snapped intake cam on a gen III Options

[match220]

Is it common for the 3rd gen to snap a camshaft? I don't think it matters, but I'm running 3sgte cams in a 3sge head (head has turbo springs). As far as I know the 3sgte and 3sge heads are the same with the exception of the valve covers.

[Special_Edy]

Is it common for the 3rd gen to snap a camshaft? I don't think it matters, but I'm running 3sgte cams in a 3sge head (head has turbo springs). As far as I know the 3sgte and 3sge heads are the same with the exception of the valve covers.

It would take a catastrophic event to snap a camshaft. Im fairly certain that the valves or timing compenents would break first and save the camshaft. Pull off the upper timing belt cover, the piece that says "3sgte Yamaha", and verify that the timing belt and cam sprockets are intact. Now, with the upper timing belt cover removed, you can turn the engine over and verify the camshafts are turning by watching the sprockets or noting their position before and after you turn the engine over.

This post has been edited by Special_Edy: Aug 17, 2012 - 12:27 PM

[match220]

Is it common for the 3rd gen to snap a camshaft? I don't think it matters, but I'm running 3sgte cams in a 3sge head (head has turbo springs). As far as I know the 3sgte and 3sge heads are the same with the exception of the valve covers.

It would take a catastrophic event to snap a camshaft. Im fairly certain that the valves or timing compenents would break first and save the camshaft. Pull off the upper timing belt cover, the piece that says "3sgte Yamaha", and verify that the timing belt and cam sprockets are intact. Now, with the upper timing belt cover removed, you can turn the engine over and verify the camshafts are turning by watching the sprockets or noting their position before and after you turn the engine over.

I've already pulled off the head and taken it to a machine shop for them to check out. My cam sprockets are fine, and there is no scoring on the cam caps or shim buckets. I'm waiting to hear what they say about it once they check it. I can get another set of cams, or another head. Either way I'm baffled. I've only had these cams about a year, so I don't know if something happened on the engine that they came off of or what.

[Special_Edy]

Is it in 2 pieces? That sounds pretty gnarly if it is. It seems like it would take a pretty massive amount of force to snap an inch wide shaft of steel.

[match220]

Is it in 2 pieces? That sounds pretty gnarly if it is. It seems like it would take a pretty massive amount of force to snap an inch wide shaft of steel.

yes it's in two pieces and it's a clean break, almost perfectly straight across. It isn't exactly a solid steel shaft. It's cast so it's very porous, which makes it more brittle than a solid piece.

Here's a pic



This post has been edited by match220: Aug 17, 2012 - 6:25 PM

[lagos]

Where your valve clearences all in spec when you installed them?

[Bitter]

A warped head will snap cams like that, have them check the head for flatness and check that the bearing journals are all aligned.

[match220]

Where your valve clearences all in spec when you installed them?

yes

A warped head will snap cams like that, have them check the head for flatness and check that the bearing journals are all aligned.

I'm pretty sure the head isn't warped, but I'll find out for sure when I get it back from the machine shop tomorrow or Monday.

[Bitter]

Also, sometimes you just get a defective part.

[match220]

A warped head will snap cams like that, have them check the head for flatness and check that the bearing journals are all aligned.

the head is warped, 7/1000s of an inch. So I asked them to deck it. They said last thursday they would let me know in two days, and it took them over a week..erg..which is frustrating.

[Bitter]

Damn, I hate it when I'm right!