I was reading through the 68-69 judging guide and noted that my 69 coupe should have been equipped with a aluminum radiatior because it has the L46 engine option, manual trans. and no A/C. It goes on to say that it should have a metal fan shroud. My car has a replacement copper radiator and a plastic/fiberglass fan shroud. I am the 4th owner of this car. The 2nd owner did the restoration. I interviewed him and he said that the plastic shroud was on the car when he bought it along with the original radiator. He couldn't recall if the original radiatior was copper or aluminum. The car was built on 12/09/69. Have any of you seen factory deviations in the use of metal vs. plastic shrouds? Also, should my car have a surge tank? It doesn't have one now and doesn't appear to have ever had one. There are no holes where it would have been mounted. There are little dimples where I would suspect the holes would have been drilled if ever a tank were to be mounted. I saw these same dimples on my other 69 base motor turbo 400 air coupe. It had a copper Rad and no surge tank. Any thoughts?
-
-
Re: 69 surge tank, Rad, & fan shroud
Ken-----
1969 with L-46 and without A/C could have been equipped with 2 different radiator systems. The first was the same as the base engine small block. This included the GM #3155316 aluminum radiator, GM #3016340 aluminum supply tank mounted on right fender well, and the GM #3938943 round, metal fan shroud. This application also used radiator support GM #3966591. With this support, the radiator is mounted into 2 cup-shaped brackets with rubber insulators on the bottom and retained by one, "center"-mounted bracket with rubber insulator on the top.
The other possible radiator system for the L-46 was a copper/brass radiator of GM #3018803 (26" core width). This application used NO supply tank; the tanks were integral with the radiator in the usual configuration and the filler cap was located on the top of the right side tank. The shroud used with this radiator was a plastic shroud of GM #3956109. The radiator support was GM #3966594. With this support the radiator is mounted into 2 "U" shaped brackets welded to the bottom of the support which use "U" shaped rubber insulators. At the top, the radiator is secured by 2 similar u-shaped brackets which are bolted to the support with rubber insulators within.
It sounds to me as if your car was originally fitted with the second of the above 2 possibilities. This same set-up was used for most 70s with L-46, most 70s with LT-1, and all 71-72 with LT-1 (except ZR-1).
By the way, the radiator hoses, upper and lower, used for the aluminum radiator set-up are completely different than those used with the copper/brass radiator. Also, the copper/brass radiator system is nearly identical to the system used with base engine and/or THM-400 or A/C. However, with THM-400, the radiator used was GM #3018802. This radiator had transmission cooler fittings in the right side tank but was otherwise identical to the 3018803.In Appreciation of John Hinckley -
Re:Joe
Joe
I noticed you said MOST 70's.There's a thread near the bottom titled "1970 expansion tank" Had an email discussion a week or so ago about only base small blocks having surge tanks in 1970.. Was told this comes from the judging manual, 3rd edition, 70-72. I disagreed, and I think your statement suggests other 70 small blocks may have a surge tank. I believe the 70 ZR-1 uses one and possibly L-46.My 70 L-46 has one.(owned it since 72). I think its original. Maybe someone can confirm the small block surge tank use in 70.Comment
-
Re:Joe
Dennis-----
I believe that at least some 1970 Corvettes with L-46 did use the 3155316 aluminum radiator with aluminum supply tank. In fact, you, apparently, have one. When cars with the 3155316 are converted to copper/brass radiator, almost always the conversion uses the copper/brass "replacement" for the 3155316 aluminum radiator. This radiator is NOT configured anything like the copper/brass radiator used for other 1970 L-46, LT-1, and the THM-400 and/or A/C equipped small blocks. With this radiator, the circular steel fan shroud and aluminum supply tank are usually retained.
By the same token, when one finds a 1970 Corvette with the 3155316 aluminum radiator (or the copper/brass "replacement" for it) it's VERY UNLIKELY that the car was originally equipped with 3018802 copper brass radiator and, subsequently, converted. The conversion would involve changing the radiator, radiator support, fan shroud, attaching hardware/brackets, and radiator hoses. I really can't imagine that many folks would EVER have gone to this effort. Especially since, in the "old days", the 3155316 aluminum radiator, by itself, cost about twice as much as the 3018802 or 3018803 radiator.
For 1969, I think that most L-46s were equipped with the 3155316 aluminum radiator with external supply tank and SOME cars were equipped with the 3018802 copper/brass radiator without external supply tank. For 1970, I think that most L-46 Corvettes were equipped with the 3018802 copper/brass radiator and SOME Corvettes were equipped with the 3155316 aluminum radiator.
For 1970, I also think that some LT-1s were equipped with the 3155316 aluminum radiator and external supply tank. However, the vast majority were equipped with the 3018802 copper brass radiator. All 1971-72 with LT-1 (except ZR-1) were equipped with the 3018802 copper/brass radiator, though. ALL 1970-72 Corvettes with ZR-1 were equipped with the GM #3007436 aluminum radiator (same as 3155316 aluminum except that core was 2" wider and upper radiator hose neck was curved instead of straight) and external supply tank.
All 1963-72 Corvette aluminum radiators require an external supply tank of some sort since NONE have integral tanks. Original copper brass radiators generally have integral tanks and do not require external tanks EXCEPT for 69-72 big block with the GM #3019190 radiator. This unit has integral tanks, but still is designed to be used with an external supply tank. It's the only original Corvette copper/brass radiator that ever was.In Appreciation of John HinckleyComment
-
Re:thanks Joe!!!!!
Thanks Joe, once again you have supplied the straight scoop. I owe ya.Comment
-
Re: 69 surge tank, Rad, & fan shroud
Ken,
My "late" production '69 was built 14 days before yours on 11/27/69. It is a 350/350, L-46, 4-speed, no air conditioning. I have owned the car since 1/75 and believe none of the cooling components were changed before my ownership, including the water pump. The radiator setup in my car is copper/brass and is configured with all the parts described in Joe Lucia's description of the copper radiator setup for 1969.
Hope this is of some help.Comment
-
LT1 Radiators
This is new for me, I didn't know or remember. So, those few LT1s with the aluminum radiator use the typical metal circular fan shroud? It's an interesting detail to sort out. Usually we see the other configuration, actually I only have access through photos, living so far...
Roberto, NCRS #30019, RMCComment
-
Re: LT1 Radiators
Roberto-----
Yes, I've seen only a few and they were all 70 models. For the reasons that I described earlier, I'm sure that they weren't radiator conversions. However, it's always possible that they were original small block/manual trans cars that were converted to LT-1 configuration. The cars appeared to be originals, but, of course, I didn't get into a "documentation focus". Plus, like I say, I've never seen a 71 or 72 LT-1 with the 3155316 radiator. I would think that if base engine cars were going to "grow up and become LT-1s" without the radiator conversion, it would happen to 71 and 72 models, too. I've never seen one of those, though. Might just be a coincidence, though.
Also, keep in mind that the 3155316 aluminum radiator had a VERY high cooling capacity. I'm sure that it was equal to or greater than the copper/brass 3018803. I really don't understand why the 3155316 were not used on ALL 70-72 L-46 and LT-1. Also, remember that the 70-72 ZR-1 and ZR-2 used the GM #3007436 aluminum radiator. This "heavy duty" radiator was virtually the same as the 3155316 except that its core was 2" wider. That would only provide about a 10% increase in capacity over the 3155316.
Personally, if given the choice of the 3018803 copper/brass or the 3155316 aluminum radiator, I'd go with the latter without a doubt. Absolutely. Positively.In Appreciation of John HinckleyComment
-
Re: LT1 Radiators
Thanks, yes I always thought that the radiator options were a little complicated. I know the different reasons for using so many different radiators but it would have been more easy to use a similar radiator for the less optioned small block cars. Perhaps those alum. equipped L46 and LT1's are those without cooling related options...
Roberto, NCRS #30019, RMCComment
Comment