Where do you measure the rod bolts on a z?

[betamotorsports]

Am I correct in that the rods themselves are different, meaning you cannot use the 9mm bolts in a rod that originally had the 8mm bolts?

You are correct. You need the rods and caps out of a 1973 L24 engine. OEM Nissan rings are pretty damn good for an IT build.

[spawpoet]

You are correct. You need the rods and caps out of a 1973 L24 engine. OEM Nissan rings are pretty damn good for an IT build.

Thank you John. I wasn't sure what year they went to the bigger bolt. Also what do you think of the Deves rings??

[mom'sZ]

Chris: I'm almost sure ARP makes bolts specifically for this application. I took pictures of all the packages (showing the part numbers) when Bob first got the parts. I'll look when I get home and see if I can get you a P/N. Failing that, I'll call Bob and ask him. I need to get ahold of him anyhow.

[spawpoet]

I've got the part numbers for the ARP bolts Andy, but I've gotta figure out whether to get the 8mm or 9mm rod bolts. The 240's came with 8mm bolts through 1972, then they switched to a 9mm bolt. I'm not sure which size the rods we are going to use are. I DO need your machinists number though. I'll shoot you an e-mail tonight or in the am.

[Parrish57]

By all means, if you have and can use the 8mm rods then do so. They are lighter than the 9mm later rods and will give you more horsies! And if you are going with the ARP bolts you don't have to worry about the 8mm parts failing. I've been using them for more than a decade and have never had a bottom end failure.

Also, the Deves rings are a good choice.

[spawpoet]

By all means, if you have and can use the 8mm rods then do so. They are lighter than the 9mm later rods and will give you more horsies! And if you are going with the ARP bolts you don't have to worry about the 8mm parts failing. I've been using them for more than a decade and have never had a bottom end failure.

Also, the Deves rings are a good choice.

Steve, I thought that might be the case with the smaller bolts. Obviously the ARP's 8mm will be much stronger than the stock bolts, and as you said it's a little less rotating mass in the assembly. This isn't going to be our "hot" motor anyway, so I just want to upgrade from stock to ARP whether they are 8mm or 9mm. We WILL seek out 8mm sized rods though when we build our full race motor. Thank you for the info Steve. It's good to know that someone has run the smaller bolts for years in IT without a problem.

chris