I have a 1997 XK8 and I replaced the heater hoses under the intake. The car ran great and had no issues for about 20 miles then developed a knock and miss that seems to be coming from the top left side of the engine. I thought something could have possibly fallen into the engine when the intake was off (although unlikely). I pulled the intake and looked into the intake ports for anything unusual, found nothing. I pulled the plugs and found nothing unusual. I pulled the cam cover and found nothing unusual. I did a compression check on the left side starting from the front of the engine and got 120 psi, 150 psi, 90 psi, and 120 psi.
I was thinking about changing the engine or getting rid of the car and getting an XKR.
Can anyone give me some good advice...
Thanks

 

One reason for such varied compression readings is cam timing. Got metal tensioners?

Remove the left valve cover and turn the engine over by hand to align the cam flats. On the left side the flats should be almost perfectly aligned. You will be able to see the difference if you have jumped a sprocket tooth.

Knock sensors connected after working around them?

Buying a XKR is a very good idea but you might want to salvage some value out of this car first.

 

The above is some very good advice.

 

I will check the cams as directed and let you know what I find! Thank you so much!
If it did jump time, what should I replace? chains, sprockets, tensioners What is the normal cause of jumping time?

 

Failing or failed tensioners, especially the plastic ones that came with the car. If you have plastic you MUST replace them and with the suspicion of a jumped tooth before you drive it again. This is a very unforgiving situation.

Most get away with just replacing the upper tensioners themselves and the shorter bolts required. About $120 in parts on line. If there are signs of chain wear from rubbing the metal tensioner shoes you will have to decide on the chains also.

If you took the intake manifold off you can certainly do this. If you jumped a tooth, and it will be clearly evident in cam flat alignment, you will need to do the full Monty, cam lock down tool job.

If you have a disconnected knock sensor you should be getting a CEL.

There are lots of pictorials on the exact procedure of tensioner replacement. Just do a search.

And . . . welcome to the forum . . . sorry that it had to be under these conditions.

 

+1 to the cam advice.

You should expect compressions to be within about 5 psi across all cylinders.

Tempting though it must be to offload the problem, what are you likely to get for an XK8 with a suspect and part dismantled engine. Scrap value?

Worth a little investigative work and a few $$ if it's only jumped to fix it up and then trade for an XKR.

Just my thoughts.

Graham

 

What! thats not so!

 

OK, I ordered the tools. We took the intake and cam covers off and it appears to have jumped time on the left side and the secondary timing cain appears to be stretched. The tensioners are plastic as are the chain guides. I was thinking about replacing all of the tensioners, guides, chains and of course gaskets related to the reassembly. There is a set on e-bay with all of the chains, tensioners, guides and gaskets for $689. Does anyone have any idea if this would be a good thing to buy or experience with the seller. It is Christopher's Foreign Car Parts.
I replaced the water pump less than a year ago, but I am going to replace the idler pulley as the bearing feels a little loose (maybe just replace the bearing).
Oh yea, we broke one of the bolts of my harmonic balancer puller and had to stop for the day, we now have to remove the little piece left in the balancer, it seems to be stuck but we stopped trying before we made a mess out of it. I will pick up a tool to remove it today!

 

Good day!!

If you can get all the gaskets you need for less than $240, there is a guy that has all the tensioners, chains, and guides for $444 with free shipping... I'm not sure if I can post a link to his auction, so just do a search for cr051948... It might be the same guy but I'm not sure...

Additionally, if your harmonic balancer is like mine, it might be worth an attempt to get the center ring moving before the balancer... Here is mine... I had to use one of those HD puller from Advance...





I think if you soak it with Pblaster or WD40, then tap on just the balancer, it will free up the center ring that locks everything together... Just my 2 cents...

Good luck!!

Cheers!!

 

Split cone damper removal

bob gauff

 

Two things to watch for: I have had good luck removing the balancers by taking out the center bolt (which is obvious!) and then just popping the inside of the balancer hub with an air chisel using a blunt tip. The vibration will usually pop the cone from the center. Just be careful. As for the chains, when you get into the timing chest pay attention to the two lower sprockets. The teeth do not align the same way. One is staggered compared to the other. Just pay attention and mark parts as needed as you remove things. Actually, an easy job.

 

I worked on it again last night, before recieving the posts. I broke three hardened washers with my puller after I got the broken bolt out from the previous day.
I am so glad I have everyone here that is so helpful!!! I will try again tonight as my tools are supposed to be here.
I still need to order the parts, so it will be a few days until I find out if I will be successful!
Thanks again for all of your help.

 

We finally received the tools. We removed the harmonic balancer after tapping with a hammer and soaking it with sea foam.
The front left secondary tensioner appears to have broken and the piece went between the chain and the sprocket which caused the chain to jump time and stretch. I bought the parts locally and replaced all four chains, tensioners and guides.
We put everything together and it runs beautifully, but now I have an ABS/Stability Control Failure light on, I think it might be a plug or something, but I can't figure out the cause.
Does this sound familiar to anyone?
Once again I want to thank everyone for their advice and help.
Thanks,
Jim

 

JagRepair.com - Jaguar Repair Information Resource
Your problem is with the ABS system. You need to get the codes read, and a generic reader will not work. The above by Jagrpair .com will help in diagnosis.
RJ___________________
97XK8 86 K mi

 

I drove the car about an hour or two and the ABS/Stability light went out. I guess the computer took a little while to reset.
Now, on the way to work, I am 99% sure it jumped time again...
Has anyone ever had this happen?
Before it jumped time the first time, I had the oil changed to Mobil 1, somebody said Mobil 1 is too thin.

 

Did you replace the bolts on the secondary tensioners with the new shorter ones? The 3rd generation metal tensioners require shorter bolts or they will not seat or pressurize properly.

 

That would be a bummer after all that work.
If you do have to change the bolts I understand it is a good idea to pull the fuel pump relay and crank the engine over to pump the tensioners up before starting.

 

Yes, we replaced the bolts. I think the origional ones were 35 mm long and the new ones were 30 mm long.

I don't think it is related to initial oil pressure as we cranked it for 30-45 seconds (maybe longer before starting). It ran great for 100-200 miles.

One good thing, I will be able to tear it down in a relatively short period of time if required, but my fiance' will think I don't know what I am doing if it is not working properly after all the work and money.

 

I had a tow truck bring the Jag home from work today. After hooking the code reader to it it said failure on coil G. All of the coil plugs on the wiring harness on the left side of the engine are in really bad shape, I messed with them and reset the computer and it is running great again! It passed smog and I will be able to reregister it tomorrow!

A mobile mechanic stopped by to see if I needed any help and he noticed a noise he said was chain slap. He said dump out about four quarts of oil and add 4 quarts of tranny fluid and run it at 1000 RPM for 30 minutes to clean everything out, then drain the oil and replace the filter and fill it with Valvoline 20-50 full synthetic racing oil and a bottle of Lucas oil stabilizer see it the sound goes away, if not sell it quick! I said, if the sound was still there couldn't I just replace the gears. He said yea, but it is a really big job. I said I would rather just replace the gears than sell the car, at this point.

Since I bought this car, we have replaced the serpentine tensioner, replaced the tires, battery, rebuilt the transmission, replaced the micro-switches for the gear selector, and now the timing chains, tensioners, guides, serpentine belt, serpentine idler pulley bearing. There is not much left...is there???

Please give me your opinions on the oil idea. I am afraid of putting the transmission fluid in the oil and running it. Maybe I am just over cautious?

 

Hi,
sounds like you have put a lot of work in to the car.
to recap
you have replaced the timing both primary and secondary(everything sounded great)

you then were driving car and suddenly it seamed timing had gone again( it turned out it was coils)

can you hear chain slap. I reckon you know your car better than any mechanic having done the timing(you did this, is that correct)

If I was you and I could hear timing slap after carrying out replacing everything, id consider what could have gone wrong. are those primary tensioners working correctly, I have not done this but there is an issue regarding a plate being removed where the new primary tensioner goes, did they go on properly.

Given you took it all apart, it would take no time to pull it apart again and check it all, then you would have piece of mind.

As for oil, dont understand why he suggesting pooring transmission fluid in to the engine.
I have just had a final thought, you could have a blocked oil pick up from debris in the oil pick up. this potentially could restrict oil. needs doing anyway, remove sump, unbolt oil pick up, give it a shake and you will find loads of plastic debris inside.

I think you will sort this.

stephen