Tappet Guide Hold Downs?

[Dad]

Apologies if this has been amply discussed before - tricky topic to search on.

Watching some videos and noticed the guys at the Classic Engine Workshop in Worcester highly recommend adding tappet guide tie-downs (or ‘hold downs at Moss) to avoid potential catastrophe in the event of a guide working loose, which apparently happens from time to time in well-driven cars.

Mine is not a well-driven car and only has a handful of miles on it, with only a small number added each year.

I also understand installing tappet guide tie downs isn’t trivial and requires drilling and tapping the cylinder head, which is something I’d prefer to avoid.

Any advice would be greatly appreciated - thanks.

[bitsobrits]

If the car is low miles and if the engine has never been seriously overheated then I wouldn't trouble myself with installing the hold down kit. But if the head needs to come off for any reason, or perhaps when it's time to set cam clearance (i.e. cams need to come out) then I might install the kits. I'm on my 3rd E type and didn't have the hold down kit on the first two, and never worried about it. I did install a hold down kit (exhaust side only) on my current car "just because" when I had the cylinder head upgraded (larger valves, porting, cams). This is one of those XK engine things that people say you must do, but the number of cars that actually have issues is small, IMHO, and primarily was an issue with the last of the XK6's in the smog era sedans of the late 70's and early 80'. But it can be an issue in race cars or street cars with seriously neglected cooling systems. But you can find many "brothers uncle by marriage's son in law" stories out there about a massive engine failure caused by loose tappet guides. So choose wisely.

[abowie]

We would always install them during a head/engine rebuild.

You could install them with the engine in situ, but as you say there's a lot of drilling and swarf and IMO the risks probably outweigh the benefits.

Although movement of the guides is a recognised problem, I have personally not heard of one or seen one myself.

[Dad]

Many thanks for the helpful replies. Saved me lots of time and effort. And some cash.