ARP flywheel bolts
03-18-2011, 01:21 PM
#1
Le Mans Master
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ARP flywheel bolts
I am about to use ARP flywheel bolts. They did not come with star washers. Do I need them? I am using an aluminum flywheel.
03-18-2011, 01:35 PM
#2
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What I do recommend is some kind of hardened washer under the bolt heads, though. Even the smooth underhead area of the ARP bolts will wear the aluminum somewhat. A thin (.032) AN washer would work.
And as long as I'm recommending stuff.... be sure to follow the ARP guidelines to "break in" the bolt threads by torquing and releasing the bolts 4 or 5 times each prior to final torquing and use some ARP lubricant on the threads.
Jim
03-18-2011, 02:59 PM
#3
Le Mans Master
Thread Starter
You don't need and I'd specifically recommend against star washers with an aluminum flywheel. They will bite into the aluminum and, potentially, chew it up.
What I do recommend is some kind of hardened washer under the bolt heads, though. Even the smooth underhead area of the ARP bolts will wear the aluminum somewhat. A thin (.032) AN washer would work.
And as long as I'm recommending stuff.... be sure to follow the ARP guidelines to "break in" the bolt threads by torquing and releasing the bolts 4 or 5 times each prior to final torquing and use some ARP lubricant on the threads.
Jim
What I do recommend is some kind of hardened washer under the bolt heads, though. Even the smooth underhead area of the ARP bolts will wear the aluminum somewhat. A thin (.032) AN washer would work.
And as long as I'm recommending stuff.... be sure to follow the ARP guidelines to "break in" the bolt threads by torquing and releasing the bolts 4 or 5 times each prior to final torquing and use some ARP lubricant on the threads.
Jim
They say if you use their assembly lube, to torque to 60ft lbs.Using 30wt oil the torque would be 80ft lbs.
They don't mention torquing and releasing. But it sounds like a good idea.
They made no mention of steel vs. aluminum.
03-18-2011, 03:25 PM
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Thanks Jim. ARP has all kinds of warnings about using washers. I just opened the package.
They say if you use their assembly lube, to torque to 60ft lbs.Using 30wt oil the torque would be 80ft lbs.
They don't mention torquing and releasing. But it sounds like a good idea.
They made no mention of steel vs. aluminum.
They say if you use their assembly lube, to torque to 60ft lbs.Using 30wt oil the torque would be 80ft lbs.
They don't mention torquing and releasing. But it sounds like a good idea.
They made no mention of steel vs. aluminum.
friction is at its highest point when a new fastener is first tightened. This "friction" inhibits the fasteners ability to achieve the required preload on the first several cycles. In fact, ARP's in-house Research and Development department has proven that new fasteners using motor oil and other commonly used lubricants such as Moly and EPL typically require 5-7 cycles before final torquing to level out the initial friction and achieve the required preload.
I discussed this with people at ARP and with RAM, which made the flywheel. Both sides agreed that washers were a Real Good Idea. The odd thing was that ARP didn't offer a washer and long-bolt combination specifically for use with aluminum. The use of a thin AN washer was my solution.
Scott, as far as chamfering the bolt hole.... I'm sure it's a good idea. And after one washerless torque cycle with an aluminum flywheel, it has become "self chamfering", so to speak.
Jim
03-18-2011, 07:30 PM
#6
Le Mans Master
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