Lousy aluminum casting quality

[Barry K.]

I recently picked up a '78 L82 that needs a lot of clean-up work. i'm working on the motor and engine bay first.

I was at my friends house almost 8 hours on Sunday using his glass beading cabinet on the parts I've removed from the engine bay and motor on my '78.
One of the many parts I was glass beading to clean up was the original L82 aluminum intake manifold. Now, i couldn't see details on this intake previously because if was so completely covered in dirt, grease, grime, and mice droppings (from having been sitting unsed so long - found 2 old mice nests during disassembly).

so, I get the intake into the glass bead cabinet and start shooting it. First thing I noticed was that it was painted silver over the aluminum underneath all the other grime and the old silver paint was coming off easily in sheets from the blasting. Second thing I noticed was that the intake has to be one of the worst quality aluminum castings I've ever seen..... PERIOD!

I glass beaded the intake from my '65 just a few months ago and under the dirt, etc the aluminum was beautiful, consistent appearance, and a well made original piece. This intake from the '78 was just plain BAD. some parts of the casting are nice and smooth where others are badly pitted. Other areas almost look like they were put together from small pieces of aluminum and just frickin' glued together! A couple of places on the intake have something on it that looks to be JB Weld or some other type of hard putty or epoxy that must have been put on to fix a particuarily bad spot. There is no way to accurately describe how bad the casting quality of this intake is, even the pictures I took of it make it look a LOT better than is really does.

If this car wasn't was a fully original under 9,500 mile car I'd just throw this intake in the trash because it was made with such poor quality and replace it but I guess I'll have to keep it.
I checked my NCRS TIM&JG on this and find that the '78 L82's did have the aluminum intakes painted a dull silver which explains why there was paint in it. It also explains to me WHY GM choose to paint aluminum manifolds with silver paint when they didn't used to.
Obviously, GM's quality control had gotten so poor in the late 70's that instead of trying to improve the quality of their castings they found it easier and cheaper to just cover up stuff with paint instead. Looks like I'll have to do the same thing. I'll respray this intake with AlumiBlast paint and hope it covers up and hides the serious flaws on it. If I left it bare as it is now I'd be too ashamed to ever open the hood on the car!
GM should be ashamed to have ever used something of such poor quality as this.

My friend that allowed me to use his glass beading cabinet is also not only an NCRS judge but also the chairman of his local NCRS chapter so he knows Vettes pretty well and has seen more than his share of various aluminum intake manifolds over the years to say the least, and when he saw this one all he could do was shake his head in amazement that it was so bad. He said it was BY FAR, the obsolute worst casting of any intake he has ever laid eyes on.

Take a look for yourselves and see what you think. Link to pictures is below.




intake manifold

[Kevin M.]

Re: Lousy aluminum casting quality

Can you even see the manifold with all the crap on a 78? I think the 5 foot rule must have come into play, open the hood and see if you can pick out these close up flaws I doubt it.

Kevin

[Gary S.]

Re: Lousy aluminum casting quality

Have you checked the archives for posts about glass beading and the resulting finish? I think that they are chock full of comments about glass beading affecting the final appearance of things like aluminum intakes.

That is a pretty rough casting.

Gary

[Barry K.]

Re: Lousy aluminum casting quality

Kevin
that is the only saving grace on this. On these later model C3's, between the dual snorkle air cleaner, and all the hoses everywhere you can barely see anything anyway.
i'll repaint it silver again, that will hide a good portion of the flaws and than most of the rest is hidden from view from all the other stuff on the motor.

If this was on a much earlier C3 or a C1/C2 like my '65 I would never put this thing back on my car.

[Barry K.]

Re: Lousy aluminum casting quality

Gary
Yes, I'm very aware that if you glass bead an intake some people can tell the difference in the surface appearance. You may even lose a few points in judging I suppose.
That is the least of my concerns. I never plan on taking this car thru judging so my only goal was to get it as cleaned up as possible and looking presentable. As you can see in the link I posted it was filthy to say the least and glass beading it was my best option and easiest method to get it clean.
Besides, even if I were to take the car thru judging, which I'm not, the intakes were painted silver at the factory and it will get painted silver again. I'd venture a guess that once the paint is put on any slight surface differences between a glass beaded intake or a clean untouched intake wouldn't be noticable anyway.

[Barry K.]

Re: Lousy aluminum casting quality

Gary
forgot to also mention in my last response to you.......... considering how bad and rough the original casting is anyway, I don't think my glass beading it is going to have much of a negative affect on it. I can't imagine anything making it look worst than the casting quality itself already does!

[Chuck G.]

Re: Lousy aluminum casting quality

Barry used my glass bead cabinet. That casting was as rough as a cob. I've never seen one so bad.

Saw something else I've never seen, and that was that casting flaws and DEEP pits in the intake were filled with a JB Weld/epoxy type filler to hide the pits and casting flaws. The whole intake was then painted silver.

This is off of a very low, 9500?? original mile car that had never been messed with. The intake had never been off the car.

This intake was FAR beyond worrying about the original skin or "patina". Chuck

[Michael W.]

Re: Lousy aluminum casting quality

Barry,

You weren't tempted to take it through the Bowtie route? (That was me that suggested it on the CAC)

[Joe L.]

Re: Lousy aluminum casting quality

Barry----

Many early GM aluminum manifolds from the C2 and earlier C3 era were painted with aluminum paint, too. It's use was not limited to these later C3 manifolds.

I don't know what the manufacturing source was for these 78-82 aluminum manifolds. I always thought that it was Winters Foundry. However, I don't see any Winter's casting mark on this manifold. I know, for sure, that Winter's still made aluminum engine parts for GM until, at least, 1992. However, GM may have used some other source for these particular manifolds. It's even possible that they were an early in-house attempt by GM's own aluminum foundries to produce aluminum manifolds. However, the manifold appears to be a sand casting and I don't think that either of GM's aluminum foundries of the period---Bedford, IN and Massena, NY, were set up for aluminum sand castings. It's possible, though.

The large "A" on one of the runners or the "cm" seen near the "GM" may be casting symbols for some other outside aluminum casting supplier to GM.

[Barry K.]

Re: Lousy aluminum casting quality

Chuck
thanks for backing me up on how bad this thing truely is.
as you know, if you look at the pics I put the link to, they don't begin to show just how bad it really is as seeing it in person

[Barry K.]

Re: Lousy aluminum casting quality

Mike

yes, actually, I did consider that, and as Chuck can attest to I even asked him about it to get more details regarding Bowtie judging.

the biggest issue for me was simply that Bowtie judging is only done at national events, not regional or chaper events. My understanding was that the next time a national event is relatively close to me is Boston in 2007 and I couldn't wait that long before getting this car fixed up, so that, unfortunately, eliminated Bowtie judging for me.

[Barry K.]

Re: Lousy aluminum casting quality

Joe

yep, i noticed there was no Winter's mark on there either so I assumed it wasn't made by them.
Whether it was GM who produced it or another outside vendor they should be ashamed of the quality of it no matter what!

as for earlier intakes and painting, it was my understanding, including from the TIM&JG that they weren't painted except for some overspray on the sides but I very well could be wrong in my understanding. At least that's my understanding on my '65.
I sure don't claim to be an expert by any means and i'm just trying to learn this stuff so I'd never presume to argue or debate you on the point. You are probably very correct.

[Patrick H.]

Re: Lousy aluminum casting quality

Mike,

I thought the same thing, but of the 6502 1978 Pace Cars made, I think 6498 would still qualify for Bowtie judging, so a low mileage 1978 isn't exactly "rare."

A non-Pace Car low mile 78 would be, however.
I also wondered what had to be done to make the car "run and drive" that required intake removal, but...

Patrick

[Terry M.]

Re: Lousy aluminum casting quality

"It also explains to me WHY GM choose to paint aluminum manifolds with silver paint when they didn't used to."

The 1970-1972 small block aluminum inlet manifolds were also painted silver. I have always believed (with absolutely no proof) that this was to cover engine orange overspray, but maybe there were more reasons. I have never heard a complaint about the quality of the 1970-1972 aluminum inlet castings, but I have no personal experience to base a quality assessment on other than having looked at a lot of assembled examples.

[John L.]

Re: Lousy aluminum casting quality

Barry, on my 79 L-82 intake it is the same. It was painted also, mine has the A cast into it also (early July build) mine has been cleaned, but it wasn't quite as rough as yours but almost. A interesting side note, the pipe plug on the left side wasn't painted , it was in a natural state leading me to think it was installed after the painting process at the foundry. Not sure what the pipe plug is for; maybe Joe will fill us in.