Guest rsd9699 Posted December 16, 2011 Share Posted December 16, 2011 Hi to all,In my never ending quest to a/c my various Olds - I keep getting stuck on the accessory head bolt issue.An accessory head bolt is a "regular" looking head bolt with a threaded stub on top of the hex head of the head bolt.I have never found a source for them - they were discontinued making several years ago and none seem to left on shelves at the places I have checked with.So my question is can I use a stud and a cap nut to simulate a head bolt and what grades should I look for and avoid.ThanksRon Link to comment Share on other sites More sharing options...
Guest Fitz Posted December 16, 2011 Share Posted December 16, 2011 something like this?Fitz. Link to comment Share on other sites More sharing options...
NTX5467 Posted December 16, 2011 Share Posted December 16, 2011 Over the years, there have been OEM applications for such bolts in some GM vehicles. Some might be in GM's "Standard Parts" catalog . . . BUT the stud on top is usuallly of a smaller diameter than the basic bolt's thread is, which might be a sticking point of sorts.Seems like there were some on the Olds 5.7L diesels?One "trick" part on the old 5.7L GM diesels was the radiator hose clamp on the thermostat housing. In addition to the basic clamp, it had a curved shield attached to keep the a/c belts from touching the upper radiator hose, as they flexed with the a/c compressor running. Not sure if they are still around, but they were really neat for other applications which had flexing a/c belts!Just some thoughts . . .NTX5467 Link to comment Share on other sites More sharing options...
1937-44 Posted December 16, 2011 Share Posted December 16, 2011 Not sure if this would work, but thought I would throw it out their and see what people think. Could you screw a nut onto a stud to the length needed for the head and then weld the nut in place leaving part of the stud for your ac bracket? Link to comment Share on other sites More sharing options...
Guest rsd9699 Posted December 16, 2011 Share Posted December 16, 2011 Yes Mr. FITZ those are the types of creatures I am seeking.Did you machine them? I have a old/little 6 inch Atlas that I pondered doing it on but I am a novice in machining.The tops of the head bolts are 3/8 inch SAE and the bottoms are course threads.I will take some pictures tomorrow and post the pictures and lengths.Mr. NTX5467, the bolts used on the 330 thru 455 are 7/16 if I recall correctly and the 303 thru 394 are 3/8. The 303 and 324 are a little shorter than the 371 and 394 and they will work I think (never tried one). We need to meet sometime - I live on the east side of Lewisville.Just think if Olds had used 1/2 head bolts on the Diesels, the history may different for Olds?Mr. 1937-44, I thought of the welding as well but I was afraid that the tensile strength of the bolts would be altered and the last thing I need is a snapped head bolt when I flip the a/c switch at 100 MPH. Link to comment Share on other sites More sharing options...
Guest rsd9699 Posted December 16, 2011 Share Posted December 16, 2011 Mr. Fitz - nice paint job!!!!!!!!!!!!!!!!!!!!!Ron Link to comment Share on other sites More sharing options...
Guest rsd9699 Posted December 16, 2011 Share Posted December 16, 2011 Mr. 1937-44,I was thinking of putting a cap nut on the stud and putting an allen screw thru the nut to lock it to the stud - we think along the same lines.Ron Link to comment Share on other sites More sharing options...
joe_padavano Posted December 16, 2011 Share Posted December 16, 2011 Mr. 1937-44,I was thinking of putting a cap nut on the stud and putting an allen screw thru the nut to lock it to the stud - we think along the same lines.RonYou didn't specify if you were working on a first gen or second gen Olds V8, but the accessory head bolts for the second gen (1964-1990) motors are quite common. Note that the 1964-76 motors used 7/16" head bolts and the 1977-90 motors used 1/2" head bolts. The bolts show up on ebay frequently. Link to comment Share on other sites More sharing options...
NTX5467 Posted December 17, 2011 Share Posted December 17, 2011 Mr. 1937-44, I thought of the welding as well but I was afraid that the tensile strength of the bolts would be altered and the last thing I need is a snapped head bolt when I flip the a/c switch at 100 MPH.No flow-thru ventilation at that speed? Worried about a bolt? What about the a/c drive belt???Enjoy!NTX5467 Link to comment Share on other sites More sharing options...
Guest rsd9699 Posted December 17, 2011 Share Posted December 17, 2011 In this case - the 303 thru 324 engine group.40+ years ago - I did that quite often - that is - flip the a/c on and rolled up the windows as there was a "sand belt" just west of where I was raised - someone sneezed and you had a dust storm that lasted one or more miles. Got to love power windows and a/c. I was running a single belt on the S/F and wondered why they wanted two on it? At that time I could not afford a matched set of belts....Hey - I was younger and dumber.....Ron Link to comment Share on other sites More sharing options...
Guest Fitz Posted December 17, 2011 Share Posted December 17, 2011 Yes Mr. FITZ those are the types of creatures I am seeking.Did you machine them? I have a old/little 6 inch Atlas that I pondered doing it on but I am a novice in machining.The tops of the head bolts are 3/8 inch SAE and the bottoms are course threads.I will take some pictures tomorrow and post the pictures and lengths.Yes I made it for my Pontiac L6 1953 engine. The old one did not hold the spec. bolt torque. I don't remember the steel code quality, but I can get back for you I have the info somewhere, or make a set at your specific need if you want.Fitz. Link to comment Share on other sites More sharing options...
Guest rsd9699 Posted December 19, 2011 Share Posted December 19, 2011 Well - I put the bolts right where I could put my hands on them but my hands seems to have forgotten where they put them.Rain forcast Monday so I will force the hands to find them.Ron Link to comment Share on other sites More sharing options...
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