block the emissions tube in Cosmo housings
09-23-10, 03:46 AM
#1
block the emissions tube in Cosmo housings
Anyone ever block the emissions tubes in their 20B or 13B-RE rotor housings?
It makes sense to reduce unecessary manifold heating for more power, does it not? So how does the heat get in there? Through the side plate ACV channels leading up from the exhaust ports. Does it not also sound like a good idea to reduce side plate heating at the same time? Maybe reduce some of that unwanted heat in your cooling system that we're always so concerned about with these boosted engines in ovens, or I mean FD engine bays. Letting it go out through the exhaust system sounds better to me.
I'm going to look into some ways to plug these things. Maybe a steel NPT pipe plug is the answer. Or maybe an aluminum rod lathed down to the right diameter. Hmm, would the emissions tube need to be pulled first? Somebody said it may be brass, but I think it's steel. Haven't checked yet.
Any racers out there done this already?
It makes sense to reduce unecessary manifold heating for more power, does it not? So how does the heat get in there? Through the side plate ACV channels leading up from the exhaust ports. Does it not also sound like a good idea to reduce side plate heating at the same time? Maybe reduce some of that unwanted heat in your cooling system that we're always so concerned about with these boosted engines in ovens, or I mean FD engine bays. Letting it go out through the exhaust system sounds better to me.
I'm going to look into some ways to plug these things. Maybe a steel NPT pipe plug is the answer. Or maybe an aluminum rod lathed down to the right diameter. Hmm, would the emissions tube need to be pulled first? Somebody said it may be brass, but I think it's steel. Haven't checked yet.
Any racers out there done this already?
09-24-10, 12:31 PM
#2
Update. The emissions tube is steel. It is directional with two locating slots on the bottom. The top has two 45° bevels to clear an edge on the Cosmo exhaust sleeve I guess.
I grabbed a chissle and just had to grind a little off the edge until it was the right width to fit the slots like a big screwdriver. First I tried turning it counterclockwise with an adjustable wrench like a big screwdriver. No go. Then I figured it was probably simply pressed in, because that makes a little more sense. So I grabbed a BFH and tapped on the chissle. It tapped the tube up into the port and out. Pretty easy.
The tube measured 14.02mm. The hole in the housing must be 14.00mm for a press fit.
How do I block it? Add an old stud in the tube and weld it? That might shink the tube a little, so no. Do I turn down some aluminum rod stock to 14.02mm and hammer it in the housing? No rod and no lathe. Hmm...
Do you have an old tranny? I had a section of shifter rod from a shifter relocation a few years ago. It is 13.95mm. It slides in with a little coaxing. Perfect if I can somehow make it stay in place.
I cut off three little pieces about yay long. I chose to beat on it with the bfh until it mushroomed slightly. The middle grew to 13.97mm but the ends expanded to 14.05 and 14.10mm or more. If it can be tapped in, it's not coming out, I explained to myself.
It took some effort to smack them into the holes, especially the ones that were beaten not quite 100% squarely (they needed a little grinding here or there). But they went in and it will take a lot of heat cycles before they even think about loosening up. But what if they did? Eek!
So what can I do to guarantee they stay? I think I'll dimple the edges with a center punch. It's what machinists do. It's what Mazda does on side plates and e-shafts to keep brass plugs in.
By the way the T2 sleeves went in just fine once the emissions tubes were gone. Not sure why others suggested it necessary to remove some aluminum before they can go in. If anything, the way the ports will flow now is slightly less than ideal due to the way it is shaped right after the chrome bevel. Instead of entering straight like any T2 housing, it angles up and down a lot directing exhaust flow right into the edges of the T2/FD sleeves. Interesting. No one ever talks about this.
The sleeves are already installed with roll pins now. But had I thought more about it, I may have attempted expanding them a little to better match the Cosmo ports. As it sits right now, I'll just port the sleeves a little to more of a knife edge so they don't stick up in the way so much.
Is it even possible to expand these sleeves without cracking them? They say the NA sleeve diffuser wings can be grabbed with a vice grip and broken off so that tells me the metal is somewhat hard or hardened = brittle. Heck Mandeville kept the T2 sleeves as they are with just a bit of porting when he built an engine for C.Carlisi a while back. Good enough.
I grabbed a chissle and just had to grind a little off the edge until it was the right width to fit the slots like a big screwdriver. First I tried turning it counterclockwise with an adjustable wrench like a big screwdriver. No go. Then I figured it was probably simply pressed in, because that makes a little more sense. So I grabbed a BFH and tapped on the chissle. It tapped the tube up into the port and out. Pretty easy.
The tube measured 14.02mm. The hole in the housing must be 14.00mm for a press fit.
How do I block it? Add an old stud in the tube and weld it? That might shink the tube a little, so no. Do I turn down some aluminum rod stock to 14.02mm and hammer it in the housing? No rod and no lathe. Hmm...
Do you have an old tranny? I had a section of shifter rod from a shifter relocation a few years ago. It is 13.95mm. It slides in with a little coaxing. Perfect if I can somehow make it stay in place.
I cut off three little pieces about yay long. I chose to beat on it with the bfh until it mushroomed slightly. The middle grew to 13.97mm but the ends expanded to 14.05 and 14.10mm or more. If it can be tapped in, it's not coming out, I explained to myself.
It took some effort to smack them into the holes, especially the ones that were beaten not quite 100% squarely (they needed a little grinding here or there). But they went in and it will take a lot of heat cycles before they even think about loosening up. But what if they did? Eek!
So what can I do to guarantee they stay? I think I'll dimple the edges with a center punch. It's what machinists do. It's what Mazda does on side plates and e-shafts to keep brass plugs in.
By the way the T2 sleeves went in just fine once the emissions tubes were gone. Not sure why others suggested it necessary to remove some aluminum before they can go in. If anything, the way the ports will flow now is slightly less than ideal due to the way it is shaped right after the chrome bevel. Instead of entering straight like any T2 housing, it angles up and down a lot directing exhaust flow right into the edges of the T2/FD sleeves. Interesting. No one ever talks about this.
The sleeves are already installed with roll pins now. But had I thought more about it, I may have attempted expanding them a little to better match the Cosmo ports. As it sits right now, I'll just port the sleeves a little to more of a knife edge so they don't stick up in the way so much.
Is it even possible to expand these sleeves without cracking them? They say the NA sleeve diffuser wings can be grabbed with a vice grip and broken off so that tells me the metal is somewhat hard or hardened = brittle. Heck Mandeville kept the T2 sleeves as they are with just a bit of porting when he built an engine for C.Carlisi a while back. Good enough.
09-24-10, 12:43 PM
#3
So what have you guys done to eliminate intake manifold heating, and side plate heating due to ACV exhaust comunication?
I've seen some pics of manifolds where aluminum was welded into the ACV ports. That's great for keeping the mani cool, but what about the side plates?
I've seen other pics of the side plate ACV ports under the intake ports blocked with devcon or quicksteel. I've done it myself on several '85 or older 4 port 13Bs and a 12A just recently. Allows compatability with SA intake manifolds which outflow FB manifolds, and VERY necessary when adding freeze plugs to the rotor housing water ports. No one ever talks about it. All that manifold heating can't be good for power.
I once added quicksteel to an intake manifold. It eliminated the need for an ACV cover plate (money and time saved) and kept the manifold icy cold because carbs will do that for you
and the coolant ports are plugged. It's an R5 engine. Maybe those tubes come out the same way? It'd keep the intermediate plate cooler.
I've seen some pics of manifolds where aluminum was welded into the ACV ports. That's great for keeping the mani cool, but what about the side plates?
I've seen other pics of the side plate ACV ports under the intake ports blocked with devcon or quicksteel. I've done it myself on several '85 or older 4 port 13Bs and a 12A just recently. Allows compatability with SA intake manifolds which outflow FB manifolds, and VERY necessary when adding freeze plugs to the rotor housing water ports. No one ever talks about it. All that manifold heating can't be good for power.
I once added quicksteel to an intake manifold. It eliminated the need for an ACV cover plate (money and time saved) and kept the manifold icy cold because carbs will do that for you
and the coolant ports are plugged. It's an R5 engine. Maybe those tubes come out the same way? It'd keep the intermediate plate cooler.
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