Anyone seen the Katech article on 941 vs 918 springs?
10-01-2002, 05:34 PM
#1
Anyone seen the Katech article on 941 vs 918 springs? Anyone seen the Katech article on 941 vs 918 springs?
Was on their site yesterday, I can't find it today.
Said they had some 941 failures but the 918 didn't control the valve train well above 6400 rpm.
I only skimmed it yesterday I wanted to read it now.
Thanks
Was on their site yesterday, I can't find it today.
Said they had some 941 failures but the 918 didn't control the valve train well above 6400 rpm.
I only skimmed it yesterday I wanted to read it now.
Thanks
10-01-2002, 11:35 PM
#4
Re: Anyone seen the Katech article on 941 vs 918 springs? There was a graph that showed the valve bounce and it was bad around 6400 with the 918's then cleared up. Must have been a harmonic or something.
Didn't see anythingon the 916's mentioned.
Didn't see anythingon the 916's mentioned.
10-02-2002, 01:36 PM
#5
TECH Veteran
Re: Anyone seen the Katech article on 941 vs 918 springs? Here is the complete article! <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
KATECH TECHNICAL BULLETIN ******
Comp Cams Valve Spring CC941
Valued Customer,
Lately there has been an industry wide breakage problem with the Competition Cams #941 valve spring that we have used in many of our Gen 3 "Off-Road" applications.
High mileage customers probably have no need for concern as we have had no problems with earlier batches of these springs. However, we will replace any #941 valve springs for any of our customers at their discretion, regardless of when they were purchased through Katech. To date, all failures we have experienced have been low mileage applications.
Although we strive to supply the best product for the application to our customers, there is always a risk involved with high performance parts. We also pride ourselves with the fact that we test all of our parts, no matter if we manufacture it in house or a part that is supplied to us by an outside source.
Spring manufacturing is batch oriented in nature and may produce erratic results between batches if all variables are not identical between runs. Quality control in the manufacturing process will usually catch any possible defects. Though a batch problem is still suspect, we do not believe this is the primary problem with these springs.
Through testing and feedback from a limited number of head and cam customers with spring failures, we believe the root cause of this problem is from overstressing the spring at high rpm operation. The failure may not be immediate, but after being overstressed the spring will eventually fail after further cycling. See testing results here.
Please see below for our replacement policy and successes with the CC #941 springs.
Katech Inc.
Replacement Policy:
Short Term - The short term policy for Katech products is to use the Comp Cams #918 spring in all applications. As stated above, any Katech customer may opt to trade in their #941 springs for either a new set of #941 or alternatively #918 springs. If you have not experienced failures, swapping springs may not reduce the chance of future failures.
To receive new springs you must purchase a new set. A full credit will be applied upon our receipt of your original spring set.
Katech does not feel that the #918 spring performs as well as the #941. Due to widespread use of the #918, we believe it is the only acceptable alternative available at this time.
Long Term - We are still evaluating alternatives for a long-term replacement, possibly even to the point of having a spring manufactured to our specific needs and applications.
RPM – Katech strongly suggests customers using either the #941 or #918 springs should limit there rpm below 6400 to allow proper valve control. If you over-rev your engine you will likely incur a valve spring failure. 6400 RPM surpasses peak power for most applications so power is not compromised and higher revs may overstress the spring. This would apply to all of our current cams: CC3349, CC3414, CC3722.
Additional Suggestions - It appears from testing that a stiffer push-rod helps either spring immensely in controlling valve bounce.
Success of the Comp Cams #941 Valve Spring:
Katech has utilized this spring in many high horsepower racing applications with much success including:
Spectre Werkes 24 hour of Daytona Corvette
Callaway Corvette in Grand Am
Fountain Boats record setting speed runs
…many hours of other types of off road applications
To our knowledge, Katech has never had any spring breakage problems with this spring on any of our performance package 7.0L engines built in-house. The only problems to date have been head and cam customers where the engine was not built at Katech.
KATECH TECHNICAL BULLETIN ******
Comp Cams Valve Spring CC941
Valued Customer,
Lately there has been an industry wide breakage problem with the Competition Cams #941 valve spring that we have used in many of our Gen 3 "Off-Road" applications.
High mileage customers probably have no need for concern as we have had no problems with earlier batches of these springs. However, we will replace any #941 valve springs for any of our customers at their discretion, regardless of when they were purchased through Katech. To date, all failures we have experienced have been low mileage applications.
Although we strive to supply the best product for the application to our customers, there is always a risk involved with high performance parts. We also pride ourselves with the fact that we test all of our parts, no matter if we manufacture it in house or a part that is supplied to us by an outside source.
Spring manufacturing is batch oriented in nature and may produce erratic results between batches if all variables are not identical between runs. Quality control in the manufacturing process will usually catch any possible defects. Though a batch problem is still suspect, we do not believe this is the primary problem with these springs.
Through testing and feedback from a limited number of head and cam customers with spring failures, we believe the root cause of this problem is from overstressing the spring at high rpm operation. The failure may not be immediate, but after being overstressed the spring will eventually fail after further cycling. See testing results here.
Please see below for our replacement policy and successes with the CC #941 springs.
Katech Inc.
Replacement Policy:
Short Term - The short term policy for Katech products is to use the Comp Cams #918 spring in all applications. As stated above, any Katech customer may opt to trade in their #941 springs for either a new set of #941 or alternatively #918 springs. If you have not experienced failures, swapping springs may not reduce the chance of future failures.
To receive new springs you must purchase a new set. A full credit will be applied upon our receipt of your original spring set.
Katech does not feel that the #918 spring performs as well as the #941. Due to widespread use of the #918, we believe it is the only acceptable alternative available at this time.
Long Term - We are still evaluating alternatives for a long-term replacement, possibly even to the point of having a spring manufactured to our specific needs and applications.
RPM – Katech strongly suggests customers using either the #941 or #918 springs should limit there rpm below 6400 to allow proper valve control. If you over-rev your engine you will likely incur a valve spring failure. 6400 RPM surpasses peak power for most applications so power is not compromised and higher revs may overstress the spring. This would apply to all of our current cams: CC3349, CC3414, CC3722.
Additional Suggestions - It appears from testing that a stiffer push-rod helps either spring immensely in controlling valve bounce.
Success of the Comp Cams #941 Valve Spring:
Katech has utilized this spring in many high horsepower racing applications with much success including:
Spectre Werkes 24 hour of Daytona Corvette
Callaway Corvette in Grand Am
Fountain Boats record setting speed runs
…many hours of other types of off road applications
To our knowledge, Katech has never had any spring breakage problems with this spring on any of our performance package 7.0L engines built in-house. The only problems to date have been head and cam customers where the engine was not built at Katech.
10-02-2002, 01:38 PM
#6
TECH Veteran
Re: Anyone seen the Katech article on 941 vs 918 springs? I didn't know I had family in the boat racing industry... <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
