On 7/26/2025 at 10:35 AM, Zed Head said:

Like these? What kind of problems has your machinist had with the flat bottomed pads? Not sure that the dimpled ones are actually "stock type" for an L28. Don't know.

https://jdm-car-parts.com/products/kameari-performance-valve-lash-pads-for-nissan-l-engine

https://datnissparts.com/stock-thickness-120-lash-pads-datsun-nissan-l4-l6-l16-l18-l20a-l20b-l24-l26-l28-13218-y7000/

@Zed Head he's mostly worried about them popping out while driving. He's had this happen to one of his customers in the past and was very much against using the flat bottomed ones.

I did find the JDM-parts ones right after making this post and it'll probably be where I will get them.

Thanks for all the help guys
Cheers
Jan

8 minutes ago, Pomorza said:

one of his customers

Sample size cannot get any smaller. I doubt that that's why they come out since the the space between the rocker arm and the valve/pad assembly would have to open up enough to allow the lash pad to pop out. No logical reason for the divot to stop that from happening. Besides the fact that many people have had that happen when they restart old factory stock engines that have been sitting for a while. Most people think it's caused by sticking valves. Maybe your guy sets his guide clearances too tight.

But, he's the builder. Good luck.

Edited Sunday at 07:02 PM1 day by Zed Head
Added more words.

6 hours ago, Zed Head said:

Sample size cannot get any smaller. I doubt that that's why they come out since the the space between the rocker arm and the valve/pad assembly would have to open up enough to allow the lash pad to pop out. No logical reason for the divot to stop that from happening. Besides the fact that many people have had that happen when they restart old factory stock engines that have been sitting for a while. Most people think it's caused by sticking valves. Maybe your guy sets his guide clearances too tight.

But, he's the builder. Good luck.

Not disagreeing with you, had a quite lengthy discussion about the topic with him. He's rebuilt dozens of Z engines in the past so I'll take his word on it.

Arguing with your machinist is worse than arguing with you doctor, he's always right no matter if he's wrong.

On 7/27/2025 at 2:01 PM, Zed Head said:

Sample size cannot get any smaller. I doubt that that's why they come out since the the space between the rocker arm and the valve/pad assembly would have to open up enough to allow the lash pad to pop out. No logical reason for the divot to stop that from happening. Besides the fact that many people have had that happen when they restart old factory stock engines that have been sitting for a while. Most people think it's caused by sticking valves. Maybe your guy sets his guide clearances too tight.

But, he's the builder. Good luck.

I bought an N42 that had been in machine shop jail for a few years, guy never came back for it and I paid maybe $200 for a newly rebuilt head with an oiler cam installed. Put it on and went about 5 miles and the god awfullest noise came from the valve train. Limped back home and found a lash pad had come off. Thank goodness there was no damage and @Jeff 78 280z talked me down off the ledge, told me how to fix it and I've not had to look back. Runs great every since.