my intake cam snapped?!!?
another
This was at 7,000+ RPM at the track
Exhaust manifold off, saw this:
Then finally head off, saw this:
I was AMAZED there wasn't more damage at the RPM it failed at.
This was at 7,000+ RPM at the track
Exhaust manifold off, saw this:
Then finally head off, saw this:
I was AMAZED there wasn't more damage at the RPM it failed at.
Last edited by GST Motorsports; Mar 11, 2009 at 10:19 AM.
I can't believe that there are so many cams failing like this. I wonder if these companies are all sourcing their cams from the same foundry/manufacturer. This has got to be a material/manufacturing defect, whether microstructural/metallurgical or design based.
Can everyone who has/had these failures post what type of cams they are, both brand name and car type?
Also, does anyone know whether these companies reselling these cams have any machining/heat treating done after receiving them from the original manufacturer? I'm wondering if maybe these cams are case hardened by the original manufacturer, then they are machined later on by someone else (for example for the grooves on the IX cam) and thus destroying the case hardening in that area and not properly re-hardened, etc.
Can everyone who has/had these failures post what type of cams they are, both brand name and car type?
Also, does anyone know whether these companies reselling these cams have any machining/heat treating done after receiving them from the original manufacturer? I'm wondering if maybe these cams are case hardened by the original manufacturer, then they are machined later on by someone else (for example for the grooves on the IX cam) and thus destroying the case hardening in that area and not properly re-hardened, etc.
Last edited by l2r99gst; Mar 11, 2009 at 10:31 AM.
one cam that i can say seems to be built correctly is the fp cams(made by comp cams). the groove has full a radius at the bottom of the grooves and the groove itself is cut 50 thousand more shallow that the stock one so there is 100 thou more material in this known weak spot.
these i'm sure aren't the only ones out there made properly but just the only ones i've been able to measure personally.
these i'm sure aren't the only ones out there made properly but just the only ones i've been able to measure personally.
Last edited by smack_evo; Mar 20, 2009 at 02:19 AM.
Improper fillet radius will absolutely magnify any stresses at that point. I mentioned that originally in tnt's thread about his snapped cam.
Since I couldn't see in the pic and am not familiar on the IX cams, I couldn't comment completely, but if the cams are machined for those grooves that the IX cams have and are not properly radiused, then any stress perpindicular with the axis will be magnified at that junction and eventually cause a fatigue failure. I would imagine it may be worse if the machining reduces or eliminates the case hardening in that area as well.
Since I couldn't see in the pic and am not familiar on the IX cams, I couldn't comment completely, but if the cams are machined for those grooves that the IX cams have and are not properly radiused, then any stress perpindicular with the axis will be magnified at that junction and eventually cause a fatigue failure. I would imagine it may be worse if the machining reduces or eliminates the case hardening in that area as well.
Last edited by l2r99gst; Mar 11, 2009 at 10:44 AM.
Thread Starter
Evolving Member
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From: lewisville TX
Ouch man, sorry to see that! 
It looks very similar to what happend to tnt1106 with his GSC S2 MIVEC cams.
I am in the process of fixing up my own car after a cam issue. Luckily not as catastrophic as either of yours, but after seeing these issues I am really questioning both GSC S2's and Kelfords TX272! The two cams that are at the top of my list of replacements!
What gives? Is it the case that these issues are limited to the MIVEC cams? Has anybody seen a case of such catastrophic failure on an Evo 8?
From looking at the breakaway of your cam though, I have to say it looks like a structural fracture. Very likely to be a materials flaw in the core just like tnt's cams. Keep us posted as to how Kelford deals with your situation.
It looks very similar to what happend to tnt1106 with his GSC S2 MIVEC cams.
I am in the process of fixing up my own car after a cam issue. Luckily not as catastrophic as either of yours, but after seeing these issues I am really questioning both GSC S2's and Kelfords TX272! The two cams that are at the top of my list of replacements!
What gives? Is it the case that these issues are limited to the MIVEC cams? Has anybody seen a case of such catastrophic failure on an Evo 8?
From looking at the breakaway of your cam though, I have to say it looks like a structural fracture. Very likely to be a materials flaw in the core just like tnt's cams. Keep us posted as to how Kelford deals with your situation.
im converting to 8 anyways, im not going to take any chances with my stroker motor!
one cam that i can say is built correctly is the fp cams(made by comp cams). the groove has full a radius at the bottom of the grooves and the groove itself is cut 50 thousand more shallow that the cosi so there is 100 thou more material in this known weak spot. these are the cams i've decided to go with now.
these i'm sure aren't the only ones out there made properly but just the only ones i've seen.
these i'm sure aren't the only ones out there made properly but just the only ones i've seen.
From what I can see in the pictures, I think you guys might be onto something with the non-radiused MIVEC groove as a failure point.
What are the dates like for these failures? When did you guys buy these cams and install them and then how long until failure? What mods did the cars have? For example did the cars have camgears/stock timing belts/etc?)
Lets get as much information about the specific failures out as possible and see if there are any other factors that may have played a role in exacerbating these failures.
It could be a valuable source of info that could save many Evo 9 motors!
In addition, someone above mentioned that FP series (made by Comp Cams) makes an Evo 9 cam that DOES have the correct OEM like radiused MIVEC groove. Does anybody know of any other brands that have a correct groove as well?
So far the problem seems to be present in the following EVO 9 MIVEC cams:
GSC S2
Kelford TX272
Cosworth M3
Lets get some dates on there too.
Thus far, the Evo 8 seems to not suffer from that issue. Although my particular set of early GSC272's (NOT GSC S2's) suffered failure from incorrect lobe hardening due to manufacturer error. So anybody with early GSC's would be advised to inspect their cams immediately. Or risk this:
https://www.evolutionm.net/forums/ev...mage-pics.html
It should be noted though, that in my case, GSC was aware of the defect and Greg@GSC stepped up and offered to replace the defective cam with a new GSC S2.
What are the dates like for these failures? When did you guys buy these cams and install them and then how long until failure? What mods did the cars have? For example did the cars have camgears/stock timing belts/etc?)
Lets get as much information about the specific failures out as possible and see if there are any other factors that may have played a role in exacerbating these failures.
It could be a valuable source of info that could save many Evo 9 motors!
In addition, someone above mentioned that FP series (made by Comp Cams) makes an Evo 9 cam that DOES have the correct OEM like radiused MIVEC groove. Does anybody know of any other brands that have a correct groove as well?
So far the problem seems to be present in the following EVO 9 MIVEC cams:
GSC S2
Kelford TX272
Cosworth M3
Lets get some dates on there too.
Thus far, the Evo 8 seems to not suffer from that issue. Although my particular set of early GSC272's (NOT GSC S2's) suffered failure from incorrect lobe hardening due to manufacturer error. So anybody with early GSC's would be advised to inspect their cams immediately. Or risk this:
https://www.evolutionm.net/forums/ev...mage-pics.html
It should be noted though, that in my case, GSC was aware of the defect and Greg@GSC stepped up and offered to replace the defective cam with a new GSC S2.
Last edited by ktk; Mar 11, 2009 at 11:44 AM.