No lubrication. You'll never get the correct torque reading if you lube the bolts.

 

Not motor oil anyway. Epecially if it drips down into the hole and doesn't allow the bolt to tighten all the way down.

You can use torquing lube (I don't know what it's actually called, but it's lube specially made for bolts that need to be torqued).

Really though, you don't need anything. Just make sure the hole is cleaned out and there isn't any liquid in the bolt holes

 

caulk04 is correct. Do not use engine oil or similar to lube the bolts they can build in the bottom of the hole and cause hydraulic pressure that will not allow you to fully seat the bolt. There by it will not truly be applying the clamping force needed. There are proper lubricants that are formulated for torquing bolts.

 

Head bolts typically require lube to get the correct torque values unless they are in a water passage (some engines) when they then need a thread sealant. FSM on the 4.0l doesn't specify to oil threads that I see, they do say one bolt needs sealant. Not sure about you application.

http://www.enginebuildermag.com/2012/10/ten-head-bolt-installation-tips/

The above link seems to like lube on the head bolts. I've always been under the impression that you need the lube to get proper torque, otherwise you are fighting the coarseness of the threads and getting less actual holding pressure on the head. YMMV.

 

I have read the FSM for the HEMI and it does not mention lubricating the bolts, just the proper torque sequence. I also see a lot of people in threads saying it is critical to lubricate to get proper torque numbers. I just don't want to mess it up.

 

Well think of it this way. They $20 to $30 for the torque lube and 10 extra minutes to use it is cheap insurance for the longevity of the engine.

 

If the engine does not require bolt lube from the factory do not lube the bolt. This isn't NHRA this is a street engine designed a specific way for a reason.

 

Not sure what your experience with engine building is but it doesn't sound like much.

Felpro recommends cleaning and lubing head bolts

http://www.fme-cat.com/#

ARP recommends lubing head bolts

arp-bolts.com/p/FAQ.php

Mobil Oil also recommends lubing head bolts

https://mobiloil.com/en/article/car-maintenance/how-to-do-it-yourself/how-to-change-a-head-gasket

I'm sure I could find a dozen more references if you'd like. Dry threads/ bolts have more resistance and won't achieve the desired torque values.

 

This is confusing. There is no place whatsoever where the factory service manual for a 5.7 says anything about pre-lubrication of the bolts. Help me out here, I'm trying to understand.
As far as ARP and others are concerned, I'll bet that they have their own torque requirements that are quite different from the torque values from the FCA 5.7 engine manuals.

 

The FSM does state to "clean and oil all cap bolts" (speaking of main caps) but they don't state that when speaking of head bolt torque. Do new head bolts from the factory come with a lube or thread locker on them? I know they often don't want you to re-use head bolts.

Then again the FSM doesn't seem to address re-use of the head bolts either, at least on the 2004 5.7 hemi FSM section I found. Which I also find strange.

They also state to tighten to 40 ft. lbs. then another 90 degrees. Which makes me wonder if they are a stretchy bolt that would be a one time use. I still cant get my head around a dry torque for a head bolt though. A little more abrasiveness on some of the block threads would mean more variance in bolt torque from my point of view.

Very strange stuff.

I think I'd buy ARP bolts and follow their direction. I've never had a bad time with ARP products.

 

Yes, the factory head bolts are TTY, which to be safe, would mean a one time use. I guess I will have to wait and see if the bolts come with anything on them. If they don't, I think I will just use a small amount of oil to lube the bolt. Not a lot, just like rub an oil soaked shop towel over the threads and washer.

 

So no lube?

 

If it is not called for in the FSM then no lube is not required for stock bolts.

 

Call a jeep dealership and ask the techs.

 

I've got a question, why were the heads pulled?

 

I am replacing them with the economy heads from Inertia Performance. I want to ensure I don't drop a valve seat. Will being doing this when I install a cam and headers this July.

 

If you're upgrading, why not go to an ARP bolt or stud kit? Are you going to replace your bolts? Are these a 1 time or 2 time use bolt? I didn't see anything about re-use in the FSM I skimmed over.

20 questions over here, but I'm an upgrade junky. Haha, I've been know to not leave well enough alone.

 

I am not going boosted or anything that might require the extra strength. The ARP kit is not cheap and I don't plan on removing the heads ever again (knock on wood). For my purposes, I think the factory bolts will be just fine.

Some have reused the bolts. I believe the FSM says to check them for stretch/length. Personally, spending $100 to get new ones is not even a thought. Not a place you really want to risk it and have a head gasket blow out.

 

Good approach. Do it right the first time.

 

If it were me I'd use NEW bolts, NO thread lube or sealant, and torque them to the specs. outlined in the FSM. Having spent (in the distant past) a number of years in aircraft quality assurance, I can tell you that any thread lube/anti-seize/sealant IS A LUBRICANT and will not allow you to properly torque the bolts. As said several times above, if the FSM doesn't say to use it, DON'T. Same goes for spark plugs, but that's a whole different can of worms. Just my two cents.