K-Line introduced Bronze Guide-Liners to the market over 20 years ago and is the leader in bringing thin wall bronze liner technology to today's ever changing market. Focusing on quality, efficiency of installation and most of all durability, they have been working for over 25 years to bring the most advanced technology to the demanding users through their patented Guide-Liner system. 

K-Line-Guide Liners were originally popularised by those in the trucking industries, where utter dependability and high mileages are their bread and butter. Commercial vehicles can be demanded to run for 250,000 miles and more, time off the road is an expense that the owners cannot afford. 



The Guide-Liners are made of spring tempered phosphor bronze, which is an anti-seizing, anti-wear, high strength-to-weight ratio material. It is more dense than cast iron, has a higher rate of thermal conductivity, a lower coefficient of friction and insures higher lubrication retention due to the interrupted spiral feature of the product engraved on to the inside of the liner. 

Utilising a patented geometric inner design, lubrication can now be held in the guide, enhancing wear characteristics and reducing the possibility of excessive oil pass through. This patented design feature provides superior installation and fitting characteristics.

There is no better system to combine efficiency and durability than the K-Line Bronze Bullet Interrupted Spiral Bronze Guide-Liner System. Combining the durability benefits of phosphor bronze with the efficiency of thin wall installation, K-Line has made valve guide repair a very simple and adaptable operation but does require specialist tooling beyond the budget of repair shops

Continued advancements in the tooling and installation process means that we can produce premium quality valve guide repairs, and upgrades, in the most efficient manner.

Quality, Performance & Durability

Since the early 1970's K-Line has run numerous dynamometer tests in conjunction with major production engine builders and O.E.M.'s. Repeatedly the Guide-Liners and has out performed cast iron guides and has become the approved method for rebuilding. In fact, these tests have found the Guide-Liners to be up to three times more durable than cast iron. Further more, the minimisation of both guide lubrication and guide to stem clearances have failed to induce either a seizure or cause metal transfer. 

Most major manufactures have tested the product and confirmed K-Line's Guide-Liner system as an approved product for use in rebuilding their engines.


Fitting and Fettling Liner Shown in Red

Increased Efficiency

Our best result was with one customer who, after 50,000 on his BSA A10, still had 2 and a half thou or less clearances valve to guide. Less than they would have been when they left the factory. Standard replacement such as those Norman Hyde sells, guides run at clearances of 2 to 3 thou. Same as the the tolerances on the new 1999 model Harley-Davidsons and others. The standards of early original factory parts can sometimes even be as bad as the parts they are replacing, so it is worth checking that your parts supplier knows what they are selling you.

Closer Tolerances Valve to Guide Offer a Number of Benefits to the Owners of Classic, Vintage, High Mileage or Racing Vehicles

 As the rocker action on the tip of the valve places lateral forces against the guide and wears it into an oval, it also forces the head, or rim, of the valve to cut into the newly cut cylinder head seats. Reducing tolerances minimises this making for a longest lasting head,

They also allows for a greater transfer of heat from the valve to guide and away into the head and stops oil and air being sucked down the side of the guide. With unleaded petrol running at far higher temperatures, in hot climates or in racing conditions, this is good news, Improved fuel economy and cooler running,

Quieter running, increased responsiveness, some racers claim that their engines now tick over for the first time. Greater vacuum created in the inlet port in engines improves all round general performance to the point of requiring re-calibration of the carburettors.



Everyone can Benefit from K-Liners.

Increased Performance & Durability



Unmatched Durability




With K-Line Guide-Liners fitted, matched to quality new or refaced valves and freshly cut seats, we guarantee owners to return 2 to 3 times the miles one would expect. One racing head we set up, a championship leader, did 3 seasons without need a head job and still was still in better shape that it would have been straight from the factory at the end of it season. Nothing more than a light lapping with Solvol Autosol was necessary to send it out for its fourth year racing.

More recent tests have shown that K-Line's Bronze-Bullet Interrupted Spiral phosphor-bronze Guide-Liners exhibited 41% less wear than smooth wall liners, as used by other tuning shops, under harsh durability testing environments even at similar tolerances. K-Line manufacture and stock the only complete selection of Guide-Liners and Guide-Liner installation tooling in the World.

Due to our many years of successful adoption of this technology, any problems in wear following the fitment of K-Liners or Nucleus Sports Elite Valves can be traced to the lack of carburettor adjustment. The penultimate combination would be to have Nucleus Power Guides fitted with K-Line Guide-Liners. Bespoke fit, incredible heat transfer and many other individual benefits for differing models.



Cast in Guides or Delicate Vintage Head?




If guide durability is critical to you, or you own one of many engines than have cast in guides where it is not possible to replace them, K-liner are also the way to go for you. Likewise if you have old, rare or delicate heads where one would wish to avoid knocking out guides from the head casting. 

Knocking out guides cause erosion in the casting that lead to small oilways being created down between the guides and the head. To avoid this, and it is good practice, fit Guide-Liners. As long as your guides are tight in the head, liners can be fitted. They come in a variety of different sizes.

	Lower co-efficient of friction, High lubrication retention, Low Price, Expert Service,
High strength-to-weight ratio, more dense than cast iron, Higher rate of thermal conductivity,

The Bronze Bullet Guide-Liner takes K-Line Guide-Line technology to a new dimension by incorporating the proven benefits of phosphor bronze. This design feature allows for efficient installation without requiring any chamfering of the cylinder head. 

K-Line's patented process allows us to maintain consistent material thickness through the length of the where it's needed. insert so that at final sizing the bullet configuration disappears, providing a consistent internal diameter. finish -throughout the length of the guide.

Look closely at the spiral in the illustrations. Notice that the spiralled grooves do not align at the seam. The reason? Lubrication is now suspended in the guide, reducing any possibility Of excessive oil pass through. Another benefit is;

The Bronze Bullet Guide-Liners Costs Less Than Fitting
New Guides and Can be Replaced at a Later Date.

RESULTS OF A DYNO TEST


K-Linel Guide-Liners Experience 
41% Less Wear Than Smooth Wall Bronze Liners.

Type of Test: 200 hour durability test. 3% margin of error allowed.

Tests were conducted with both smooth wall bronze liners and Interrupted Spiral Guide-Liners. 

K-Line Guide-Liners hold infinitely better tolerances than the typical aftermarket valve guides and should last 50,000 miles before they need replacing. We can fit them to tolerances of less than .3 of a thou.