valve guide hold down kit

johnhcrighton · Post by **johnhcrighton** » Sun Dec 11, 2011 3:55 am

I have noticed reference to a simple kit to prevent valve guides coming loose. Seems like a sensible precaution. Can the kit be fitted without removing the cams? If not, I will wait until I need to remove the cams for some other reason

Post by **mgcjag** » Sun Dec 11, 2011 10:33 am

Hi John. Just been through this myself, Had quite a loud tapping noise from the exhaust side & expected to find one or more of the guides loose. after removing cams there was no sign of them comming loose or damage to the tops of the guides. however the tappets were loose in the guides, so replaced the tappets & re shimmed but decided not to fit the hold down kit. If you have read through this & other forum posts you will find that some fit them as a matter of course but I was not convinced enough to fit them (didnt fancy drilling the head & fitting chunks of metal) however if the guides were loose I personally would have had them replaced .....Steve

Dave K · Post by **Dave K** » Sun Dec 11, 2011 4:48 pm

johnhcrighton wrote:I have noticed reference to a simple kit to prevent valve guides coming loose. Seems like a sensible precaution. Can the kit be fitted without removing the cams? If not, I will wait until I need to remove the cams for some other reason

John,

I fitted them to my 3.8 while the head was on the engine and everything in place. Straight forward job done with no issues.
I think you need fit them to the exhaust tappets.

Dave

Post by **mgcjag** » Sun Dec 11, 2011 6:06 pm

Hi Dave. Out if interest why do you think they need to be fitted.....Have read that the process for fitting replacement guides can vary & not result in a tight fit & the hold downs then fitted.....But if the guides are ok why fit the kit?....Steve

PeterCrespin · Post by **PeterCrespin** » Sun Dec 11, 2011 7:55 pm

mgcjag wrote:Hi Dave. Out if interest why do you think they need to be fitted.....Have read that the process for fitting replacement guides can vary & not result in a tight fit & the hold downs then fitted.....But if the guides are ok why fit the kit?....Steve

Same reason some people buy travel insurance and some don't - it's your attitude to risk. The kits aren't expensive so cost is hardly an issue and if you take care with grease on your drill bit you won't lose significant swarf. Some people want peace of mind, others are content to wing it. So long as you wouldn't kick yourself if your tappet popped up on a hot trip one day then relax. If you would kick yourself, fit them now. Must say if I'd just taken the cam off for new tappets I'd probably have fitted them during that time of good access.

Did the new tappets cure the noise to your satisfaction Steve?

Pete

Post by **mgcjag** » Sun Dec 11, 2011 8:38 pm

Hi Peter..The new long skirt tappets & shims have totaly transformed the car, the engine is now really quiet & the performance is noticablly improved (put a write up under Technical/adjusting tappets a few weeks ago)..Steve

christopher storey · Post by **christopher storey** » Sun Dec 11, 2011 8:40 pm

These kits are only necessary where the original tappet guides ( not valve guides) have been replaced. The originals were shrunk into the head and Jaguar in the entire history of the XK engine never deemed it necessary to fit such a device. If it ain't broke......

Dave K · Post by **Dave K** » Sun Dec 11, 2011 11:54 pm

mgcjag wrote:Hi Dave. Out if interest why do you think they need to be fitted.....Have read that the process for fitting replacement guides can vary & not result in a tight fit & the hold downs then fitted.....But if the guides are ok why fit the kit?....Steve

Steve,

Like Pete says a bit of belt and braces to be honest. They are cheap at least from the States they are, got them from Dick Maury at Coventry West for about ?20 - thanks Pete.
Fitting them is straight forward, I still fitted them even though I have been told the 3.8 doesn't need them only the 4.2.

Dave

andy303 · Post by **andy303** » Mon Dec 12, 2011 1:03 am

Apparently the stake-down kit was a "factory" solution, at least Jaguar North America solution, developed to deal with the factory installed guides becoming loose after some indeterminate number of cycles of heating and cooling with very high head temperatures caused by Federal emission controls due to lean mixtures and the use of catalytic convertors on the SIII XJ6.

See Dick Maury's article: http://www.georgiajag.com/Documents/Hea ... XKHead.htm

I asked the Jag-lovers forum about the kit last year and the consensus was to install the kit, at the very least, on the exhaust side, and preferably the intake as well, especially if the car has ever overheated. See that thread here: http://forums.jag-lovers.org/av.php?1443651m77

I checked my guides and didn't see any damage, and I haven't installed the kit yet, as my engine seems to run rather cool anyways, but may do so the next time I have the exhaust cam off for a valve adjustment.

Andy

johnhcrighton · Post by **johnhcrighton** » Mon Dec 12, 2011 6:58 am

Thanks everyone for your contributions. Dick Maury's article is excellent - thanks for drawing it to my attention. I think on balance I am inclined to take out 'the insurance' and fit the elegantly simple fix proposed in Dick's article. Cheers, John C

Dave K · Post by **Dave K** » Mon Dec 12, 2011 7:41 pm

I found this photo on xkedata.com of my engine showing the stake down kit if anyone is interested.

http://www.xkedata.com/gallery/zoom/?id=31634

Dave

johnhcrighton · Post by **johnhcrighton** » Mon Dec 12, 2011 11:41 pm

I am intrigued! Your kit was supplied by Dick Maury of Coventry West. In his article (referenced above) he says he prefers the simpler approach used by Coventry West. I am surprised then to see that he fitted a Jaguar style hold down kit. I wonder if he has changed his mind about the better approach to use. Did you discuss this with him?
cheers

john c

Dave K · Post by **Dave K** » Mon Dec 12, 2011 11:50 pm

johnhcrighton wrote:I am intrigued! Your kit was supplied by Dick Maury of Coventry West. In his article (referenced above) he says he prefers the simpler approach used by Coventry West. I am surprised then to see that he fitted a Jaguar style hold down kit. I wonder if he has changed his mind about the better approach to use. Did you discuss this with him?
cheers

john c

John,

Never knew there was a simpler approach? I ordered the parts Pete brought them back and I fitted them. I really don't know any more about it.

Dave

andy303 · Post by **andy303** » Tue Dec 13, 2011 12:04 am

The method preferred by Dick Maury is still the cap screw approach, which is probably more difficult for the home mechanic to accomplish as it requires more precision, not to mention drilling a pocket into the tappet guide which is much harder than the aluminium head. The stake down kit is much easier to install.

Larry Wade · Post by **Larry Wade** » Tue Dec 13, 2011 8:56 pm

Hi guys,
Every mechanic in the US recommends fitting these as a matter of course.
1. They are cheap.
2. They are trivial to install.
3. They work...and were invented because of some pretty spectacular failures.
4. Suppose you install new tappets and guides: how many of them are likely to be craptastic just like many of the parts we buy today? You don't need to worry with a hold down kit in place.
5. Jaguar did not consider driving these cars 50 years on when designing or building them. As an engineer I guarantee that people as competent as Bill Heynes would have chosen to install them on his car today. The 'if it's not broken' argument should include the word 'yet.'

If you replace tires when bald or oil by 5,000 miles, then you care enough to install a hold down kit the next time you've got your cams off.

Check the discussions on the Jaguar lover's forums. The consensus, for such a stubborn group of individualists, is remarkable.

Best regards,
Larry

johnhcrighton · Post by **johnhcrighton** » Tue Dec 13, 2011 10:03 pm

Hi Andy

I get the impression from what Richard Maury says in his article, and from the photo he included, that the screws are located in the aluminium adjacent to the guide, not part in the aluminium and part in the steel guide. I imagine that the head of the screw needs only to project a little over the lip of the guide to prevent it moving, so as long as it is hard up against the guide, the hole for the screw need not bite into the guide. The reason I raise this query is that I plan to do this early next week and it would help to clarify.

cheers

john c

andy303 · Post by **andy303** » Wed Dec 14, 2011 2:20 am

John C:

I posted this earlier: I asked the Jag-lovers forum about the kit last year and the consensus was to install the kit, at the very least, on the exhaust side, and preferably the intake as well, especially if the car has ever overheated. See that thread here: http://forums.jag-lovers.org/av.php?1443651m77

There was a lot of good discussion, although like many jag-lover posts it began to deviate badly near the end...

However, I suggest you read that. About 2/3 the way in, there is a post by Jim Ashworth with pictures: http://www.jag-lovers.org/snaps/snap_vi ... 411881&n4=

Note the Bridgeport machine setup. Not a DIY proposition unless your shop is very well equipped! The third photo shows the machining done to the tappet guide.

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