Tappet Guide Hold Down Plates

Moss Motors sells these plates on their website. Is there really a need for them? Would it be a good mod to do if you had your head off anyway or just a waste of money? I think I can make them if there is a need to have them.

They are a VERY good idea, primarily on the exhaust side. IT’s an inexpensive, easy mod to do, and just gives a bit of peace of mind.

I put them on my 150 and can post pictures of the process. No hard to do if you know how to drill and tap. The screws that came with mine were crap and I replaced with cap screws.
Pat H

Wonder why these are $ 110 at moss and $ 60 at SNGBarratt.

Free market capitalism… gotta love it!

It looks like someone has installed the hold down plates on three of the exhaust tappet guides. There are some stampings by each cam bearing in the cam cover gasket sealing area such as XE1, XE2, etc,etc,. Is this something that would be done at the factory or a repair garage?

Maybe because the Moss kit has 6 plates and 12 screws, and the SNGB kit has 3 plates and 6 screws, so you need two kits to do both camshafts…

Both are kits with 3 plates, as only the exhaust side needs this kit.

Have you read the info on the web sites? It clearly says that the Moss kit has 6 plates and 12 screws, and the SNGB kit has 3 plates and 6 screws.

So, assuming equal quality (a big assumption), if you only want to do the exhaust side, buy the SNGB kit, of you want to do both sides (as many do), buy the Moss kit.

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Not factory. Just one of the many ways people have come up with to keep the tappet guides in place.

My 1rst E type simply had socket head cap screws installed with the head just nipping the shoulder of the guides. I’ve also seen grub screws used (tapped hole is part guide and part cylinder head) and various plates such as now sold by the usuals.

Back in the day this was disputed. With the advent of the hotter running engines due to US pollution requirements, there was discussion as to whether zero, one (exhaust) or both sides needed protection.

stamped numbers are factory and identify the matching cam bearing caps that should (must) have the exact same numbers stamped on the caps, and match, at each location as the caps must always be returned to the same place and orientation.

I have had the intake tappets come loose on a XK120 head. I lock them all down on all heads. Easier than going back in for a repair, especially if one breaks and bends a valve.

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I plan on putting the plates on all of them. Like you say easier and cheaper to do now. Are there any more quirks about these engines that would be helpful to know now?

Oh lordy…!!!

The list isn’t terribly long, but there are… idiosyncrasies, about the various stages of the XK. What year is your engine?

A 1962 B engine 3.8 liter with a manual trans.

Ok… if you replace timing chain components, be very careful which are used.

You need the Renolds hydraulic tensioner, NOT the Rolon brand.

There is no question about it, I will be rebuilding the motor. I pulled the round cover off the oil pan and there was about a quarter inch of crud in there and a five-inch-long piece of plastic. I guess the plastic is from a timing chain guide. The real issue is the harmonic balancer was loose on the crank with a bunch of slop in the keyway. I’m just hoping I can save the crank. This is going to be hell for the next few months getting this done in my over filled garage now that I’ll be adding a motor stand. If anyone has any advice on the rebuild don’t be shy. I’ve rebuilt US V-8s, several air-cooled VW motors, motorcycle motors, and small engines in manlifts. Any advice is welcome on any upgrade or modifications that I can do to improve the engine. Thanks.

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Because of the crud, it will be a “must-do” job to pull the journal plugs out of the crank, pull the gallery plugs out of the block, and thoroughly clean the gunk out of each.

The damper cone was in four pieces, the keyway in the crank was opened up, and the woodward key was shape like an hourglass. I am hoping I can get the keyway recut to a standard size and make a stepped key for it. With a little luck, I’ll get the motor out tomorrow. Thanks, I had pulling the crank plugs on my list of things to be sure and do.

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