Hey there everyone. I have a '72 240z. When I removed my carbs and exhaust manifold, some of the studs came out of the block. What I didn't pay attention to was which studs came out of what hole, and which holes took the bolts. Some studs remained in the block. I also notice that some studs are shorter then the others and so I need to know where they go. Hope someone can point me in the right direction, or tell me the bolt and stud configuration. Thanks for the help.

I found that they were all the same size, if you order a new set from the dealer, that is how they come. I replaced mine with the stainless set from ZCarCreations, and they are all the same size.

Will

I just had my 72 motor apart. On the exhaust the hole nearest the firewall was a bolt. From there forward was studs. Aleast thats the way mine was. But yes all the studs should be the same size. I would look and see if you broke one off inside the head.

Edited February 28, 200916 yr by carguyinok

So are all the top intake bolts, bolts?

Thats how mine was. Lower was all studs but the one on the end and the top was all bolts. Now after thinking about it yes there are smaller studs. Three of them that go in the center for the exhaust. One dead center top and the two lower ones just under the center one. I think everything was 13mm but those three and they where 11mm I think.

Edited February 28, 200916 yr by carguyinok

The green dots are where the smaller studs are

I'm glad to Zee that your garage looks alot like mine!...thanks for the help, and the picture.

If in doubt just use a probe and see how deep the hole is and use the stud accordingly. I used studs on all and anti seize a plenty.

, yes that part of the shop is a huge mess at this point. But, it's not my mess LMAO. I will take a few photo's today and put up alittle tour of our place. We have a speed\hobbie shop here called Extreme Machines. We are a group of close friends that have taken over an older GM dealership here on main st (RT 66). At this point we have 12 members and have been going strong since 2001. So needless ta say with that much going and that many people working on things at all hours of the night and day. Things can and do get dirty rather fast.

We try for one day a week in cleaning the place up. But some are better then others on that.....

According to the Section 3 illustration, there are at least three different studs used on an L24 head's breathing side. They are numbers 12-14 in the figure. They are all 1.25 thread. What I can't tell from this is how they differ and exactly how many of the 12s and 14s are used. There is only one #13 used for the rear sling (part 26).

The fiche calls for 6 of the #14s on both the L24 and L26 so maybe those are just the upper row of studs. But it calls for 10 of the #12s on an L24 but only 4 of them on an L26. WTF?:stupid: I can't make much sense of the equivalent illustration for an L28E head.

Even though the fiche is screwy, it appears that all the "hangers" on a factory L head are studs and no bolts are used. Almost 40 years later, how many cars are OEM? I know that mine aren't.

So, regardless of what stud you use, if it has enough thread so that you can tighten down the accompanying nut, you should be in good shape.

S30fiche3-1.PDF

Edited March 3, 200916 yr by Seppi72

I know when I have ordered these studs they are all the same for every head. There should be 11 studs total. All are the same thread size but some are longer than others, depending on what is attached. The threaded side of the studs that go into the head are all the same lenth. There is also heavy duty washers that go on the studs before the nut does, this is because it holds both intake and exhaust on one stud.

I have uploaded a pick of my N42 head and colored the items for you.

Blue- Intake studs

Purple- Intake Bolts

Purple/Green- Short Intake Bolts

Red- Exhaust Studs

green/Red- Short Exhaust Studs

Sometimes you will notice the 1 & 6 studs have been replaced with bolts or resized like mine is. This is due to the exhaust manafold having a warping. It warps upward and out causing a leak and most people replace them with larger bolts.

Wow, thanks alot for all the help!...This is forum is a great tool.

Bought studs and had studs and bolts and had no idea what went where. This forum gave me the answer in a matter of moments.

Thanks to all who take the time and effort to answer questions. Some day I hope to contribute more. Thanks again, Cheers Richard.