Datsun l18 cam lobe wear problem

[BMID]

Hi everyone,
the engine this is happening to is a l18 that I bought quite a while ago, not sure the specs of the engine all I know is the head is shaved and the cam is stamped M445. I noticed the cam wear last night, when I went do do a oil change I decided to take a look under the valve cover and to my surprise cylinder number 2s exhaust lobe is worn down just enough to catch your finger nail on and its worn slightly to the rear of the engine. What would this be from? I would like to get the cam reground but I would like to know what's wrong so it doesn't eat a lobe again.
Thanks

[datzenmike]

Well it could be the cam blank isn't up to the task. Best ones are old reground cams.

Is the valve train wet with oil?

Has the rocker arm turned blue from any heat?

Are you running after market valve springs?

If you are using today's engine oil, look no further. When your engine was new, the zinc anti scuff additive ZDDP was over 1,000 PPM. Today's engines don't require this much protection and it ruins the catalytic converters on them so for the last 20? years oil suppliers have slowly been reducing the ZDDP content and it's around half what it was. Oil companies maintain that today's oils are reverse compatible but it's my valve train and I don't believe they will replace everything if it doesn't work.

I run Shell RotellaT4 in 15w30 and have used 15w40. It's a diesel oil that still retains the old 1,000+ ZDDP levels from 40 years ago. Chevron Delo 400 is similar and any over the counter oil marked R for racing.




If your cam is worn the rocker arms may be damaged also.

[BMID]

Well it could be the cam blank isn't up to the task. Best ones are old reground cams.

Is the valve train wet with oil?

Has the rocker arm turned blue from any heat?

Are you running after market valve springs?

If you are using today's engine oil, look no further. When your engine was new, the zinc anti scuff additive ZDDP was over 1,000 PPM. Today's engines don't require this much protection and it ruins the catalytic converters on them so for the last 20? years oil suppliers have slowly been reducing the ZDDP content and it's around half what it was. Oil companies maintain that today's oils are reverse compatible but it's my valve train and I don't believe they will replace everything if it doesn't work.

I run Shell RotellaT4 in 15w30 and have used 15w40. It's a diesel oil that still retains the old 1,000+ ZDDP levels from 40 years ago. Chevron Delo 400 is similar and any over the counter oil marked R for racing.




If your cam is worn the rocker arms may be damaged also.

Everything looked normal lots of oil no evidence of heat. this engine was built over 20 years ago or more so the wear could of been happening for a while. I'll try switching to rottella oil for the time being. If the oil is the problem would switching now to rottella be too late? The cam is about half as bad as the picture you showed.

[MikeY]

A m445 is a Shadbolt regrind. If you want it again you will need to supply another stock cam. The Shadbolt owner recently passed. So if that business has closed try colt cams. They will have something.close. I've run the m445 for years in many cars with stock springs and retainers. Just need to replace the stock lash pads. Proper break in lube and oil is important.
Lash pads from precision shims in Australia and reground/polished rockers from Delta cams in Tacoma.

[datzenmike]

The wear is cumulative if the wrong oil. Certainly won't hurt to switch to Rotella. It's too late for the damage that is done but if the crappy oils of today is the cause this should stop it getting worse. Have a look at your rockers.