Ok, heres the deal. 72 ragtop, build date sept 3/71. Alt on the car was the int reg type and volt reg was gone, but the holes on firewall were still there. This was an add on date code on alt was mid 80's and this may have been why it burned actually. Anyway, so I order up a 72 alt, it shows up as the int reg case but with the correct connector(location on top, not the back). I tell them its not the one I want and leave. But I get home and my 72 chassis manual shows that style for 72. WTF?? I was expecting the older style case but the 72 manauls shows the int reg style case with volt reg on the firewall. So when did they change to that style of alt (still ext regulator but with newer style case)?? Thanks Tim
Tim, Dave Tumas (Daves69) is looking into the 72 alt differences. You might want to PM him. Say hi for me and tell him I sent you. Duane
Ok, thanks Duane....BTW I sent you a couple e-mails about the brake pedal pads but never heard back? later Tim
Tim, Yeah, I'm trying to catch up with everything. I figure the price of the pads and $6.00 should cover everything, if not I will pay the rest. Duane
Ok, sounds good, i'll get a money order out to you. Interesting on the alternators. Some quick research there were 5 avail in 72, only one was the old case style (63amp 1100891). Only 1 was the internally regulated style (80amp, 1101018). All the rest are the new case style (ie, look like int reg) but use regulators on the firewall. Of all those, it looks like only two were used on the GS/Skylark style according to the service manaul specs. Funny thing here is the p/n's match but the specs do not...the 37 amp (42amp) 1102449 standard alt and the optional 55amp (63amp) 1102448 and both those use the firewall regulator. Those are production part numbers, there are also service #'s as well. the lower amsp are form the service manual. OK, BUT the 72 assembly manual shows the 80amp setup in the A-body so it must have been used at one point? dated 4-26-71 Also, it looks like all the alts except the int regulated use the " I I " style connector (as opposed to the " - - " style). The odd part of all this?? How come every 72 I look at has the an old style alternator?? They weren't even used on the GS/Skylark according to the service manaul, parts book delcotron section and the assembly manual. Whew! ou: later Tim
Sheeeeeesh, Tim! I think you need to take a break and go skiing, snowmobiling or ice fishing. You are starting to scare me! :laugh: If you keep this up, you will talk in your sleep and start using Duane here as your userid. LOL ! :Brow: :laugh:
Nah, did that last week. Seriously, I scare myself, George! I actually enjoy the research, how wierd is that??? :laugh: Kind of intriquing to wade through all this and try to sort it out, plus I simply didn't know any of this and assumed they were the old style so I learned something new today again. Cool. later Tim
alternator 72 was the first year of the internal reg.71 used a external that looked identical except the plug had the II type plug marked f-r instead of the --marked 1-2,like tim said.early 63-70 used the plug in the back like you are used to seeing.since 72 was the first internal,it's possible the holes in the firewall for external reg were carried over from original design,but never used.does your harness have the 4 prong plug for the external reg,with the build date you should,however the alt will have the ribbed case with the II style plug :Smarty:
Actually 71 had the internal reg style on some models as well (p/n 1101015, 80amp). The 72 had a mix of both but it looks like the GS style cars were all still ext reg using the new style case with the " I I " plug, unless it was 80 amp which was internally regulated (and although assembly manual shows it on a-body cars, the other books say not avail on the a-body. Go figure). I'm taking this info from the assembly manuals, service manuals, and parts books (which has a great breakdown of the delcotron p/n's). Holes in firewall were tapped with threads at some point (ie, they were used) and harness is set up for volt reg, although assy manual shows jumper to plug in to bypass it so anything is possible. later Tim
again! the 1101015 80 amp was a big car only alt,used with a/c & rear defogger.never a-body.HOWEVER;i have heard the wyoming state patrol had a few 70 gsx cars in their fleet,i found this in a spring rate chart.it is possible the 80amp was a "fleet" option,but i have never seen one on ANY gm a-body uzzled:
72 Alternator Does anyone know which part number would be correct for a 72 Skylark GS455 w/AC and no other power options? If my car was built in the Fall of 71, how much earlier should the alt date code be compared to the the car's manufacture date? Thanks for the help,
Thats what I said (maybe I wasn't clear enough), the 80 amp was not avail on the a-body (as per most sources) even though assembly manual has a pic. That was one of the questions. Could be like you said a cop car thing (wierd!). So by elimination all the 72 Skylark/GS cars had external regulator but new style (ie, ribbed) case. According to the sources I have here, only two alts were used on the A-body cars, both ext reg, but new style cases. later Tim
I went through the same research. Mine had an external with the I I plug. I found one and had www.kenbrunomotorsports.com redo it with 100 amp internals. It works great and looks great. He is a Corvette specialist but has all the old books from Delco so he had all the info. This was for a 72 stage 1. You also have the pulley to figure out. The best info I can get is that it was over sized and black. Hope this helps!
Hi Rob, according to what I have here (not saying its 100% corrrect), the alt you should have on your car would be p/n 1102448, 55amp (service manual spec) or 63amp (delco spec).That is the new style case (ribbed), with the " I I " connector and a voltage regualtor on the firewall. I do believe the a/c cars all got the higher output alt. That is the production alt # and the service replacement alt listed by GM would be 1102451(if it was changed out). The date should proceed by the car by a few weeks most likely. Does that help?? Please remember that not all sources are correct, there are typos etc, thats what makes all thsi stuff good. later Tim
Hi Mike, good info, thanks!! Its kid of odd, the 70 and 71 cars everyone has down cold but the 72 seems to be its own little mystery all the time, lots of conflicting info.... Cool on the vette too, have a freind with a 62 split window vette, man that is a great car... later Tim
Tim, You are correct on the case, it is the newer design with the ribs. Vette is a very nice car. 340 hp 4 spd that does run very nice. Black/Black with a beige top. Pretty close to concours with everything numbers matching except the block. Everything is brand new. Not as nice to drive as the Buick, but nice for that change of pace. Check out Ken as he was very good. Mike
Sorry, meant 63 split window...kinda funny as its parked in my Moms garage right now under my "GS Parking Only" sign..I bugged him about it and he moved the sign!!! :laugh: Black/black/beige is cool, love to see a pic if you have one. Here is a funny little story. My ragtop had several alternators in the trunk when I bought it. So five years ago I looked at them when cleaning up the car after purchase (thought internal reg so wrong style) put them in a box in my crawlspace for maybe core values one day and forgot about them. So after all this I actually went digging and pulled one out of the box and guess what? Correct p/n for 72, new style case, square connector and build date two weeks before car was produced!!! Can't be 100% sure but I'll bet its the original. Thats pretty nutty and here I almost tossed it due to my own ignorance. Still has a paint code on ths side as well. I'm wondering if the larger pulley on your alt is to slow it down a bit? Didn't the stage 1 cars get a larger a/c pulley as well in 72?? later Tim
Yea, I caught the 62/63 typo! Not sure about the pulley on the A/C. I think it is the same as all the others. I am sure about the pulley on the alternator. I have one that I pulled off my car that is a 76, I think date code, but has the big pulley. Right plug but replaced it as the date code was wrong.
Tim thanks for the great info! Now I begin my quest for an 1102448 alternator core with the correct date code. Anyone have one laying around they would like to sell? I mostly want it for the numbers because I am going to send it out and have it rebuilt and cranked up. Thanks again,
i will go thru my cores for you tomorrow :TU: the only delco pullys that are numbered are the rolled steel double,for a/c.for some reason,delco didnt number the stamped steel single o No: ford(motorcraft)did,& a lot of rebuilders(myself included)interchange them on a regular basis. I am going to send it out and have it rebuilt and cranked up. dont forget,i do this :laugh:
