stripped camshaft sprocket thread fix/workaround

[Dolomite_]

Getting the last bits on the engine ready to fire up on the weekend and somehow one of the cam shaft sprocket threads stripped when I was hand tightening it. Not sure how, I was just hand tightening both of them up equally.

To save me trying to find a new camshaft or tapping a new thread. How bad of an idea/fix would it be to just get a slightly longer bolt and use a nut to hold it in place? There is enough room on the other side for a nut.

[Johnwebley]

I guess there are several methods

Simplist is what you thought,

But it makes it out of balance,

Or can you helicoil?

Or my solution, fill the hole with weld,drill,and tap,

A decent engineering shop could do that,

Let's face it, we don't want any loose bits flying around inside the motor



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[Orcade-Ian]

Firstly,
Are you sure it's the hole in the camshaft and not the thread on the bolt?  As John says putting a nut on the end of a longer bolt would upset balance, although it's only running at half engine speed and not large diameter - so do both of them - you say there is room for a nut.  The cam flange at that point where the nut would seat is as forged and not really flat, so if was going that route I would use 'staytite' nuts, not nylocs.

Ian

[Bryanj]

As the surface is not flat a nut would not be a good engineering fix, there should be plenty of used cams out there and at the present stage replacing it will not be much work

[Dolomite_]

After my initial panic has settled, I think it actually is the bolt that stripped. What are the original bolts made of?

Hopefully, I can find a suitable bolt so I can get it up and running this weekend.

Out of interest, what are the camshafts made from?

[TrickyMicky]

Part No. 90081246000.     7x12 Bolt. DSS has them in stock.

[taysidedragon]

After my initial panic has settled, I think it actually is the bolt that stripped. What are the original bolts made of?

Hopefully, I can find a suitable bolt so I can get it up and running this weekend.

Out of interest, what are the camshafts made from?

The original bolts are high tensile steel. Don't be tempted to use an ordinary mild steel bolt, that may be what a previous owner has used and has now stripped.

[Bryanj]

Camshafts are meonitic cast iron

[Laverda Dave]

Camshafts are meonitic cast iron

Are Honda camshafts cold chilled Bryan or did Honda actually apply a surface finish such as case hardening? I remember a good few years ago having a worn 400/4 cam stellite treated and re ground after being told Honda didn't use case hardening.

[K2-K6]

They are, effectively "case hardened" but more realistic to call it "peripheral" in how we understand metal treatment.

It's the propagation of molecular structure through the chilling process that controls the change in outer layer to give more resistance to wear.

"Case" usually refers to adding carbon etc into the surface of steel to change that outer surface similarly, but its fundamentally a different process with that addition to alter the metallurgy as opposed to re arrangement of already existing internal mix of the casting batch by chilling in manufacture.

Most production camshaft for years are the same, don't think Honda had used anything different.

[Laverda Dave]

Thank you for the explanation Nigel.
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