5/16 Carr rod bolts

[1972ho]

What type of application would such a small rod bolt apply to would this be for a 4 or 6 cylinder with not a lot of hp and rpm.Thanks just curious??

[amc fan]

Are you talking about Carrillo bolts? The ones that were made by standard press Steel or SPS?

[SupStk]

Small block Ford?

[MadBill]

I recall reading 20+ years back that when Cosworth got into the US market, they developed a SBC rod that exceeded all requirements using just a 5/16" bolt, but it was a commercial failure until they upped the bolt size, because no one trusted such a tiny fastener. Could still be some of them around I guess...

[1972ho]

Carrillo has this bolt size in there catalog and I think arp has a 5/16 rod bolt also and the ones that I saw where carr sps 60

[jeremyinlinepro]

We have run them on the 4 cylinder naturally aspirated engines for many years. Steel rod a little over 6.0” 400g, 260g piston, 4.173” stroke, 10,800rpm. Never had a bolt/rod failure.

[Warp Speed]

We used them in our qualifying engines, back before weight rules ect.

[dwilliams]

Cologne V6 rod bolts are 8mm, .323 vs. .312 for 5/16.

[pdq67]

What size rod bolt did the '55, 265" SBC have in it, I forget?

pdq67

[6.50camaro]

SJ rods had 11/32" bolts didn't they . Dan

[pdq67]

Right, now I remember, 11/32" and then went to 3/8".

And way overkill was the BB rod forging made for a SB with 7/16" rod bolts.

pdq67

[dwilliams]

Some pre-WWII connecting rods had studs... machined integrally as part of the rod shank.

[swampbuggy]

Warp Speed, you HAVE to use 3/8" rod bolts with the setup you are using currently correct ??? Mark H.

[Momus]

Australian V8 Supercar 5 litre SBF's use or have used 5/16 rod bolts. Up to 650 hp at 7100/200 for 3000 km.

[swampbuggy]

What does the CARR stand for ? Always figured it was short for Carrillo? Mark H.