Factory Piston Coating?

Dirgle

Conjurer of Boost
Mar 30, 2005
1,632
0
36
41
Pauma Valley, CA
Did Toyota ever coat the factory 7M_GTE pistons? I just pulled the pistons out of a 1992 motor and the top of the pistons look like they have a gold coating. Even after cleaning them up there is a clear line. I'll get pics up in a minute. I don't remember my 1987 pistons looking like this.
 

Dirgle

Conjurer of Boost
Mar 30, 2005
1,632
0
36
41
Pauma Valley, CA
Interesting, wonder where they got these. To the best of my knowledge The motor has never been open. But I could be wrong.

WARNING! Links to large files.
DSC_0611.jpg

DSC_0615.jpg
 

IJ.

Grumpy Old Man
Mar 30, 2005
38,728
0
0
61
I come from a land down under
Hmmm dunno, never opened up a "factory" GTE, last one I built the owner had already pulled it down and replaced the stock slugs with Ross forged when it got to my place..

Be interesting to find out what it is!
 

Dirgle

Conjurer of Boost
Mar 30, 2005
1,632
0
36
41
Pauma Valley, CA
Yep, true OEM. The previous owner got the car in 2007 and he never did anything with the engine, before that I can't account for. However, when I removed and disassembled the motor and the little plastic details that people usually break and don't replace were all there. Ground point were all in the correct location, and they usually move when people usually pull the engine. While it's not definitive proof, it does point to a motor that hasn't been touched. Other than the pistons, all the parts are OEM and like they should be. I measured the head and it has never been touched. This coating is the only thing that has me confused.

DSC_0617.jpg
 

CyFi6

Aliens.
Oct 11, 2007
2,972
0
36
Phoenix
www.google.com
1331415511153.jpg

Grabbed an old set of OEM pistons I had and sure enough they look like yours.
 

mk3_7m

Member
Jul 21, 2007
536
0
16
melbourne
Actually i can vouch for these. When i pulled apart my last 7m with all oem internals, their pistons looked pretty much the same as yours. I never paid attention to the coating though as this engine was a part out.
 

supraguy@aol

Well-Known Member
Dec 30, 2005
4,232
37
48
Atlanta
Those aren't oem's...exactly.
NPR offers a oem replacement piston with an 'anodized' top. Supposed to protect slightly against hot spots or something.
I bought a set about 5 years ago for a rebuild, then sold them when I decided to go forged.
 

Dirgle

Conjurer of Boost
Mar 30, 2005
1,632
0
36
41
Pauma Valley, CA
Did you miss the picture with the Toyota name and part number cast into the side skirt? And the other side has aisin cast into it. They are definitely OEM. The coating though, what is the back story there.
 

Poodles

I play with fire
Jul 22, 2006
16,757
0
0
42
Fort Worth, TX
I can say that my pistons didn't look like that though in the two motors I've had apart (89 and I think 87). Really interesting though.
 

Backlash2032

New Member
Sep 20, 2010
1,823
2
0
Nebraska
Both my GTE pistons and my GE pistons did not have this coating. Or my NPRs. Not that that matters.

Sent from my HTC Rezound
 

Bmettie

Member
Apr 27, 2010
188
0
16
Florida
Or maybe someone got the stock pistons coated? Pointless now a days with all the aftermarket, but 20 ish years ago, i defiantly see it happening.