Rotec TBI Carburetor - Zenith Aircraft Builders and Flyers2024-03-29T08:53:22Zhttps://zenith.aero/forum/topics/rotec-tbi-carburetor?feed=yes&xn_auth=noI made the heat muff myself.…tag:zenith.aero,2023-06-13:2606393:Comment:9054122023-06-13T03:28:22.111ZPeter Eibergerhttps://zenith.aero/profile/PeterEiberger
<p>I made the heat muff myself. I did add a coil of copper wire inside to increase the amount of heat produced. </p>
<p>I made the heat muff myself. I did add a coil of copper wire inside to increase the amount of heat produced. </p> Great job of analyzing and so…tag:zenith.aero,2023-06-09:2606393:Comment:9053522023-06-09T17:18:31.684Zcharlie rosenzweighttps://zenith.aero/profile/charlierosenzweig
<p>Great job of analyzing and solving that airflow issue. Thanks for sharing the info, I am sure it will be helpful to many others.</p>
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<p>Your round heat muffs, where did you get those? Did you add door springs inside the muff as others have suggested?</p>
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<p>Charlie </p>
<p>Great job of analyzing and solving that airflow issue. Thanks for sharing the info, I am sure it will be helpful to many others.</p>
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<p>Your round heat muffs, where did you get those? Did you add door springs inside the muff as others have suggested?</p>
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<p>Charlie </p> Well, hot weather brings hot…tag:zenith.aero,2023-06-01:2606393:Comment:9046472023-06-01T23:40:54.691ZPeter Eibergerhttps://zenith.aero/profile/PeterEiberger
<p>Well, hot weather brings hot weather problems.</p>
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<p>PLEASE NOTE: I do not have the Weseman/WW lower cowl, I made a custom one for myself.</p>
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<p>Anyway, at 85*F+ ambient temps, I could easily get the right (#1) CHT over 380* measured under the head in a climb (60-65kts @3150 RPM). The highest I saw was 392*F before I chickened out and lowered the nose. The way it was climbing, I am confident it would have easily gone over 400*F. </p>
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<p>So the only logical course of…</p>
<p>Well, hot weather brings hot weather problems.</p>
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<p>PLEASE NOTE: I do not have the Weseman/WW lower cowl, I made a custom one for myself.</p>
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<p>Anyway, at 85*F+ ambient temps, I could easily get the right (#1) CHT over 380* measured under the head in a climb (60-65kts @3150 RPM). The highest I saw was 392*F before I chickened out and lowered the nose. The way it was climbing, I am confident it would have easily gone over 400*F. </p>
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<p>So the only logical course of action was to increase the exit area. I cut the lower cowl flap and opening forward of the nose gear and made a new air deflector. </p>
<p><a href="https://storage.ning.com/topology/rest/1.0/file/get/11258985678?profile=original" target="_blank" rel="noopener"><img src="https://storage.ning.com/topology/rest/1.0/file/get/11258985678?profile=RESIZE_710x" class="align-center"/></a></p>
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<p><a href="https://st11.ning.com/topology/rest/1.0/file/get/11258996657?profile=original" target="_blank" rel="noopener"><img src="https://st11.ning.com/topology/rest/1.0/file/get/11258996657?profile=RESIZE_710x" class="align-full"/></a></p>
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<p>The results were worth it! Peak CHT in climb will not exceed 360, even at continuous full power climb (3150 RPM). Cruise temps also dropped 30*F, and oil temps dropped over 10*F. I haven't noticed any loss in cruise speed due to the additional cooling drag either. </p>
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<p>In hindsight, the elevated under cowl temps could have been a contributing factor to my vapor lock problem. I have spoken with a couple others who use the Rotec with the Weseman cowling and had no such issues. </p>
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<p></p> Thanks. I've been through tha…tag:zenith.aero,2023-04-10:2606393:Comment:8985072023-04-10T23:59:36.312ZStephen M. Easthamhttps://zenith.aero/profile/StephenEastham
<p>Thanks. I've been through that. I'll just have someone copy the scrap flanges Azalea sent me or just re-use them since they are not proprietary. Just need the exhausts and intake for my Rotec TBI and I'll be closing her up and searching for an A&P to inspect her.</p>
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<p>Azalea and WW will no longer sell parts to me though. Azalea stole my paid oil cooler and sent defective exhausts and WW doesn't want a Spyder owner using his site (spent $3K on common parts there with him…</p>
<p>Thanks. I've been through that. I'll just have someone copy the scrap flanges Azalea sent me or just re-use them since they are not proprietary. Just need the exhausts and intake for my Rotec TBI and I'll be closing her up and searching for an A&P to inspect her.</p>
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<p>Azalea and WW will no longer sell parts to me though. Azalea stole my paid oil cooler and sent defective exhausts and WW doesn't want a Spyder owner using his site (spent $3K on common parts there with him including a new prop, Rotec and oil cooler). Very territorial this Corvair stuff.</p>
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<p>As a retired military pilot, I don't have time for games with these Corvair guys and will solve the problem eventually.</p>
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<p>Thanks for the help.</p> If you want to learn to weld…tag:zenith.aero,2023-04-10:2606393:Comment:8985012023-04-10T21:39:58.716ZPeter Eibergerhttps://zenith.aero/profile/PeterEiberger
<p>If you want to learn to weld for your own education and ability, great. Learning to weld is an invaluable skill, I won't discourage anyone from learning. That said, if your goal is a flying plane, you are adding a fair amount of delay and additional risk to your build. </p>
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<p>As I stated above, I made my flanges (on my lathe) and clamps, I don't know if you will be able to purchase those easily. </p>
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<p>If you want to read some 20-year old info on exhaust:…</p>
<p>If you want to learn to weld for your own education and ability, great. Learning to weld is an invaluable skill, I won't discourage anyone from learning. That said, if your goal is a flying plane, you are adding a fair amount of delay and additional risk to your build. </p>
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<p>As I stated above, I made my flanges (on my lathe) and clamps, I don't know if you will be able to purchase those easily. </p>
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<p>If you want to read some 20-year old info on exhaust: <a href="http://www.n56ml.com/corvair/exhaust/" target="_blank" rel="noopener">http://www.n56ml.com/corvair/exhaust/</a></p>
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<p></p> I need to weld my own intake…tag:zenith.aero,2023-04-07:2606393:Comment:8981662023-04-07T14:26:42.914ZStephen M. Easthamhttps://zenith.aero/profile/StephenEastham
<p>I need to weld my own intake and exhaust pipes for my Corvair engine and Rotec carb. Do you know what individual piece parts and tubes I need to buy from Burns Stainless or other vendors in 304 1.5" and the piece parts, flanges, etc? I don't have the jig and fixture but I do have a set of exhaust L/R from Azalea that were from his scrap bin I can use as a port to port reference for a jig/fixture. I guess I can just eyeball the intake pipe measurements and add a 13 deg intake flange to clear…</p>
<p>I need to weld my own intake and exhaust pipes for my Corvair engine and Rotec carb. Do you know what individual piece parts and tubes I need to buy from Burns Stainless or other vendors in 304 1.5" and the piece parts, flanges, etc? I don't have the jig and fixture but I do have a set of exhaust L/R from Azalea that were from his scrap bin I can use as a port to port reference for a jig/fixture. I guess I can just eyeball the intake pipe measurements and add a 13 deg intake flange to clear my rear starter and flywheel.</p>
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<p>I've asked welders locally but they don't want the "liability" so I am going to take a welding class and practice first. I'm not welcome at WW's anymore as a Spyder owner (spent $3K there) and Azalea screwed me after $5K spent there and owes me parts. Can't get local welders to help me in PHX AZ due to "liability." This should be interesting. </p> I seriously considered changi…tag:zenith.aero,2023-04-06:2606393:Comment:8982502023-04-06T13:47:31.809ZPeter Eibergerhttps://zenith.aero/profile/PeterEiberger
<p>I seriously considered changing out the fuel selector valve for a duplex feed/return unit. A newton unit is nowhere to be found currently and I didn't want to redo the entire console panel for a different fuel valve.</p>
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<p>Cheaper options:</p>
<p><a href="https://www.andersonbrass.com/6-way-selector-valves" target="_blank" rel="noopener">Anderson</a></p>
<p><a href="https://www.ebay.com/p/25017007162" target="_blank" rel="noopener">Grocco</a></p>
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<p>I seriously considered changing out the fuel selector valve for a duplex feed/return unit. A newton unit is nowhere to be found currently and I didn't want to redo the entire console panel for a different fuel valve.</p>
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<p>Cheaper options:</p>
<p><a href="https://www.andersonbrass.com/6-way-selector-valves" target="_blank" rel="noopener">Anderson</a></p>
<p><a href="https://www.ebay.com/p/25017007162" target="_blank" rel="noopener">Grocco</a></p>
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<p></p> The Rotec is a bit different…tag:zenith.aero,2023-04-06:2606393:Comment:8981532023-04-06T13:30:06.998ZPeter Eibergerhttps://zenith.aero/profile/PeterEiberger
<p>The Rotec is a bit different since it has the diaphragm to regulate pressure internally, allowing it to run on anything from gravity feed to 15 psi, but that's likely where the vapor is building up since using the purge button clears it (purge button just manually opens the diaphragm). </p>
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<p>My fuel line is firesleeved and I have a blast cooling duct for the gascolator.</p>
<p>The Rotec is a bit different since it has the diaphragm to regulate pressure internally, allowing it to run on anything from gravity feed to 15 psi, but that's likely where the vapor is building up since using the purge button clears it (purge button just manually opens the diaphragm). </p>
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<p>My fuel line is firesleeved and I have a blast cooling duct for the gascolator.</p> I'll be running a Corvair on…tag:zenith.aero,2023-04-06:2606393:Comment:8981522023-04-06T13:09:37.843ZStephen M. Easthamhttps://zenith.aero/profile/StephenEastham
<p>I'll be running a Corvair on my 601 HDS with wing tanks only. Took out my header tank to make way for an avionics bay. Thanks for the information of different types of fuel and temps. It get's pretty hot here in Phoenix, AZ.</p>
<p>I'll be running a Corvair on my 601 HDS with wing tanks only. Took out my header tank to make way for an avionics bay. Thanks for the information of different types of fuel and temps. It get's pretty hot here in Phoenix, AZ.</p> Peter, I don't know if it is…tag:zenith.aero,2023-04-06:2606393:Comment:8980912023-04-06T12:22:17.265ZJohn Austinhttps://zenith.aero/profile/JohnLAustin
<p>Peter, I don't know if it is relevant to your carb/fuel line configuration, but I also have a TBI carb (Sonex "AeroInjector" installed on a Jab 3300) and there are many instances of those carbs having the "burps": Momentary hesitation of the engine due to vapor bubbles passing through the carb. However, contrary to your experience, most of the AeroInjector Jab 3300 equipped engines will idle OK.</p>
<p>What was emphasized by AeroInjector support was to ensure that from firewall-forward,…</p>
<p>Peter, I don't know if it is relevant to your carb/fuel line configuration, but I also have a TBI carb (Sonex "AeroInjector" installed on a Jab 3300) and there are many instances of those carbs having the "burps": Momentary hesitation of the engine due to vapor bubbles passing through the carb. However, contrary to your experience, most of the AeroInjector Jab 3300 equipped engines will idle OK.</p>
<p>What was emphasized by AeroInjector support was to ensure that from firewall-forward, keep the fuel line run as short as possible and that the fuel line always must travel upwards with no downward turns that could act as a trap for vapor bubbles to collect. It also helps to insulate the fuel line to keep down heat soaking. (I used fire sleeve and a second layer of heat reflecting sleeve.)</p>
<p>My engine would occasionally "burp"/hesitate prior to this, but once I routed the fuel line properly and insulated the fuel line, I have had ZERO "burps" running 93 no-ethanol mogas for hundreds of hours.</p>
<p>John</p>
<p>N750A</p>