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Post by tabletennissport on Mar 21, 2013 16:14:53 GMT 10
Can anyone tell me how often the head studs on my '39 120 should be tightened? And what tension? Thanks...
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Ozstatman
Full Member
"Out of chaos comes order" - Nietzsche.
Posts: 130
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Post by Ozstatman on Mar 23, 2013 15:11:53 GMT 10
Dear Abby Tabletennissport, At the Technical Forum held recently during PACA's 15th National Rally, and currently underway on Phillip Island, this very subject was raised. IIRC Peter T, PACA's Technical Officer, advised he uses 55 ft/lbs as the figure he tightens the nuts to on his head studs. The initial tightening of the nuts is done in increments, in the pattern laid out by Packard for this procedure, until the 55 ft/lbs is attained. Then tightened again soon after, following hot running, when the whole engine has been thoroughly warmed up. Followed by tightening again after further operational warming and cooling cycles. It then should be checked periodically to ensure the nuts remain at that pressure. Although Packard specified 55-62 ft/lbs, Peter leans to the lower side especially when old studs are involved. Pic is of PACA member Wade H tightening head nuts on John M;s '39 TJ Richards Six Sedan Attachments:
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Post by larry51 on Jul 9, 2013 9:51:50 GMT 10
If it's helpful, the Workshop Manual for 51-54 straight 8's stipulates same procedure. Torque figure is very slightly different, 60 to 62ftlbs.
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Post by peterpackard on Oct 27, 2013 17:13:21 GMT 10
It should be noted that the Torque figure quoted for any Packard or other vehicle is for "lubricated" bolts or nuts. It is surprising how different (lower) the end result is if "dry" bolts or nuts are torqued. I lean toward the lower torque recommendation as many of the Packard head bolts are in direct contact with the water in the block and the threads are often corroded at the end of the stud. PT
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Post by elwoodp44 on Mar 8, 2014 2:06:15 GMT 10
The original question was 'how often' should the head studs be tightened? The head nuts should be checked after the first time the engine is started and brought up to temperature. Then, after a month or so of operation they should be checked again.
If the torque value of the nuts at this point is close to what it should be then checking every 6 months should be adequate. I'm looking for a service bulletin or note somewhere in the Packard shop documentation that talks about this. I suspect that many Packards came out of the factory and after the initial dealer shop-check of the nut torque, they ran for years without further maintenance.
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Post by peterpackard on Mar 15, 2014 21:25:59 GMT 10
There will be no Factory mention of an annual/periodic head re-torque because you were supposed to have your vehicle serviced regularly, and at least annually. I understand that a de-coke was an annual tasking and this involved the removal of the head, replacement of the gasket and torqueing as specified. It is only after slackers such as me have had vehs not serviced by Packard that we have fallen behind. My 94,000mile 38 Super Eight, ex Sir MacPherson Robertson travelled only 300 miles in 17 years. Your suspicion of benign neglect is soundly based. The best test is to retorque every year or so, or if you start losing water or your top radiator water goes a bit frothy or has some bubbles circulating....indicating a possible head gasket leak. The main reason fro rechecking the head torque is because Packards will blow out between cylinders if the head gasket is not kept tensioned. PT
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