Bell's New Coolant Reroute: a Review
05-28-2009, 10:45 PM
#1
Boost Pope
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Location: Chicago. (The less-murder part.)
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Bell's New Coolant Reroute: a Review
Having finally had a few days off and back at home, I installed the BEGi coolant reroute package that's been sitting on my workbench for weeks.
To be clear, doing a proper reroute with the head still in the car is a slightly unpleasant task. Imagine doing a clutch job, and just before you unbolt the pressure plate from the flywheel, you shove the entire transmission up your *******. It's not quite that bad, but you get the idea. If you're squeamish about having all of the skin shorn from your fingers, con someone else into doing this for you. Hats off to Mazda, who managed to machine a perfect razor-sharp edge onto pretty much every surface you'll encounter while working back there.
That said, the kit which I got from Bell was pretty nice.
Interestingly, the spacer came without either a fitting for the heater hose or a plug to block off the auxiliary port on the top. Fortunately, these two pieces were easily obtained at the local ACE hardware store, and hey- it wouldn't be the full Bell experiance if all the parts were there, now would it?
The first order of business was to remove the stock water outlet at the back of the head. Somewhat to my surprise, it was held on not with two bolts, but with one bolt and one stud/nut. A word of advice: use the double-nut method to remove that stud. You can use the nut that came off, plus another M8x1.25 jammed together. I stupidly tried removing it with channel-lock pliers first, which buggered the threads without actually turning it. With that done, it took almost an hour of tedious vise-gripping to get it out.
Once it's off, you'll note that the speedo cable is secured to the firewall with a little metal tab that's spot-welded to the body. In order to gain clearance for the spacer, you'll have to unhook the cable from that bracket and then flatten the bracket out. It's just sheet metal, so it's easy to do.
Now, the new parts. I tested out the fitment of the new stack (the spacer, the new water outlet, and the two gaskets) and found that the two bolts which were included with the kit were entirely too long. The longer of them, in fact, had quite a bit of unthreaded portion protruding beyond the assembled stack, and couldn't even fit between the firewall and the head.
I measured the length of the original bolt and stud relative to the original water outlet, and found that both protruded appx 10mm beyond the housing. I then measured the stackup, and concluded that a new set of bolts, one 60mm and one 80mm, would provide exactly the same thread engagement as the originals, so another trip to ACE later I had the proper bolts (again, these are M8x1.25, and you want the non-shouldered class 8.8 versions.)
One interesting feature of the spacer is that the hole for the factory CLT sensor is raised up quite a bit, such that the body of the sensor barely protrudes at all into the main cavity. I expect that this was done out of concern for interfering with the thermostat mechanism. With the OEM design, this might be a problem, though with the Stant unit that I have, there's quite a lot of clearance. Although there's plenty of space around the sensor element, a potential downside here is that if air is going to get trapped anywhere in the system, it's going to be around that sensor. Hopefully the turbulent flow of water through the housing will eventually purge most of the air from that cavity. If not, I guess I'll just have to roll the car over onto its side to clear the air bubble.
The groove for the thermostat, incidentally, is absolutely perfect both in depth and diameter. The thermostat fits snugly into the cutout as though it was made to sit there. And as you can see, the spacer is grooved on both sides. I'm not entirely sure why this is (if you flipped it over and rotated it so that the heater outlet was again horizontal, the CLT sensor would hit the transmission.
A note on the water outlets. I ordered my kit without one, as I'd already purchased a Protege water outlet on the advice of a fellow forum member. As it turns out, the Protege outlet is far too small to work in this application. Here's a comparison of the stock 1.6 Miata outlet and the Protege outlet:
The major diameter (the hump at the end) of the stock outlet is 1.3", and the minor diameter (the main body of the shaft) is 1.23". By comparison, the Protege outlet measured 1.17" and 1.10" respectively. The Protege outlet flopped around inside the stock radiator hose like a hot dog rolling down a hallway.
So, after a couple of phone calls, I located a thermostat housing from an '01 Kia Sephia, 50 miles away in Fort Myers. A few hours later I'm back home again with my new housing in hand. Compared to the Miata housing, the outlet neck is very slightly larger in diameter such that a bit of silicone grease was needed to make the hose slip over it easily, but it fits just fine. It's P/N 0K24715172A, available from any Kia dealer, but please save yourself the trouble and just get the one that Bell includes in the kit.
I wound up only using two of the hoses that Bell gave me. In the back, I cut the smallest of the three midway through the turn, and used the shortest of the included pipe sections to join it to the long hose section. Here's a shot of the assembly laid on top of the engine, to illustrate how it is situated once installed.
I'll also pause here for a moment to say that the hose clamps which Bell included in the kit are easily the highest quality worm-screw units I have ever seen in my life. They're big, thick, heavy, and feel like they'd probably hold the propeller shaft onto a submarine without complaining. Compared to a normal clamp, the band is about 3x the thickness, and the slots in which the screw turns appear to actually be machined into it rather than stamped. They do not go all the way through, so the side of the band which rests against the hose is perfectly flat. Even the formed piece that holds the screw is astoundingly thick and robust. I tightened these things with a 3/8" drive socket wrench, and never felt like I was at risk of stripping one.
Ok, back to the action.
Here's the spacer and outlet installed in the head:
As you can see, I did not have to slot the water outlet in order to get it in. The gaskets included in the kit were self-adhesive on one side, so after setting the thermostat into the spacer I applied a gasket over it, which held the thermostat in place and in position. Another gasket on the other side, and I now had four pieces all stuck together in one easy-to-handle piece. On went the cover, in went the bolts, and all else being equal, it was relatively easy to maneuver the stack into position and get the bolts started. It took some time, but not having to deal with the gaskets and thermostat as separate pieces helped a lot.
One possible concern I have is that it looks like the CLT sensor might interfere with a CAS when installed in the 1.6 engine where it's on the intake cam. I don't have a CAS to verify this with, but it's one thing Bell probably needs to double-check.
Next, it was time for the coldside pipe. The pipe, as delivered, was very much on the long side. In this image, I've marked with white paint on the hoses where each end was.
I decided to remove about 4.5" with a hacksaw, bringing the overall length to 12.25". And yes, I did re-groove the cut end. Poorly. (God, how I miss my lathe.)
Here's how it came out in the end:
As you can see, for the forward section I simply took the upper radiator hose and turned it around the other way. It's a close fit, but it's not actually hitting anything at the front. I bent the fuel hardlines outward a bit for clearance, and the rear hose does come into contact with them, however with the hard plastic sleeve over them I don't foresee any problems.
You'll also note that the entire thermostat housing is gone. Bell includes a very nicely made plate that allows you to just remove the upper thermostat housing and then cover it over. I wanted to clean that area up, so I removed the whole thermostat housing and drove a freeze plug into the head (the hole in the front of the head is smaller than the opening where the thermostat goes, so the plate won't work in that location.) This is definitely the hard way, as you have to remove the timing belt and then the plate behind it in order to unbolt the lower thermostat housing and plug the hole.
Note that if you have a 1.6, bell will drill & tap the plate for you to accept the stock thermoswitch, and even if you don't, they'll also drill & tap it NPT for a turbo feed or whatever else you need. Since my turbo is oil-cooled, and my fans are controlled by the Megasquirt, I didn't need any holes drilled. And of course, I wound up not using the plate anyway.
Doing away with the lower thermostat housing meant that the hoses which normally go through it were homeless. As you can see in the above picture, I simply ran a new length of 5/16" hose from the nipple on the mixing manifold to the oil cooler on the other side of the engine. (I eliminated the coolant path through the throttle body and intake manifold air valve.) Here's a close-up:
That's about it, really. After all was said and done, I had one bolt left over. I have absolutely no idea where it came from. I did remove the fans and radiator during the process, which was necessary only because I fucked up installing the first freeze plug and had to drill it out to remove it. But I'm pretty sure I re-installed all the bolts I took out when I did that. This one is just a mystery...
Also, here's a picture of my turbo, for no other reason than because I think it's feeling lonely, as all of my recent projects have been unrelated to it. I think that's a good thing, actually. It just sits there reliably making huge amounts of power without requiring any kind of maintenance or adjustment at all.
Lastly, while I was doing the install a rather odd creature crawled across the driveway just outside of where I was working:
I honestly have no idea what this. I mean, we have some weird bugs in Florida, but this one takes the cake. It was about 2.5 inches in length, and just sorta looked at me funny while I was photographing it.
Seriously- does anybody know what the hell this thing is?
Ok, so now that it's all together, how does it work? I have no idea. I finished the install on Tuesday, and the RTV silicone that I used to seal the freeze plug was still curing when I left town on Wednesday. It'll be a couple of weeks before I can give real-world results, but on the plus side it'll likely be in the mid 90s when I get back, so it'll be a good test. The car has been pretty consistently overheating in slow traffic lately (temps of up to 230°F with the fans off have been observed) so it'll be pretty easy to tell what we've gained.
All in all, a pretty nice kit. The price was right, and the parts are well made. They need to get the bolt length right and start remembering to include the fittings for the spacer, but those were easy things to fix and really all I can find to complain about. I wound up not needed the mid-length piece of pipe or the mid-length hose section, though I'm sure some folks who route their hoses differently might find them handy.
To be clear, doing a proper reroute with the head still in the car is a slightly unpleasant task. Imagine doing a clutch job, and just before you unbolt the pressure plate from the flywheel, you shove the entire transmission up your *******. It's not quite that bad, but you get the idea. If you're squeamish about having all of the skin shorn from your fingers, con someone else into doing this for you. Hats off to Mazda, who managed to machine a perfect razor-sharp edge onto pretty much every surface you'll encounter while working back there.
That said, the kit which I got from Bell was pretty nice.
Interestingly, the spacer came without either a fitting for the heater hose or a plug to block off the auxiliary port on the top. Fortunately, these two pieces were easily obtained at the local ACE hardware store, and hey- it wouldn't be the full Bell experiance if all the parts were there, now would it?
The first order of business was to remove the stock water outlet at the back of the head. Somewhat to my surprise, it was held on not with two bolts, but with one bolt and one stud/nut. A word of advice: use the double-nut method to remove that stud. You can use the nut that came off, plus another M8x1.25 jammed together. I stupidly tried removing it with channel-lock pliers first, which buggered the threads without actually turning it. With that done, it took almost an hour of tedious vise-gripping to get it out.
Once it's off, you'll note that the speedo cable is secured to the firewall with a little metal tab that's spot-welded to the body. In order to gain clearance for the spacer, you'll have to unhook the cable from that bracket and then flatten the bracket out. It's just sheet metal, so it's easy to do.
Now, the new parts. I tested out the fitment of the new stack (the spacer, the new water outlet, and the two gaskets) and found that the two bolts which were included with the kit were entirely too long. The longer of them, in fact, had quite a bit of unthreaded portion protruding beyond the assembled stack, and couldn't even fit between the firewall and the head.
I measured the length of the original bolt and stud relative to the original water outlet, and found that both protruded appx 10mm beyond the housing. I then measured the stackup, and concluded that a new set of bolts, one 60mm and one 80mm, would provide exactly the same thread engagement as the originals, so another trip to ACE later I had the proper bolts (again, these are M8x1.25, and you want the non-shouldered class 8.8 versions.)
One interesting feature of the spacer is that the hole for the factory CLT sensor is raised up quite a bit, such that the body of the sensor barely protrudes at all into the main cavity. I expect that this was done out of concern for interfering with the thermostat mechanism. With the OEM design, this might be a problem, though with the Stant unit that I have, there's quite a lot of clearance. Although there's plenty of space around the sensor element, a potential downside here is that if air is going to get trapped anywhere in the system, it's going to be around that sensor. Hopefully the turbulent flow of water through the housing will eventually purge most of the air from that cavity. If not, I guess I'll just have to roll the car over onto its side to clear the air bubble.
The groove for the thermostat, incidentally, is absolutely perfect both in depth and diameter. The thermostat fits snugly into the cutout as though it was made to sit there. And as you can see, the spacer is grooved on both sides. I'm not entirely sure why this is (if you flipped it over and rotated it so that the heater outlet was again horizontal, the CLT sensor would hit the transmission.
A note on the water outlets. I ordered my kit without one, as I'd already purchased a Protege water outlet on the advice of a fellow forum member. As it turns out, the Protege outlet is far too small to work in this application. Here's a comparison of the stock 1.6 Miata outlet and the Protege outlet:
The major diameter (the hump at the end) of the stock outlet is 1.3", and the minor diameter (the main body of the shaft) is 1.23". By comparison, the Protege outlet measured 1.17" and 1.10" respectively. The Protege outlet flopped around inside the stock radiator hose like a hot dog rolling down a hallway.
So, after a couple of phone calls, I located a thermostat housing from an '01 Kia Sephia, 50 miles away in Fort Myers. A few hours later I'm back home again with my new housing in hand. Compared to the Miata housing, the outlet neck is very slightly larger in diameter such that a bit of silicone grease was needed to make the hose slip over it easily, but it fits just fine. It's P/N 0K24715172A, available from any Kia dealer, but please save yourself the trouble and just get the one that Bell includes in the kit.
I wound up only using two of the hoses that Bell gave me. In the back, I cut the smallest of the three midway through the turn, and used the shortest of the included pipe sections to join it to the long hose section. Here's a shot of the assembly laid on top of the engine, to illustrate how it is situated once installed.
I'll also pause here for a moment to say that the hose clamps which Bell included in the kit are easily the highest quality worm-screw units I have ever seen in my life. They're big, thick, heavy, and feel like they'd probably hold the propeller shaft onto a submarine without complaining. Compared to a normal clamp, the band is about 3x the thickness, and the slots in which the screw turns appear to actually be machined into it rather than stamped. They do not go all the way through, so the side of the band which rests against the hose is perfectly flat. Even the formed piece that holds the screw is astoundingly thick and robust. I tightened these things with a 3/8" drive socket wrench, and never felt like I was at risk of stripping one.
Ok, back to the action.
Here's the spacer and outlet installed in the head:
As you can see, I did not have to slot the water outlet in order to get it in. The gaskets included in the kit were self-adhesive on one side, so after setting the thermostat into the spacer I applied a gasket over it, which held the thermostat in place and in position. Another gasket on the other side, and I now had four pieces all stuck together in one easy-to-handle piece. On went the cover, in went the bolts, and all else being equal, it was relatively easy to maneuver the stack into position and get the bolts started. It took some time, but not having to deal with the gaskets and thermostat as separate pieces helped a lot.
One possible concern I have is that it looks like the CLT sensor might interfere with a CAS when installed in the 1.6 engine where it's on the intake cam. I don't have a CAS to verify this with, but it's one thing Bell probably needs to double-check.
Next, it was time for the coldside pipe. The pipe, as delivered, was very much on the long side. In this image, I've marked with white paint on the hoses where each end was.
I decided to remove about 4.5" with a hacksaw, bringing the overall length to 12.25". And yes, I did re-groove the cut end. Poorly. (God, how I miss my lathe.)
Here's how it came out in the end:
As you can see, for the forward section I simply took the upper radiator hose and turned it around the other way. It's a close fit, but it's not actually hitting anything at the front. I bent the fuel hardlines outward a bit for clearance, and the rear hose does come into contact with them, however with the hard plastic sleeve over them I don't foresee any problems.
You'll also note that the entire thermostat housing is gone. Bell includes a very nicely made plate that allows you to just remove the upper thermostat housing and then cover it over. I wanted to clean that area up, so I removed the whole thermostat housing and drove a freeze plug into the head (the hole in the front of the head is smaller than the opening where the thermostat goes, so the plate won't work in that location.) This is definitely the hard way, as you have to remove the timing belt and then the plate behind it in order to unbolt the lower thermostat housing and plug the hole.
Note that if you have a 1.6, bell will drill & tap the plate for you to accept the stock thermoswitch, and even if you don't, they'll also drill & tap it NPT for a turbo feed or whatever else you need. Since my turbo is oil-cooled, and my fans are controlled by the Megasquirt, I didn't need any holes drilled. And of course, I wound up not using the plate anyway.
Doing away with the lower thermostat housing meant that the hoses which normally go through it were homeless. As you can see in the above picture, I simply ran a new length of 5/16" hose from the nipple on the mixing manifold to the oil cooler on the other side of the engine. (I eliminated the coolant path through the throttle body and intake manifold air valve.) Here's a close-up:
That's about it, really. After all was said and done, I had one bolt left over. I have absolutely no idea where it came from. I did remove the fans and radiator during the process, which was necessary only because I fucked up installing the first freeze plug and had to drill it out to remove it. But I'm pretty sure I re-installed all the bolts I took out when I did that. This one is just a mystery...
Also, here's a picture of my turbo, for no other reason than because I think it's feeling lonely, as all of my recent projects have been unrelated to it. I think that's a good thing, actually. It just sits there reliably making huge amounts of power without requiring any kind of maintenance or adjustment at all.
Lastly, while I was doing the install a rather odd creature crawled across the driveway just outside of where I was working:
I honestly have no idea what this. I mean, we have some weird bugs in Florida, but this one takes the cake. It was about 2.5 inches in length, and just sorta looked at me funny while I was photographing it.
Seriously- does anybody know what the hell this thing is?
Ok, so now that it's all together, how does it work? I have no idea. I finished the install on Tuesday, and the RTV silicone that I used to seal the freeze plug was still curing when I left town on Wednesday. It'll be a couple of weeks before I can give real-world results, but on the plus side it'll likely be in the mid 90s when I get back, so it'll be a good test. The car has been pretty consistently overheating in slow traffic lately (temps of up to 230°F with the fans off have been observed) so it'll be pretty easy to tell what we've gained.
All in all, a pretty nice kit. The price was right, and the parts are well made. They need to get the bolt length right and start remembering to include the fittings for the spacer, but those were easy things to fix and really all I can find to complain about. I wound up not needed the mid-length piece of pipe or the mid-length hose section, though I'm sure some folks who route their hoses differently might find them handy.
Last edited by Joe Perez; 05-28-2009 at 11:06 PM. Reason: Added picture of speedo cable bracket
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05-28-2009, 11:19 PM
#7
Cpt. Slow
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awesome, this kind of write up is exactly what I needed to get a better picture of what these reroute shenanigans mean. Anybody know what the difference is between this kit and BEGI's racer kit? All that seems to do is run the coolant from the heater core outlet to the upper radiator hose. And if that's the racer version that has issues heating up, I like it! I can make that at work.
Where would that hose go if you have a 1.6 without the stock oil cooler/water heater? Thanks again for the writeup Joe!
Where would that hose go if you have a 1.6 without the stock oil cooler/water heater? Thanks again for the writeup Joe!
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05-28-2009, 11:21 PM
#8
Newb
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Nice job & write up Joe. Next time home come on over and take a look at the kits I am making.
By the way that is a Crayfish also known as a "ditch bug" in Louisiana & is a Cajun delicacy. Next time you are in New Orleans try some. Proper Ditch bug eating edicate is: tear off the tail & eat then suck the "goodies" out of the head, repeat Etc.etc.
Safe trip, see ya' on the return.
By the way that is a Crayfish also known as a "ditch bug" in Louisiana & is a Cajun delicacy. Next time you are in New Orleans try some. Proper Ditch bug eating edicate is: tear off the tail & eat then suck the "goodies" out of the head, repeat Etc.etc.
Safe trip, see ya' on the return.
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******* hilarious. Nice write up too. thanks.
05-29-2009, 09:29 AM
#13
Boost Pope
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Nice job & write up Joe. Next time home come on over and take a look at the kits I am making.
By the way that is a Crayfish also known as a "ditch bug" in Louisiana & is a Cajun delicacy. Next time you are in New Orleans try some. Proper Ditch bug eating edicate is: tear off the tail & eat then suck the "goodies" out of the head, repeat Etc.etc.
By the way that is a Crayfish also known as a "ditch bug" in Louisiana & is a Cajun delicacy. Next time you are in New Orleans try some. Proper Ditch bug eating edicate is: tear off the tail & eat then suck the "goodies" out of the head, repeat Etc.etc.
Still, I thought those things lived in the water? Granted it's been raining a lot lately, but for one to have gotten up on my driveway he'd have had to travel quite some distance from the nearest canal. Do you get these things in your yard?
I've seen the pictures you posted of your reroute setup, and for the later NBs running a coldside S/C, it looks pretty good. In particular, I very much like that formed pipe section you've got.
From the image I posted of my turbo as well as the overall wide shot from the front you can see why that arrangement would not work for my car, even though I have neither a CAS nor stock ignition coils. With the top-mount manifold, the turbocharger and its wastegate can and heat shield sit right in the area where your coolant pipe runs. Folks using side-mount manifolds might be able to run their pipe down the hotside, provided their heat shield does not occupy that space. Still, I expect the coldside routing to be more popular with turbo users, despite the fact that it's a bit more crowded over there (especially on the early cars with the keg-sized charcoal canister).
Also, bear in mind that your routing is incompatible with 1.8 NAs (as well as NBs which are using an MS1) as they have a CAS poking out the back of the exhaust cam, and probably incompatible with anybody pre-'01 who is using the factory ignition coils as well. Not that anybody who is serious about boost should be using those coils anyway. :rolleyes"
I spent some time on the phone talking with Steph and Corky and convinced them to flip the names. This one that I have was originally labeled the "Racer" reroute, and the other one the "Turbo" reroute. That made no sense to me, as this one is ideal for street cars, whereas the other is pretty much a track-only affair.
In my setup, I'd originally placed the oil cooler between the outlet on the intake manifold and the inlet on the throttle body. So I simply removed the line leading from the oil cooler to the throttle body, and the one from the TAV to the mixing manifold, and ran a new hose from the oil cooler outlet to the mixing manifold.
If you don't have an OEM 1.8 coil cooler on your 1.6, you'd simply run a hose from the outlet of the thermostatic air valve on the top of the intake manifold down to the nipple on the mixing manifold, as I've illustrated here:
If you do not have an oil cooler, and you also wish to eliminate the factory interheater (the coolant running through the TB and TAV), then you can just block off the coolant outlet on the bottom of the intake manifold and the coolant inlet at the mixing manifold, and run no hoses at all. With the thermostat removed from the front, it's no longer crucial to have coolant circulation through that circuit.
Of course, if you use the blockoff plate supplied by Bell, rather than removing the lower thermostat housing from the head, you can leave the stock hoses alone and they'll work just fine.
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05-29-2009, 10:55 AM
#14
Great write up Joe! Im eventually going to do another reroute to the MSM but ive just been too lazy. And i know two people who got sick off of sucking the heads on the crawfish. Stick to the butt as that where the good meat is...(waits for flood of *** jokes to follow)
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05-29-2009, 11:34 AM
#16
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I still don't understand why the t-stat must go on the back of the head where access is limited as opposed to in an in-line housing next to the intake manifold. I'd also use a housing that fit a common t-stat that flows well and has lots of aftermarket. Camaro or something.
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05-29-2009, 12:04 PM
#17
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Because you isolate the thermostat from the motor with 4-5" of stagnant water that takes longer to heat up than the water in your motor does. Putting it on the back of the head means the heater core feed is constantly drawing water directy past the thermostat, so when your motor heats up, so does the thermostat.
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05-29-2009, 12:18 PM
#18
I agree with Sav. I don't like the m-tuned reroute for that very reason. Which gives me an idea...
If there's enough exposed meat on the remote housing you could just tap it for the heater core or the factory oil filter cozy to get some fresh hot water flow to the t-stat.
Where can you get a two piece remote thermostat housings anyway. A quick search for "remote thermostat housing" at Summit only turned up some expensive spacers.
If there's enough exposed meat on the remote housing you could just tap it for the heater core or the factory oil filter cozy to get some fresh hot water flow to the t-stat.
Where can you get a two piece remote thermostat housings anyway. A quick search for "remote thermostat housing" at Summit only turned up some expensive spacers.
Last edited by MazDilla; 05-29-2009 at 12:33 PM.
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Forget the heater core. You just need to circulate some hot water from the head to the thermostat. You can route the return where any where on the low pressure side of the thermostat, preferably bypassing the radiator for a street car.
