I purchased a set of the Hayward and Scott heat exchangers for my 1975 3.2 liter conversion several months ago. The conversion was performed 5 years ago and designed around the Billy Boat heat exchangers and muffler system. I was not happy with the B&B system because of the inadequate flow of hot air it delivered, and decided to give the H&S system a try. Attached is a picture of the H&S heat exchangers.

Unfortunately, and not surprisingly, we encountered significant fitment issues with the H&S heat exchangers. First of all, the exhaust primaries would not bolt up with the cylinder heads without enlarging the bolt holes on the exhaust flanges. Not a big issue, just enlarge the holes. The hot-air exit tube on the exchangers needs to be extended by several inches to bolt up to the heater-control valves. The collector end of the exhaust would not mate up with the B&B muffler, necessitating the purchase of a standard 911 banana-type muffler.

The most significant fitment issue, however, is that the system interferes with oil changes and exhaust-valve adjustments, requiring the exhaust to be removed in order to do an oil change or an engine service.

We reluctantly decided to retain the B&B system for the car, and new heater-control valves did significantly improve the hot-air flow. All-in-all, this has been a very expensive lesson.

The H&S exchangers come with 1-3/4" primaries and a 2" collector. The driver's-side comes with an O2-sensor bung installed. I am willing to sell them for considerably less than I paid for them ($2,900 including shipping). I will be posting an ad in the classified section.

I know a guy who may want those...will point him at this thread.


For more airflow, look into the marine world for inline bilge fans.
I recall they are 2 inch diameter, or maybe a bit larger.
Fit inline in the front trunk so you can move more air.
Work really well and run on 12 VDC.

Is there a reason aftermarket HE never seem to be designed like the factory units? I don't get it. I have yet to here of a good result from aftermarket HE's.

We need to get these made by the 914Rubber team!

I was expecting better quality than that.

Those welds and the way the box is attached suck.


They may have been expecting you to use the stock /4 valve extensions?

Fits the stock banana but not the B&B?
I'd expect that one.

Have to drop the exhaust for service??? No fuching way am I doing that everytime. Sounds like a poorly designed system to me.

It's a bummer that SSI, M&K, Dansk or some other manufacturer with the expertise to do this right has not done 914-6 stuff (maybe long ago but I mean now.) The market is just not there I guess.

I am so sorry to hear that! I had identified those as the most likely heat exchangers for my car. But as I am putting a 3.2 in my car I would face the exact same problems. Pulling the heat exchanger to change oil is not going to work for me. So it looks like I am back to my stock heat exchangers with heater valves that are in the best possible condition to make sure I get heat.

If i had stock HE's, I would run them. Maybe you loose 10-20 hp at wot, doesn't matter, with your engine, you are still spinning the tires at will. factory fit is still best. NOS flapper valves are available for less than $200/pair. I would ceramic coat the he's.

Thank you to the original poster for an honest review.

This kind of feedback will save several form wasting their money. It is a shame no one makes a good set of exchangers,. As noted, one would think the demand must not be there, BUT at least 2 companies thought there was enough demand to put out for the tooling to make these poor fitting sets, so how bad could it have been to make an authentic reproduction in S.S.

Bending SS tubing is the big issue, and that's why no one is jumping out there to make these.

Plenty of companies make pre bent sections though. A good welder could make a jig, fab them up, clean up the welds and done. I see the biggest issue being properly stamping the heater shells. This would require either a hammer form and a LOT of manual labor hand hammering them, or making a set of dies for a XXXX-ton press and stamping them. Either way, it wouldn't be cheap, so the question is .....is there enough demand

Even made from mild steel with a ceramic coating they will outlast a 914...factory ones were painted outside only.

A combined effort between a good tubing shop and someone like restoration design for stamping may make it a worthwhile thing to do....

I'm in, but I don't have the facilities/skill to do it. I've been thinking about this for quite some time. Yea, stainless is nice, but mild steel and then get it coated would make it much easier to produce. The sheet metal heat exchangers (and the thru holes for the exhaust nuts) would be a little bit of work, but once you got the pattern done.
Just look on the VIN registry-there are a lot of 'real' sixes still out there, plus a bunch of conversions. They can't all be in SoCal where you don't want/need heat so you can run headers.

By the way, if anyone knows how to adjust the exhaust valves on a six WITHOUT removing the heat exchangers, or dropping the engine/trans slightly, I'm all ears. I've never been able to figure out how to get the valve covers off, let alone adjust the valves with removing them.

Turbo valve covers cannot be removed with the engine mounted, unless you trim them.
Stockers, no problem.
I've adjusted the valves without removing the heat exchangers, not easy but do-able .
A lift makes it a lot easier switching from intake to exhaust.
Best to remove the wheels and lay under the car with your feet extended toward the side opposite the bank you're working on.
Rotating through the firing order will have you up and down many times. Or six times.
Remove the plugs to ease turning the crank, (use a medium length 19mm wrench at the pulley). The ignition rotor and the marks on the crank pulley will tell you where you are.
Later crank pulley ? AC pulley ? crank fire ? Remove the engine.
OR use a long stick (chopstick ?) to feel each piston come to the top of its stroke, verify clearance at both valves, adjust away !

There is also the backside of the cam method.

Or simply adjust all the exhausts while under the car, the do the intakes from the top after the exhausts are done.

However, as easy as it is to drop the engine, it almost makes sense to drop the engine, adjust the valves, clean everything up, and reinstall!

Maybe Chris could put a box around his headers for us.........

John

Mark, I thought that you were contemplating removable clam-shells to work with Marty's headers. We PMed about it a while back. Is that off the table?

What is the process for lowering the engine for valve adjustment if you use a pivoting mount like Patrick Motorsports?

Disconnect shifter and heaters and just drop the rear mounts? That seems a bit too easy.

John

Don't worry, your motor will always be easy to adjust..........on the workbench

Grandpa Rich
7 lbs 15 ounces...Elenore Louise Towle 11/14/14. 5:30 pm

Woooo Hooo!

Well congratulations

Now it is confirmed. You are an old fart.

John

Well, I find this thread most unsettling Been sitting on my H&S ss exchangers for a few years now hoping to install them after I fix the body on my six. Not looking forward to this job now

If MSDS or Tangerine can make headers that get solid reviews and fit great - why can't these other manufacturers do it for heat exchangers?

A faulty weld on a header won't kill you.

Since 1966 there has not been a Porsche heat exchanger with welds inside the heat collector. Never. Same thing with aircraft manifold heat.