'69 L-71 Alternator
I have read that some '69's could have had '70 part-number alternators, so I'm looking for you guys expert opinions. The car started down the assembly line on October 10th, 1969. I am wanting to purchase the most likely candidate, but want to hear from you guys before I make a mistake. I love this car and want to do right by it!
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Re: '69 L-71 Alternator
If you're after judging points, use the part numbers shown in the judging guide and the standard date coding allowances.
Can you give a specific example of what you're talking about? -
Re: '69 L-71 Alternator
Mike, yes I'd like the points. At this moment I can't recall where I saw that late 69's could have '70 part numbers. Possibly I found that in the tech archives. I have been speaking with a gentleman that has several alternators and I'm anxious to select one while they are available. I'm not sure yet how to obtain a judging manual being realitively new to NCRS. I guess that's something I need to fix. Meantime any help with part numbers is welcomed. Thanks for your past help as well on Corvette Forum!Comment
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Re: '69 L-71 Alternator
You can purchase judging manuals at the NCRS Store, found on the tool bar at the top of this pageDick WhittingtonComment
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Re: '69 L-71 Alternator
I have had a thread on the alternators part# and dates, and have the judging manual. All the advice I get is that the part # must be correct for the application, and the date on the alternator can't be more than 6 months prior to engine build date nor of course after that. I don't think the judges would be swayed by some article about '70s parts put on '69s.Big Tanks In the High Mountains of New MexicoComment
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Re: '69 L-71 Alternator
If one compares 1969 and 1970 alternator numbers as called for in those respective judging guides -- many of the numbers are the same for both years. Thus one creates a miss-impression by calling any alternator number as specific for 1969 or 1970.
Once one gets past the numbers, and beyond the Ray Charles school of Corvette judging, one has to look at the specific configuration details of the alternator to determine if it is appropriate for 1969 or for 1970. I know someone has already posted pictures of rear case external details for each year on this board.TerryComment
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Re: '69 L-71 Alternator
G Dan------
The judging guide allows for either 1100825 or 1100884 alternator part numbers. While the JG does also allow for the 1100882, it's not specifically called out for a non-L-89 L-71. However, I think that it could very well have been used for a non L-89 L-71. The 1100884 is the alternator that was used for both 1969 and 1970 Corvette applications.
Finding ANY of the above alternator part numbers, regardless of date, will be one of the most challenging parts of your restoration effort. IF you find one, you will find it to be one of the most expensive pieces you could imagine. It's even tough for anyone to create a "re-stamp" for one of these because the case configuration, both drive and split ring end, is unique and rare. The only other alternator part numbers that ever used these case halves are also pretty rare, so the supply of "re-stampable" cases is VERY limited.In Appreciation of John HinckleyComment
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Re: '69 L-71 Alternator
Joe is spot on with all his comments. I would also caution you to be aware of counterfeits, as they are out there.Comment
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Re: '69 L-71 Alternator
the advice I get is that the part # must be correct for the application, and the date on the alternator can't be more than 6 months prior to engine build date nor of course after that.
Close...
The carb met the assembled engine at St. Louis for final vehicle assy. Engines shipped from either Flint (SB) or Tonawanda (BB), were test fired using propane. So, they weren't equipped with carb, fuel pump or other 'bolt-on' components.
So, the 6-month rule applies to the birthdate of the CAR and not the date of the engine sub-assy...Comment
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Re: '69 L-71 Alternator
Dan-------
Here are photos of a 1969 GM #1100882 alternator for both the drive end and split ring end case halves. This particular example was assembled September 17, 1968. Note that this alternator was a 55A rated unit. Not all GM #1100882 alternators were rated at 61A like many folks think.
Note that the drive end case has 6 narrow ribs extending all the way to the perimeter of the case. This style drive end case was used only for 1969 and, possibly, all or part of 1970. This style drive end case is VERY hard to find, regardless of stamped alternator part number. All 1969 alternator part numbers are almost impossible to find and some are a lot harder than that.
On the split ring end case half, note the 7 fin heat sink. This configuration was used only for 69-70. Also note the nearly "flat" grounding lug boss. This configuration was used only for 1969. All 1970 and later use a ground lug boss which is raised about 3/8" off the rear of the case. I'll post a photo of that in a following post. Also, 1970 has a small, raised rectangle below the Delco-Remy script. 1969 does not have this feature.In Appreciation of John HinckleyComment
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Re: '69 L-71 Alternator
Dan------
Here's a photo of the 1970 and later style grounding lug boss on the split ring end case half.In Appreciation of John HinckleyComment
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Re: '69 L-71 Alternator
My alternator case is "grainy" like the ones pictured above.
Is this correct or has the case been bead blasted?Comment
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Re: '69 L-71 Alternator
Most likely, it's been bead blasted. The one in the photo has definitely been so-treated.
However, the original alternator case halves were not as smooth as many folks think. I have NOS alternators manufactured as far back as 1971 and also many NOS case halves, both drive end and split ring end. Many of these evidence a quite rough finish, very similar to what one gets with bead blasting.In Appreciation of John HinckleyComment
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Re: '69 L-71 Alternator
Joe,
Thanks for the info.
I always thought mine was a little rougher than it should be.Comment
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Re: '69 L-71 Alternator
Joe- First let me say that I am very appreciative of your help. Your knowledge is priceless.
I have been studying archived threads today about this subject and am much better versed now. I was not aware of the thread boss height difference between 69 and 70. Your pictures will be invaluable. One item after reading the posts is still confusing though. The 884 seems to have been installed on L-71's according to members with original alternators. However, there is a photo of an L-71 GM brochure in one post, and the members state the alternator must be an 882 since the engine shown is not an L-89. My conclusion is that the alternator of choice for the L-71 on the production line was an 882 but for various reasons 884's could have also been installed. Have I been a good student?
DanComment
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