I bought some 78 cams with lifters and housings. When they arrived, some of the lifters were loose in the box. I'm not sure whhich holes they came from. I know that your supposed to keep them on the same lobe but now I cannot. And to be honest, even if they were all still i n the cam housing, who's to say the PO didn't mix them up.

Can't I take the lifters lap them smooth and flat again so that I can use them? Are there any issues with doing this?

Thanks

 

Depending on your plans for the motor, advice varies from don't worry about it, to buy new lifters.

 

Thats why I'm asking here. I'm hoping someone with experience will chime in.

 

I don't know about the lifters on a 928, but all the lifters that I have ever seen are not flat, as one would think. They actually have a slight crown to them, this act's to allow them to rotate in the bore so as not to wear out in one spot.

 

I have a couple of sets at the shop, I will check them tomorrow, for some reason I think the 928 cam followers, buckets, lash adjusters, lifters, what ever any body wants to call them, are flat.

And you are right, most others have a crown.

 

I have always read that you need to keep them matched up with the lobe they have been riding on because they wear together and that if you switch them around the cam lobes will wear very quickly. Is this somehow untrue on a 928? If so, please explain why.

Thanks.

 

If there are any marks on the lifter face from contact with the cams, blow the lifter guts out into your hand via compressed air thru the bleed hole. Then get a couple of pieces of 220 grit sandpaper, lay it on a piece of glass, spray the sandpaper with WD-40 and sand in a circular motion until the marks are gone. Then repeat with 400 and then 800 grit paper. You ought to end up with a nice flat surface. If you can't sand out the marks, then the lifter is done.

Before:



After 800:

 

I do not think it true on the 928. I could be way off base on the 928 cams so take what I say with a grain of salt until I check it tomorrow.
Of course it is always going to be better if they go back where they came from, but it is not anywhere as critical as on say a Chevy.


On lets say a SBC camshaft the cam lobe is not flat and neither is the lifter.

There is a slight angle to the cams and the lifters have a off center crown.

On a American OHV type cam the only lube the cam lobe gets is from windage.
That is why with big cams how you start the car EVERY time is critical in whether the cam last 10,000 miles or 100.

The most scary thing you can do with a OHV type cam like that, is put new lifters on a old cam, it is almost a given that it will take a lobe off.

EDIT: I would not worry a bit about putting new lifters in a 928.