As an experienced Jaguar mechanic, I’m happy to share some knowledge about a common issue with the 1980-1987 XJ6 models: the tappet guides often come loose, making stakedown kits a popular and necessary upgrade.
One of my customers recently reached out with questions about installing a stakedown kit, and he suggested I share my response with the community since others tackling this job might face similar challenges. Here it is:
Q&A Session
1) The tappet guides all seem to be about 1/4 inch up from the head surface.
Answer:
That’s correct. The tappet guides should protrude about 1/4 inch from the head surface, thanks to a shoulder that sits above the head. Check to ensure that all the shoulders are at the same height above the head surface. If they are consistent, you can proceed with your installation. If not, it’s best to take your cylinder head to a machine shop for further inspection and adjustment.
2) Only about 1/2 of the screw (3/8″) will actually thread into the head from this height.
Answer:
That’s right. You’ll have approximately 1/2 inch of head thickness where you’ll be drilling, and it’s perfectly normal for the screw to only thread partially into the head. The screw isn’t supposed to thread all the way through, as this allows you to drill a hole just shy of penetrating completely through the head. This way, you can prevent any drill swarf from falling into the oil galley underneath. To ensure accuracy, use a drill stop set at 7/16″ when drilling the holes.
3) Should Loctite be used on the screws during final assembly?
Answer:
ABSOLUTELY. You definitely don’t want those screws coming loose. Applying Loctite during the final assembly will help secure the screws and prevent them from backing out over time.
4) Anything else I should know?
Answer:
A few additional tips:
- Alignment Gauge: It might be helpful to make a simple alignment gauge to ensure that you’re drilling the holes perpendicular to the head surface. It doesn’t need to be anything fancy, just something to avoid relying solely on eyeballing the angle.
- Drilling Tips: Consider using a small vacuum attachment to catch metal shavings. Coating your drill bit with grease and drilling at a low speed will help the swarf stick to the bit, minimizing the amount flying around.
- Patience is Key: Take your time and don’t rush the process. Even if it means renting a car tomorrow to get to work, patience will pay off. Aluminum is relatively easy to work with, but care and precision are important.
Good luck with your installation!
See our Jaguar Parts Store Catalog to order parts.
