Removing 1995 XJR Motor
 

Hello, looking for experienced advice on pulling the motor from my 1995 XJR. Cylinder head is bad and I am considering replacing the whole motor if I can find a reasonably priced rebuilt or used one. Can the motor be pulled without removing the transmission? Or is it easiest to pull the motor and transmission at the same time?

Do you have a hoist available or four jack stands and a floor jack, Assuming you have a engine crane it can be done either way. What is a matter with the old head?

Larry Louton

Hello Larry and thanks for your reply. I see you are on Longboat Key. We are at our winter home on Fort Myers Beach and bought this Jaguar from the estate closer to Fort Myers off McGreggor last summer. I have been restoring classic cars for 35 years and have a full restoration set up at my garage at my summer home in Arkansas - 2 lifts, paint booth, ect.. Will need an engine hoist which I usually rent as they take up a lot of space when not in use.

This Jaguar was sitting neglected for about 5 years before I bought it. Towed it to a trusted mechanic who got it running after rebuilding the complete fuel system due to bad gasoline. When he got it running would only fire on cylinders 1 - 4? He was at the end of his Jaguar knowledge and so I had it towed to a great foreign car shop for further diagnosis. They found that the cylinder head has problems in that they found the exhaust valve in the 6th cylinder was "burnt". They quoted a "starting" estimate of $5K open ended depending on how difficult shimming the replacement valves would be? Decided to drive it home and think about it? On the way home (12 miles) it lost 3 qts of oil with no external oil leak or smoke screen? It is on its 4th set of spark plugs at the 2 shops due to dirty plugs so, conclude it is burning oil big time. At home I flushed the cooling system and found no oil in the fluid at all. So my conclusion is the head gasket is still sealed. At a minimum, the cylinder head needs to be pulled and rebuilt. Worst case, some of the piston rings are warn and it is using oil there rather than through the valve guides? So am researching just rebuilding the head or rebuilding the whole motor? I can pull the head or the whole motor in my garage. I have a Jaguar experienced head rebuilder lined up and am researching rebuiling the whole engine vs buying a rebuilt or used one?

Hello Rmbaker, First, Make sure that you have the correct amount of oil on the dipstick, Road test on five cylinders for twelve miles to confirm the loss of oil again, if no oil is lost, Then they did not put enough oil in the first place. Piston rings and bores are unusually robust on this model. Can you conduct your own cylinder balance test? (Disconnect the two wire connecter from each coil while idling) to confirm the # 6 cylinder fault. If the cylinder you disconnect fails to respond to the input you just made, That's the one to work out from. More then likely one or both exhaust valves froze in place during it's period of inactivity then the piston tapped it while making it's upstroke
with the valve fully extended. Knowing if it backfires out of the intake or the exhaust would give you another clue. Unbolt exhaust manifold from cylinder head, Pull away from head and lower carefully downward so as not to damage O2 sensors, Mark and disconnect O2 sensors before that last move. With fuel pump relay removed, With all coil two wire connecters removed, Observe exhaust valves going up and down with observation mirror and flash light while assistant cranks over motor. watch for one that doesn't move in cylinder #6 that is different then the other ones. Have assistant tap ignition key to briefly engage the starter and leave cylinder#6 exhaust valves fully extended. Look for one of the two that has a bright ring around the seat area and one that has a lot of black built up around it. There is a old Technical Service Bulletin about exhaust valve failure. I don't believe you have any warranty left. I am trying to help you narrow down the fault and then help decide the course of action after that. I was looking to purchase a 95 XJR in the Fort Myers area more then a few years ago but never got close to it before I bought one over in Daytona beach. The one I was looking at in Ft. Myers was Turquoise/ Cream and the one I bought was Turquoise/ Cream. Who knows.

Larry, Thanks for the information and great help. You may have been looking at the same Jaguar XJR I bought? I too find it hard to believe that that the piston rings are the cause of the oil usage. I like your line of thinking about the valves sticking due to no use for a long period. Regarding the oil usage, I checked the oil level before I left the 2nd mechanic and it was full to the line. Then when almost home doing 20mph, oil pressure dropped very low and I limped it home and found no oil on the dip stick next morning on level surface. Took 3 qts to get oil up to 1/2 way between dip stick marks. Neither cylinders 5 or 6 are firing?

What would happen if the 6th piston hit the extended exhaust valve per your theory? To my thinking, it would at least bend the valve stem and damage the valve guides? or worse also damage the top of the piston? I have been told by a cylinder head rebuilder that worn valve guides can cause oil usage? The diagnosis was a "burnt" exhaust valve in cylinder 6, so why is cylinder 5 not firing. Could it have had a stuck valve too?

I have not noticed a backfire? Rather than removing the exhaust manifold for more diagnosis, can't I just pull the rocker cover and see if all the valves are moving the same? Pulling the exhaust manifold would allow direct viewing of the valves on cylinder 6 and 5 and may be the best solution. Manifold will have to come off anyway if I pull the head. Thanks again for your time and help.

Maybe Motorcarman will weigh-in presently. Seems I recall an XJR (or maybe several AJ-16's) through his shop showing #5 and 6 are the first to surrender when these engines are catastrophically overheated, as in, "the b*st*rd hose blew but I didn't have far to go" Consequently, they generally don't go far, and still don't have far to go....
Just a thought. If true, your most cost-effective move is probably swapping in another engine from a breaker.

"the b*st*rd hose blew but I didn't have far to go"
Consequently, they generally don't go far, and still don't have far to go....

Brilliant. I think a little bit more work on this and there's a literary prize in the offing

That is an interesting theory. Maybe some other Forum member has had experience with AJ-16 overheating or knows of someone with that knowledge?

Thanks very much!

How much longer are you going to be in Ft. Myers? I am in Venice now, (Sold the house in Longboat Key). I have half a mind to come down with just enough tools to do a compression test and a flash light to look down the spark plug holes to see if a valve punched a hole in the top of the piston. Or to see if #5 and #6 pistons are scored to the block during a overheat condition that wasn't revealed to you by previous owner. Either one will pump oil. Do you have any oil dripping out of exhaust system joints? The exhaust valves, guides, springs, buckets run in a oil bath while exhaust cams are spinning, Perhaps the valve stem seals are dislodged, acting like a umbrella and when the valve is forced downward by the camshaft, the umbrella pumps oil down the valve guide. Would love to tear this engine down in laboratory conditions.

Larry Louton

Larry, I would most welcome your help in diagnosing the problem correctly rather than replacing/rebuilding the head or the whole motor. I will be in Fort Myers Beach until May 20 when I plan to load it on a trailer and head north. Happy to pay you for your time. Could you be available before the 20th?

I will check the exhaust system joints for oil dripping tomorrow AM and let you know.

Larry, refound this Jag form exchange from my saved file. 1995 XJR owner with 5th and 6th cylinder not firing - here is his comment after switching the coil harness on 5 & 6? In my case does not explain oil usage and the earlier diagnosis that the 6th cylinder exhaust valve was burnt as it was passing compressed air to the exhaust system (air hooked up where the spark plug inserts) when the exhaust valve should have been closed.




Dear Sparkenzap,

I was so excited writing it that my thoughts went faster than my writing and now that i read it, it does not make sense to me either https://www.jaguarforums.com/forum/i...lies/smile.gif
Sorry for that
Reply to your questions:
1. In the ECM there are coil signal apmlifiers called IRFR120, there are 2 on each coil a total of 12 piece. Yes, it is a 1995 XJR 4.0 Supercharged
2. In the ECM there are injector signal amplifiers called Darlington Motorola BU323Z, there is 1 on each injector.
3. The cylinder compression test is done and it is 9kgs on each one, which i suppose is good.

"And now, I just switched the 5h and 6th coil harness and it was exactly why they didnt work https://www.jaguarforums.com/forum/i...lies/smile.gif However i dont understand why they did it like this, doesnt make sense the last coil to be upside down. Now everything seems working"

Hello RMBaker47, I have seen other technician's make this mistake before, But like you say, doesn't explain where the oil went and maybe the burnt valve was just a false claim. If you have a Torx set of screw drivers, Remove the coil cover and observe the coils and the wiring connecters. The two coils closest to the firewall are the ones in question. The coil closest to the firewall is #6. The wiring harness to #6 should be at least twice as long as #5. If #6 coil harness is short and #5 is long please unclip harness plugs and reverse so that the long harness goes to #6 and #5 is short. I am assuming that the vehicle ran poorly during your 12 mile ride home. Top off the oil and repeat road test please. If you need a photo of cover and harness let me know.

Larry Louton
Cell # 941-416-4030

Larry, I have the time this afternoon to dig into the Jaguar as you have suggested. Will pull the coil cover, check the wiring, pull the plugs and check for fouling and flashlight the 6th and 5th pistons to see their condition. I am very concerned about driving it at you suggest as it could stall on me and require a tow back home. Will let you know what I learn.

This is exciting, But I am still planning on driving down to you to test the compression / leakage test no matter what the result. No cost to you, I need to get out of this house after entertaining my brother and his son/wife and 10 month old daughter for ten days. My car needs a free way romp any way's.

You have my phone # for scheduling compression test.
Larry Louton
941-416-4030

Great Larry, Really appreciate your offer to help diagnose my engine problems! My phone number is (Removed personal info) is about a mile south of the Intercoastal bridge. Best to have you come in the afternoon as the car is parked in my driveway in full shade in the afternoon. How about Friday or Saturday afternoon or early next week?

I was able to remove the coil cover, remove the coils and the plugs and do an initial flashlight of the pistons via the plug holes and took pictures. 1) the # 5 and 6 coil wires are in the correct position - see picture someone has marked the #6 coil wire with a yellow piece of tape I believe is to keep it marked as #6. 2) Plugs 1 - 4 show that they are firing with a very rich mixture. plugs 5 and 6 I do not believe are firing as their ends are completely clean - see pictures of all 6 and two closeups of 1-3 and 4-6. 3) noticed some oil on the top of the 2nd plugs hex nut and more oil on the top of the 3rd plugs hex nut - see picture of oil that drained on to the white cloth. 4) There is a storm coming now and I was able to only do a preliminary flashlight look at the pistons - #6 was TDC and #5 was 1/2 way down with the others at various positions below TDC. Pistons 1-4 no damage to the top was visible and there was soot on the piston top from firing. Pistons 5 and 6 were bright and shiney = not firing as indicated by the plugs Could not see any damage to the top of either one but, #6 being TDC I could only see the center of it. Storm kept me from rotating #6 piston down so I could see more of its face. Look for pictures in my text to you.

I've edited out your personal contact info, it would be better to share this by PM.

Message received and will see you Saturday at 1:00 P.M. Larry

On 5/11/2019, Went to Rmbaker47's home in Ft. Myers, Florida. Performed a compression test on all cylinders and a cylinder leakage test on #6. Found extensive air leak from exhaust valves. No damage noted to top of pistons to support theory of bent valves. Supplied Rmbaker with Technical Bulletin about carbon build-up of exhaust valves pertinent to this vehicle. Rmbaker is going to procure a borescope to better inspect cylinder #5 and #6 bore. If cylinder bore looks good, next move would to remove/lower exhaust manifold away from cylinder head and inspect via flashlight and inspection mirror. If carbon build up is noted, attempt to clean valves with a sandblaster but equipped with walnut shell medium. Once clean, repeat compression test. If good results are found, inspect exhaust manifolds for cracks, Replace if needed with known good manifolds and gaskets.

Larry Louton