con rod torque?

[carrerarsr65]

whats the proper setting I'm getting different numbers from different publications, is 20nm, right? which would be 14.75 ft/lbs is this correct???????? thanks for any and all input

[mattC2993]

don't know the exact number (what engine?) but its a lot higher than that

[JFairman]

Yeah, it depends on what year and model motor and the thickness of the bolts, the manufacturer of the bolts like original Porsche connecting rod bolts or ARP or Raceware and what lubricant is on the bolt and nut threads like 20w 50 motor oil or something like more slippery ARP fastener assembly lube.

Then some people will only go by the amount of bolt stretch carefully measured before and during with a high quality micrometer. Some of those are made real skinny for doing that through the spigots while the crank is still in the case and with regular ones you probably have to have the crank out of the case.

edit: My Raceware rod bolts for 1987 3.3 rods were torqued to 52 foot pounds with 20w50 non synthetic motor oil on the threads in 3 steps up to the final 52 ft lbs. That's what tech support at Raceware told me to do when I called and gave them the part number of my rod bolts.
I did it with the crank in the case while the motor was in the car with the back of it lowered down about a foot on to a jackstand with a recently calibrated 3/8 drive snap on click type torque wrench.

[carrerarsr65]

sorry guys its a 3.0 with new rod bolts/nuts oem

[ZOA NOM]

I would avoid using torque, and use the stretch method. Easier to be accurate, and the peace of mind is better knowing the bolt was tightened to the manufacturer's spec, without the variability of torque wrenches.

[Green993]

Originally Posted by ZOA NOM

I would avoid using torque, and use the stretch method. Easier to be accurate, and the peace of mind is better knowing the bolt was tightened to the manufacturer's spec, without the variability of torque wrenches.

^^^do this. Buy the stretch gauge and sell it when you are done. ARP makes good ones.

[H2odiesel]

I don't know what the stretch spec is for OEM bolts, but this is a decent gauge at a great price. It has a heavier spring on the dial indicator so it can hold itself in place while you tighten.
http://www.summitracing.com/parts/lun-98401/overview/

[Walt Fricke]

Well, the Porsche spec book for 78-81 SCs says lubricate threads and bearing surface with oil, and torque to 50-55 Nm.

It would be interesting to know what a rod bolt stretch spec would be. I've never seen one for the OEM bolts, as Porsche doesn't have a stretch spec. I suppose a guy could figure this out by carefully tightening a pair of bolts to those torques, with before and after measuring.

You can't really use a standard micrometer for this. For the stretch method you want your measuring instrument to have pointy ended anvils, which will nestle into the dimples on each end of the rod bolt. The typical dial indictor will come with one such anvil, and the stretch gauge will have one pretty much fixed in place on the other end.

[H2odiesel]

A follow up to a post I made above. The Lunati cams rod bolt stretch gauge is not suitable for Porsche rod bolts. It has a nice spring loaded Dial indicator so the gauge will stay in place but it will not adjust wide enough to accommodate our bolts. I was able to get by with the fixture and a different indicator I had on hand supplemented with a couple rubber bands.

[Steve@Rennsport]

Originally Posted by carrerarsr65

sorry guys its a 3.0 with new rod bolts/nuts oem

Walt got this one for you; 55nm/40.5 lb-ft. This is ONLY for OEM bolts. ARP ones are stretch to spec.

[carrerarsr65]

thanks steve,finally getting round to installing those je pistons you had made up for me