ARP head/rod/main worth it?

[belize1334]

Quoting ApexHunter:
Stock head bolt torque was originally spec'd at 69 by Mitsu, then later they changed spec to 80. There was a TSB.



Does this mean that my un-touched OEM headstuds were only torqued to 69 ft-lb and that I can just retorque them to 80 ft-lb to help prevent HG failure as I turn up the boost?

 

[talon]

I wouldn't recommend torquing them to 80ft-lbs, because you have a high chance of stretching the bolts to much, or even breaking them.

 

[talon]

Whats the most common cause of rod knock? Stretched rod bolts!

So if you change the stock rod bolts to ARP's, then you are less likely to stretch the rod bolts. So I would say to install the ARP Rod bolts.

 

[Barnes]

Yeah. He should install rod bolts because it helps prevent all these spun rod bearings at 300hp. *sigh* /ubbthreads/images/graemlins/banghead.gif

Also, the 80ft-lb figure for head studs is correct. As Apexhunter said, he got this information straight from ARP.

 

I went with ARP rod bolts just for inexpensive piece of mind. I didn't feel comfortable re-using the old rod bolts, and rather than order new OEM rod bolts I got a set of ARP's locally for $35. It cost $12.50 per rod to have the ARP's installed and the big end rebored. Total = $85. Got a set of NIB head studs from somebody on here IIRC for like $65. Skipped the mains because I've never heard anybody say they were remotely necessary for my power level and don't know that I've ever heard of somebody having an OEM main bolt fail unless they were making huge power. None of them would be required for a low/stock power daily driver, but head studs and rod bolts are cheap insurance IMO.

 

[MitsuDriver274]

Interesting I've never heard of having to replace rod bolts, I have never had to replace a set yet and have built multiple 4g's that are still running fine today. I still have yet to bolt the head on the block, i've been looking at mitsubishi mls headgaskets and the cheapest one I could find was 150. Plus another 100 for arp head studs would mean 250 just in a head gasket and studs.

 

If you're building a low to medium power daily driver then why not use a stock composite head gasket with ARP's, which will stand up to plenty of power and boost and be cheaper than the MLS?

 

[MitsuDriver274]

So I ended up picking up arp head studs and rods studs, decided against the mains just because they don't have the pickup pipe mount. I'm still unsure on what head gasket to run.

 

[mooserage]

I've started to come around to the idea of using the standard composite head gasket from mitsu with ARPs. You get the clamping force that you really need when turning up the boost from the ARPs. But, with the composite gasket, first it is more forgiving to imperfections on the block and head and secondly it acts as the weakest point (like a HG should). So if conditions get too harsh you blow a head gasket rather than damaging a more expensive or hard to replace part. That's my opinion anyway. Regardless, having a good tune is what will allow you to make the most power without damaging any parts.
-shamus