3100 engine broken camshaft

[road warrior]

I have a problem that i am hoping someone here can help me with.
My neighbor has a 1998 olds cutlass with the 3100 engine it siezed up due to a lower intake manifold gasket leak so i installed a used engine from a 1996 lumina in it.
I replaced the L.I.M gaskets with the upgraded metal and rubber ones from felpro as well as some other gaskets and after i finished with installing the new engine it ran great it was nice and smooth with no leaks and no problems.
Now 4 months later they tell me the engine quit and that it was due to a broken camshaft so i checked it out and sure enough it is broken i checked the oil and it looks normal so no antifreeze is in it.
I checked the old engine and i found that the camshaft is broken in that one also what i was wondering is this a common problem with the 3100 engines?
Are the stock hollow core camshafts defective or is the another reason the camshaft could break?
Any help would be apreciated.

[stewartfn18]

the 3100 and some early 3400's were prone to camshaft breakage. not sure why but to answer your question, yes.

[Superdave]

The only way that cam will break is if the cam bearings went out, i'd pull the pieces and see what they look like.

[pocket-rocket]

The second engine could have been victim of the same problem, but the gaskets could have gotten changed before you got it. That would have allowed coolant into the oil which will kill bearings fast. A winter or two ago I had to redo an engine in a 98 TranSport that the gaskets failed, got changed, then a few months later it ate the cam bearings, but not enough to break the cam or wallow out the bearing bores, so we got lucky and basically overhauled it.

[road warrior]

Thanks for the info!
So this is a common problem with the 3100 engines what i want to do is replace the camshaft with a new aftermarket sealed power camshaft so hopefully there is nothing else damaged except possibly the cam bearings.
What about the valves would they get bent when the camshaft breaks or are these non interference engines?

[pocket-rocket]

They are interference engines, so you could pour some water or something in the ports to see if any valves are bent but not bad enough to see. For sure replace the cam bearings with the cam. In fact, you can use SBC bearings, but the center bearing for the SBC will not get used. The SBC bearings are wider than the 3x00 cam bearings so they support the cam journals better.

[road warrior]

So if you can use sbc v8 cam bearings in the 3100 v6 i assume you can use an sbc cam bearing remover and installer tool to replace the cam bearings?

[pocket-rocket]

So if you can use sbc v8 cam bearings in the 3100 v6 i assume you can use an sbc cam bearing remover and installer tool to replace the cam bearings?

Yessir

[road warrior]

Awesome! Thanks for all the info i hope this goes well as i will be pulling out the engine in a couple of weeks.