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Slipping head bolts... better solution?

Old 03-18-2021, 05:22 PM
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Default Slipping head bolts... better solution?

Guys,

This has happened on both engines though the first one came into spec and I got it done. I ended up breaking one bolt and replaced the set.

Iím torquing bolts down in five pound increments after 50 pounds... at this point hoping the washers would stop spinning but a couple just wonít cooperative.

Using ARPís lube, Iíve brushed some under the bolt head at the shoulder and on the threads. Per ARPís suggestion, I have sanded the bottoms of the washers and a flat plane with 80-grit in a straight pattern to rough up the surface to catch the spot face on the head. I still have a few that slip... I donít want to break bolts, or worse, pull threads. Almost wishing I had bought studs but the heads came with the ARP bolt sets.

Post-corona this is becoming a real b itch. I am wore out.

Would appreciate some suggestions.
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Old 03-18-2021, 05:31 PM
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Are sure the bolts arenít bottoming out ? 502 blocks have blind head bolt holes.

And 5lb increments sounds odd. Sometimes it can take that or more extra to get the bolt to move over what the actual torque is.

Last edited by SB; 03-18-2021 at 05:33 PM.
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Old 03-18-2021, 05:42 PM
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The increments were to avoid slippage. But I get what you mean.

The ARP head bolts I have are the ones for the 502 block. With exception of the long outside bolts, theyíre the same length as the factory bolts. The long bolts arenít slipping.
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Old 03-18-2021, 05:45 PM
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When you say slipping, what do you mean? Can you not reach a final torque or just concerned the washers are spinning while the bolt spins?
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Old 03-18-2021, 05:47 PM
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I have everything at 65 pound now. Iíll leave it over night and then back everything out and start again tomorrow evening. I did the same with the first engine and it was okay.

I made sure everything was clean on the heads (no lube between washer and head). This has been a new problem for me.
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Old 03-18-2021, 05:49 PM
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The washer no longer bites the head, the torque needed to turn the bolt decreases, and if you keep going, the bolt will stretch beyond yield.
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Old 03-18-2021, 05:59 PM
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Never heard of the 5lb increment deal. Seams as though that may have something to do with your issues. Do like 3 steps till final torque and call it good. Works for everyone else.
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Old 03-18-2021, 06:02 PM
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What is ARP calling for on their specs? Not sure, but since you have torgued the bolts once already to 65lbs and say you are gonna pull them and start over, you may wanna check stretch and see if they already have before re-torquing them.
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Old 03-18-2021, 06:03 PM
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Washer doesn't bite the head, can you spin the washer with your fingers after torquing them?
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Old 03-18-2021, 06:25 PM
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The washer is supposed to bite the head. Itís not. Thatís the issue. You cannot spin the washer.
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