Using a rod stretch gauge – Carnage Plus episode 104

Scotty does some testing to see if it’s necessary to resize the rods in our L67 due to its upgraded bolts


PEOPLE love to play expert and debate all kinds of nitty-gritty details around cars, and engine building is by no means immune to this.

Scotty was copping some questions (and criticism) about the use of ARP rod bolts in our supercharged L67 builds for project Supermang. It seems that some are concerned that by using higher-tension bolts without resizing the rods, things would not end well.

In most cases that’d be correct, and it’s not uncommon for standard rods to be resized to suit upgraded bolts in big-horsepower builds.

Scotty decided to put the theory to the test for our latest L67 build. The key difference here is that L67s don’t use pressed-in bolts with nuts to hold the rod cap on like most conventional engines. Instead, the bolts thread into the rod as one piece, with the heads of the bolts used to hold the rod caps.

We ordered a rod stretch gauge from our friends at Speed Pro, and with that in hand, Scotty set about torqueing the upgraded rod bolts to spec to see what’s what.

After following the correct processes, torqueing, re-torqueing, loosening off and using a dial bore gauge, Scotty concluded that in the case of the L67 it’s fine to use upgraded bolts without resizing the rods.

So that’s exactly what we’re going to do! Part two of the L67 rebuild will be hitting your eyeballs soon, and then our VN Berlina should finally be ready to hit the track.