So with the powder coat colors chosen for the CB160 engine is was time to start the coating process on the good engine components. The plan was to shoot the cylinders, head, and valve cover with matte black. The upper and lower engine case will go HD bead blast silver and the side covers will be colored with anodized aluminum.

I am still very new to the whole powder coating process and have learned quickly that one similarity between anodizing and powder coating is the extensive prepping process required to ensure good results. In the case of the engine components I want to ensure that everything is out gassed and then surface prepped properly.

Engine has been out gassed and glass bead blasted. Onto the masking process.

Everything is masked and plugged and ready for the preheat

The first step involved an extensive amount of good old fashioned cleaning using a solvent tank and pressure washer. Once I had as much grease, oil, and dirt off the components as possible I proceeded with the out gassing. I fired the powder coating oven up to 550 degrees Fahrenheit and baked all the engine components for 2 hours. It was certainly evident from the smoke and the oil that leeched out that the out gassing process was accomplishing its intended task. I made sure that I bolted the cylinder to the cylinder head before out gassing in order to prevent the cylinder sleeves, and head inserts, from coming apart.

Head and cylinders mounted onto an adapter plate I made so that I would be able to spray the fins vertically.

Set in the oven for a preheat session up to 160 degrees.

Once everything was out gassed I headed over to the glass bead blast cabinet. With all the important casting sections either taped off or plugged I proceeded with blasting everything clean. As with anodizing it is important to ensure that none of the blasted components have oil on, or in, them as the blasting tends to drive the oil and grease further into the pores resulting in a failed finishing process. This is why the out gassing is performed before the blasting.

Matte black powder fogged on. Careful inspection with a flashlight indicates everything got coated.

Completed and baked coating, fairly happy with the results.

With the blasting completed it was time to give everything a major bath and scrub it all down with hot soapy water. Once clean the time consuming process of taping off, and plugging, of crucial sections of casting could begin. Components with gasket surfaces got taped using high temp tape and all the bolt holes, and studs, were covered using silicone plugs.

Engine case after it has been out gassed and glass bead blasted.

Hot water and dishsoap was used for the clean up.

I wanted to lay the powder onto the finned engine components with the fins in a vertical position. If I sprayed the powder onto to them horizontally I feared that I would get too much powder build up in between the fins. I welded up an adapter that would allow me to suspend the head and the cylinders vertically and would also give me a way to rotate the assembly as I sprayed.

Masked and ready for preheating and coating.

The powder went on great, good coverage, no issues.

So with all the prep work done there was nothing left to do except lay on the powder and hope my rookie endeavor will experience a successful outcome. Over the course of the next few evenings I was able to get through all the engine components and complete the coatings. There were lots of lessons for me to learn and some flaws in the coating that defines my ability however overall I am very pleased. The finishes all flowed out nicely and the overall effect is great. The coverage is good and the color was what I expected.

Baked and completed HD Bead Blast Silver case.

So with all the engine components now coated I will be able to send the cylinders and the head out for machining. While waiting for their return I should be able to start reassembling the bottom end.

Sorry, no pictures of the side cover process however here is my good set of Aluminum Anodized powder coated covers.

Comments
  1. Matt McLeod says:

    Gord, awesome. As usual. What machining are you sending out? I’m trying to find ways to keep all my machining in my own shed, even if it means spending outrageous amounts of time and money getting tooling sorted out. Boring cylinders is my biggest problem but on Harley jugs I’ve seen YouTube vids of them mounted on an adaptor plate, chucked and bored in the lathe. What are you getting done outside?

    Cheers,
    Matt.

    • gordsgarage says:

      Hey Matt, thanks for the comments. You and I have the same obsession; we both need to keep everything in house even though it makes no financial sense. I just spent $400 on some tooling to be able to machine something that I could have bought for $70.

      I decided though to outsource the head and the cylinders. The cylinders need to get punched out 1 size over and the valves, and seats, require a proper grinding. The tooling for the valves I may have been able to pull off. I too have seen cylinders being machined on a lathe. In the case of the CB160 the sleeves are very easy to remove from the cylinder housing therefore mounting them on a lathe would be easy. This would still leave me with acquiring the tooling. In the end I decided against it. I know of a very reputable small engine machinist and opted to save some time, money, and potential failure, and have the work done. Yes there are feelings of guilt and failure on my part as I do what I can to keep all work performed in the confines of my garage walls however…we all have our weaknesses.

      Thanks!
      Gord

  2. Alfonso says:

    Hey Gord, awesome work like always. One question i have never powder coated before, but on those plugs for the holes one the powder coat dries, how hard are they to remove? Do you need to cut them loose before pulling them out? or do your remove them while the powder coat is still wet wet?

    • gordsgarage says:

      Hi Alfonso, I neglected to mention the details in the posting. After I fog on the powder I place the part into the oven for approx. 4 minutes. This is just enough time to set the powder up so that it won’t brush off if lightly handled. This is the point were I remove the part from the oven and strip off all the masking and plugs. It then gets put back into the oven for the full bake session. I am not sure if there are other ways of doing this however these are my own, self developed, methods.

      Thanks!
      Gord

  3. karl says:

    how did you deal with the gasket that is in the valve cover? Did you leave it in and just go ahead with the powder coat?

    • gordsgarage says:

      Hi Karl, all the gasket surfaces were taped off using high temperature tape. I carefully followed all the gasket “lines” to ensure I didn’t have any bare aluminum showing yet I had a good sealing surface.

      Thanks!
      Gord

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