20-50w or 10-30w has nothing to do with the sound. 20-50w is right for an engine this old and down south.

There has got to be an oil spray bar. I would not run it until you get it back on.

I can't speak for all l28's, but mine doesn't have a spray bar either, the cam is (and always was) drilled for internal/direct lobe lubrication.

There's a complete N47 head with cam at my friend's shop, and it has an internally oiled cam.

Look for little holes on each of the cam lobes. If they are there you have an internally oiled cam. Perfect to run without a spray bar. For peace of mind a spray bar can be installed, just remove the block off plates on the towers. It does have the little block off plates? Right? If not, fish around with a magnet all over the top of the head, in the oil pools.

PS My 73 has the internally oiled cam with block off plates.

Bonzi Lon

Edited March 8, 201015 yr by Bonzi Lon
more info

Yup cam has little holes. Made sure of that when I was looking at the top of the engine. Not sure if there's block off plates as there was a huge puddle of oil but I'll look next time I have the cover off.

Thanks

Jan

I didn't acknowlege the comment about it 'having to have a spray bar' since that has been discussed so many times over the years........

Edited March 8, 201015 yr by sblake01

Update.

I went over to a friends house last evening and pulled out the old stethoscope. Walked around the entire valve over from front to back and the sound was nowhere to be found. Finally I placed the stethoscope on the flat top part of the transmission. BINGO the sound could be heard. My efforts were then disturbed by some nasty rain so I couldn't pinpoint the noise but it sounds like its coming from that area. Ideas?

Jan

Does the noise go away when you push the clutch in? Throwout bearings?

Just a thought...

Does the noise go away when you push the clutch in? Throwout bearings?

Just a thought...

Nope noise stays.

And you're positive it's coming from the transmission?

When you back off the throttle there is a slight"rattling marble"sound as it comes down to idle.Then if you listen close,you can here that rattle again at idle.It's NOT a bearing.

The N47's I have on my shelf (and presumably the on in my car) are internally oiled cams. This means there are holes in the lobes where the oil comes out to lubricate the rockers. The earlier heads did not have this, and therefore used a spray bar to reach the upper valvetrain components.