Painting SS heat exchangers yes/no?

75Carrera · 75Carrera's Garage

I'm in the process of rebuilding a 3.2. The exhaust system is off so I'm cleaning it up to paint with some high heat stove paint (recommended by several people) that heats to a near ceramic hardness. I cleaned up my SS heat exchangers with a brass wire wheel and they look pretty damned good. My question is about rather or not to paint them. They're magnetic stainless. I'd keep them shinny but am concerned about future rust. Waddaya think?
Here's how they look before and after cleaning them up; I haven't started on the pipes themselves yet.

DW SD · 10-15-2008, 02:22 PM

don't paint. do the same treatment in another 27 years.

Doug

spence88mph · 10-15-2008, 02:42 PM

I'll be the prick here... So you are rebuilding the engine with some trick new parts, obviously performance minded and putting the stock 3.2 heat exchangers back on? At least get some 993 exchanges or maybe some SSIs, the 3.2 set up isn't optimal...

That aside your hard work has paid off, they do look great and if you're keeping them I agree with Doug.

gtc · gtc's Garage

Quote:

Originally Posted by DW SD

don't paint. do the same treatment in another 27 years.
Doug

+1. Painted stainless steel is tacky.

the · 10-15-2008, 03:06 PM

Are the actual exhaust pipes (as opposed to the heat exchanger sheet metal) also stainless?

canamfan · canamfan's Garage

Another plus on the polished work and "ney" on the paint (don't go thereon stainless). They look really good all cleaned up & polished!

75Carrera · 75Carrera's Garage

The more I look at these stainless heat exchangers the more I really like them. My muffler is an altered stock with two out and is stainless too. So are all the rest except for the test pipe and piece my O2 sensor is on. My wrench thinks all but the test pipe is SS with the exhaust pipes being a non-magnetic stainless. I'm painting those.

As far as the 993 set up or SSI, I agree, except I and my car live at 5300 ft and run twistie mountain byways a bunch so the upper mid-range tempo (4500-6000) I run at most of the time and in second and third 80% of the time. We all love the top end but I don't spend a lot of time there. With my motor's set up and thanks to Steve Wong it gives me all I can handle and sometimes a little more. I would sure like the more open 993 set up under different circumstances.

75Carrera · 75Carrera's Garage

BTW: The Ross pistons described below are gone! Replaced with Nikasil cylinders and 9.5 Mahle carrera pistons, reworked heads and valves, keeping the 964 cams. I will be posting later about the lame *********s who built this engine before I got it. Amazing what some people do or try to do...

fastfredracing · 10-15-2008, 04:02 PM

It had ross pistons??, I wonder if this is going to turn into antoher motor meister thread. I think that is what they used to push

911pcars · 10-15-2008, 04:30 PM

Jet Hot coating or equivalent coating should provide a similar appearance and keep the stainless from corroding, but I too vote for the early style heat exchangers (SSI) for a little better exhaust flow.

Sherwood

75Carrera · 75Carrera's Garage

Quote:

Originally Posted by fastfredracing

It had ross pistons??, I wonder if this is going to turn into antoher motor meister thread. I think that is what they used to push

You are very preceptive grasshopper...
Researching the numbers on the Ross pistons I found they were a MotorMeister sold product. I've learned that they have a routine to drill the cylinders (even nikasil) to a slightly oversized bore. Then they slap in forged pistons to swell into place with crappy rings. These motors run for about 8-10,000 miles (if you're lucky) and then they need a complete rebuilt with lots of replacement parts. I bought a complete motor from a dismantler in Georgia with the belief it was fresh from the heads down (not true at all). It looked great and leaked down at 5-6%. I did some extra work on it and installed it. Now 10,000 miles later I'm completely rebuilding it from the bearings up. "Another MotorMeister Thread" oh, yea, they must be stopped!

88-diamondblue · 10-15-2008, 05:12 PM

Here is some of the tacky SS

VHT clear baked on after sandblasting the heat exchangers. Pretty much look just the same after three years on the car. The connection at the exhaust ports has darkened but finish is holding up just fine. The clear darkens slightly during the baking process.

3.2 CAB · 10-15-2008, 05:55 PM

I think that they would look damn good if you had the "chrome" type of jet-hot coatings done inside and out. Being that they are coated both inside and outside, I wouldn't think that there would be any(or possibly just a fraction amount) of the heat dispersal headaches that would come with just painting the outside with high-temp paints. Just my thoughts, Tony.

tdatk · 10-15-2008, 07:22 PM

I bought a set of dirty SSI's and just sandblasted them. Look great, and an even texture to the finish. I'll do them again in ~10 years.

88-diamondblue · 10-15-2008, 07:57 PM

Here is what they looked like before they were baked.

The cost for this was $15.00 plus my time. Jet hot or not coating the exchangers are good choices. There was not money in the budget during the rebuild for Jet Hot or some of the other coatings I was looking at. The VHT coating is about as tough as I have used. I would have preferred if to be clear but areas that get really hot have bronzed in color. There has been no peeling of the paint and I have spent time a the track in fairly warm temps.