FE ARP head bolt torque?

[Rory428]

I am about ready to bolt the TFS heads back on my fresh 428 short block, but it appears that  I have misplaced the instruction sheet that came with the ARP head bolt kit, PN 155-3601. Anybody have the torque specs that ARP called for with these bolts? Thanks.

[mike7570]

I have it in the garage and will check in the morning. If I remember correctly there were two different numbers, one for the short bolt and one for the long bolt. It wasn’t much of a difference and I set all of mine the same at 100ft lbs. using the ARP lube.

[blykins]

100 lb-ft on head bolts.

[mike7570]

I thought I saw something about a difference between the 2 bolts of about 5-10 lbs, not sure where. (I Found it, it was the Edlebrock torque spec for their aluminum heads. 110 top row, 100 bottom row.)

[frnkeore]

FE, TFS uses the same torque spec as Edelbrock FE heads.

[My427stang]

I use the ARP spec. Never an issue with iron or aluminum, although 5 extra lbs wouldn’t hurt anything either.

[blykins]

ARP head studs torque at 110.  Bolts at 100.

I go by fastener instructions, not cylinder head instructions. 

[pbf777]

............... there were two different numbers, one for the short bolt and one for the long bolt.

       The difference in the torque values (greater for the longer fasteners whether bolts or studs) is in an attempt to "take-up" for the greater elasticity presented in the longer fasteners length.  Generally the initial intention in the torque specification is to tighten/preload the fastener based on the fastener material at hand and its' cross sectional minor diameter this presenting a tensile stress something of approximately 80% of the yield point load; this to say leaves "some" on the table, so in the problematic instances it is often practiced to push the limits of the longer fasteners, and which will thru this greater elastic value present be more receptive to such, and also nullify an unappreciated result presenting a more consistent clamping load on the gasket.   

       Torque specification values normally are based on the fastener; but at times, particularly in this after-market industry which often presents great ideas, but perhaps with out any "real" engineers' consideration for the "whole picture", one needs to give thought to whether a particular assembly can tolerate the forces imparted with your newly chosen "super-hy-torque" fastener!   
       Scott.

[mike7570]

  Torque specification values normally are based on the fastener; but at times, particularly in this after-market industry which often presents great ideas, but perhaps with out any "real" engineers' consideration for the "whole picture", one needs to give thought to whether a particular assembly can tolerate the forces imparted with your newly chosen "super-hy-torque" fastener!   
       Scott.

The Ford engineers decided the 427 FE head torque with the factory bolts from the ‘60s was 110# and 390-428 were 90#,  good enough for me.

[blykins]

I guess I'll clarify my answer based off of Scott's post. 

I do not put any stock into what the cylinder head manufacturers tell you to torque at, I follow the fastener manufacturer's specs.  Until.....you get to aluminum block stuff.  Everyone knows not to use bolts on aluminum blocks, but the main/head stud torque spec for an aluminum block is generally considerably less than on an iron block. 

I also do not change the torque spec based on whether it's a 390 block or a 427 block.  The blocks are all torque plate honed with ARP fasteners, torqued at what the ARP specs say (unless it's an aluminum block of course)....

[frnkeore]

TFS, recommends the common, ARP155-3601 bolts, for their heads and recommends 110 upper,100 lb lower of torque for them.

Both TFS & Edelbrock designed the heads to use that torque setting.

If ARP does not recommend that their head bolts be torqued to 110, is the only reason I would lower the tq setting. I would think that TFS & Edelbrock would have explored that before giving their recommendation.

[cleandan]

Just to toss in a bit more confusion, and based on the ARP tech sheets that have accompanied the fasteners I have used, the lubricant used on the threads makes a difference too.

Yup, when using studs the lubricant in the block are not terribly important but what you use on the bolt and washer does have an effect on the running torque while tightening things to final torque.

I don't have my sheets in front of me but I do remember the ARP assembly lube uses a lower final torque than engine oil, and both of those use a lower torque than assmebling dry.

I am with Brent on using the fastener manufacturers specifications when torquing.
Especially when using a specifically engineered fastener like the ARP offerings.....They have spent a lot of time and engineering figuring out the best application and torque specs for their fasteners.
I would bet they have a good handle on the torque specs they are stating, as well as the installation techniques to be used along with their fasteners.

If you can't locate the tech sheet for your specific fasteners I am certain you can contact ARP and get the required information for the exact fasteners you are using.....espectially if you have the kit part number.

[pbf777]

If ARP does not recommend that their head bolts be torqued to 110, is the only reason I would lower the tq setting.

     ARP in their "Recommended" torque values, is positioning themselves within the window of the elastic range and as stated previously at generally 80% of that which the fastener will tolerate and still be useful, this is simply a safe bet by ARP that even if excessive production variances do exist it wouldn't become an issue; but at say 90% of the actual yield of the fastener this is still just fine, as long as the production 'is' as intended, and is pretty much what is being suggested with the higher numbers.   

     But do note that ARP is not saying that for every application in which their fastener might fit or be retrofitted into, that the recommended torque sum is correct for other surrounding items involved, their just speaking for their fastener, it's your job to establish if it's a good idea or not.   

     Remember, when one decides to substitute the O.E.M.'s stuff for something else, well, that makes you the new engineer!   

     Scott.     

[My427stang]

I would call this arguing about shades of color. Expansion rates of the  alloys, compression elasticity, thickness of the head bolt location, length and stretch of the bolts, head gasket material, operating temp, you name it. I think using one or two variables to justify is just bench racing when so many change from build to build.

100 works and is documented, if you want to split it, split it, but in the end I try to repeat what we do on the deck plate. Even then it does not account for everything.  I would say the likely there is a 20 or more ft lb range that would work fine

Call me lucky but ARP lube liberally at 100 is still doing well on my own stroker at 16 years, but I will watch it 

[frnkeore]

I call ARP, earlier today and they do not recommend any more than 100 lb of torque on the 155-3601 bolts, period. That surprised me since both Edel & TFS recommend 110.

I tried to call TFS but, they were closed for today, I'll try to remember to call them on Mon. I think it's something that needs to be straighten out.