Head bolt torque and sequence? - ClassicOldsmobile.com


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Old March 7th, 2011, 04:00 PM   #1
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Head bolt torque and sequence?

Hey all! I was hoping that someone could give the proper torque (I think its 80 ft/lbs) and what sequence to torque heads on a 425?
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Old March 7th, 2011, 06:04 PM   #2
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Frank, 95ft/lb.
I am having trouble in describing the sequence but starts in centre bolt between valves ,then other bolt opposite , centre --near xhaust . Sorry buddy we need a pic for this
mike
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Old March 7th, 2011, 06:05 PM   #3
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Work from the center bolt in a spiral pattern out. Someone correct me if i wrong.
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Old March 7th, 2011, 06:06 PM   #4
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hang about

exhaust side
10 4 2 6 8

9 3 1 5 7
intake

Last edited by geckonz08; March 7th, 2011 at 06:08 PM. Reason: to correct
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Old March 7th, 2011, 06:12 PM   #5
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Old March 7th, 2011, 06:36 PM   #6
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80-85 ft lb; gecko has the right sequence.
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Old March 7th, 2011, 10:41 PM   #7
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Quote:
Originally Posted by Run to Rund View Post
80-85 ft lb; gecko has the right sequence.
Hey it`s strange .My 66 C.S.M. says 95FT/LB. You n other references quote 80- 90.
Which is correct?
Is it to do with oil on the bolts /or not ?
Is it concerning a 7/16 or 1/2 " bolt ?
Is it not that critical ?

Pretty keen to find out b4 I let the builder loose with my C.S.M.

CHEERS MIKE
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Old March 8th, 2011, 05:09 AM   #8
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Here's what the '66 CSM says:
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File Type: jpg 66 Head Bolts.jpg (50.2 KB, 42 views)
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Old March 8th, 2011, 09:27 AM   #9
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My 66 csm has 80 ft lb in the text and in the summary at the end of the section. Definitely clean the bolts and block, oil the bolts, threads and shoulders, and let them drain onto a paper towel before installation.
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Old March 8th, 2011, 12:09 PM   #10
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Quote:
Originally Posted by Run to Rund View Post
My 66 csm has 80 ft lb in the text and in the summary at the end of the section. Definitely clean the bolts and block, oil the bolts, threads and shoulders, and let them drain onto a paper towel before installation.
THANKS .I am wrong again and apologise to Frank when I said 95 ft/ lb torque.It is 80 as others have stated. I did the classic "too fast n no finesse" when I mistakenly looked at the 66 L6 --Not the v8 -425.

mike
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Old March 8th, 2011, 02:13 PM   #11
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Smile bolts

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Originally Posted by Franks425442 View Post
Hey all! I was hoping that someone could give the proper torque (I think its 80 ft/lbs) and what sequence to torque heads on a 425?
torque bolts in a three stage circular pattern, from the center of the head outwards. so like 30, 60, then final...add 5 lbs. if you re-use bolts. 80 lbs. sounds about right.
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Old March 9th, 2011, 07:11 AM   #12
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be sure to blow out the bolt holes before installing heads
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Old March 9th, 2011, 12:31 PM   #13
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Smile yeah

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be sure to blow out the bolt holes before installing heads
i even heard of dudes runnin' a flat bottom chaser tap to clean-out the threads. i've never done that, i did like you said and used compressed air to clean out the holes along with a good blast of Berrymans chemtool. never had a problem with that method and even reused head gaskets. i think olds. motors have good clamping pressure around the cylinders so maybe torque isn't so critical. i know my torgue wrench is like +/- 10% at best, on a good day, so who knows.
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Old March 9th, 2011, 12:41 PM   #14
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I'd definitely run a tap through the threads first.
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Old March 9th, 2011, 01:08 PM   #15
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Thanks for all the help guys! This site really helps a lot! You can find thousands of websites and info on bowtie motors at any given time, but you really gotta dig deep in google for some reliable olds info!
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