Technical
STK Competition Valve Springs and Retainers
STK Competition Valve Springs and Retainers are a must if you are considering a Camshaft with High Lift , intend to run at Higher Rpm ranges for NA & Turbo Application. STK Performance Valve Springs will eliminate coil bind and valve float when installed correctly and are made from High Quality Chrome Silicone Materials , rated at 8500rpm and suitable up to 14mm of Camshaft Lift. STK Valve Spring Retainers are lighter and stronger being made from Chromoly 4140. Installation of the STK REV KIT 1. The Spring Heights and Spring Travel need to be Measured & Adjusted accurately to avoid coil bind ,breakage or damage to the camshaft lobes. 2. Allow an Automotive Engineering Specialist or a Master Mechanic to install these springs correctly 'cause if you get it wrong it's gonna hurt your pocket ! Modification of the Cylinder Head maybe necessary in order to ensure reliability when fitting the Spring Kit , so ensure that a Master Mechanic fits these products to avoid damage to the camshafts, valve train and engine. What Valve Spring is right for your application ? Keep in mind that Motorsport Companies do not use standard valve springs in their “state of the art“ Cylinder Heads, have you ever wondered WHY ? The standard valve spring is designed for a production vehicle which is generally well looked after at a moderate rpm. Whereas a competition engine is designed to run at maximum rpm whether it be 8 000rpm or 10 000rpm , they need reliability and components that can handle the pounding from the high lift, high duration Camshafts they use. With this in mind a Cylinder Head or Engine will be destroyed due to incorrect installation or incorrect valve spring applications due to valve float and coil bind. So, when you decide to build a trick head ensure you do your homework thoroughly and get expert advice. STK Performance Hi-Rev Valve Springs bedding process ! • Ensure correct Spring Pressures, Spring Travel, Spring Height & Clearances. • On Initial Start-up limit between 1500 & 2000 Rpm until operating temperatures are achieved. • Shut-off engine and allow to cool to room temperature. This break-in period will reduce the risk of Valve Spring failure and prolong the life of your Valve Springs.
CAMSHAFT MATERIALS
At STK Performance we manufacture Camshafts as explained below : 1. CHILLED CAST IRON CAMSHAFTS “So if it ain’t Chilled cast , it ain’t good enough “ STK use this process for mass production of their Camshaft Blanks and it is the only material for producing Performance Camshafts , it’s that good reliability wise that we manufacture most of our Standard Camshafts in this way too. What is Chilled Cast ? When the camshaft is cast in the foundry, the iron is poured and hardened off very quickly ( known as chilling ) this causes the material to form a matrix of carbide on the camshaft lobe , this material will cut glass and is exceedingly scuff- resistant. 2. MACHINED BILLET CAMSHAFTS STK use this process for low quantity Camshaft production and generally costs more due to the additional work involved in producing this type of Camshaft. Machined Billet Camshaft means that the camshaft is turned from a round steel bar and is Nitride Hardened after grinding to ensure hardness and reliability of the Camshaft Lobes
STK High Performance Stainless Steel 21-4N Billet Valves
The STK Performance Valve is forged using 21-4N Stainless Steel which is strong and can handle most applications. What is 21-4N ? 21-4N Super alloys or high performance alloys have an ability to function at temperatures above 540ºC(1000ºF) with deformation resistance and high surface stability. Super alloy 21-4N valve steel is widely used in the manufacture of automotive High Performance Valves. Most production valves are made from two components to make up the valve , the valve head and the valve stem and are joint bonded by electric-resistance-heat-aided friction welding. Usually the two components are made from two different types of material / Steel. 21-4N is usually considered to be the premium material for performance exhaust valves. Most of our Stainless Steel valves we produce with extra overall length. This is to aid with under-bucket shimming and eliminates the use of a shim between the valve and Bucket/lifter. The Valve is Undercut and reshaped around the head area for optimum flow and reliability. This is best used with high rev valve spring applications to avoid valve failure , standard valve heads may break at the joint due to additional force of valve closure caused by the additional poundage of a Competition valve spring.
CAMSHAFT BREAK-In
STK Performance Valve Train Products (VTP's) are manufactured from the finest Quality Materials available and have been Developed & Tested under severe Motorsport conditions. To ensure that your STK Performance VTP performs to its optimum ensure that the following “Break-In” Procedures are strictly adhered to: STK Camshafts & STK Heavy Duty Camfollowers ( VW ) • New camfollowers must be fitted with a new STK Camshaft . • Coat Camshaft & Camfollowers with Cam Lube during fitment. • Do not run on idle during the first 20 minutes of operation. • Run at 2500 - 3000Rpm . Do not run at high Rpm during this break-in period. • If any changes need to be made during this period switch off engine (Do Not Idle) Once this Break-In procedure is completed your Camshaft & Camfollowers will be bedded. STK Performance Hi-Rev Valve Springs • Ensure correct Spring Pressures, Spring Travel, Spring Height & Clearances. • On Initial Start-up limit between 1500 & 2000 Rpm until operating temperatures are achieved. • Shut-off engine and allow to cool to room temperature. This break-in period will reduce the risk of Valve Spring failure and prolong the life of your Valve Springs
STK Performance Limited Warranty
STK Performance warrants that all of its product are free from defects in material , workmanship and against excessive wear for a period of 12 months from the date of purchase. This Limited Warranty shall apply for a period of 12 months from the date of purchase and shall cover only the original purchaser. This Warranty is valid on camshafts only where new lifters/camfollowers and proper valve springs are used , such as those available in STK Performance kits. It is the clients responsibility to ensure that Valve Spring Heights & Valve Spring Travel are adjusted to avoid coil bind and damage to the camshaft lobe areas. STK Performance obligation under this warranty is limited to the repair or replacement of its product. There is absolutely no warranty on the following : 1. Any part used in racing applications. 2. Any product that has been physically altered,improperly installed or maintained. 3. Any product used in an improper application , abused or not used in conjunction with the proper parts. There are no implied warranties of merchantability or fitness for a particular purpose. There are no warranties which extend beyond the description on the face hereof. STK will not be responsible for consequential loss or damage . property damage or personal injury damages to the extent permitted by law. Implied warranties of merchantability and fitness are limited for a period of 12 months from date of original purchase. Warranty Returns All merchandise returned for warranty consideration , inspection , repair , regrind , etc. must be sent prepaid to STK Performance . Should you encounter problems with any STK product kindly contact STK , as most times problems arise from the specific application and its variances and can easily be solved over the phone. Kindly notify STK prior to returning goods and kindly forward a written explanation of the reason for return.For Hydraulic & Solid Lifter application camshafts include the camfollowers with your return for evaluation. Damaged Merchandise All shipments from STK are insured ( if shipped with STK's designated courier ) , All claims should be made via the Freight Company , kindly contact STK should you require assistance in this regard. Contact Us STK's Office Hours are Monday to Friday 08h00 - 18h00 , and are closed Saturdays & Sundays and all Public Holidays. sales@stk.co.za or Whatsapp +27 65 597 8744 Please Note : We assume no liabilities for errors contained herein and it is the responsibility of the installer to ensure that the components are correct before installation. We assume no liability for any errors made in components selections or installations. STK Performance reserves the right to make any necessary changes in products it supplies and markets at any time to improve product performance.