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1928 Buick Standard Six Head bolts


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Rod, 

       I replaced the 17 Head bolts with Studs.  New studs are 5 ½” long.  Old studs (and there were 2) were 5 ¼” long with ¾” of threads on the end.  Common now is 1” of threads each end, so ¼” was added to the overall length to keep the studs flush with the top of the cylinder head nuts when assembled.

Studs were ARP brand.  Teflon thread sealant (for cylinder heads) was used. Part #ARP 070-100-9904  Using a toothpick I was able to wipe the inside of the threads in the block, and using a toothbrush I was able to get into the thread grooves on the stud.  If you stay with bolts, consider Grade 5 minimum or Grade 8.  I used Studs so that I would not disturb the thread sealant if I retorqued the cylinder head at a later date.   Hugh

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I would question the use of high grade bolts.  You don't want to increase the torque value for the head bolts.  Stressing the castings and threads are not a good idea.  Think of the bolts as springs, High grade steels will have higher spring rates.  I am a believer in installing hardened washers under the head bolts to prevent damage to the cylinder head.

 

Bob Engle

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When I installed the head on my 1925 Buick, I struggled with finding a cylinder head torque sequence diagram.  I just found it in a 1926 Buick care and operations manual that I had shipped in from Australia.   There are several versions out there that I did not agree with, and the later model straight 8 Buick is a very odd bolt tightening pattern IMO.  Because of the unusual bolt spacing pattern on these 6 cylinder Buicks, they "paired" some of the studs in this diagram.  The GM Export book also contains the patterns for Oldsmobile and Oakland.  Hugh

 

IMG_0428.thumb.JPG.d578634f86998339c74ac59b511acf83.JPG

 

 

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On 5/28/2020 at 5:27 AM, Robert Engle said:

I would question the use of high grade bolts.  You don't want to increase the torque value for the head bolts.  Stressing the castings and threads are not a good idea.  Think of the bolts as springs, High grade steels will have higher spring rates.  I am a believer in installing hardened washers under the head bolts to prevent damage to the cylinder head.

 

Bob Engle

Are you suggesting keeping the original bolts too?

Thanks, Bob.

Rod Miles

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I wouldn't hesitate using the old ones, as long as they torque up properly, if one feels stretchy replace it,. You can kind of feel it on the torque wrench if it's not right. Torque patterns always start in the center and spiral outwards to the ends.  It's important to do it in several stages so as to get even pressure,  I agree with Rod. Grade 8 bolts may not have enough give. 

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I always enjoyed the 1932 Buick specs and adjustments manual.  "It is important that the cylinder head bolts are not pulled down tighter than can be done with a 9" wrench using one hand on the wrench."

 

Bob Engle

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Bob,

Kind of gives you an idea of just what is needed for these "really high" compression engines back whe they were new.

 

This is yet another "over thunk" issue by guys who have worked on more meodern engines.

 

Im near 80 and I remember the crazy stories my dad told me about working on engines way back when and when just getting back on the road was the real objective.

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Rod, 

 Attached are what I am using for Torque specs on my 1925 Buick Standard.  Also my notes on the retorque on your cylinder head at a later date.   Hugh

 

1181431455_TorquespecsBuick1.thumb.jpg.3526f33b87a1ac789a0e26ca8d0b8773.jpgTorque.thumb.JPG.2b3e0ca98f8fe4a24479229573671c22.JPG

 

 

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23 hours ago, Rod Miles said:

And what is your suggestion for the torque settings?

Thanks.

The Motor Auto repair manual says for the 8 cylinders  65-70 ft lbs for 7/16 bolts, or... if a "tension indicating wrench" is not available, the aforementioned 9 inch wrench.  

Seriously... I recommend 65 ft pounds.  

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Here's what happens over 80 years. I milled the head down by the thickness of the hardened washers.  I turned the head bolts to give a good square shoulder.  I used my 9" wrench to torque the head.

 

 

 

Bob Engle

30-50 head.jpg

32-50 headbolts.jpg

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