Head Bolt Lengths


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By paul2748 - 2 Years Ago
I got the info I was looking for
By Ted - 2 Years Ago
What info were you originally looking for?  Just curious.
By paul2748 - 2 Years Ago
A friend of mine was installing  rebuilt  heads on a 55 292 and all the longer bolts were the same.  He questioned me on the longer end ones and I was going to get the lengths for him.  While looking up the info (after my post here) I found an article on Y head bolts by Gil Baumgartner (CTCI web site) with the information.  Per his article, the 54 and 55 long head bolts were the all same, the longer end ones started in 56.  I assume this agrees with your info?. 

https://www.ctci.org/gilsgarage/ford-y-block-head-bolts-239-256-272-292-312-ci-engines/
By Ted - 2 Years Ago
That agrees with what I have seen.  My ’55 272 had all the same length bolts on the top row.  When I rebuilt the engine, I installed the longer 1957-up bolts in the end top row holes.
By KULTULZ - Last Year
That agrees with what I have seen.  My ’55 272 had all the same length bolts on the top row.  When I rebuilt the engine, I installed the longer 1957-up bolts in the end top row holes.


I am trying to figure out the why of FORD going to different length head bolts in the mid/late 1956 production year. There were several changes also made (valve-train) along with this.

Rhyme or reason? Is the difference(s) in the head or block casting?
 
I would think a SERVICE LETTER was released regarding this.

- CORNFUSED IN W(BY GOD)V ... Blink

By charliemccraney - Last Year
The Upper end holes loose some thread length because of the counterbore for the dowels.  I would guess that there were some problems as a result of the reduced thread engagement that caused them to lengthen the end bolts.  Another possibility is simple human error.  Maybe the original intent was to use longer bolts but somehow the documentation had an error.  I would expect bulletins to exist for either of these.
By FORD DEARBORN - Last Year
http://forums.y-blocksforever.com/uploads/images/e196c233-bae0-4579-858f-93c3.jpg
By KULTULZ - Last Year
FORD DEARBORN (10/29/2023)


http://forums.y-blocksforever.com/uploads/images/e196c233-bae0-4579-858f-93c3.jpg


!!! THANK YOU SIR !!!

EXACTLY WHAT I WAS AFTER ...


By KULTULZ - Last Year
charliemccraney (10/29/2023)


The Upper end holes loose some thread length because of the counterbore for the dowels.  I would guess that there were some problems as a result of the reduced thread engagement that caused them to lengthen the end bolts.


!!! THANK YOU SIR ALSO !!!

You hit it on the head ... Wink ...(pun intended)


By paul2748 - Last Year
The bulletin does not explicitely say, but I guess it was ok to use the longer bolt in the 54's and 55's since there was no warning about not using the longer bolts in the 54 and 55 engines.
By Ted - Last Year
paul2748 (10/30/2023)
The bulletin does not explicitly say, but I guess it was ok to use the longer bolt in the 54's and 55's since there was no warning about not using the longer bolts in the 54 and 55 engines.

I have had no issues using the four longer bolts at the top end holes in the heads on the ’54-55 Y engines.  As Charlie and the Ford Bulletin mentions, thread retention on those four particular holes (two per side) is improved when using the longer bolts.  When using the ARP head bolts, I will install the bolts first without the washers to ensure that the bolts do fully seat against the bolt heads before removing to install the washers and then torquing the bolts.  When milling the heads and blocks, the head bolt thread lengths do get dicey.

By KULTULZ - Last Year
So of what Charlie posted, the dowels were moved further into the block (machining protocols - both early and late used the same dowels according to the MPC), for whatever reason and the added depth required longer bolts at the dowel locations?

This change came on the first run 1956 production? Wonder if FORD had gasket sealing problem(s) on the 54 and 55 block?

Learn something new everyday.
By charliemccraney - Last Year
No, I don't think the position of the dowels changed.  It is simply that the reduced thread engagement caused by the counterbore caused issues, which a longer bolt fixed.
By KULTULZ - Last Year
No, I don't think the position of the dowels changed.  It is simply that the reduced thread engagement caused by the counterbore caused issues, which a longer bolt fixed.


Now that makes sense. Reduced bore thread as a result of the dowel insertion.


THANX!