*Flow Chart Samples

Valve Job The valve seat has three purposes: to seal the port, to cool the valve, and to guide the air through the valve opening. So, you can see why the quality of the valve job is crucial to the performance of your cylinder head. Great caution is taken when cutting a valve seat. First, to insure there is no run out (or mis-alignment) between the valve guide and the valve seat. Second, to position the seat with the valve regarding angle, diameter, and width. By eliminating run out, the valve will seat properly without unnecessary side load on the valve guide. Every valve job features multi angles; at least three on the seat and two on the valve. In addition, the area where the seat contacts the valve is positioned on the very outside diameter of the valve. For example, dis-assemble a stock 350 Chevrolet head. There is a 1.5 inch exhaust valve, but the area where the seat contacts the valve face is anywhere from the extreme inside diameter to the middle of the valve face. What is the point of using a 1.5 inch valve if you’re only going to cut a 1.4 inch seat? By positioning the seat to the outside and using multiple angles, you will gain several cfm in air flow even on un-ported heads with stock sized valves. Price Comparison Have you ever wondered why similar products have such a vast difference in price? Take titanium retainers for example; we sell a set of 16 Manley titanium retainers for $130.00 while mail order magazines offer a set of 16 for around $60.00. Could these be the same retainer? No. Manley purchased a set of these retainers for analysis from a company whose name we probably shouldn't mention (but their initials are Chet Herbert). It was no surprise to learn the Russian-made retainers were not aero-space grade titanium as are the USA-made Manley's. In addition, only two of the sixteen retainers offered the same installed height. We rely on many different brands of quality parts for our stock heads, but on our performance heads, we rely exclusively on Manley Performance Products. We are consistently impressed by the precision of their valves, springs, retainers, and keepers.

Valve Guide Replacement

The valve guide is the heart of the cylinder head. If the wrong material is used or the wrong procedure followed, the valve guide will fail and nothing else will matter. The installation process of the guide is as important as the material the guide is made of. The most common scenario (on domestic cast iron heads) is to machine the head for ½ inch O.D. guides. The valve stem to guide clearance is then reamed to size using the go-no-go method. Unfortunately, it is not uncommon for a valve guide of this nature to have a very short life span. Here’s why; the machining process that allows the ½ inch guide to be used leaves minute imperfections between the head and guide. These are microscopic air pockets that do not allow heat to transfer from the guide to the water-cooled head. When valve guides over heat, they burn up the oil that lubricates the valve, which causes the valve to gall or seize in the guide. In addition, the crude method of setting up the clearance leaves rough, uneven surfaces inside the valve guide which promote premature valve stem and valve guide wear. By reaming the guides too, the final size is only determined by how sharp the reamer is.

The Bronze Bullet liner takes K-Line Guide-Liner technology to a new dimension by incorporating the proven benefits of phosphor bronze and K-Line's exclusive Interrupted Spiral and bullet nose.

Phosphor Bronze
* High strength-to-weight ratio
* More dense than cast iron
* Higher rate of thermal conductivity
* Lower coefficient of friction

Interrupted Spiral Note that the spirated grooves do not align at the seam. The reason ? Lubrication is suspended in the guide, reducing the possibility of excessive oil pass-through.

At Louthan Competition, we install phosphorous-bronze valve guides, and every guide is honed to an exact dimension based on the valve that is going in that guide. Tolerance is measured with a Sunnen dial bore gauge and is accurate within .0001" (1/10 of one thousandth of an inch). By fitting the valve guides accurately with a hone and a dial bore gauge, oil consumption is better controlled and longevity is increased by many times due to smoother wear surfaces and increased surface area for better heat-transfer. The good news is that our prices are very competitive, so you won’t pay extra to get a lot more !