fdbabb

Hi All,

Went to straighten the fins out on my oil coolers today. Left one is done, but the rubber at the top of the duct is completely shot. Felt up the right duct (she seemed to enjoy it ....
- sorry ;-) ) .. and the rubber on the right is shot too.

I think this just allows the air to shoot up and over the cooler, completely bypassing it. Especially when the oil cooler fins are bent over closing off air passages anyway. So beware.

I'm getting some aluminum tomorrow and using the old rubber piece as a template , I'm gonna fab the AL and rivet it in place. Already drilled out the rivets out of the duct.

1st Q
Anybody know why Mazda would put a chunk of rubber ther and not just make the duct a onepiece in the first place??

2nd Q
Is it a one piece on later models?

The 3rd Q is :

I have a down pipe and am missing the shield that goes between the Primary Cat/Downpipe and the turbos.
When I shut the car down all that heat is rising and baking the crap outta the intake side of everything and the engine bay in general.
Anybody have a design/temoplate/plan whatever for a heat shield?
Is 1 sheet of aluminum enuf? How thick,etc????

4th Q
Has anybody thermal coated their downpipe?

No offense to anybody, but those with experience in this, your answers are most valued and appreciated.

I've even contemplated opening up the right side cowl opening under the right wiper to vent the engine bay or to serve as an INTAKE for a small (6") fan, blowing downward.

5th Q Anybody done that?

Thanks,
Jeff
2 month owner of BB FD R1

EpitrochoidMan

Thermal coating on the whole exhaust system definitly helps.

A single fan blowing DOWNWARD???!! How about a whole bunch of big fans blowing upward.

fdbabb

Cuz the idea is to keep all the heat from the DP and Exhaust manifold from baking the Y Pipe, the solenoids, ABS, Intake, etc.

I'd rather have a fan blow the hot air downward and have it exit underneath the car.

How much cooler can I expect the engine bay to be with ceramic coating?


J

NewbernD

iTrader: (1)

When I rebuilt my coolers I glassed over that gap. I also installed a 1/4" mesh in the opening to keep the fins from getting beat up too.

Pic here

dubulup

Cool pics Dave.

alberto_mg

Yeah, I'm trying to make some oil cooler ducts for my car too. I have the 15th Anniversay nose and I'm not sure what material to use to make the ducting. I have a thread going here if anyone can comment https://www.rx7club.com/forum/showth...24#post2139324

How are you going to handle the transition from the small opening in the nose to the larger sized oil cooler with AL?

fdbabb

Disclaimer: I take no responsibility for any of your actions. This is what I did. If you screw up or die, that's your problem.

Accompanying photos are at: http://photos.yahoo.com/fdbabb

STRAIGHTENING THE FINS OF THE OIL COOLER:

This past week I straightened out the fins on the oil coolers of my 93 Black RX7 (R1, woohoo!). I used a steel pick (from Harbor Freight, 4 different types), and inserted the tip into the bottom of the "V" that the fins form, and pulled downward and to the left or right a few millimeters or so, until aligned forward. I then would put the pick in the top of the inverted "^" that the fins formed and did the same operation again.

You go along a whole row and do this, alternately going to the top and bottom of each fin. Then I went back with 2 long flat blade screwdrivers and inserted one on either side of a fin and straightened out the rest of the fin. Now the top and bottom were aligned and the fins were straight.

This took about 15 minutes per row. Only the 4 bottom rows were damaged on both coolers. Then I used compressed air and blew out all the rocks and bug particles FROM THE BACK.

Well, that's all done, but I realized that the rubber of the cooler ducting was just lying there, I thought when I had felt it before that it was some trim piece or cushioning - hey I've only had the car for 2 months. Later as I removed the ducting , I realized I'd have to be careful when re-installing the ducting or I'd mash the fins. Which leads me to ......




REPAIRING THE OIL COOLER DUCTING:

Now I have a question. Why didn't Mazda come to me 10 years ago and ask me if I thought they should just mold the entire duct out of one piece of plastic? The answer would have been a resounding "Yes", I would've charged them consultant fees equal to that of a new 93 RX7, and nobody would have had to scratch their head wondering what the best way to repair this was, or risk slicing their hand open on sharp aluminum flashing. I mean, they had to pay someone to rivet this rubber thing to the plastic. Extra steps and materials are a no-no in manufacturing.

The following is very easy to accomplish when the car is driven up on a set of ramps.

I bought some aluminum flashing at the Home De... I mean the local hot rod shop, of course. I pulled the lip off the bottom of the bumper.

I undid the plastic fasteners that held the bottom plastic duct work to the bottom tray and the front of the fender wells.

I unplugged and removed the turn signal/running light fixture.

I finally had a good reason to use the "headlights up, but not on" switch. Use it.

I removed the fasteners holding the ductwork in place. I pulled the top of the duct forward and got it below the metal tabs it's fastened to. Pulling the bumper's ducting as far forward as I could, the duct almost drops out.

Use a 5/32 drill bit and drill out the rivets (three?) left holding the rubber piece on.

I used 2 pieces of flashing about 14 inches long by 10 wide. I stacked them and drilled 2 holes in opposite corners and riveted them together.

I laid the rubber piece on top and used it as a template. The 2 rubber pieces are mirrors of each other, you'll be flipping one over to use on the other duct. I had to remove the other duct to find this out for myself before I started cutting the aluminum.

Using a permanent marker draw around the rubber piece, adding an 1/8 of an inch to the edge/perimeter, except in the "cut-out area" where the aluminum will tuck under the two "overhangs". When you see them you'll know what I'm talking about. Use a straight edge to help you make the additional 1/8 inch perimeter nice and neat.

This extra 1/8 inch is needed, and its lack of prsence on the rubber piece is one of the reasons it's not worth repairing the rubber.

Mark the holes, too. I added 4 more along the bottom and two at the top and two on each side. I don't want the aluminum to become like a reed in a sax or clarinet and produce strange sounds (and only at speed, never when standing still, that'd be a bitch of an intermittent to track down, eh?)

In the two corners of the inside cutout drill a 5/32 hole. You dont want a sharp inside corner because over time the aluminum will use that corner to start and propagate a crack. See 4th & 5th photos.

Drill the holes first, _then_ use high quailty aviation snips and cut out the 2 pieces at once.

I use a 5/32 rivet and a small fender washer whereever the original riveter had opened up the holes too much.

With a couple of rivets in place, use the additional holes in the aluminum to drill corresponding holes in the duct. I used smaller washers on the holes I added, when I finally riveted them.

I cut the edge off of one side of the fender washer so it doesn't touch the cooler. You can see it in the photos.

Re-install the ducts, lower duct trays, and lip.



LEMME KNOW wuchu think!
J

NewbernD

iTrader: (1)

That's the same technique I used.. the 2 screwdriver method. It worked pretty well but my damage was a good bit worse than yours from the sound of it. The jack-*** body-shop guy sprayed paint over both of them when they repainted the front of my car so I had to try to get paint off of them first, without beating them up even further. Sometimes it was just easier to pull the top layer of fins off. So tedious.

ptrhahn

iTrader: (9)

Guys,
FWIW, I just installed the CWR dual coolers w/ carbon fiber (tight fitting) ducts, to replace my single, 90k old stocker.

HUGE difference, the coolers themselves are larger, denser, and obviously more efficient, and are getting better flow due to the ducting.

My water temps (from PFC) have dropped (average) about 3C (its not uncommon to see temps in the high 70's on the highway), and they are MUCH more stable, and barely fluctuate even in traffic.... by the time you go through all the trouble of repairing the stockers, it might be worth considering this upgrade.

NewbernD

iTrader: (1)

Believe me, I thought about it. More and more as I was cleaning the paint off of them. Also thought about hanging on a couple of setrabs and plumbing some lines but in the end realized that the stock coolers were really adequate for what I needed and I really didn't want to spend a grand on replacement parts that I wouldn't fully appreciate.

Now if I had to do it again it might be a different story.

fdbabb

Hindsight I know but you're the 2nd person thats told me they had some fool spray paint already folded over cooler fins.

Did anybody try brushing on some paint thinner? Think it'd work?

Jeff

NewbernD

iTrader: (1)

I used several cans of paint stripper, (worked to the easy stuff off) soaked them in parts cleaner and brushed with a horsehair brush. I also put them into a parts shaker (parts cleaner can with an agitator that shakes back and forth) for about 6 hours. That, a lot of patience, and some compresssed air and I finally got them mostly clean.

I finished them off by running pipe cleaners through the fins. The bitch was that you had to clean enough paint off to be able to straighten them, to be able to clean more of the paint off. I definitely spend more of my time that it would have cost me to re-engineer. Should have gone after the body shop.