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Post by racket on Oct 16, 2016 19:12:18 GMT -5
Go with the single port scroll, the twin ports increase losses so less energy downstream for making power
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barnyard
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Joined: October 2016
Posts: 36
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Post by barnyard on Oct 31, 2016 11:26:33 GMT -5
I'm working on a new combustion chamber for the engine, I'll put up some pictures soon.
Hey question, has anyone used a hot surface igniter on liquid fuelled turbine engines? I've been using a spark plug with mediocre results. My only thought with the hot surface igniter is the fuel spray might cool the igniter surface down to much to ignite.
I've seen the Hot Streak igniter that Smithy is using, but that has its own fuel supply right? It acts like a small blow torch used to light the main fuel supply?
James
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barnyard
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Joined: October 2016
Posts: 36
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Post by barnyard on Oct 31, 2016 18:10:28 GMT -5
Hi guys, another question, as I design the flame tube, seeing as I'm using a spray nozzle, not an evaporator, should I start the primary holes farther down to flame tube, instead of putting then close to the top (nozzle end)? I attached a quick sketch I did to show the spray pattern and where it would hit the wall. The nozzle I have is. 4gph 60 degree cone spray. With a 60 degree spray, the spray will hit the flame tube wall 5.375" down from top cap. Should I start the holes around there? Jet spec says I need a 16.25" long flame tube, so I wonder then if I should just shrink the distance between the secondary and tertiary holes, so that I have extra room above the primary zone. Thanks, and I hope I'm wording my question clear enough! James
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Post by racket on Oct 31, 2016 19:14:46 GMT -5
Hi James
Try 12 holes at 7/16" dia at 4.5 inches down from the top , I'm assuming you are still using the 70 mm inducered comp , secondary holes at 9 inches down and tertiary at 12 inches .
Cheers John
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Post by smithy1 on Oct 31, 2016 19:59:30 GMT -5
I've seen the Hot Streak igniter that Smithy is using, but that has its own fuel supply right? It acts like a small blow torch used to light the main fuel supply? James I'm using a small "propane" injector across a spark igniter for primary ignition, once I see a suitable egt rise I can then introduce the "real" fuel.....seems to work extremely well.....no more pops or bangs during the first phase of starting. Prior to this I had the.... "wait for it pop/bang"....was rather stressful waiting for the inevitable....you knew it was coming but not exactly when ...and when it did, it certainly got your attention...John knows what I'm on about..! It is possible to use a small ceramic glow type igniter, some of the small RC turbines use these to great effect. I think Anders was dabbling with something similar. I do use a Hot-Streak system for the afterburner ignition, fuel is supplied via a separate pump and a "normally closed" solenoid operated by a momentary switch on the steering wheel... works first time every time..! Cheers, Smithy.
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barnyard
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Posts: 36
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Post by barnyard on Nov 1, 2016 13:56:20 GMT -5
Hi James Try 12 holes at 7/16" dia at 4.5 inches down from the top , I'm assuming you are still using the 70 mm inducered comp , secondary holes at 9 inches down and tertiary at 12 inches . Cheers John Hi John, thanks for the advice, it's much appreciated. I was originally thinking to do 5/16" holes for primary, but with your advice I'll change it up to the 12 primary holes at 7/16", 6 secondary holes at 1/2", and 10 tertiary holes at 5/8". It's a lot less holes to drill then with 5/16" Thanks, James
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barnyard
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Joined: October 2016
Posts: 36
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Post by barnyard on Nov 1, 2016 13:59:46 GMT -5
Smithy I know what you mean by the inevitable "Pop"! I like your idea of a propane injector blowing across a spark plug, I think that's the route I'm going to try. Simple and I have the materials for it! (I'm cheap)
Thanks, James
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ausjet
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Joined: May 2013
Posts: 133
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Post by ausjet on Nov 1, 2016 23:23:19 GMT -5
Hey mate let me know if you need any info on your CAT turbo I should be able to help out- part numbers/exploded view diagram, prices, disassembly/assembly instructions etc
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barnyard
Member
Joined: October 2016
Posts: 36
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Post by barnyard on Nov 5, 2016 22:47:14 GMT -5
Hey mate let me know if you need any info on your CAT turbo I should be able to help out- part numbers/exploded view diagram, prices, disassembly/assembly instructions etc Hey thanks ausjet! Sorry for the wait for a reply, I was finding turbo numbers. I could definetely use some help finding a torque number for how tight to tighten the compressor quill nut. I took it off to inspection and guess at how tight it should be. Dunno if you have any info on that, but if u do I will take it! Here is a picture of the tag on the turbo with part number. Maybe they mean something to you. Thank, james
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barnyard
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Posts: 36
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Post by barnyard on Nov 5, 2016 22:48:05 GMT -5
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ausjet
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Joined: May 2013
Posts: 133
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Post by ausjet on Nov 6, 2016 18:24:48 GMT -5
All 3208 Marine Engines and 3400 Industrial, Marine Engines Equipped With Turbocharger Models 4MF, 4MFW, CMF And CMFW;
631E, 769C, 773B, 834B Tractors;
768C, 772B Trucks;
988B Loaders
Over tightening of the 7N0239 Compressor Retaining Nut can result in mushrooming the shoulder of the shaft where the 4N7609 Thrust Ring seats. The over tightening can also result in a bent shaft that will damage bearings at disassembly and assembly.
The current specifications of 60 N·m (44 lb ft) can be excessive, if the friction is low at the nut seating face and/or at the threads due to differences in plating or lubricants. Therefore, it is important that the tightening procedure be changed to the "torque plus turn" method which results in a much more consistent joint loading.
NOTE: Do not put side force on the shaft when tightening or removing the nut that holds the compressor wheel in position. Use a universal joint or universal drive socket when tightening.
1. With the compressor wheel on the shaft, put a small amount of clean engine oil on the turbine shaft threads and the compressor wheel face that make contact with the nut.
2. Install the nut, and tighten it to a torque of 14 to 17 N·m (125 to 150 lb in) to push the compressor wheel on to the shaft.
3. Remove the nut from the shaft. Apply 6V1541 Quick Cure Primer on the threads of the shaft and the nut.
4. Put 9S3263 Retainer Compound on the threads of the shaft and the nut.
NOTE: Do not let the retainer compound get into the compressor wheel bore or on the shaft, because it can make removal of the compressor wheel difficult during future turbocharger disassembly.
5. Install the nut, and tighten it to a torque of 4 N·m (30 lb in). Then tighten the nut an additional 75° of rotation.
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barnyard
Member
Joined: October 2016
Posts: 36
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Post by barnyard on Nov 6, 2016 20:53:38 GMT -5
Wow that's awesome info ausjet, thank you so much! I hope I haven't over tightened it already, but I think I'm safe. Now I won't have to worry about the compressor coming off and blowing up in my face!
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barnyard
Member
Joined: October 2016
Posts: 36
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Post by barnyard on Jul 13, 2017 12:02:07 GMT -5
Hi, it's been a long time since my last post, but here are some pictures of the completed combustion chamber. I was able to re use the turbo flange and the flame tube cap from the old combustor. I'm using a single scroll turbo now to, and with this setup the engine is running great! I can run it up to around 15psi boost, and it starts reliably. I'm still limited by my fuel pressure of 80psi, and am working on modifying a boat hydraulic trim pump to be the new fuel pump, hopefully with pressures up around the 500psi mark. Definitely a success in my books though! Thanks for all the help in sizing a new combustor guys.
James
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barnyard
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Post by barnyard on Jul 13, 2017 15:58:19 GMT -5
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Post by racket on Jul 13, 2017 16:53:11 GMT -5
Hi James
Looking good :-)
Yep , more fuel required .
Cheers John
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