Can anyone confirm that these are the correct valve cover bolts for a 1971 240z?  The ones that came with my car were not original.  These came from a slightly later engine - I believe they are from a N42 block/N42 head L-28 (which is probably from 1975 or 1976).

  

Those don't look right. The valve cover should have all flange bolts, not separate lock and flat washers. 

 

They look correct to me. Here's a replated set I have on hand. These match the OE bolts on my car.

Edited March 18, 20214 yr by jfa.series1

Let the exhaustive discussion begin on which one is right for what year range.  GO!

Actually I have no clue. I just looked in the valve cover bolt bin and pulled out four unique examples. There may be more....

That one on the right might not be a valve cover bolt at all...

My series 1 has the ones to the right.  

22 minutes ago, duffymahoney said:

My series 1 has the ones to the right.  

My series 1 as well.

9 hours ago, zKars said:

Let the exhaustive discussion begin on which one is right for what year range.  GO!

Hahahahaha!  Oh man, there are better things to do than that for sure!  Welp, it seems with our little sample of three, that there were... "variations" 😜

In case anyone cares, here is what Nissan has in stock - the part number changed again by the way:

  

 

Edited March 18, 20214 yr by inline6

Call me a rebel.

Allen head stainless, polished.

 

12 minutes ago, Racer X said:

Call me a rebel.

Allen head stainless, polished.

😖 UNACCEPTABLE  Rebel!

Edited March 18, 20214 yr by inline6

12 minutes ago, inline6 said:

😖 UNACCEPTABLE  Rebel!

Told ya I was a rebel.

 I like the oem bolts, the binding head cap screws, with a smooth shank where they don’t need threads. Simple, effective. I just wish they could be had Allen head and stainless.

For what it’s worth, these are on my 72.

 

14 hours ago, inline6 said:

In case anyone cares, here is what Nissan has in stock - the part number changed again by the way:

  

 

I don't know what the original bolts looked like on the earlier cars, but I can confirm from tearing down a couple later cars, the bolts pictured above were used on the ZX motors. Don't know when they started, but I can confirm that's what they ended with. Flange heads and no separate washers.

Another data point.  75 280. L28

Has pair of SEMS washers. 

Now I’ll go check my 71

Edited March 19, 20214 yr by zKars