CamMan

Mate, there are many issues I have with your comments here.
Firstly, like I said in the e mail that someone posted. We never used the 'Japan' core when it was made from Ductile Iron, so we never had the hard facing issue that other companies had. Also, I do not have a quiry from you on this, so why are you confusing the issue here?

xspsi4

iTrader: (67)

I would like to test the rockwell between the stock cam and the broken cam.
If anyone want's to send me a stock cam and a broken cam Like the op I would be willing to test and share the results.

There is a few other things I can test as well such as a magnaflux for cracks etc.

A test like this could shed some light on the situation, Pm me if anyone would like to do this.

CamMan

Some good points and some clarification needed.
Firstly belt harmonics..?
Have you ever watched a timing belt when the engine is on the dyno under acceleration and deceleration? Belt harmonics definatly have a part to play in this, how to measure them and minimise them is near impossible, finding a way to strengthen parts to help protect from their effects is possible.

Mivec map..?, maybe that is crap, but as mentioned I am not an experianced tuner but know my way around an engine pretty well and every option needs looking at. How do you know that at a certain rpm belt frequency is not effected by movements in the map?

Cores..? I was probably not clear enough in my e mail. We use both cores and have done for a long time. The one you call the FP or Comp Cams core has been our core since long before those guys even knew what a EVO IX was.
That core has its own set of issues but it is stronger in the front journal area. Motovicity has had our 9-177-C and -D on the Japan core for a while now as we ran out of the other core earlier this year.

Its a simple fix..?
We put a polished radius in the corner of the mivec grooves and the cams we tested still broke with the same amount of force as the non polished radius cams.
we note that sudden impact is how these break, not even pressure. We are still busting cams daily to look at this and we are just making some more equipment to do so so that we have hard numbers on it for comparison.

Is everyone replacing their tensioner? When I had my EVO IV my local Mitsubishi dealer told me it is a use once item and is mandatory to replace when doing a belt. Any official Mitsubishi word on this would be appreciated if anyone has it.

I am not going to get into argument on here and won't answer hundreds of random questions. If there is something you need to know that directly affects you, e mail me.
I am not really a forum reader or contributor, I will however chime in with info that is pertanant to this discussion or to offer correction and clarification if I think I need to do so.

EVO8URV8

iTrader: (1)

I just surely hope so.

Cool. That's what I'd like to hear.

ktk

iTrader: (9)

Absolutely DO NOT try to loosen the belt to save tension on the cam gears. Make sure your timing belt is tensioned to spec before even thinking of running the motor. If a loose belt slips off, you can suffer the same catastrophic engine failure, exactly like these guys whose cams broke in half.


As for lubing the cams, that is always a good idea, using assembly lube on any moving parts when installing is a must, that said, it is unlikely that the cap breakage issue is related to installation lube problems. The damages due to lack of lubrication tends to look very different and will happen at the bearings or cam lobes.

Once installed be sure to follow the cam manufacturers break in procedure as well.

Ticking noise after cam install is a common side effect of not bleeding the lash adjusters (some people call them lifters, but I don't think they lift anything in the Evo application...).

https://www.evolutionm.net/forums/ev...r-lifters.html

DannyGSC

Just to chime in to everyone. we are running our own series of tests on Greg's GSC camshafts. I will post results up eventually, I can only run tests in the lab on weekends due to time constraints from work. However I will be running every test and scenario possible to check for failure modes including an SEM shot of a fracture area to check for gas pockets in the castings.

I apologize for not introducing myself, I will do this at a later date.

-Danny

KevinD

iTrader: (56)

its been pointed out that it takes tremendous force to break the cam with a single impact force. GSC apparently hit it with a sledge hammer to proove the strength of the cam.

however, in almost every one of these cases the break wasn't immediate. it was after months and thousands of miles. i would put much more thought into metal fatigue failures. maybe belt harmonics are weakening the cam over time. and your safety factors in the cam design are not great enough. there is obviously nothing wrong with your core that FP uses in the MIVEC groove area is there? if that is where the kelford/gsc style core is breaking, beef it up!.

to think that something happens causing an instant stress on the cam enough to break it like that.... which is stronger? the belt tensioner, the belt, the cam? and why doesn't every evo with all different cam types suffer the same fate?

denver

iTrader: (9)

I have absolutely seen these harmonics you are talking about, on many many cars, with a variety of cams. I not saying the harmonics are not there, what I am saying is I find it hard that these harmonics are changing just with a cam. The harmonics are there with the stock cams, the belt tension is the same, so the harmonics generated shouldn't change much, maybe a little with the change in cam profile, but if the profile alone is going to change the harmonics so much that the cam is going to fail, maybe there needs to be a study preformed on optimal belt tension with specific cams. Do you see what I'm saying, the tension in the belt is the same, so where how are the harmonics changing?


I apologize for my comment "thats crap" that was unprofessional. I can only speak of the two cams I had fail in my area (DFW, tnt1106 and booster9), this argument doesn't even come in to play, unless you are suggesting that these cams can not operate utilizing the stock MIVIC map. Booster9 was on a stock mivic map and tnt1106 was not. Both had the exact same failure, so you could conclude one of two things.... The MIVIC map did not effect the failure of the cam, or the cam is not designed to hold up utilizing a stock mivic map.

Are you a representative from the Core Manufacture, or Kelford, or what? When did you change cores? Maybe this could shed some light on why these cams are failing. Again, I do not believe that the machining of the cam etc is the only reason for the failures, I am saying it is machined not using the best practices it could, I do not see a reason both groves could not have a large radius in the bottom in stead of relatively sharp edges present on theses cams. Im also not saying the "FP" cam is perfect either, it still has a sharper edge there then i would put in there... I have designed small light objects for race cars (Formula SAE for 7 years while in college) and currently design LARGE industrial equipment, in all cases I have always been taught to put as large of radius I can stand on shafts, supports etc, if at all possible, never design anything with a sharp edge, especially on a minor diameter with high stress, AKA mivic grove. I suggest the following....


NOT DRAWN TO SCALE... just something quick to get the idea across....

I would like to know in what context Mitsubishi was referring to. I understand they need to be replaced when Mitsubishi recommends replacing the timing belt, but I do not think they recommend replacing them every time the belt comes off the car. AKA faulty water pump, etc... not many reasons to take the belt of the car....

I am not here to argue either... I think the people using the products should be informed, and on the same page. I have nothing to gain or lose from this, but I recognize a problem, it interest me, so I am sharing my thoughts with the community. I have Kelfords in my 8, I love them, I'm not taking them out, and I want this issue to be resolved, the affected people taken care of, and I would like to go back to recommending the cams again, they are GREAT CAMS!

l2r99gst

iTrader: (2)

There is a very simple solution here...send in a failed cam or two to a failure analysis lab. Done.

The testing that is being done by the cam manufacturers may be beneficial, but it doesn't represent real world use. From the one picture of the fracture surface that was posted in the other thread (I forgot if it was in this thread), it looked like there was evidence of fatigue. It's hard to go by one picture posted in an internet thread, but there looked to be beach marks, which is a telltale sign of fatigue. Whether it was just the lighting or not, I can't say, since I can't see the cams in person.

Fatigue is a failure due to smaller, repetitive forces over time...forces under what wouldn't normally cause a breakage. A breakage due to a sledge hammer hit is not the same kind of failure and proves nothing if these cams are really failing due to fatigue.

Fatigue can be verified by simple fractography and confirmed by high magnification under an SEM. A qualified lab can do all of this as well as test the alloy composition and look for defects, etc. Not only can a lab verify if this was a fatigue failure or not, they can verify the crack initiation point(s).

I think simply sending a couple of the broken cams to a qualified lab will get the quickest results and real cause of the failures.

denver

iTrader: (9)

I agree 100%. I have spoke with the Lab I use for testing at work and I am working with TNT to get his sample there. It would make things easier if the core manufacture would share their design specs like: Material, Heat Treatment, and Hardness, so the test lab could compare the sample to the design specs, but I'm pretty sure that is information they will not share, so I am planning to compare to the stock cam.

They are also set up to do a failure analysis.....

Its in the works here.....

tnt1106

My cam is in the lab, when I get results as I have stated before I will post for sure. I don't want any other fellow evo owners to experience this failure or be handled in the manner I have in all this (up to this point).

jimib

I have no doubt that belt harmonics, mivec maps, detonation, balance issues, an many other conditions could have an affect on the cams other than normal operating conditions. However so could spinning the engine to 8k plus, which the cams allow/require us to do. My point is, its admitted that there is a weak spot. The o.e. cams do not seem to have this problem. Even if there are a few isolated cases, how many more thousands of o.e. Cams are out there? So far no fp cams have broke. In the one case I have personal experience with, the cams only came out of the box once to look at, and then were installed by a person that has probably done more 4g63 timing belts than a lot of this site combined, @ arguably the top 4g63 shop in world... As far as fp using the same cores.. The general consensus, is that it is finish machining that needs to be looked at. Its admitted that a larger machined radius would improve it, but then it would move to the next weakest link... I agree, but that's easy to say since that is not done. And who is to say that the next weakest link is too weak for the possible conditions? I'm not trying to argue or point fingers. I'm looking for answers/solutions.

popadel

I’ve read the many interesting views and until the facts are confirmed in a lab speculation will continue. In the meantime i will be playing with the idea of introducing a longer hollow bolt with recesses and cross drilled to allow the oil to flow as necessary, while at the same time offer more support to the actual weakened area of the intake cam. That should make a huge difference given the tensile strength of steel being some 100kg per mm square. A 3mm wall thickness bolt will do wonders for adding to it all. Only condition is that the internal thread needs to run right through, about 15mm longer than the current bolt.

In the past i have snapped off rockers from coil bind on the cossie cams and they worked fine for thousands of miles after that at 8500RPM plus on the track. Harmonics is a bugger!

laramie_05MR

iTrader: (20)

both cars have the stock crank pulleys

JKD

iTrader: (10)

TDC = Top Dead Center