1969 Corvette engine questions

**Chuck S.** · December 17, 2003, 02:00 PM

Re: 1969 Corvette engine questions

Kelly:
(1) If the surface rust is not too bad, and you are trying to hold restoration costs down, I would probably just use an inexpensive cleaner-polish car wax like Turtle wax.

What happens when chrome rusts is that you have very minute penetrations of the chrome plating which spread to large rust-colored areas on the surface. The polish removes the rust that is on the surface, making the part look fairly attractive for awhile, but you will still have the rust penetrations and you will have to repeat the polishing occasionally. There is nothing you can do about that short of having the parts replated.

(2) Probably the stud was not installed for paint. An ordinary bolt may have been installed to secure the alternator support bracket and the water pump. Later, when the upper alternator adjusting brace and the AIR pump adjusting brace were installed at Saint Louis, the ordinary bolt would be removed and discarded, and the stud installed for the final assembly.

Does the TIM&JG say anything about the stud being painted engine orange? If nothing is said, then the stud should probably be black oxide, black phosphate, or possibly zinc (less likely). If the stud is NOT engine orange, it was NOT on the engine as it shipped from the engine plant.

(3) Maybe someone with an actual observation will have something to contribute here. I have seen no documentation of this taping myself. If I HAD to interpret what the TIM&JG meant, I would probably apply logic and see what purpose GM had for this taping. It may have been to prevent paint from obstructing future easy removal of the harmonic balancer, in which case, I would probably apply one short piece of 2" masking tape, raggedly torn, over the shaft end.

(4) I believe that grease pencil suffix marks have been observed both on top of the paint and under the paint. In some cases, the paint in that area was so thin that the marks could conceiveably be seen THROUGH the paint.

**Kelly Burnside** · December 17, 2003, 02:25 PM

Re: 1969 Corvette engine questions

Thanks for the quick response. I will try to clean up the sheidling with the turtle wax as stated.
Now the stud/bolt. The TIM does not say if it were painted or not. Mine is the original and from what I can find, no-one has one availble except for big blocks. So I am not sure if you can get one for a small block atthis time. I cleaned mine up but far form looking perfect. I will probably paint it unless I can locate another one.
As for the taping the front of the H.D., the pulleys cover front the area so I really do not see why or how they can judge that part. Makes sense to cover the front of the shaft but I was wondering why they would add this to the TIM if it can't be seen!
As for the grease pencil markings, were these on the headsas well? I have seen pictures in some books showing the markings on the heads.

**William C.** · December 17, 2003, 02:41 PM

Re: 1969 Corvette engine questions

The assembly manual will provide your answer as to the bolt for the alt brace. I don't have a '69 to reference but the convention is, if a bolt is removed and replaced, it is referenced on the AIM as "Existing Bolt". If a new bolt is used, it will be called out with a part number listing.

**John H.** · December 17, 2003, 02:52 PM

Re: 1969 Corvette engine questions

The engine's suffix code was written on both sides of the raw block (with the block upside-down, so the code is upside-down with the block in car position) in grease pencil so the subsequent assembly operations knew what internals were required for that particular engine. After painting the completed engine, those markings were covered (some better than others). I've seen several original heads with the suffix code grease-penciled on the front of the passenger head as well; I'd assume that was a visual clue for the guy who whacked the pad with the gang-stamp so he could grab the correct holder for the next engine by glancing up the line to see which holder he needed (he couldn't see the marks on the side of the block, as it was now right-side-up and had the heads on).

**Kelly Burnside** · December 17, 2003, 03:02 PM

Re: 1969 Corvette engine questions

The assembly manual shows a part number as 3889313. Must have been added after the fact. Is there any place that sells this stud for a small block? I see a lot of big block stud bolts for sale but is it the same bolt for a small block? Mine is pretty beat up but still usable. Would be nice to get a new on on there.

**Chuck S.** · December 17, 2003, 03:23 PM

Re: 1969 Corvette engine questions

Bill, you make a good point that I failed to mention.

On my 70 AIM (still not a 69, but close), when further assembly deals with any part that came with the engine, the re-used part will be marked with small square with one diagonal half shaded and the word "Engine" shown. See UPC 6 for why the lower alternator support bracket should be orange; that symbol will be shown.

Kelly, you can also contact your year class Team Leader (see names/addresses in the Restorer for questions like the taping of your balancer. Sometimes such information is included solely for purposes of accurate restoration; that's why they call it a "Technical Information Manual & Judging Guide".

You can also ask your Team Leader about the stud; personally, I am doubtful it should be orange. I know of no case where GM reused an engine fastener that was removed for further assembly. Painting may make it look better (not necessarily original), but it could cost you a point or two in judging if it's not supposed to be painted.

**Terry M.** · December 17, 2003, 03:40 PM

Re: 1969 Corvette engine questions

Kelly,
The tape on the front of the balancer is so that paint build-up (like a drip that hardens before it falls off) will not affect the alignment of the pulley that bolts to the front of the balancer. Of course most of us know that the engine plants didn't usually put that much paint on the engine, but the guys who wrote the paint specifications called for that tape. In general, any location that was later to receive a part where the alignment or seal was important (spark plugs and exhaust manifolds, if they were not installed before paint), or bolts were to be installed (engine mounts, and so on) was masked in some way.
You are correct that the lack of paint on the front face of the balancer can not be judged, but there are a lot of items in the TIM&JG that are not judged. When I was team leader I was continually asked to include items that could not possibly be judged. As Chuck correctly points out, that is why it is now called a Technical Information Manual & Judging Guide. Many years ago it was called a Judging Manual and it contained only the items we judged. Popular demand has changed the contents enormously.
I have found a product called Semichrome works wonders on the kind of chrome corrosion you have described. I get it in a tube from the local Harley shop, but it is also available on-line.

**Chuck S.** · December 17, 2003, 04:37 PM

Re: 1969 Corvette engine questions

Kelly, that same part number (3889313) is used in the same location for the 70 LT1 with AIR. It was definitely added new at the Saint Louis assembly plant, so I would expect it to be black oxide or black phosphate rather than engine orange. Maybe someone with a 69/70 with AIR can confirm the finish for you.

I haven't shopped for this one (no AIR on mine ), so I don't know if anyone is selling it. Frankly, I am doubtful because the offerings in repro fasteners is pretty scant.

You may be able to find one in the used parts world. If it's something you can wait on, you might find one in the junk piles at Carlisle; but, take the old one as a sample to insure getting the thread size and lengths right. If you are in a hurry, try Paragon's vintage parts department. Even if you find a used stud, you will probably have to re-finish it. There IS some good news...at least you don't have to worry about getting the headstamp right.

**Dick W.** · December 17, 2003, 05:46 PM

Re: 1969 Corvette engine questions

John, I have also seen several emgines with the grease pencil markings. As the paint ages and deteriorates, the marks become more visible.

As for the stud, I would have to believe that it is black phospate or oxide. I probably would just replate the one on the engine.

**Paul B.** · December 17, 2003, 08:08 PM

Re: 1969 Corvette engine questions

I have both a '68 327/350hp & a '74 L-48 that have this particular stud. Both of these cars are unrestored and in both cases this "stud" is natural & unpainted. It is also NOT black oxide, but some type of silver colored "zinc" as they both have no rust or deterioration to them unlike natural bare steel or iron that oxidizes and rusts like the exhaust manifolds.

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**Kelly Burnside** · December 18, 2003, 10:34 AM

Re: 1969 Corvette engine questions

Looks like I will have to keep the bolt as it is for now. I know paragon does not have it and checking other catalogs do not list it. I will eventually probably get it replated in time. Thanks for all of the help.

**Dick W.** · December 18, 2003, 07:36 PM

Re: 1969 Corvette engine questions

Oops! Close only counts in horse shoes and hand grenades. Sorry for the mis-info.

**Joe L.** · December 21, 2003, 06:51 PM

Re: 1969 Corvette engine questions

Kelly----

The stud was unpainted. Stud GM #3889313 was NEVER available in SERVICE from GM. Instead, a similar stud, GM #3883980, was the part available in SERVICE. Unfortunately, it was discontinued in 1971.

**Terry M.** · December 21, 2003, 07:09 PM

Re: 1969 Corvette engine questions

I looked on my 1970, and it appears to me the stud in question is plated a silver color, likely zinc.

1969 Corvette engine questions

1969 Corvette engine questions

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