KOYO Aluminum Radiator Install Notes:
Still under construction...pics coming as soon as I get them developed and scanned (digi cam died...bah).
Wow...the KOYO all aluminum radiator for the JZA-70 chassis is perhaps the nicest and biggest direct fit radiator I have ever seen for a Supra. A fair bit larger in thickness than the Fluidyne (53 mm versus 38 mm), this is about as large as you can go and still use the factory fan/shroud setup. That said, this is not exactly a perfect direct fit radiator for the MA-70, and what follows is some notes I have taken to help you install yours.
Size:
Big...actually, it is dimensionally almost the same as the factory radiator. The Koyo is 8 mm taller than the old Toyota one, and the same width, allowing fairly easy fitment. After all, the JZA-70 was the same overall chassis. Thickness however is a new world. The factory one is rated at being 31 mm (1 1/4"), and this monster comes in at 53 mm (2 3/16"). Almost double the core size.
Finish:
The finish is second to none. The aluminum tanks and spouts are polished to a mirror finish and the packaging keeps the chance of damage to the function and fashion to a minimum. Not a single fin was out of perfect place when it arrived, the welds are all very nice, and there were almost no imperfections in the mirror polished tanks considering how far this radiator has traveled. You might want to go over this with a polish to remove any packaging touches (hand prints, slight mist of oils, etc.) but that is about all it needs. Some minor blemishes in the edges can be taken out with polishing compound, but I was not willing to risk screwing it up. The radiator comes with a plastic butterfly drain valve, but does not use the little drain hose like the Toyota one did. Would have made for a nice touch if they did, but it is pretty unnecessary.
Fit:
Here comes the catch...this radiator is made for the JZA-70, not the MA-70, and while the chassis are the same, the radiators are slightly different for the 2 engines. First, and foremost, there is a hole in the lower tank about where the A/C or auxiliary fan bolts to the MA-70 radiator. This pipe fitting is for a temperature switch that the 1JZ-GTE engine uses, and we do not, or we have it on the thermostat housing and they do not. Either way, this needs plugging. I found that the fitting is a standardized 16mm x1.5 thread pitch pipe fitting, and so the plugs exist. Trick is finding a hose supplier that can get them. If you need some extra help on this one, email me at the address on the home page for more information on suppliers. There is one in Canada I have found, and one in the US. Unfortunately, you cannot get aluminum Russell or Earl's style fittings for this one, and so plated steel or brass are the only options. I got a cadmium plated steel one, using an Allen key head that incorporated a rubber washer in it. (PICS) Once the hole is plugged, you move onto the next couple of fitment issues.
Second on the fit list, the shroud and A/C or auxiliary fan are is not a perfect fit. The following pictures give you an idea of how much is going to be needed to get this all to work. (PIC) Unlike the MA-70, there is no 'L' shaped groove for the bottom of the fan shroud to sit in. To cap it off, the little tabs on the shroud don't line up with any bosses in the radiator, and of course the auxiliary fan housing hits the new plug and has no boss to bolt into. There are a pair of bolt locations on the lower tank of the radiator though, so on to how to make this work...
Fabrication:
Now my friends, you need to become metal fabricators to make brackets to get this to work. It will take nearly a day without the right tools to reproduce mine, but a machinist should be able to get it done in very little time at all. In both cases, the brackets are made of 2" x 1/8" aluminum bar, and less than a foot is really needed. For the passenger side bracket (LHD cars), the bracket is based on 1/8", but needed a tab of 1/16" material to be able to bend easily to fit under the shroud as the shroud tab and radiator boss on that side are about 1/4" different in height. (PIC) Wanting the shroud to fit close to the core, and look right, I elected to have the gap overcome with an extra tab. That increased the amount of work required, as now you have a two piece bracket to make. Both brackets are almost the same length and both end up an "L" shape, and simply need holes drilled to finish them, and a means to attach the tab on the passenger side bracket.
I took the aluminum stock, and using a jig saw, cut the basic shape of the "L" brackets out. After completing this, I bolted up the shroud and fan on the table with all of the top half fasteners. This fixed their positions so I could mark accurately where the holes needed to be drilled in the new brackets. At this point, I had to make the tab for the passenger side bracket and figure out how to attach it. The reason for the tab is that as stated above, there is a 1/4" high boss coming off the radiator, and the shroud has to fit flush. 1/8" aluminum is too thick to bend easily down to the surface of the radiator and has a tendency instead to stress fracture, so 1/16" aluminum sheet stock left over from the old "FIPK on the Cheap" intake heat shield was then cut and bent in order to attach to the shroud. This was then riveted to the main bracket using an aluminum rivet, and is then ready for putting the all of the bolt holes in. The reason for not using 1/16" for the whole bracket is the ease with which 1/16" bends. It would allow vibration and under pressure, would allow the shroud to come away from the surface of the radiator. The bends in the little tab help ensure that it will not bend as force is applied the length of the metal for the most part, and into the back of the sturdy 1/8" bracket. A few tests confirmed the strength of this design.
In the case of the passenger side bracket, I drilled the hole to line up with the radiator boss first, and then proceeded to mark the other holes, ensuring that they all lined up when completed (3 holes are needed and have to line up in 3 dimensions due to the height differences...makes getting them perfect a little more important). After drilling, the holes that the shroud attach to on the bracket need to be chamfered from the back for both side brackets. With these brackets, they sit so close to the radiator itself that I wanted to use countersunk machine screws to minimize or eliminate rubbing of hte screw heads on the core. It is a pretty tight fit to keep the shroud tight to the radiator. Once everything is drilled, it is time to start attaching everything.
I wanted to make sure the brackets were in keeping with the quality of the radiator, and so I proceeded to use a belt sander to even up the jig saw cuts and round the corners properly. After each side was completed, I proceeded to polish the new brackets to the same or similar standards as the radiator tanks. I got it fairly close, but not perfect. Now came time to fasten it all down.
Fasteners used except for the 2 radiator boss attachment points that use Toyota 10mm headed bolts were selected for their look and durability. Home Depot has the stainless fasteners you need to complete this. I chose to use #10-32 countersinking machine screws for the shroud as they fit well through the little shroud holes, and are available in 1/4" or 1/2" for our purposes. Using 1/4" screw, a shiny stainless acorn nut and a washer fit well over the end of the passenger side tab, and has about 5 threads holding it together. A 1/2" screw was needed for the driver's side as the tab is thicker, and then requires a nylon lock nut and washer to be used as the acorn nut does not fit on properly (bottoms out early). For the A/C fan housing, the bolt used was a 1/4" standard hex head 1/2" long and I have used a lock washer on the bolt head and another acorn nut and washer to hold it together. You need to put the bolt in from behind the bracket here and tighten it down with a wrench as there is no clearance at all with the plug you inserted earlier. In all, a set of shiny and durable fasteners in keeping with the looks of the Koyo radiator.
Install:
Here comes the pain. After putting it all together to make sure it all fits, you get to take it apart. Tighten the shroud to bracket screws down as they are going to be installed keeping the other screws and bolts are lined up, and of course because the shroud screws are inaccessible once the shroud is installed on the car. Then fully remove the shroud and fan. At this time, with a box cutter or similar, cut the top of the rubber feet off so there is about 1/8" left of the wider seat that meets the radiator. This ensures that the radiator sits low enough to get the top mounts on properly. Then squeeze the rubber feet on to the pegs and drop in the radiator. Secure it with the top mounts and make sure it fits properly. Now, lower the shroud down, being careful not to hit the fins. It is a very close squeeze, but will make it with some patience. After the shroud is in, bolt the top down and put the A/C fan in. Then move to under the car where the brackets need to be bolted to the radiator, and the lower fan bolt installed. Hook up the hoses, and fill'er up.
Conclusion:
Well, that wasn't so hard...well it was, but you just got the largest chassis fit radiator into the car you can. The Fluidyne is a little easier on the fitment, but the Koyo is a fair bit bigger still. Some will suggest that this radiator needs too much work to be worth the money compared to the Fluidyne, but I prefer the larger capacity, and the quality of the Koyo unit. Installed pics appear below.
(PICS)