Advice: SS 3.2 - rod bolts and springs

Alan.UK · 05-30-2005, 11:58 PM

Hi,

The engine build for my SS 3.2 has started. The base motor is a 78 SC which was rebuilt recently and I have this stripped down but did not plan on splitting the case as it was rebuilt recently. This motor will be having s grind cams and brand new, 98mm barrels and pistons with 10.5:1cr, and 46 PMOs

My questions is with the and rod bolts and valve springs. I do not want to use stiffer springs unless necessary, due to the extra wear on the cams but after reading past posts it sounds like stiffer springs should be used. This motor will be rev'ed to make sure the cams are used (7200rpm) but not for long periods. Should I be changing the original but relatively new rod bolts for some ARP ones?

Thanks in advance for any advice

Alan.UK

jpnovak · 05-31-2005, 06:27 AM

Alan, From what I have read the larger valves of an SC should use a stiffer spring compared to factory stock. This is to keep up with the extra mass (inertia) of the larger valves when using a high lift cam.

Camgrinder sells a sport spring and a race spring with Ti retainers. I think either one would be a good choice for your build. I will plan to use the race springs in my heads since I am putting an even bigger cam than you.

Alan.UK · 05-31-2005, 06:38 AM

Thanks for the advice Jamie, I guess I should also fit ARP or Raceware rod bolts as well?

Thanks again

Alan

jpnovak · 05-31-2005, 02:38 PM

I think the stock SC rod bolts will be fine at that redline rpm. I will be using new stock rod bolts in my build. It was the smaller diameter 3.2 rod bolts that had problems with stretch at high rpm.

dd74 · 05-31-2005, 07:16 PM

Quote:

Originally posted by Alan.UK
This motor will be rev'ed to make sure the cams are used (7200rpm) but not for long periods. Should I be changing the original but relatively new rod bolts for some ARP ones?

Thanks in advance for any advice

Alan.UK

I've heard the components in the stock valvetrain are good for 7300 RPM, so if you're getting up to 7200 for short bursts, I believe you should be fine.

Also, I don't think you'd have to change out the rod bolts. 3.0 rod bolts are more robust than 3.2s.

Alan.UK · 05-31-2005, 11:09 PM

Thanks for the advice. I have bought some performance springs from John (Camgrinder) and after reading your responses I will be leaving the new "stock" rod bolts in place.

Thanks again

Alan.UK