[Stephen Lyttleton]

Not being as experienced as most on this board, I have a question about my camshaft that I just removed and will be replacing for other reasons.

I found that the journal at the front of the shaft had a flat spot ash shown in the picture below. My assumption is that it's not supposed to be like that. Is this correct?

Thanks!

 

[lynall]

Ive been thinking about that flat spot and I cant see how it was formed/worn in the engine as its just a bearing journal, is the shell bearing okay?

 

[Wimblowdriver]

Must have been a flat spot in the rough metal before it was machined into a camshaft.

 

[Stephen Lyttleton]

lynall: actually your suspicion is right on. The bearing has some gouges in it (no, I didn’t do it while pulling out the camshaft). But I don’t know how this would have caused a flat spot.

Wimblowdriver: that is as good of an explanation as I’ve heard.

Now, the flat spots on the #1 cam and tappet roller are likely cases by oil starvation or a sticky guide. But I can’t for the life of me figure how a round peg in a round hole gets a flat spot.

I appreciate your insights as I’m trying to make a case to argue with the seller of this engine that they sold me a pile of crap. I bought it last September through a restorer of Defenders and I think the engine came from Bearmach.

Oh, Merry Christmas!

 

[Wimblowdriver]

The bearing has some gouges in it (no, I didn’t do it while pulling out the camshaft). But I don’t know how this would have caused a flat spot.

If as I suspect the flat spot is a manufacturing defect, then the void it creates between the cam and the bearing would be a dirt trap. Hence the damage to the bearing.

 

[jamesmartin]

Not being as experienced as most on this board, I have a question about my camshaft that I just removed and will be replacing for other reasons.

I found that the journal at the front of the shaft had a flat spot ash shown in the picture below. My assumption is that it's not supposed to be like that. Is this correct?

Thanks!

thats been flat since manufacture, surprising it didnt throw oil into the timing case

 

[Wimblowdriver]

the flat spots on the #1 cam and tappet roller are likely cases by oil starvation or a sticky guide.

surprising it didnt throw oil into the timing case

Probable that loss of oil / pressure at the bearing was starving the No 1 tappet.

 

[Stephen Lyttleton]

If as I suspect the flat spot is a manufacturing defect, then the void it creates between the cam and the bearing would be a dirt trap. Hence the damage to the bearing.

Yeah, I thought about that too. But the gouges on the bearing are perpendicular to the direction of the camshaft journal travel

 

[jamesmartin]

the gouges are from poor fitting i expect, front does get more as it has the pull from the cam belt as well as valve spring pressure

 

[moth]

I had noticed that flat spot too. It looks like it's intentionally machined. Does it allow oil out to the camshaft thrust bearing?

 

[Stephen Lyttleton]

I had noticed that flat spot too. It looks like it's intentionally machined. Does it allow oil out to the camshaft thrust bearing?

After much trouble with my camshaft, this flat spot on the front journal became the least of my worries. But I think I have to agree that it may be intentional to allow oil flow, as you mention. I see no way that it could have happened from wear since it is so tight against the bearing and it is completely smooth.

 

[steve2286w]

I just seen this post, I had this on one of my cam journals, it was an end and with it’s uniform machined look, guessed it was supposed to be there, looking at how the oil gets moved around it’s pumped up to rocker shaft from no1 cam journal so the flat spot would probably help with this