chris928

I know this has been discussed and I was wondering if we could bring it up again.

I'm ready to do my valve covers and then I am going to do my manifold. I was thinking of powder coating and then read the threads on how it bubbled. Did anyone try a "texture" powder coat. It not as prone to bubbles showing I'm told??? Also, a shop I talked to said something about pre-heating the parts to get them to outgass prior to coating. Any thoughts.

Mike Schmidt

I had my valve covers and intake done at two different places, and there were problems with the bubbles both times. Those parts are magnesium or some sort of magnesium alloy. I don't know if they were pre-heated either time or not. I had a magnesium oil filler neck done recently. The guy who did that was pretty busy with a lot of powder coating, so the oven was pretty much on all day. He said that he left the oil filler in the oven most of the day to outgass before coating it, and it turned out perfect. Another local 928 owner just had his S4 intake and valve covers done, and those came out looking great, so apparently problems that occur are due to the way it's done.

Thom1

Chris,

See this post for my methods of outgasing and painting. It is holding up very well after 6 months:

<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=14&t=001977" target="_blank">http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=14&t=001977</a>
<img src="graemlins/burnout.gif" border="0" alt="[burnout]" />

Steve J.

I just got mine back. They were blasted with sugar sand, baked for three days and powder coated inside and out. I chose nickel silver. Several local 928 owners had theirs done (one in blue!) and have 3 yrs./50K mi.+ and still look great. Total cost was $100. I painted the letters with paint pens.

DougM

Steve,
Who did yours? Did the price include the blasting and coating?
Doug

Dave H.

yeah, those look sweet.

Steve J.

Doug-
I used Crosslink Powder Coating in Dallas mainly because they had experience with 928 engine parts and they came highly recommended by other local shark owners. I found quite a few powder coating businesses in the yellow pages and got quotes ranging from $100 to $450+ for the intake and cam covers. The price I paid included sand blasting and all prep. The crossbrace was done in black. My main concern (besides bubbling or flaking) was that particles of blast media, especially glass beads, could be trapped in the intake, later to be released and sucked through the engine. The thought of one glass bead being sucked through the engine makes me cringe.

WallyP

Worrying about blast media being left in crevices and passageways is a very realistic fear - I have a friend who wiped out a very expensive aircraft engine when some glass beads got left way down in a long oil passageway.

chris928

Thanks for the advice, sounds like bake-out is the key. I was also told that there is a sealing process which uses a bake out/ high pressure coating which gets infused into the pores of the magnesium or other porous cast material that yields excellent results when powder coated. I was told by the guy doing my parts that it would be way too expensive to leave my parts in the oven for 3 days.

Mike Schmidt

When I had my valve covers done, the guy coated the insides with teflon. It sheds oil better than I would have ever believed. After a year I pulled the valve covers and the teflon still looks absolutely new. I couldn't say what the reason was, but there was no problem with outgassing or bubbling on the inside of the valve covers when the teflon was put on.

chris928

Mike,

It sounds like you could cook off of your engine!

I'll check into the teflon. I've used it before on some industrial parts I designed.

Deepice

I thought you could not "bake" the covers due to magnesium? are the 944 covers diferent?

SL8GT

SteveJ,
Your stuff looks great! Which paint pens did you use?

Thanks.....

Steve J.

Thanks Rick-
I used Testors paint pens available at hobby supplies - used for painting models. I got the idea from Tony H.'s site. The tip is the perfect width and it was easy to do. The paint isn't as tough as I would like, though.

Mike Schmidt

[quote]Originally posted by deepice:
<strong>I thought you could not "bake" the covers due to magnesium? are the 944 covers diferent?</strong><hr></blockquote>

The covers be can powder coated and baked. You can't get them ceramic coated though. The temperature that the ceramic coating is cured at is higher than what's required for the powder coating. As far as I've been told, the 944 covers are the same.