00 S with a broken chain

(Bill Fleming) #1

Looking at a really low mile/clean 2000 S Type 4.0 that has thrown a timing chain. Currently I don’t know which side but per the Owner the shop that looked at it scoped the holes and there is no piston damage. So I am hoping I just have to replace a few valves at most. That said, if I DO have to go deeper, I can readily get spares from a local wrecking yard that almost always has one or two 98-2003 XJ8’s sitting around.
My question is this. Just what WILL work from an XJ8 4.0 (heads, pistons, etc) just in case I need something?

(Rob Reilly) #2

Apparently nobody on here knows specifics, but according to the brochures, both models use the AJ-V8 engine.

(Eric Capron) #3


I hope that you take this S Type project on because it would be very interesting to learn from someone first hand, exactly what gets damaged when this engine looses a timing chain. I imagine that the failure will be one of the upper chains due to one of the upper chain tensioners giving up. You probably know that at the age concerned they would have been the first generation plastic ones which can crack and fail. The third generation aluminium bodied ones are the ones to use and if one of the upper has failed it must be worth changing all the timing chains and tensioners.

The 2000 S Type has the AJ27 version of this engine which I don’t think ever had Nikasil coating. The XJ8s of the age you mentioned will have AJ26 engines. One of the main differences is in the variable valve timing. AJ26 has a two stage 30 deg. system whereas the AJ27 has a stepped variable up to 48 deg, I am told. I have one of each in an XK8 and S Type. I notice other small differences when looking at both engines.

I have still to change the tensioners on the XK8 which I must get on with.

(Bill Fleming) #4

Rob thanks. I bought the car and have since found that the only real difference is the right head has a different sensor port (which is the side the chain broke on). Too cold and windy to mess with outside right now so will have to wait until it warms up and/or I can get into the shop with it to chase the problem.

(Bill Fleming) #5

Inspection. Started at the front (5) and found a dirty plug. Plugs in 6 and 7 were were pretty well consumed but dry and clean.
Plug was flat as a pancake. Got the borescope out and I saw bad things…mainly the wrist pin…through the hole in the top of the piston caused by one of the valve heads. Head (top of the bore) was pretty well beat to crap as well. I couldn’t get a look at the side-wall so I’ll pull the head next time I have two hours to do nothing else. If the side-wall will hone I’ll find a piston and head and just put it back together. If the wall is too scarred, I’ll have a lot of engine parts for sale from the left side of a low-mile (86,000) 4.0



(Rob Reilly) #6

I would think a used engine out of a crashed car will appear somewhere on ebay or buyusedengine.com. I’ve found some parts deals on go-parts.com and rockauto.com