Page 8 - 2015 XK Parts Supplement

Engine Parts For The Classic ‘XK’ Engine

Long-Style Tappets

Sometimes progress isn’t really progress at all, but let us explain:
From the XK-120 through the early Series II XJ-6, Jaguar sup-

plied “long-style” tappets; they then switched to a shorter
version (by 3.175mm or about 1/8”) and have since superseded

the item many times to a part that hardly resembles the original.

While the current part may be great for a new V-8, we feel
the original design is best for older engines. The extra length

spreads wear to a larger portion of the tappet bore and can
reduce rocking, resulting in a quieter-running engine. These

tappets are manufactured by XKs Unlimited to exacting toler-

8” Taller
ances. We recommend replacement in engine-sets only.
Order Number CO-44010 each

Why Fuss Over 1/8 Of An Inch ?

In the illustrations you see as the camshaft Camshaft

rotates it pushes the tappet down the tappet Tappet Guide

guide against the resistance of the valve spring. Tappet
Of course as the camshaft continues its rotation

the valve spring pushes the tappet back up the Valve Spring
tappet guide. The shorter the tappet the greater
Valve
the likelihood for the tappet to ‘rock’ or ‘wobble’

in the tappet guide. This rocking leads to undue
wear, causing a ‘rattling’ sound from the valve

train. The long-style tappets are the sure-ire
cure to quiet running. If you’re having your

head redone, make sure to use top quality parts

throughout, and especially these longer tappets.
Less than $10 each buys a lot of peace of mind.

Reduces Mechanical Clatter!
These cutaways drawings illustrate the short distance the tappets travel, heightening the need for the

long-style tappet. Note we’ve chosen to show only a single valve spring for clarity.

Valve Shim Assortment

Our valve shim assortment includes three
each of sizes .085” to .092”; four each of sizes

.093” to .103”; three each of sizes .104” to .124”
-- that’s 130 shims.

Shim Kit Order Number 01-1272

Individual Valve Adjustment Shims
800-444-5247
Individual shims manufactured by XKs Unlimited are back! Each
805-544-7864
shim is laser etched with the part number and thickness and are
available in the standard A-Z (.085” to .110”) range and oversizes

from .111” to .124”.

See page X15 for complete listing of these individual valve shims

800-444-5247 www.xks.com
8 Catalog Supplement