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Guys, I bought a stake down kit. I have a very loud clatter or clunking under this cam cover. I removed the cam cover and set a stake down in it. Exactly what is this supposed to stake down? I tried some light tapping with a hammer and punch on the shim surround thingy but it did not move down. I guess I don't understand how this is going to fix my noisy clatter under this cam cover. Here's pics of each section and all the shim pockets appear to be the same height off the head floor. The underside of the stakes do not sit on the head floor. They are elevated a little. It seems to me that the soft aluminum would just pull the threads out trying to tighten them down. I'm lost here
The shim surround thingy (if I've interpreted your post correctly) is actually the tappet or bucket and is moved by the cam lobes and moves the tappets via the shims which are there to set the correct gaps/ clearances.
The stakedown kit actually holds the circular raised part (tappet guide) which, on first inspection, may look integral to the head. These are the parts that can come loose and hit the cam lobes and cause the clattering.
It may not be the cause of your rattle but the stakedowns are worth installing anyway.
Other causes are often the upper timing chain or improperly gapped valve clearances.
This page on an alternative way to hold the tappet guides should show what the stakedown kit holds. See pic 3 in particular.
Ok, I just tried feeler gauges. I have a couple that no feelers will go under with the lobe off the tappet. This leads me to believe the buckets have popped up. I also can see the back of the lobes are shiny on the two the feeler gauges will not go under at all. What is weird is that all the buckets are about the same distance out of the head. What I don't understand is how to get the buckets back down in the head to install my stake kit. Do I need to remove the head? Maybe a special tool to press them back down?
There is a guy on this site Lagonia I think who has posted some great pictures on the thread that is about his rebuilding a Jag engine great pictures of stake down kit installed close up posted a couple of threads above this one
Lagonia, does the stake kit sit all the way to the head? When I place my stakes in their positions, there is a gap underneath=between stake bottom and head.
Also, the big question is how do I get the buckets pressed back down since their popped up already? I'm afraid that trying to use the stake kit to push them back down will strip the threads for the stake bolts.
Lagonia, does the stake kit sit all the way to the head? When I place my stakes in their positions, there is a gap underneath=between stake bottom and head.
I am pretty sure they do but will check for you tomorrow and get back.
I had done mine as a preventative measure. The tappet guides had not popped-up when I had this kit installed.
Originally Posted by Hafrod
Also, the big question is how do I get the buckets pressed back down since their popped up already? I'm afraid that trying to use the stake kit to push them back down will strip the threads for the stake bolts.
Yes, do not use the stake kit to push them down. How to push them down, do not have a good answer. If it was me, I would first figure out how many mm the tappet guide is supposed to sit above the head and then use a hydraulic press with the correct fittings to push them down. May be easier said than done due to the angle that of the valve wells.
I can't see why a raised guide would close the valve clearance unless there is some serious distortion.
Might be worth removing the camshafts and checking if the buckets are free to move up and down and then remove the shims and recheck if the buckets move down to touch the valve stems.
If they do then maybe you need to re shim, but zero or negative clearances seem a bit extreme.
Have a sucker or strong magnet to remove the buckets, it's hard work tipping the engine upside down and shaking it!!
When the Jag 6 was still in my car , I had the same problem. The tappet guides (which are press fit into the head, had come loose and their edges were making contact with the cam lobes, broaching them as you would if you were manufacturing gear sets) in fact one was so bad it needed to be replaced. It seems this was never a problem with pre- catalytic cars.
But as the cylinder head temp rises, the head becomes hot enough (with the help of the catalytic converter) it expands the aluminum and allows the hardened steel bucket to escape, / come out of its bore to the point it contacts the spinning cam. Happens mostly on the exhaust side - logical.
I would (if the buckets are still serviceable) use a brass drift and try to re seat them down into their bores so that they are all level with each other.
A light tapping with a hammer on the drift contacting an edge of the bucket may force it back into place.
In my case (until I found out what the problem was) there was this high pitched metal on metal sound from the engine compartment while the engine was being subjected to a heavy load for a sustained period of time. IE going uphill on a long ascent at mid speed - then the shrieking would start,.. . almost like activating the starter after the engine is already running. It was at this point I was getting annoyed with the Jag,... I had just replaced the head gasket a few months prior and now this design failure ,..almost sold it cheap. But installed the Stake down backyard fix. Seemed to work.
I did like other things about the car,...so I gave it more chance. Then the head gasket blew again....after having replaced the old head and installed a new head gasket a few months prior
This car had not been abused or neglected. Just did not seem to handle heat related issues very well. One issue would lead to another. Head gasket again?? ... That's when the drive train and I finally parted,... enemies.
Clarity, from a guy that never messed with this! It is a nomenclature thing. The tappet guides should stay fixed in the head, well down from the cam lobes. The "stake down" kit assures this.
In turn, the buckets ride in these guides. Up and down to open the valves. It is the bucket to lobe clearance that the shims adjust.
Sidebar. Those "slotted cap screws" in the picture would not denote much confidence by me. Definite bias against slotted fasteners here.
Tech far to low for a nice engine. Were it mine, Allen heads would replace them.
Sidebar. Those "slotted cap screws" in the picture would not denote much confidence by me. Definite bias against slotted fasteners here.
Tech far to low for a nice engine. Were it mine, Allen heads would replace them.
I hear you. They have been on the head for over 100K miles and were installed by a professional in 1998 who has done hundreds of XK heads. They feel solid. I'm just gonna go with "if its not broken...."
I let the engine get to temp, shut it down and removed the cam cover. I used a brass punch and tapped on it checking each time with a .005 feeler gauge. It is the smallest feeler I have and it will not go between the cam and tappet. I got mad and hammered it very hard in a star pattern and it did not go back down. I'm assuming that valve spring tension is causing it to not go back down. Or it could be that it needs even pressure, or both. Could there possibly be a shim .012 smaller, install it, and then the stake kit to keep it from going further up? Where do I get shims? This is about the only option left other than removing the head and putting the head in a press. I just tried removing the exhaust heat shield too and the bolts are seized.
I let the engine get to temp, shut it down and removed the cam cover. I used a brass punch and tapped on it checking each time with a .005 feeler gauge. It is the smallest feeler I have and it will not go between the cam and tappet. I got mad and hammered it very hard in a star pattern and it did not go back down. I'm assuming that valve spring tension is causing it to not go back down. Or it could be that it needs even pressure, or both. Could there possibly be a shim .012 smaller, install it, and then the stake kit to keep it from going further up? Where do I get shims? This is about the only option left other than removing the head and putting the head in a press. I just tried removing the exhaust heat shield too and the bolts are seized.
It would be nice to have a photo that shows where exactly you are hammering. If you are hammering on the tappet itself, it will do you NO good. You have to remove it (use a magnet) and replace the shim. It is spring loaded.
If you are hammering on the tappet guide then that would make more sense to me.
If you look carefully at the cutaway section of the head I posted earlier you will understand why the guide height has no effect on the valve clearance. It's been quite a while since I rebuilt any Jaguar heads but I seem to remember that the bore of the guide was a straight bore and I don't know of any that aren't. Note the last picture posted by Lagonia shows the straight through bore.
The clearance you seem to be measuring is set by the valve stem, the shim and the tappet/ bucket in relation to the camshaft, and is not affected by the guide. It's easy to get some idea stuck in your head and you need sometimes to step back take some time to think about it and tackle the problem itself. If you want to convince yourself then turn the can so the lobe is on the tappet and see how far the tappet is depressed, it's much further than the 12 thou you are trying to achieve so, logically, the guide is having no effect on the valve clearance.
Use something like a depth gauge or vernier (the tail end of the vernier calliper has a depth gauge) to measure the height above the deck of each GUIDE and see if they are equal.
Is there any damage to the GUIDE edges indicating they have been in contact with the cam lobes?
if not and there is some clearance between each GUIDE and the cam lobes and the heights are the same then fit the stakedown kit. If you are still not sure or there are some differences in the guide heights then you can carry on trying to get them level or fit the alternative grub screw method I posted earlier. Either way, stop measuring the valve clearance as a way of determining the guide position/ height.
Look elsewhere for the valve clearance/ gap problem. As I said earlier it's unusual to have that small a clearance but I don't suppose it's unheard of either, maybe the valves were replaced at some stage and not re-shimmed, maybe there's excessive wear on the valve seats.
Stake down kit help
