Replacing Cam Taper pins with bolts/nuts

[MoeK]

Hello,

I am going to be replacing two of the cam lobes on my CS 10/2 and I am wondering if anyone has had success replacing the taper pin with an apporiate size bolt? Perhaps a hex bolt with locking nut? It seems to be a better way to go than hammering in a taper pin.

Thanks

Moe

[MoeK]

Jens,

I am replacing the two lobes that drive the fuel pump (one on each side).  The engine is an original Lister CS 10/2 made in 1949. The cam was never removed from the engine and is the original. I dont know how many hours are on it, but the engine was left outside for a long time (several years) before I got it.  I think the rust caused by the water ingress has caused a lot of the issues.

These lobes have extensive pitting but the ones driving the valves are ok. I see differences between the two with the side driving the pump for Cylinder-1 having the worst pitting. I have not run this engine before, so I am not able to comment if the difference is due to a lack of lubrication. It may very well be because I see pitting on the roller tappet as well. I do not plan on making any changes to the lubrication system at this point, as I am looking to keep the unit as close to original as I can.


Regarding comments for other twin owners, (a) drilling out the taper pins is the best way of minimizing the use of a hammer. Knocking them out was not simple (b) tried taking the cam to a shop to get the lobes re-ground but was told I needed to know the lobe profile, and this  is a challange. Therefore I think it's simpler to replace the lobes.

[Wizard]

For type of taper pins, try to find a way to press it out with stready pressure.  This way avoid mushrooming the narrow end of pin.  Once done, redrill straight through and install strongest possible roll pin or reuse.  Ideally make one piece camshaft.  There are cam grinder shops that can make cam lobes on the shaft.

But keep in mind some roll pins are soft, or shaft is soft and could wallow out the hole.  I have this problem on my 5 speed transmission transverse lever shifter roll pin chewed up the shaft due to abusive shifting.  I'll have to redrill and install next size up roll pin.

Cheers, Wizard

[listerdiesel]

The biggest issue with taper pins is finding which end you are looking at.

Once you know, just put a small drill accurately into the small end to clear the end off, then punch through with a good quality pin punch such as made by L S Starret Co, cheapo punches won't do the job.

I've got a new genuine 5/1 camshaft, I'll see what is involved in making up a drawing of the profile, or even the whole cam.

Peter

[MoeK]

Peter,

I removed the taper pins exactly as you suggested, and did destroy a cheap punch pin in the process. It seems that I should be able to replace the pin with a bolt once I replace the lobe.

I would appreciate any insight on the profile.

Thanks.

Moe

[Oilengines]

The thing to be careful of is that the bolt won't hold the cam tight on the shaft, as the bolt cannot squeeze the cam to grip the camshaft tightly, therefore unless you have a reamed hole and fitted bolt, it is going to work loose.

I'd be inclined to get a taper reamer for the next size up in Metric taper pins and fit a Metric pin. I have seen bolted cams work loose and destroy the camshaft through fretting and rattling once they come loose.

The other option is to drill and tap right through the cam and shaft and Loctite a machine bolt through the lot.

I'll dig the camshaft out later, there's a twin camshaft in there as well, don't know if that's a petrol (TL) or a CS diesel.

Pare

[MoeK]

Thanks Pare. That makes sense since the fit with a bolt will not be as precise. I have the taper pins and can get more from McMaster, so I will just replace them and try to keep the hammering to a minimum.

Moe