Performance valve springs leads to cam bearing failure?

[heresolong]

I have some thoughts I want to run past you guys. Over the past couple years I have had four bikes in my shop that have had catastrophic failures of the cam system. In each case the front inner cam bearing had completely failed, necessitating a new engine as the cases were unusable. Each of the bikes was originally performance upgraded by a different shop in Washington state. Two of the bikes had S&S gear drives, and two of the bikes had HD performance cams. What they had in common was that they had performance heads. One had custom built heads from a shop in Seattle, two had HD SE heads, and one had HD HTCC heads.

The latest is what started me wondering whether the inner cam bearings (they all had Torrington replacement bearings) on the 88/95 are not strong enough to withstand the extra pressure from high performance valve springs. I had previously assumed, due to the small number of problems I had seen, that the mechanics had made a mistake somewhere. With the inner bearing torn out it was impossible to tell if the bearing had been installed backwards and that was my suspicion. However, with four identical problems from four different shops, it seems to me unlikely that the bearings were improperly installed that many times.

I was also thinking about the fact that HD changed the inner bearings to a larger diameter and that I haven't seen this failure in any newer bikes (although by def. the newer bikes might have less miles on them).

Has anyone who works in a shop seen this problem on a regular basis and have you noticed whether or not they each have had performance heads?

[LoCo1969]

I've built a ton of engines with both the regular SE Heads and the HTCC over the past 10 years and have to say I've never seen a Torrington fail. I can think of several with over 50K on them. I know this doesn't help you much, but thought I'd add my experience.

[springer-]

I would have a hard time believing the cam bear was the ultimate issue if it was a full compliment bearing.

Consider that many EVO's have increased spring pressures. The EVO has one cam and supports all 4 valve springs. The EVO cam bearing is the smallest of the bunch. So the B-138 bearing supports twice the spring pressures in a performance EVO build than the B-148 or B-168 in the twin cams.

[TXCHOP]

Originally Posted by springer-

I would have a hard time believing the cam bear was the ultimate issue if it was a full compliment bearing.

Consider that many EVO's have increased spring pressures. The EVO has one cam and supports all 4 valve springs. The EVO cam bearing is the smallest of the bunch. So the B-138 bearing supports twice the spring pressures in a performance EVO build than the B-148 or B-168 in the twin cams.

Yup i agree. Lots of guys running 200lb springs with no problems.

[ViennaHog]

Folks in the shop have seen many TCs with stock bearings fail, but no Torrington conversion yet. No report of failure of the large diameter 2007- models stock or modified.

So might by a strange coincidence.

[springer-]

I should clarify that not all 4 springs are exerting pressure at the same time as the timing of each valve is different. But the EVO does have 2 lobes (rear intake, front exhaust if I am not mistaken) that are open at about the same time resulting in 2 valve springs exerting pressure at the same time, the twin cams do not have more than 1 at a time.

[heresolong]

Originally Posted by springer-

But the EVO does have 2 lobes (rear intake, front exhaust if I am not mistaken) that are open at about the same time resulting in 2 valve springs exerting pressure at the same time, the twin cams do not have more than 1 at a time.

Although that could be a negative depending on what direction the pressure was coming from.

However, I tend to think, since no one else that has responded has seen a problem, that it might just be a coincidence, as suggested above.

Thanks.

[Hillside]

The proper spring pressure is MANDATORY to accomodate the cams profile. Stock or otherwise.
160, 188, 200 psi seat pressures, with 450 psi on the nose, does not knock out cam bearings on XL's, Shovels, Evo's or T/C's. OEM Pan's are bushed. Something else is the culprit that would cause the failure.
Scott

[Otto]

I would be looking at coil bind se heads are notorius for incorrect setup outa the box and camlobe to case and lifter travel clearances i have 4 seasons on a race motor here with seat pressure over 300 and 900 over the nose with no bearing failures key falures yes but no bearings

[mawnanian]

Hi, this is my first post on this forum.
I'm about to upgrade (via a dealer) my 2009 glide to 103 with se-255 cams.
I'm wondering how the inner cam bearings will hold up and reading about the trouble with INA bearings whether to replace them with Torringtons rather than HD bearings.
Looking at this link
mdlcycles.blogspot.com/
it looks as if HD have recently replaced the caged bearings with Torringtons or an INA equivalent.
Is this the case and if so would the new bearings, if not Torringtons, be up to the job?

[route66paul]

I do not know about the new bearings, but do a search on that camset. There are better ones to be had on the aftermarket.