1969 350 Hp Valve Cover Restoration (Before & After)

[Kevin S.]

Did my due diligence and seached past threads here for restoring aluminum valve covers. Consensus being that the best way to do the valve covers was soda blasting.

I stripped the decals and grommets off the LH/RH finned valve covers. One of the good reasons to do restorations is to learn and discover information about your car. I learned in the process that the LH black rubber grommet was wrong, it had a "Taiwan" embossed stamp on the top. Ordered the correct grommet from Zip. There was a GM PN stamp on the underside of the RH black rubber grommet so I know that it is OEM. There were identical GM PN stamps on the underside of LH and RH valve covers, which are "P-3932418-RH C-2 CBC" and I believe the 350 Hp aluminum finned valve covers are OEM also, along with the 90 degree breather tube on the rear RH cover for the air cleaner. I orderd a new metal crossed-flag decal for the RH front cover and also ordered the "HX" valve cover engine code decal for the valve covers from Zip Corvette. I checked on water-soluble water-transfer "HX" engine code decals, info I got from my search efforts here on this site, but Zip did not carry those so I used that they did have.

My restoration steps:
1. I stripped all of the old decals, grommets, and RH breather tube off the valve covers
2. Used dawn dishwashing liquid to clean and degrease the valve covers and soft bristle brush to get crevices clean
3. My first attempt was to blast (twice, inside and out) with soda media from Harbour Freight, using a gravity feed gun
4. Washed and clean valve covers with soft brush and dawn dishwashing liquid, then blow dry with compressed air
- I just did not think the valve covers looked clean after soda blasting
5. Following day, I used glass bead media and did the covers again (twice, outside only). Insides were clean enough
- I have a small 6 gallon pot compressor, set at 120 psi, with a H2O separator and disposable filter canister on the hose
6. My results were better in my opinion, covers looks cleaner, I am happy with the results and that is all that matters to me
7. Washed and cleaned valve covers with soft brush and dawn dishwashing liquid, then blow dry with compressed air
8. I wiped the outside of the covers and then fins with acetone and let sit 30-45 minutes, wiped with clean towel
9. I decided to coat the outside of the valve covers with VHT high-temp satin clear to protect the surface, keep them lookinig nice
10. I used 200 mph metal polish and a rag to polish the chrome oil cap, turned out nice.
11. Put the grommets back in, put the oil cap back on, put the breather tube back in, attached the "HX" decal, put the crossed flag decal on the front of the RH cover. I old decal was not OEM

12. Valve cover "M" headmark bolts were blasted with 70 grit aluminum oxide and coated with zinc phosphate parkerize

Attached are Before pics, one pic of soda blast result, and After pics of the valve covers. You all have been a tremendous help to me during my restoration journey. I hope this information and details can help others.


Kevin
(KS69Coupe)

[Jeffrey S.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

Kevin,
What Parkerizing solution did you use? The one I had been using (Shooters Solution) is long gone so I am looking for a new source. Just curious what you like.
Jeff

[James G.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

IF the inside of the covers did not have the molded in drippers then they are 100% correct for 1969.
In 1970 they went to a cover with a cast in dripper over the top of the rocker arms to oil the rocker pivot ball.

[Leonard M.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

Nice job Kevin. As you know, your after picture shows that "grainy" look which is the character of the metal itself, not dirt or grime. That is the way it came from the factory. For those who want the the perfect look, it would have to come out of a spray can.
On a previous car, I used the Harbor Frieght soda blaster to do the valve covers, intake and a couple other parts. I was very pleased with the results. I only used it twice. The down side is the mess from airating a fine powder. I used it on the lawn with the wind away from the house. The results was a large area of grass damaged by the high PH of the media. The second time I used a large tarp and there was no third.

[Kevin S.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

Hi Jeff,
I have been using either manganese phosphate parkerize (black) or zinc phosphate parkerize (gray) from Palmetto Enterprise (owned by Stokes Group) out of South Carolina. Comes in a variety of sizes. I typically order the 32 oz. size.

https://www.palmettoenterprisesparkerizing.com/

[Kevin S.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

Hi James,
Here are a couple of pics of the inside LH and RH covers. What do you think?

[Kevin S.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

Hi Leonard,
I'm laughing while I was reading your reply. This was my first soda blasting experience using my hand-held gun from Harbour Freight. I have a little home-made blasting area on a concrete pad behind my Man Cave. I was very surprised by how fast my small capacity gun ran empty, in just a few seconds it seemed. And, the soda powder and dust cloud was everywhere despite my efforts to keep the powder contained within my home-made blasting area. I looked like a powdered donut when I was done.

[Leif A.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

Kevin,
World of difference in the "before and after" pictures. Vapor honing does an amazing job on cleaning old castings i.e. aluminum, cast iron, etc.

https://www.corvetteforum.com/forums...or-honing.html

[Patrick H.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

Hi Jeff,
I have been using either manganese phosphate parkerize (black) or zinc phosphate parkerize (gray) from Palmetto Enterprise (owned by Stokes Group) out of South Carolina. Comes in a variety of sizes. I typically order the 32 oz. size.

https://www.palmettoenterprisesparkerizing.com/

That’s the same source I mentioned to you as well, Jeff.
I was using Palmetto prior to Shooter’s Solutions, then went back when SS disappeared.

[Jeffrey S.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

Patrick,
Yes, I have that in a bookmark but I am always looking for additional sources. I haven't had the need yet to purchase it but will probably very soon. Thanks for keeping in touch. Hope to see you at a chapter event soon.
Jeff

[Tom R.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

Well this has been an interesting discussion to follow given my "experimental" efforts with parkerizing. BTW, Palmetto E is four hours from me and probably 20-30 minutes from Greenville. Unfortunately, don't save buy until the next regional...it may be a while in coming. But good to know.

I followed the YouTube video referenced at Palmetto. My limitation was the heat source. I used a crock pot that was woefully inadequate. I heated the heater on the stove then dragged it over to the garage where I had the crock set up. Keeping the temperature in range was challenge and I concluded my results were marginal.

What I like about that video was the "robust" heat source. I've seen those used for outdoor festival cooking, oyster roasts, chicken bog, etc. So I'm curious what others have used that have been effective as a heat source.

[Patrick H.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

Tom,

I use an old Coleman stove, and my pots & pans come from thrift stores.
These stoves are available cheap at garage sales, FB marketplace, etc.
Also, a cheap IR temp gun to monitor the temperature of the solution.

Use real Coleman or camp stove fuel, not denatured alcohol as your fuel.

PH

[Jeffrey S.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

I store my plating solutions in 1 1/2 gallon plastic pails and use a small electric hot water heater heating element. Took some fabrication on a bracket, etc. but I can heat to predetermined temperature when coupled to a hot water heater thermostat. I can regulate the temp anywhere I want and it just plugs into any 120 volt socket.
Jeff

[Kevin S.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

Tom,
Adding to Patrick's reply. I am also using an old 2-burner Coleman camping stove with the green 16 oz. Coleman multi-purpose LP fuel bottles that screw into the hard fuel line. Works great to maintain the temp you need by adjusting the gas volume up / down or just simply turning off one of the burners when you reach the desired temp.

I bought a set of 4 quart pots with internal / removable baskets with vent-hole clear lids from Walmart and two temperature probes. They work perfect. The temp probe fits through the vent hole in the lid. Lids are clear so you can see the parts. Internal basket is removable so you take the parts out all at once when they are parkerized. I used both burners on my camp stove. One pot with distilled water to clean the parts. One burner and pot with my parkerizing solution. The lids on the pots maintain the temp I need. And, I maintain the temp range by turning up or down the gas flow or just shutting off the burner. I use a long fire-starter to reignite the camp stove burner(s) when I need more heat.

Hope this is helpful.

Kevin

[Kevin S.]

Re: 1969 350 Hp Valve Cover Restoration (Before & After)

Hi Jeff,

I like the idea of using a 110V plug-in heater. I do my parkerizing outdoors but I have extension cords. My little Coleman camp stove / Coleman fuel bottles process works pretty well too. I'm always on the lookout for tips that make life easier.

Kevin