Project KP61 has been in steady progress over the last few months and although it’s taken a bit longer than I had initially planned on I think all the extra time and effort in doing it right the first time will pay off in the long run. To catch you up when we last left off HERE, I had run into an issue with the T3 motor mounts that are required to get the 4AG motor mounted in the Starlet required the factory oil cooler adapter to be positioned in a way that located the oil filter too close to the exhaust manifold.
After plenty of searching for a complete aftermarket solution and not finding anything that suited my liking, I decided to embark on designing my own kit from scratch to suit my application. Throughout my career with Cobb we’ve developed a close relationship over the years with a company called B.A.T. (British American Transfer) who is the official importer for Mocal Oil Control Systems which has a long standing reputation for some of the highest quality oil control products on the market. After taking a few measurements and a stroll through the catalog I had ordered up all the parts needed for a complete and proper oil cooler kit. One of my stipulations was that the sandwich adapter worked with all of the OEM sensors and fittings on the block which required me to select one of the more expensive but very nice low profile thermostatically controlled adapters (part # SP1TM18) which employs the use of banjo fittings that allow the adapter to fit in such a small space. The next problem I encountered was that due to the style of fittings used on the OEM style oil cooler, there was no way to thread on the Mocal adapter which is designed to thread into the fitting that the oil filter would normally be attached to.
Here is the Mocal adapter and fitting that goes through it to give you an idea.
After a bit of dissection of the OEM oil cooler I had removed a fitting that would thread into the block but it was so short that only a couple threads engaged in the adapter fitting. Not good. So it looks like I’m off to the scrapyard! After a few frustrating attempts of finding what I needed but not having the proper tools with me at the time to remove them, I ended making this little beauty after not being able to find a 12mm Allen key anywhere locally when I needed it. Fun fact: A 12mm bolt head will also act as a 12mm Allen key with the right amount of nuts welded together…
It might not be pretty but it gets the job done when you’re in a crunch. So after all of that I finally ended up getting the fitting I needed out of an old Toyota Tercel, here’s a comparison next to the original 4AG fitting that shows the extra length I needed.
With that bit taken care of I could now properly attach the new sandwich adapter to the block.
You can see here why the banjo fittings are necessary to clear the oil pressure sensor… I could have relocated the sensor but I didn’t want additional oil lines and T-fittings cluttering up the engine bay.
As you can see I also have the new oil lines in place, if you’ve never made them before here’s a quick rundown of the basic procedure. First up you will want to figure out where the oil cooler will be placed so you can measure the length of line you will need. Next, it’s time to make the cut. I’ve made quite a few AN lines in my day and I have found that a very minimal amount of electrical tape does a good job of keeping the strands together while you make the cut. I’ve also tried many different methods of cutting the steel braided line from chop saws, band saws, and cut off wheels to try to minimize the amount of fray you get while cutting and I’ve found that with proper technique a good ol’ fashioned hacksaw does the job just fine.
It might take a few attempts your first time but if you’re careful the finished cut should look something like this.
The next step is to insert the line into the socket. This can be done by simply pushing the the line into the fitting but due to the very tight tolerances that is more easier said than done in most cases. After many blisters and choice curse words over the years trying to install them that way I have come across these affordable little devices from a company called Kool Tools that help hold the socket in place and aid in directing the line into the fitting. This is half of the tool here and you can see how the taper will help direct the hose into the socket and make getting these fittings together MUCH easier.
You can now push the braided line into the socket rather easily…
Until it bottoms out on the threads in the socket like so.
The rest of the fitting can now be threaded into the socket. I would also highly recommend using aluminum AN wrenches and soft jaws on the vice to prevent scarring up those sexy new fittings which by the way are another reason why I love the Mocal stuff so much as typical Red and Blue AN fittings have always irritated me because they stand out too much while this titanium and black anodized color they offer is much more pleasing to the eye in my opinion
Repeat that step 3 more times and the lines are done! It’s also noteworthy to menti0n that while I usually prefer the lightweight black nylon hose I felt that for this car the classic stainless steel braided line was much more era-correct and suits the raw nature of this car a bit better.
Next up is the heat exchanger, the size you choose will be based on what you need based off of many different factors such as intended usage, power output, oil capacity etc. After much debate I decided a 13 row core would suit my needs well. All that’s left now is to fabricate a few brackets to mount it securely to the car…. but where? In a nod to the old works Hakosukas I decided this car could pull off the front mount location well so I thought I would give that a try.
What do you think? For now I’ll keep it there but I don’t really feel that it’s the most ideal location for a street driven car so I’m making the brackets so that the core can be mounted in front or behind the grill quickly and easily. You might have also noticed the chin spoiler that I’ll be adding after winter is over that’s resting in mock-up phase right here so I can get an idea of what the finished look for this car will be.
With that out of the way it’s on to the other part of the cooling system, the radiator. If you recall I’m using everything I can out of the donor AE86 chassis so the radiator is an AE86 unit as well. My next issue was that after fabricating the lower radiator mounts I needed to make some for the top. I also couldn’t help but notice the old radiator core support was looking pretty old and beat next to the refurbished engine bay.
So the first step was to modify some AW11 MR2 radiator brackets I came across at the scrapyard with some welded in nuts.
Which will allow me to mount them underneath the new core support that I made out of a simple bent piece of aluminum for a much cleaner look.
I also scored a slim radiator fan at the scrapyard from another old Toyota (I forgot what it was) that worked perfectly in the tight confines of the KP61 engine bay and provided ample clearance between the crank pulley.
With the new drive train in place another area that needed to be addressed was the exhaust system. This will need to be custom from the header all the way to the muffler. You can see here the modifications performed to the header just below the collector to allow it to clear the floor pan.
Here’s a view of it from underneath, the floor pan also needed to be slightly modified as well to make it work but in my opinion I would rather have a slight hump in the floor pan over a crazy tight bend in the exhaust system.
When it came to the rest of the exhaust system I was faced with a common conundrum on cars with solid rear axles…. over the axle or under? Stock routing places the piping up and over the axle which is great for clearance when the axle drops but adds 2 rather tight 90 degree bends. Under the axle straightens things out substantially but another factor comes into play that can be seen here:
The large amount droop in the stock shocks allows the axle to hang down almost 8″ when the car is raised which is fine when the exhaust is routed over the axle but quite problematic if the exhaust is routed underneath. There are a couple of ways of combating this, one would be axle limiting straps but I went with another method that would kill two birds with one stone. I ended up sourcing a full set of short-stroke Tokico HTS shocks designed for the AE86 chassis to replace the tired, 20+ year old Bilsteins. I’ll get more into detail on these later but for now we’ll talk about them in relation to the exhaust system. As you can see the Tokico’s are much shorter stroke than the OEM fitment Bilsteins which aside from the many benefits on a lowered car will also limit the amount of droop of the rear axle which will allow me to tuck the system up much higher for better clearance when on the ground without it being strained when the axle drops.
You can definitly see how much less droop there is with them installed.
Which after a few late nights allowed me to fabricate a very straight and free flowing stainless steel exhaust system.
When compared with the stock exhaust layout the benefits of the under axle setup are obvious.
I went with an small, oval-style muffler hoping to keep the sound levels in check without any resonators… we’ll see how that goes I also haven’t quite decided on the style of tip I want yet either but I don’t think it looks too shabby as is.
With most of the mechanical business taken care of it’s now time to tackle the wiring portion which I’ll admit isn’t my favorite part of the process but necessary nonetheless.
Oh boy… that’s going to be a little work. Check back next time to see if I make it out alive