Engine detailing

[Devin W]

I was reading the fuel economy thread and one of the last post is of Truk's 8V92 engine. I looked at that with the realization that my engine only somewhat resembles that.

Although I've spent a lot to insure that the motor and all ancillaries in the bay are in top mechanical shape, the cosmetic hardly tells that story. I have quite a bit of surface corrosion, etc.

What's the best way to clean that stuff up and reapply paint. Is it as simple as wirebrushing stuff, cleaning the debris out, and applying an engine paint?

Just curious how people go about people are going about this stuff. I'm not particularly anal about this stuff, but the rest of the bus looks so nice it's a shame that the engine bay isn't more on par with the rest.

[Jon Wehrenberg]

Devin,

Making the engine bay pretty can be an all consuming project of serious proportions, or it can be a less detailed effort with a nice result.

I think David Brady (Travelite) has probably put all of us to shame with his work http://forum.prevostownersgroup.com/showthread.php?4667-2002-LXi-Wanderlodge-Engine-Room-Makeover&p=66389&highlight=#post66389 but an acceptable appearance can be created in a weekend of puttering around.

The first requirement is to clean the engine and the engine area. I use Simple Green and brush it into any grease or accumulated crud and then rinse it off with a hose at a low flow. I avoid blasting water at or into the DDEC and its connections. Keep water away from the heat sensors if your coach is equipped (on the ceiling) or you will set off alarms.

When everything is clean and free of grease and oil start masking off anything that isn't going to get the color you are painting. Then paint. I end up using spray or brush depending on where the paint is supposed to be applied. When that is applied, strip the masking tape. I do it while the paint is wet because if some paint got where it is not supposed to be I can clean it off easily with solvent.

I detail it a little by using an artists brush if necessary to paint fasteners or fittings. Remember this is just puttering around so I don't care if I spend an hour painting bolt heads black.

The engine bay on my coach is gray so I scrape the rust if any, sand it where necessary to smooth it out and paint that as well. Where it is not difficult I remove items such as the Racor fuel filter or batteries, or the belts.

7691

The big air intake tube has since been stripped and polished but the 6 year old engine bay paint job is showing its age so some weekend I will re-do it again. David won't have to worry about mine looking better than his, but it will be clean and fresh looking with my Tractor Supply Company paint.

[rfoster]

Jon: Don't forget the new Anal A-1 Kevin Erion! The bottom of his bus is cleaner than a used car dealers pocket book after 4 years of Obama.

[BrianE]

Devin,

Detailing your 8V92 can be a very rewarding project. As Jon says it can be done over a weekend but in my experience there were some repairs and upgrades I decided on once I got into it.

As to cleaning I personally use a hot pressure washer VERY CAREFULLY. As long as you avoid blasting the DEDEC box/wiring and the heat sensors on the forward roof of the engine compartment it shouldn't be a problem. Non aggressive use of compressed air to dry critical areas is also a good idea. After the engine is clean suggest you apply Ospho, http://www.ospho.com/data.htm or other rust converter before painting rusty areas, this will give a rust free hard surface which is an excellent prep for paint.

As to paint, suggest a high quality high temp engine paint. Alumi-Blast by Seymour, http://www.seymourpaint.com/alumi_blast.html is great stuff and I've used it for years on aircraft and other engine projects. Taking a little extra time for some simple masking is simple to do and will give you a much better job. If you want to paint the coolant tubes you can do them in place or remove them depending on how anal you want to be. If you remove them for paint DON'T have them powder coated. Powder coating is baked on and the temperatures involved will melt the solder in the tubes.

If you have an interest in adding heat blankets the Firwin Co. in Toronto http://www.firwin.com/ was the orginal Prevost supplier. They can still supply complete blanket sets which fit perfectly and are easy to install. Have fun!

[Jon Wehrenberg]

I will clarify something Brian said........If you powder coat any components they are typically cured at around 400 to 425 degrees for 12 to 20 minutes. The variations are due to the density of the parts with thin light parts requiring less cure time and lower heat because they come up to temperature faster than heavier parts.

But all powders can cure at much lower temperatures as long as the cure time is extended. If you do have soldered parts and you do not want to melt the solder all the coater has to do is adjust the cure cycle.

However, the soldered parts are copper and a real purist would strip the Prevost applied gray paint from that copper piping and buff and polish the copper.

[BrianE]

Thanks Jon. Another case of needing to be not only vigilant but informed as well. The powder coater I used obviously was neither. Furthermore you weren't around to inform either one of us.

By the way, the purest restores to stock with perfection. You obviously belong to the chop, channel and chrome it set. :D

[Jon Wehrenberg]

My pipes still are coated with Prevost gray.

Not picking on you Brian but coaters should know they have considerable flexibility in curing coated parts. We used to go through a few tons of powder per month on the coating lines in my businesses. Depending on the parts we had to vary oven temperatures and line speeds. We were provided with cure time charts or graphs. We might need 12 minutes at 400 degrees for a particular powder, or 300 degrees at 20 minutes for the same powder.

The powders used in coating are actually curing from the moment they are produced. Unlike two part products like some wet paints that use a catalyst and have a pot life of an hour for example, powders are already combined with the catalysts, but to accelerate the cure it is necessary to elevate the temperatures. We used to store our powders in an air conditioned room to lengthen their shelf life. If they weren't used in a short period of time they just cured into a block.

The temperature not only accelerates the cure, but as part of the powder coating process that elevated temperature caused the dry powder to liquify, flow, and then gel. After it has gelled continued exposure to heat cures it so it reaches its final characteristics such as hardness, abrasion resistance, etc.