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Painting Rotor Housings - WHY?

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Old 05-14-11, 10:01 PM
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it just makes sense.

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Painting Rotor Housings - WHY?

I'm new to the rx7 scene and am beginning to learn how to rebuild an rx7 13BT motor. I noticed that the vast majority of performance rebuilds on these engines have the intermediate and side housings painted and sometimes have the rotor housings painted as well (less often though).

My question is WHY? I understand that it looks cool but besides that rather moot point does it have any performance benefits? Besides preventing oxidation (rust) it must cause the engine to retain more heat from combustion (which is a bad thing right?)

Any thoughts on this issue are appreciated, if you have technical/logical reasons for or against painting please contribute.

Also, what type of paint is used?
Old 05-14-11, 10:11 PM
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Why?

WHY???!!


Why not?




I am fairly certain t is purely aesthetic.
Old 05-14-11, 10:16 PM
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it is just for aesthetics, most people don't like going through the trouble of building a motor for it to look raw and rather ugly. why not dress it up some? it isn't just a rotary thing, just about every builder does some sort of engine painting.

the aluminum and cast irons really won't ever look like new no matter how much you scrub them. close but alot of effort for marginal return. painting is just quicker and easier.

Last edited by RotaryEvolution; 05-14-11 at 10:18 PM.
Old 05-14-11, 11:07 PM
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it just makes sense.

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what kind of paint is used? Any favorite brands?
Old 05-14-11, 11:30 PM
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VHT engine enamel
Old 05-15-11, 10:15 AM
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Originally Posted by Karack
the aluminum and cast irons really won't ever look like new no matter how much you scrub them. close but alot of effort for marginal return.
Bicarbonate blasting. I may have just pissed somebody off.
Old 05-15-11, 10:44 AM
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Engine, Not Motor

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Irons and housings are painted during a build because, well, it looks nice. Even a cheesy paint job with minimal masking and cheap spray paint will look much better than the raw metal and last at least a few years.

Originally Posted by slevenfs
what kind of paint is used? Any favorite brands?
Most of the engine enamels available at auto parts stores work well if proper prep is followed. With any paint job, prep is the key. In the past I've used VHT caliper enamel, DupliColour MetalCast and POR-15 engine enamel. Media blast following a thorough cleaning (and followed by a cleaning) is the best prep.
Old 05-15-11, 11:12 AM
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Originally Posted by slevenfs
it must cause the engine to retain more heat from combustion
Negligible, if any at all. If that was a problem, none of the builders would paint them.
Old 05-15-11, 11:40 AM
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Which hot cup of coffee is hotter longer? The coffee in the unpainted mug or the coffee in the painted mug?


I drank them both. Don't care.
Old 05-15-11, 01:06 PM
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Originally Posted by texFCturboII
Bicarbonate blasting. I may have just pissed somebody off.
i generally don't blast anything because it's even more time consuming after doing the degreasing process but it would work for a DIYer for a clean raw aluminum look.

but i also dislike the raw aluminum because it retains dirt easier and is only worsened with any type of blasting process.
Old 05-15-11, 01:06 PM
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Originally Posted by Hazard15301
Negligible, if any at all. If that was a problem, none of the builders would paint them.
+1. mazda used to paint the irons, but they stopped when they started the nitrating.
Old 05-15-11, 01:12 PM
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Originally Posted by j9fd3s
+1. mazda used to paint the irons, but they stopped when they started the nitrating.
i know way back when they used a waxy sort of paint to coat the whole engine to protect the irons from rusting, perhaps that is what you mean?
Old 05-15-11, 01:18 PM
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Cause girls like pretty colors
Old 05-15-11, 03:18 PM
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is that solid chocolate?
Old 05-15-11, 03:19 PM
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Originally Posted by Noxi


Cause girls like pretty colors
^^WOW!! haha
Old 05-15-11, 03:55 PM
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Why ?

Pride ! Your hard work should look good as long as possible.

Beside the looks it prevents rust on the irons. Some people will tell you that it wont stick on there.
I have seen lots of nice painted rotarys here on the forum and they looked good even years after install.


Steven
Old 05-15-11, 04:07 PM
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The waiting game......

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Why not? Something to do until parts come in
Old 05-15-11, 04:59 PM
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Originally Posted by 2slow4stock
Why not? Something to do until parts come in
+1

While waiting for parts....


I've since decided that I don't like the intakes copper and the front cover black....I also tried doing the front cover copper, but didn't like that either. Now I'm just waiting to get parts back from powder coating. Intakes are gloss black. Front cover, cold side of turbo, infini strut bar ends are all going silver...oh TID is going silver also.

BUT it's taking forever for them to do the work. 10 business days has turned into 5 weeks or so. I may go get my parts and not worry about powder coating....I want my engine done!!!
Old 05-15-11, 05:17 PM
  #19  
I

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wanted to try somethign never done before... never seen those two colors before! haha

couple pix
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with the turbo.
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not done yet, but at least i got it bolted in finally!
still need to prolly paint the cas, and then the water pump housing...

dont really feel likg tearing the throttle body apart to paint it... i prolly wouldnt get it back together in 1 peice lol
Old 05-15-11, 08:14 PM
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Originally Posted by Noxi


Cause girls like pretty colors

that **** looks like a easter egg
Old 05-15-11, 08:24 PM
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Talking painted & clean!

"the aluminum and cast irons really won't ever look like new no matter how much you scrub them. close but alot of effort for marginal return. painting is just quicker and easier."[/QUOTE]

not alway true bud.
if that was true then tell me how my 88 s4 22 year d motor looks like NEW ALUMINUM.
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Old 05-15-11, 09:22 PM
  #22  
Let's get silly...

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I purposely dont, Because i clean a lot of the underside and engine bay with brake cleaner ..
Old 05-15-11, 09:27 PM
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version 2.0

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Originally Posted by Karack
i generally don't blast anything because it's even more time consuming after doing the degreasing process but it would work for a DIYer for a clean raw aluminum look.

but i also dislike the raw aluminum because it retains dirt easier and is only worsened with any type of blasting process.
Yes it does, but it looks good for a while... until its covered in oil and grease.
Old 05-15-11, 10:25 PM
  #24  
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Originally Posted by Karack
i know way back when they used a waxy sort of paint to coat the whole engine to protect the irons from rusting, perhaps that is what you mean?
nope all the pre rx7 engines have irons that are painted black, with paint. when they started the nitriding they could just let the irons be iron colored.
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