such engine and gearbox, also I don't like the 4 speed box (drove the similar one in the T6 S80 Volvo) and third... Doesn't really fit the XK8

The knocking sound video:

 

The BASIC BLOCK is the same on ALL 4.0 engines. The intake cams, oil pan, torque converter drive plate etc. etc. etc are different but those parts from the AJ26 will bolt onto the AJ28 block.

I am doing a swap similar to yours. I am using a 2002 AJ28 block for an AJ27 engine to install in a 2000 XJ8.

bob

 

Well I guess if I'm sorting out a whole car I might as well do a full swap with all the "upgrades", although I do prefer to stay with the Nikasil engine if it is not in bad shape and can be repaired... Unfortunately I can't source a cheap enough option for a 4.2 swap which would be the best option if I need to swap, I think.

But otherwise what you are saying is that if the damage is anywhere inside the block, I should be fine with just swapping that. Still that would mean servicing the heads, chains and everything, so I don't know if it won't be better to do this on a newer engine...

 

Until you get the heads off and check for piston damage due to valves it's all guess work. My guess is that a secondary tensioner failed, the chain skipped a couple of teeth, and valves met pistons.

The lower end is very robust, so I would not expect bearing failure.

 

Fingers crossed

 

Sounds a bit smooth for bent pistons. You can remove the cam covers and see if the valve buckets are dropped anywhere. If there is a broken chain you can remove the exhaust cam on that side (along with broken chain pieces) and run a compression check. (realistically you could run a compression check NOW- any damage would have happened during revving.

 

I agree with dsnyder586....sounds fairly smooth...more like a stationary piece of metal is touching a rotating bit, than a knock or major engine damage....Keep your fingers crossed (and pop off those valve covers). You might luck out.

 

Mmm. Rattle/knock much more obvious when engine accelerating (under load) than when on the overrun (not).

IMO not deep enough for bottom end but something horrid at piston/small end. Tear down will give you the answer & fingers crossed for you that it isn't so.

 

There is a *possibility* that it is running smooth when revved and rough at idle that there is/are piston(s) lightly touching SLIGHTLY bent vales- I had an XJR with this condition and made a worse but similar noise that had dropped valve seats from an overheat- a quick view into the spark plug hole with a borescope verified the problem.

Is it the same when it is cold vs hot?

 

 

Make sure the battery is charged before they try to start it. If the voltage drops below about 10.8 during cranking the ECU will not allow it to start. But it would probably be better if they just took the cam covers off and checked the chains/tensioners instead. Also, be aware that the voltmeter is very inaccurate, like the oil and temp.

 

 

Can anyone recommend what brand chains kit is the one to get aside from the OEM one, or there is no quality aftermarket replacement?

 

Is this guide applicable to a AJ26 to AJ28 swap?

 

This is the running engine that I have found (only one :P) which is a 97'. Hasn't been run in the past 2 years, more than just to move the car around the lot, and 3 years prior that its been doing couple of thousand miles per year. At least that is what I'm getting from the MOT history. Currently the engine is at 133k miles. I can't get anybody to come and listen to it. The car runs fine, although I couldn't road test it, only around the lot. I know that mic sound probably won't cut it, but if somebody can catch anything it will still help