My exhaust camshaft broke in half on my race car this week-end It's a Crane Cams stg2. I had it in my motor for 2 years. Bought it used. Has anyone else suffer this kind of break? Manufacture quality problem or bad luck? No over rev, I was on full throttle exiting a curve.

 

it usually happens from cam bearing seizure, which is almost always due to using cam caps from a different head.

cam caps are machined specifically for the head they come on from the factory. every cam cap is different due to this. the only cam caps anyone should ever use are the ones that originally came with the head. using caps from a different head is just begging for cam failures just like this one.

and to be totally honest, because you posted such a good quality picture, I'm able to see the cam caps on both the left and right side do not match the head, in fact they're extremely mismatched, enough to see the journals horribly misaligned. your failure is due to whichever of these 2 cam caps is further from the timing belt, which I'd assume is the left side one because you said this is the exhaust cam. that journal seized, clamping the cam too tight, and the belt tried to keep spinning the cam even though it was locked up, so it snapped the cam.

IF those cam caps are the originals from that head, then they are either installed in the wrong orientation, or the wrong location.

 

Crane (out of business now) is pretty known for having them break right there.. between the lobes. I've experinced it years ago with cranes, I also have had some customers break some crane ls cams. Bad casting normally is the cause.

the cam caps aren't mismatched btw, i dont know what this guy is looking at.

 

Alright, interesting observation. I'm no mechanic so I'm gonna bring my car to the shop and have my mechanic check all of this. thx for the info.

 

I can also clearly see the cams do not match very well, it's hard to make out exactly if the lobes are mis-matched, but I can deff see the sides are not matching up.

 

I think they got bought by someone else. But their web site still exist.

http://www.cranecams.com/

I'm no mechanic so I can't say much about what he said. So what after market cams you running with now? Skunks2, Crowers?

 

they are still in business...

 

It is very plainly visible the journals of the cam caps and the head are not even remotely close to lined up, which makes the horizontal cam journal diameter too small pinching the cam.
And if you look closely, you can also see the top of the left side cam cap journal is mushroomed out a bit, a telltale sign of it being machined at a different height than this head, causing the journal to be too small of diameter vertically, pinching the cam vertically as well, causing it to wear and mushroom out.

if the journals don't line up absolutely flawlessly, then the caps are either from a different head or are in the wrong location or the wrong orientation. there is absolutely zero reason for the cam cap journals to not line up properly if they are the original caps and are installed correctly. because everything is machined at the factory as an assembled unit to ensure absolute precision.

well of course the lobes on the cam are mismatched; the cam is broken lol. one side of the cam was still spinning while the other side wasn't.

 

not the lobes,the caps, look at the edges of the caps, eithier backwards or from another head, the only possible way to use caps from another head is to have them line bored, the cap castings are integral to the head castings, the caps are bolted to the head casting at manufacture and then the journals are bored and reamed on a centerline of the deck surface, every single set of caps is different from any other set and unique to that head

 

exactly.
the guy I was quoting was pointing out that the cam's lobes don't line up, hence my reply to that haha.

 

When i get home, i'll show you a mark that shows the caps have been like that for awhile..

Crane isn't in business, COMP bought them out. You can't get "CRANE" cams anymore. If you take the time to search you'll noticed you're not the only one who's had a crane cam snap.

Besides none of their profiles for imports are any good, anyway.. I would use this as a lesson learn and run something more proven and better quality.

 

Ive attached a part of the pic that stood out to me.

Now to see if the cam caps aren't properly in place or facing the wrong way, a top pic is needed showing the arrows and numbers.

Look at the attached "Circled" area. This is a mark that's obviously been with the head and caps for quite sometime.

Crane was "never" good at casting cams for imports.

 

S&S cycle from Wisconsin bought Crane after they closed and rehired a few of the people that got laid off when the original Crane closed down and moved them to Florida. They do not do honda anymore.

The cores that were used are pretty much the same material used by various cam brands and manufacturers for Bseries.

Most of the time the iron cores have voids, air bubbles inside the material that make them weaker and they can break easily.


Ouf of 10 sets of iron cores, its not unusual to see 1-2 bad cams that gets thrown out if there is some short of QC in place. The issue here is that when a bad intake or a bad exhaust is indeed found, that also means that another cam has no pair to match anymore so its a significant loss if you get 1-2 bad cams every 10 sets. That is why going to billet makes sense for a manufacturing point of view because yield is usually 100% with no loss.

In the old days, people used to xray the iron cores in order to tell the good from the bad cams when it came to iron cores.

Another problem is that the major suppliers for cores only give 30 days for returns and problems are not really found unless you try to grind it and even then its very possible to still have bad apple no matter how nice and cool your lobe profile or design is.


Comp cams that you mentioned also makes bseries cams under their name and probably some other cam brand names for bseries.

 

That's good to know, When I had a customer brake a crane cam, they tried to call and got directed towards comp, once talking to a comp tech, they basically stated what I did, just referring what I had been told from someone who actually works on Comp, wasn't making it up

As for what you said, yep, that's very true. I would also advise the op to save the headache, and do away with the exh cam or intake cam which ever did not break because it is also more then likely from the same batch.

 

What I am saying is that no matter what batch it is, it will have bad ones that most likely end up getting sold anyway because most people just accept the fact that cams break and tuners. engine builders, companies can always blame installation for it etc so its really very rare to see a company throw away cams that might brake because they treat the honda market in a different manner than they would treat say the V8 market.

For the most part, honda enthusiasts are not really surprised when parts fail or break. It's just what this market is about. That is why companies with hardly any R and D and copy and paste mentality with virtual zero QC control, can do really well because price is all that matters.

When it breaks, they are ok with a replacement as long as its free and they do not care that its actually the same part that's about to break again. I knew a guy who broke 3 sets of cams in a row and he is still buying the same brand because he believes it was a bad batch.

It's just econo material for an econo market.

 

I can personally say Ive used Crane 0012 and 0016 cams and havent had any issues with either. Using Crane springs and retainers with the cams for the past 3+ years.
Im quite pleased with my idle with a 109 and 108 LSA.

 

Alright, to continue, here are some photos. It's worst then I thought. It actually broke in 4 pieces!!! So you think I can use JB weld or crazy glue to fix it? LOL! They are/were Crane Cams 0012. Engine damage: bent valves.






Close ups:

 

What valvetrain were you running? What do the inside of the cam caps look like? Did you have a drop in oil pressure ? Taking the exit at full throttle may have starved the camcaps of oil causing the cam journals to bind, judging the breakage just from the picture it appears they sheared off which could mean they bound up and twisted. We have seen this on a few different cams before and it was not the cams manufacturers fault it was due to oil starvation. Check the cam caps and see how much damage there is, not being in the car with you obviously means you will get a lot of speculation on the what happened. I had a factory cam snap about 6 months ago driving 65 mph just cruising oil pressure dropped and cam seized snapping it now that was hard to understand till I saw that a seal popped out and lost oil however this was on a engine that had a ungodly amount of milage.

 

Definetly bad casting. If the casting was good, then you would see twist in the cam refelcted in the broken areas, becuase the sheared/broken spots on that cam show no signs of "twist" or circular stretch, that means that the cam snapped before it could twsit and disfigure.

This IMO is due to poor casting, as if it were good casting, the cam would show signs of being twisted before reaching its failure point.

As for teh caps not matching up, the outer edges of the caps have no regard when used for match comparision, as it is the inside of those caps that counts. The caps are are built seperate from the head and then they are installed and bored and hoend to perfection.

Using the wrong caps can cause this but without having accurate measurement tools to measure the cam journals one cannot say for certtain whether the caps are mismatched. If you can provide a picture of the tops of them then we can see if they were installed in right locations and in right direction but thats about all one can decipher from internet pictures.

From the looks of the cams there appears to be little to no scoring or other "contact" marks that would reflect a sever decrease in oil pressure. Usually whenb the oil is ran dry, the cams will make contact with the journals and get scored to all hell and back. This doesnt appear to be the case, so i would not think lack of oil pressure casued this. If you have lost so much oil that your cams have bound and broken then there should be much more scoaring anf scaring on the cams.