GregBBRD

Everyone is always talking about how "cheap" they got their powder coating done. When I do this for a customer, it is really expensive....but the expensive part isn't the actual powder coating....it's the process that we use to put it all back together that sucks up the hours.

I get to see a lot of engines that are turned into absolute scrap metal, from this process. From cheaper older engines that people are trying to make look better to a high end Devek stroker engine. Poor preparation, poor workmanship, doesn't discriminate.

Here's why. These pictures are of a manifold that just came back, from powder coating. We blew it out, first, and them started "picking" in the corners to get all the debris out. This is a picture during that "scraping process"



And I poured what I could, onto a plate, to give you an idea of how much debris gets caught up above the venturis.

Remember, this is from one manifold that was blown out throughly!



Now, how much did you pay?

SeanR

Agree 110%. I usually spend quite an amount of time cleaning those out, it's amazing how much crap is stuck in off places.

928 at last

+1
I didn't "cheap out" and I still spent hours on the clean up before installation......

BC

The S4 intake is a tough cookie in certain ways for this issue as well. When you have the S4 intake, at least on the runners, you can really loosen everything with a wire wheel the internal size of the runner and with a drill clean them well.

Another rennlister also mentioned vinegar for treating the raw unpainted sandblasted castings. Works great for extra cleaning and particle release.

newbie9280

you have no idea... sand blasting an intake before powder coating will result in an engine failure when the embedded sand and powdercoating break loose and go through the engine.... the contaminating the oil, sanding the cylinder walls burning the rings, and the bearings.....the intake is a very soft magnesium alloy so sand blasting embeds the blasting material until it is heat cycled and bakes out... on the 1st drive....

newbie9280

hey is that **** carpet on your workbench?

Randy V

I get the engine internals powder coated just to be on the safe side.

928 at last

Actually we have a very good idea...that, I believe, is why Greg posted this in the first place.
There have been some tragic casualties....documented in the 'list.
With the new people coming in, there's a good reason to keep it "Front and Centre".
And, when you think you've got it surgically clean....do it again.....
It only takes a very (VERY) small amount of blasting medium to fry your engine.

BC

Better to be OCD and hyperactive to get these clean.

Ducman82

one reason i like the spider intakes!

clean clean clean! double and triple check

17prospective buyer

Aluminum oxide is the preferred medium for these Mg/Al alloys right? Coal slag and glass should be good too.

GregBBRD

Which brings up an interesting story.

One year, at Daytona, all of the RSR engines had cylinder heads which had casting "sand" trapped inside the castings. The manufacturer had "sealed" the castings inside with some sort of an epoxy, to help prevent oxidation. This "sealant" glued the sand in....until the heads got really hot and expanded.

Every single engine lost multiple water pumps (plastic impellers), during that race. The "factory technitions" got to the point where they could change a water pump and re-fill the cooling system in about 11 minutes.

Long night for those guys....

IcemanG17

safe to say somebody got fired for that one!!!!

SeanR

We've had two engines here that basically looked like they had sand paper running in the cylinder bores. One of them was Devek Stroker, the other one was just a standard S4 who thought they had washed out the intake "well enough". It's one of the reasons I prefer to paint them myself as opposed to sending them out to be powder coated. At least when I paint them I've had my hands on them the entire time and I know what has been done.

For those that are sent out to be coated, doing what Greg has shown is the only way to ensure that I won't be replacing an engine in a few days after the car has been delivered.

polecat702

Baking Soda is the way to go, it dissolves in water. Been using soda and glass beading my Harley motors for over 40 years. Also spray Rustoleum primer in the engine cases.

As a side note, been running my Harley parts thru the ole lady's dishwasher for as long as we've had one. She gets really pissed, but I've never had any debris from blasting in one of my engines, after a couple of wash cycles.