67 L79 intake

[John F.]

Please allow me to revisit the subject of the finish on the aluminum intake. A couple of months ago, when I decided to rebuild the cracked original block for my 67 L-79, I was curious about the proper finish for the intake. I found a well known restoration who had a technique to properly refinish the original aluminum intakes. I gave him mine a couple of months ago, but due to his other work, my motor is done and needs an intake. I can't wait any longer, so I got my unrestored intake back today. I've got to get the motor back in my car this weekend.

My car is a pretty correct "driver" but I try to follow NCRS guidlines on most of what I do to it. Can anyone advise the best method to restore my 33 year old intake. Beading is out because that's the wrong finish.

Thanks

[Scott Marzahl]

Re: 67 L79 intake

John, Your L-79 manifold is painted silver. I had sent mine to ASL because it needed some welding, they repaired and cleaned it and painted it silver. OEM brand paints makes a great silver paint called "Fresh Steel" that looks exactly like the finish ASL put on mine. Have it hot tanked to remove all the crud and paint it.

[Joe L.]

Re: 67 L79 intake

Scott-----

I agree that many GM aluminum manifolds were actually painted with silver paint. The intake on the 1968 Chevelle L-78 SS-396 that I purchased new many years ago(and,unfortunately, sold when I bought my 69 Corvette) was painted with aluminum paint. I don't know how the OEM paints "Fresh Steel" looks, though.

In any event, the primary reason for my response here is to advise that you NEVER, EVER want to put an aluminum manifold or any other aluminum part in a "hot tank". A "hot tank" usually contains a highly caustic solution which will dissolve aluminum VERY QUICKLY. Hot tanks are for cast iron or steel ONLY. The caustic solution has no effect on ferrous substrate metals.

[Scott Marzahl]

Re: 67 L79 intake

Good catch Joe! Sure wouldn't want anyones intake disappearing like that. Any tips for cleaning aluminum components?

[Keith]

Re: 67 L79 intake-What paint and how Applied?

I spent two weeks on my manifiold cleaning with Alumi-gel and lacqer thinner. It has a some what natural aluminum finish. That is what was told to me 5 months ago in a similar post. Now this post changes the story. What paint then should I use? (brand and color number). Again I have been told several sides to this story. It was told to me that only the edges where sprayed to cover overspray of orange and could cover the mounting bolts. I have also seen top flight cars with a slight orange overspray left on the manifold. I dont want to take a hit on originality. Can I get an official statement from the judges that clarifies the paint on the manifold and what it covers. Thanks Keith

[Scott Marzahl]

Re: 67 L79 intake-What paint and how Applied?

Keith, To simply quote from page 70 of the 1967 Judging manual it states, "The L79 350hp engine uses an aluminum intake painted silver." Yes, you see cars with slight orange overspray on the intake. I am sure there are many brands of silver aluminum paint that fit the bill. As I previously mentioned I like the finish of the OEM brand silver.

Scott

[Wayne M.]

Re: 67 L79 painted intakes

Scott --- Any idea WHEN the '67 aluminum intake was painted silver ? At the Winters foundry ? Would an in-the-box NOS example also be painted ? Was it entirely painted, on the top side ? If so, were the gasket surfaces masked off ? Does the '67 TM&JG "mention" the possibility of orange overspray at any location ?

[Scott Marzahl]

Re: 67 L79 painted intakes

Wayne, On the next page under attachment, it states, "Known original cars use black phosphate hexhead bolts without integral washers with "A", "NAT","UR" or "FP" headmarks. The bolts may be painted silver during the intake painting process."

Gaskets and Seals "Gaskets and seals are painted engine color on cast iron manifolds and silver with aluminum manifolds."

"The thermostat housing is cast iron, painted silver. The attaching bolts are black phosphate."

One would then assume that the intake was painted silver after it was installed on the long block and the thermostat housing painted prior to installation on the manifold, but it does not mention overspray on the intake. As mentioned earlier, engine color overspray is sometimes seen on show cars but there is no mention of it in the judging manual, therefore I did not overspray mine.

Scott

[Wayne M.]

Re: 67 L79 painted intakes

Scott --- Your assumption sounds plausible. This means that the manifold was sprayed silver at Flint, after the motor was painted orange. But as the thermostat housing was also installed at the engine plant, I would have thought that the bolts would be completely sprayed.

Rather than count sheep, or read Hemmings, to put me to sleep, I find that visualizing the worker spraying orange; then silver; then orange to cover the silver overspray; followed by silver over the orange overspray, etc ... works wonders.

[Scott Marzahl]

Sleep technique

Wayne, I like that sleep technique, maybe I'll try that out tonight. You have probably seen the old GM assembly photos. None of those painters are wearing masks or protective gear, as much as I like the smell of a fresh lacquer paint job I would imagine after a few days of painiting like that anything goes.

Scott

[Gene M.]

Re: 67 L79 painted intakes

Wayne, I think your assumption on the water housing and securing hardware being painted as assembled are correct. The completness of coverage at time of assembly varied. That's why the NCRS manual spells out the black plating on the securing bolts as it does on the intake manifold bolts also.

[Wayne Kever]

Re: 67 L79 painted intakes

How about this:

My L79 is apart right now. The engine builder said it looks like it has been beaded once already.

At this point, will it matter if we bead again before painting?

If so, what is the advice for this non-cherry intake?

- Wayne

[John F.]

Re: 67 L79 intake

Hey guys, thanks for the input and suggestions. I have to admit, it's as clear as mud! I spent the evening cleaning my intake with a sponge, diluted brasso, and a power sprayer. It looks much better but damned if I know yet what the best technique is. It will probably catch some silver paint after assembly tomorrow but I'm not going to paint the entire manifold because from what I can determine Scott's "sleep technique" is correct. Thanks, John

[Gene M.]

Re: 67 L79 painted intakes

Wayne, Are you concerned with removing the old paint build up? If so chemical striper will do less wear to an all ready abused part. I say this because the tall portion around the carb, GENERALLY has little to no silver paint in this area. Glass beading will deface the cast skin. On the other hand you could spray silver to the upper limit and cover just about the whole manifold in which case glass beading work would not be evident. In both cases GM did not cover this area of the motor as if paint was free. My impression silver paint was done to cover up all the sins in orange engine spraying to look "good enough" to potential customers.