70 Distributor Hold Down

[Joe L.]

Re: 70 Distributor Hold Down

The "WHERE USED" column for the "BLACK ENG ENAM" includes: "OIL PAN, WATER PUMP ASM, AIR INJ BRKT, DISTR CLAMP, FRT COVER, CLUTCH FORK (EXPOSED PART), TORSIONAL DAMPER, LIFTING HOOK, EXH MANIF, CLUTCH HSG COVER" Since we know they didn’t paint most of those items black on Corvette engines, perhaps they didn’t paint the “DISTR CLAMP” black for our application either. (Does that confuse you more Joe M? I am reminded of the expression "Don't ask the question if you don't want the answer.") On the other hand, it is clear they made more extensive use of black enamel than our engines show -- or at least they did depending on what engines they were producing.

This page is titled "ENGINE ASSEMBLY INSTRUCTIONS - ENGINE PAINTING INSTRUCTIONS" MOD "MARK IV, V-8 ENGINE" DWG 3-10-70 REL 3-16.

BTW: I am not shouting. These pages are written in ALL capitals, and I thought to be faithful to the quotes I should do the same.

So before anyone gets too concerned about black oil pans and water pumps, remember this is an assembly manual for ALL the big block engines they built -- NOT just Corvette engines. So the list includes ALL the places they used black paint. I know some of their marine engines were not painted at all, but I have no idea how their industrial or agricultural engines were shipped.

No doubt they had some off-line painting operation going on. I suspect from time to time it was more extensive than just the distributor hold-down clamp (note: no hold-down bolt is mentioned).

Aluminum paint is listed (with two suppliers even) and the only "where used" is "eng front lifting brkt - pass." Now THAT would be a small application assUming they painted the front lifting bracket only on aluminum intake equipped engines.

By comparison there are six suppliers listed for "3742225 RED ENG ENAM" with a revision record dated 8-28-70 stating USAGE REVISED. So we are left to speculate if they added suppliers or removed some. We may want think of that the next time we are tempted to obsess over the shade of orange/red paint used.

There is also another whole page, single spaced that begins: “PAINT ENGINE ALL OVER EXCEPT THE FOLLOWING PLACES WHICH MUST BE FREE FROM PAINT:” Joe M – Do you feel lucky, or do you want to quite while you are ahead?

Terry-----


The oil pan, water pump, air injection bracket, front cover, torsional damper, and clutch housing cover WERE painted black prior to engine assembly but only for 1969 ZL-1 engines.

Other non-PRODUCTION engines (e.g. marine, industrial, etc.), if they were painted, at all, I feel pretty confident were painted as a complete assembly, either Chevrolet orange or black.

Much later in big block history (WAY after the time they ceased to be used in Corvettes) the engines were COMPONENT-PAINTED. All of this occurred well after the change was made to "corporate black" for all engines. In this system, the blocks, heads, and cast iron intake manifolds were painted subsequent to casting and prior to machining. Other painted components were supplied to the engine plant already painted (or powder-coated) from their manufacturing source.

Why was this change made? For environmental reasons, GM wanted the engine plants to be out of the painting business and all of the air quality problems that went with it. The painting was shifted to the parts suppliers in the case of everything but blocks, heads, and intake manifolds. The blocks, heads and intake manifolds for big blocks were cast at Defiance, OH, shipped to an outside vendor for painting, and then shipped to the Tonawanda engine plant for machining and assembly.

[Joseph M.]

Re: 70 Distributor Hold Down

Terry

Do I feel lucky? I think all NCRS members are lucky to have resources like you and Joe who take the time to help less informed members like myself further advance our knowledge base. I am a Psychologist and recognize my own obsessive compulsiveness, particularly when it comes to my babies originality. I think I'll go with black. Tx again.