Where to use ARP fastners

[tdafforn]

Hi all,
Just getting to the stage of putting my engine block back together.
I was wondering which parts of the engine would be best to use ARP fastners.
I have noticed on pictures of high spec twinks they tend to be used on the big end caps but not nessesaryly the main caps...
What about the flywheel bolts?
Cheers
Tim

[rgh0]

Tim

The only really critical and very highly stressed bolt in a twin cam is the con rod bolt. I would always use an ARP or similar specialist high strength bolt for these even in a road engine. Installation is also critical and using a stretch gauge rather than torque to set the con rods bolts is a good idea if you are going to be using the engine near its limits

Main bearing cap bolts, head bolts and flywheel bolts are less stressed and do not really need specialist fasteners and the standard lotus components or carefully selected equivalent standard bolts are generally fine even in a competition engine. I end up using non standard bolts for main bearing caps and flywheels but this is more because I use non standard steel caps and flywheels in my competition engines not because the standard bolts are not adequate.

I used ARP head bolts on the last engine I built just because I needed a new set of bolts and the ARP ones were not that much more expensive than standard Lotus ones or a standard replacement grade 8 bolt. However when buying generic bolts you need to be careful of your supply source as poor quality counterfeited "grade 8" bolts are commonly sold.

If using generic bolts you need to pay attention to the the detail of the thread and overall length to ensure proper installation. Carroll Smith's book "Nuts,Bolts, Fasteners and Plumbing Handbook" is a must read if you want more information.

regards
Rohan