Head bolts

blondwookie

Where is the best place to get new Head bolts for my 308? I have half inch head bolts in my 55 308

Glowplug

Try Dale Cooper /513-821-6200/

EngineerLecompte

There's really nothing special about them, as near as I can tell. Last time I had the head off my 51 I used Grade 8s from a reputable fastener house. Black oxide finish so it wouldn't look weird.

I did use structural washers under the bolts-grade F496-iff'n you want to be technical and all. Any good fastener shop should have them, even Fastenal, although you may have to repeat yourself many, many times.

ski4life65

1/2 inch are easy to find. 7/16, not so much. I bought mine at Fastenal, but Lowes had them too, but way more expensive.

blondwookie

Thanks for the input on the head bolts and washers

Kdancy

Mcmaster carr

https://www.mcmaster.com/

50C8DAN

I wanted flanged head bolts and got mine from this place: https://www.flangebolts.com

Kdancy

It would seem to me that the fixed flange would effect the torque reading?

50C8DAN

Not sure but I have had no problems yet.  Yes, there are some differences but I tend to like flanged bolts for several reasons.  Here is an article on this subject: http://www.fbabolt.com.au/flange-bolt-tech.html

blondwookie

Chevy uses the flange bolt and has for years. I don't see an issue with torquing at all

JasonNC

I thought the original engine had the flanged bolts.  At least that's what was in my 48 when I bought it. 

blondwookie

I'm not sure. the few engine head bolts i got were just head bolts, like what is in most ford engines

blondwookie

there could also be different original head bolts used over the years.

blondwookie

On YouTube, I saw 7 different engines with 7 different kinds of head bolts used including studs, washers and stover nuts

50C8DAN

My 50C8 has studs

blondwookie

does your head bolt studs, have threads at both ends with a solid shoulder in the middle?

50C8DAN

Yes.  I believe all of the 8s were made that way and perhaps the 212s 6s too, but I do not have one to go look at.

blondwookie

i have a local bolt shop in Casper. I'll see what they have in half inch studs

Kdancy

blondwookie said:

Chevy uses the flange bolt and has for years. I don't see an issue with torquing at all

  I'm sure that GM took the flanged bolt design into consideration when coming up with the torque specs. Not saying its good or bad, but turning a fixed flange against a surface has got to create more friction then turning a bolt head against a loose washer.

I have an original  262 and a 232 on stands, both have bolts with washers.

Kdancy

Interesting article on the two types-

http://www.fbabolt.com.au/flange-bolt-tech.html

The use of hardened washers is necassary when going the bolt and washer route, ive always used them

And-

As has been explained, there are several reasons as to why flanged nuts and bolts are preferred over standard hexagon fasteners used with washers. The sensible approach is to replace like fasteners with like fasteners; unless you are feeling lucky.

Kdancy

Note back to me from the Bolt Science editor-

Hi Kerry,

 If the friction is the same in both situations, the flange headed fastener would require a higher torque to achieve the same preload. This is due to the effective friction diameter of the head increasing when a flange headed fastener is used.

 I hope that this helps

Kind regards 

Bill Eccles PhD

Bolt Science    www.boltscience.com

Tel. +441257 411503      Fax. +44 1257 411650

railknight

I replaced the head gasket on my '53 Super Wasp 262 engine last year (Sept. 2019) using new head bolts purchased from Dale Cooper.  The bolts actually cost a little less than similar bolts at the local ACE Hardware store.  

Kdancy

How much difference I asked him--

Depends upon the specifics; approximately in the order of 10% typically.

 (I would like to have edited this and put all in one response, but can no longer do that for some reason)

35 Terraplane

One other thing to consider.  Hex cap screws feature a washer face under the head and a chamfered point.  This aids in achieving correct torque value.  Also a slight amount of lubricant on the threads and washer faces aids in friction reduction.  As Kerry said, the use of hardened washers is the way to go.  Common hex bolts not have these features.  It's a good thing to look for ASME grade 8 hex cap screws and A325 hardened washers.

m.patterson56

Has anyone considered studs with a course thread into the block and a fine thread with a hardened washer and a nut on the outside? Once the course thread is seated in the block, wouldn't the fine thread give more pressure for torque value?

50C8DAN

I believe that in my old Clifford catalog he listed something similar for 308s as a stud kit.  I also think that the Nascar guys used to run studs.  Also, I could be wrong but I thought I read where Hudson used Grade 5 bolts to get more stretch during torque down?