fasteners Fastener "head stampings" or ID numbers/letters

[Careless]

I'm just rifling through the 9 million bolts here with the 01/70 resto project.

 

I found a bag of these bolts, brand new (top right: 08120-8501E) that sandwhich the trans halves together.

 

 

The ones I have pulled from the trans, and also some of the ones that I have discovered in the box-o-bolts have a head marking that says TR on one edge of the hex, and 7 on the opposite edge of the hex, and the washer is slightly thicker than the new ones.

 

On the new one, it has the italicized "7" that I have come to expect on many of the datsun bolts, as I've seen 7's and 9's embossed on the hex heads on most Nis/Dats. 

 

Now I know I'm splitting hairs here, but I have new bolts, so I might as well use them... But did the TR 7 marking ever show up on any datsun bolts? Is this an early Datsun thing? I would much rather use what came on the car, to be honest, since I'm getting them tumbled and replated at some point.

 

They are the exact same thread and length.

Edited April 23, 2015 by Careless

[Careless]

Here's another conundrum. Exact same ordeal.

 

The 71 I have here as a "reference car" has the same bolts holding the valve cover down as the ones currently on the 01/70 engine (sprayed silver, ughh).

 

The Bolts that I have that are NOS and Part Number 01125-00151 which are a match are different and have the marking "7" (on the right).

 

 

 

would you guys agree that using the originals and having them plated is prob a better way to go about it?
don't mind the huge mess of parts in the background.

Edited April 23, 2015 by Careless

[John Coffey]

As far as I can tell the embossed 7 and 9 are there for quick bolt identification during assembly on the production line.  They have no meaning regarding bolt strength.  I ahve taken original fasteners, inspected them, ran them through a tap or die, media blasted, tumbled, and had them replated.  

[Careless]

johnc from HybridZ?

 

My concern isn't really the strength, it is whether the bolt is the original one or not. There are a lot of small differences between the 70's models vs the later ones, I'm finding... If I can keep the small details 70's oriented, I'm sure the owner would appreciate it, as it will be more true-to-resto rather than rebuild.

 

I just hate seeing "DORMAN 5/16" on bolts that are in plain site. If it were in an inconspicuous location, it would bother me a little less.

 

Did the datsuns ever come with a "TR 7" bolt, though?

[zKars]

I have seen two distinct valve cover bolt designs. Early have an indented hex bolt with the 7, with a split lock and a flat washer trapped (SEMS) to the bolt, The tip is distinctly pointed as well.

Later (sorry don't know the change over date) have no washers, but the bolt head has the flange, as you see in both. These bolts do have the indented head with the 7 as well. The tip is a self starting type, no threads for a couple of theads worth and tapered, but not pointy like the early ones.

I do have some flange headed bolts that have a solid top, that appear to the same length, no SEMS washers, but no guarentee these were valve cover bolts. Might be front cover bolts.

[Careless]

that's odd... both the 01/70 and 71 I have here show the bolt head on the left of the photo that I took. the one on the left of the photo that you took, zKars, is the new style of bolt I have in the bags, and it is also the same style that is on the 73 that is here as well.

 

There are no distinct markings on the bolt on the left (70/71). It has a flat top, flange, and threads rolled to the tip.

The newer ones, and the ones on the 73 have scalloped head with the 7 marking, and a non-threaded tip for starting, as you mentioned zKars.

Edited April 23, 2015 by Careless

[26th-Z]

The bolt with the flange head is a later style.  The bolt with no markings and separate washer is 'correct' for your car, Careless.  I like your idea of restoring the original hardware instead of replacing it.

[Mark Maras]

My early 71 has the flat top bolts w-flanges.

[Namerow]

From Wick Humble's standard reference, 'How to Restore Your Datsun Z-Car'"

 

"On ISO fasteners, the grade is indicated by its number - 4, 5, 9 and so forth - on the bolt head.  But this doesn't mean that a bolt marked 5 is equivalent to SAE Grade 5.  Unfortunately, the ISO number indicates a torque capacity lower than the SAE number -- a negative safety margin if you mix them up.  For instance, the ISO Grade 7 is the equivalent to approximately an SAE Grade 5 -- for a 14mm bolt, Nissan's torque spec on this bolt is 56-76 lb-ft.  ISO Grade 9, the highest number I've found on any Z-car bolt, is torqued 80-108 lb-ft if it's a 14mm bolt.  At the other end of the spectrum, anything ISO Grade 4 -- as are many of the 10mm Phillips head bolts found on a Z -- is comparable to unmarked 'hardware-store' grade bolts.  |That means they could conceivably be snapped off with an overenthusiastic twist on a Phillips screwdriver."

[rossiz]

my 78 has the sems style valve cover bolts

[Careless]

The bolt with the flange head is a later style.  The bolt with no markings and separate washer is 'correct' for your car, Careless.  I like your idea of restoring the original hardware instead of replacing it.

 

weird.... on the left, the bolt is a flat top, but integrated flange- taken off the 01/70 and the 71 i have too. the right is the new one. perhaps I have some other bolts kicking around. I'll end up plating both sets if i do, and use whatever comes back nicer. 

[John Coffey]

From the current standards ISO markings are not like what's seen on the original Nissan fasteners. Also, the ISO TC-2 standards sub-committee did not publish their metric fastener standards until the mid 1970s so the OEM fasteners on the S30 we designed to JIC standards.