QuestionQUESTION:
Speedo says 110k miles, but I'm sure it is closer to 130+k. My car suffers from the non-working speedometer. It worked on/off for a while after I got it. I've put about 5k miles on it since then. Funny thing is I just got a used, working transducer the day before my car started acting up. I haven't even installed it yet.
This is probably a stupid question, but is there a way to pull the intake manifold and inspect/clean off the carbon on the valves or do I have to pull the head and lap the valves? I've actually done that a couple times before on a 235 chevy truck engine and a 52 Ford 8n tractor. This is a little bit more complicated considering the overhead cams. I still have all the tools, though.
Dave
ANSWER: Dave, it is a lot of work to do a valve job on a Jag as compared to a domestic V-8. So you want to be sure it is necessary by seeing the carboned up valves. I usually remove the head with the manifolds on because it is hard and time consuming to get the intake manifold off because of the location of the lower nuts.
Some of the BMW inline engines suffer from the same thing and they have a sand blaster machine that they use walnut shell to blast the carbon off. They set the cylinder that they are going to blast so the intake valve is closed and their blast gun has a rubber adapter to just cover that one intake port. Then they use compressed air to blow out the carbon and walnut pieces.
I got that info from a friend who was a BMW mechanic. We never had that equipment so we always removed the head.
If you find that it is carboned up you should get a manual even if you are a good domestic car mechanic. The manual will help keep you out of trouble and anything you run into that you want help I may be able to give advice on it. While in the dealerships I liked Jag valve jobs as I made good money doing them. To give you an idea when I started on Jaguar, I predelivered two Jag sedans for Eleanor Roosevelt and met FDR Jr.
Let me know,
Howard
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QUESTION: Wow, Eleanor Roosevelt & FDR Jr.? That's impressive! You certainly know Jags inside and out, so I'm not surprised. It's great that I (and others) have access to your experience!
Speaking of access, I'll have access to a borescope this weekend so I'll be able to get a look at the valves. I'll let you know what I find. In the meantime, I'll catch up on some house projects...my wife is giving me the "stink eye" because I've spent too much time staring at my car and scratching my head.
Oh, one more thing...I'm waiting on a new throttle cable to arrive for the XJ6. It was the stupidest thing...I disconnected the throttle cable from the throttle valve when I cleaned it. A few minutes later I smelled something hot, looked down and saw a puff of smoke coming from the cable. It had brushed up against the positive terminal of the battery. It melted the plastic liner in the cable and ruined it in about two seconds. Even if I would have disconnected the battery, this still would have happened. Guess I should have been more careful or even taken the battery out.
Dave
ANSWER: Hi Dave,
The bore scope will tell the tail. I pulled one Jag down that had so much carbon on the intake valve that it almost covered the port when the valve was open. You will have to turn the engine over to when the intake valve is all the way open to look into the spark plug hole or pull an injector and it's seat to look in that way. If it is large enough to be causing a problem it will be obvious. A small amount is not worth pulling a head. However you may need to check all if the one you are checking does not have much as sometimes one or two will not be very bad.
The way the battery is located it is very dangerous when working around it. I have and most of the mechanics in our shop have shot sparks working around it. I have saved the plastic plug that is plugged into the bolt hole on the side post batteries and I usually remove the positive cable and put the plug in the hole to keep anything from contacting it. On the top post batteries I keep a plastic cap that sometimes comes with a new battery and slip that over the post. If you don't have any you can sometimes talk a store that sells batteries into giving you some of each to keep in your tool box.
Let me know how it turns out,
Howard
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QUESTION: Hi Howard,
I have the engine stripped down (left manifolds on) and I'm trying to remove the head with no success. I've got an overhead hoist, but it's not pulling it off. I'm guessing the head bolts are frozen (can't imagine what else would be holding the head on).
Any advice on how to remove a Jag cylinder head that seems to be very stubborn?
Thanks!
Dave
AnswerHi Dave,
That is not uncommon as the head studs go all the way to the bottom of the cooling system and coolant migrates up the studs and corrodes the stud to the head. Get a couple of grade 8 nuts and double nut each stud to remove every stud. If some will not come out by double nutting, then you need to use a stud remover and buy new studs for each you have to use the stud remover on. The two front and the two rear will come out easy as they only reach to the block. Clean the holes in the head with a bore brush or drill bit before replacing the head.
When you replace the studs take a long piece on thin tubing (I use a 1/4 in.) and put it down into the block and with compressed air, blow each hole out before threading in the stud again. They have a 45 deg seat that they set in and it must be clean. Also examine the studs when you remove them for erosion from electrolysis. This usually is at the bottom. If you find any replace that stud and add a coolant additive available from big truck supply stores. Also test you engine to body ground strap.
Howard
