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02-19-2008, 09:37 AM
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Join Date: Jan 2005
Location: Phoenix, AZ
Posts: 61
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Quote:
Originally Posted by cjensen
I've talked to several of the vendors about the engine, and they say they are selling a few, and James Ball of ECi, gave me a list of customers I could contact. The list wasn't long...
I have the mount for the 320 for my 7, but the 340 will work with this mount (probably with better WB results).
The reason I want to put this out there, is if I move ahead with the planning of the carb'd version 340, is it going to be around in two or three years when I can feasibly afford an engine?
I've talked to Larry Vetterman about an exhaust, I have Fred Felix working on the numbers for a prop for me, and these are items that I can afford to buy ahead of time without including them in the finance package for the engine and a few avionics. I think the engine will be around for quite a while, but I also have thoughts in my head that if I buy the exhaust, prop, etc...that I'll get news down the road that it's no longer available.
Anyone have any thoughts on this? Robbie?
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Chad, I think the more flying 340 stroker engines that we have out there the more popular they will continue to get. They do have less stress and are a smoother running engine so I think they will gain more popularity as more pilots fly behind them and report good things. As far as buying stuff long before your are ready for it, I would wait until I need it, something new may come along. And I do think the 340 stroker is here to stay. Good Luck, Robbie
Last edited by robbieattaway : 02-19-2008 at 09:49 AM.
Reason: add on
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02-19-2008, 09:50 AM
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Join Date: Jun 2005
Location: Milwaukee, WI area
Posts: 2,967
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Thanks Robbie! I'll keep an eye on it, as it definitely sounds like a good option at 177hp for the carb'd version. My prop can be repitched if need be. I've already talked to Fred about that, so I went ahead with the order for a prop.

__________________
Chad Jensen
Astronics AES, Vertical Power
RV-7, 5 yr build, flew it 68 hours, sold it, miss it.
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03-06-2008, 01:20 AM
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Join Date: Jan 2005
Posts: 4,285
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Smoooooooooth baby
Quote:
Originally Posted by robbieattaway
They do have less stress and are a smoother running engine.Robbie
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Why do they have less stress or what kind of stress are we talking about? What is the high time ECI 340 engine? I once stroked a Chevy 350 V8, making it a 383; it was a nice engine.
Quote:
Originally Posted by Indycanard;
I to also have a small voice telling me to worry about 100LL, however in the grand scheme, I am not worried enough to not get the added HP in about the same package as a 320.
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As long as you have enough money to buy it, there will be 100LL gas for good awhile, I think. 100LL might (who knows) become more rare if/when we go to 95UL or 98UL, which is coming at somepoint. Last I heard, about 20% of the total current GA fleet needs 100LL. My O360 (8.5:1cr) will run on 95/98. I guess you can always cut the timing back a few degrees. This allows lower octan but also causes loss of power, booo.
I just filled my car's gas tank & broke the $60 mark. Yea!?  The local big airport 100LL price just hit $6.29 (where's the cry emoticon). Fortunately the GA airport is holding at $4.49. Just remember there's always the throttle & mixture control, use them. I'd think the higher compression 340 stroker 177HP will get as good or better spacific fuel burn than a 360 180hp Lyc.
__________________
George
Raleigh, NC Area
RV-4, RV-7, ATP, CFII, MEI, 737/757/767
2020 Dues Paid
Last edited by gmcjetpilot : 03-06-2008 at 03:54 PM.
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03-06-2008, 08:27 AM
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Join Date: Nov 2005
Location: Tulsa, OK
Posts: 202
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Stroker 340 - less stress?
Quote:
Originally Posted by robbieattaway
They do have less stress and are a smoother running engine. Robbie
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I'm with George on this one. What do you mean they have less stress? Are you talking torsional vibration, stress on the pistons, cylinders, rods . . . . and less stress than what? I would like you to give a response with information that can be digested, analysed and validated.
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Rhonda Barrett-Bewley
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03-06-2008, 08:27 PM
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Join Date: Jan 2005
Location: Phoenix, AZ
Posts: 61
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Stress
I'm sorry, I should have said dynamic stress on the crank as measured with a strain gauge test conducted by Jimmy Tubbs VP of Engineering at ECi. I do talk to Jimmy regularly and this is what he had told me about the test that they do on new engines. I am just repeating what Jimmy said. If you would like an explanation of this test, to resolve your indigestion, and questions, I would suggest you call Jimmy at ECi. He can elaborate on engine strain gauge testing and how to determine if it is a smooth running engine. I can only determine what a smooth engine is by flying an airplane that has one.
Last edited by robbieattaway : 03-06-2008 at 10:24 PM.
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03-07-2008, 08:12 AM
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Join Date: Nov 2005
Location: Tulsa, OK
Posts: 202
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Thanks Robbie. No indigestion, just like to see data to back up those kinds of statements. Happy to contact Jimmy, and with his permission will post his response here.
Thanks again!
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Rhonda Barrett-Bewley
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03-11-2008, 08:42 AM
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Join Date: Nov 2005
Location: Tulsa, OK
Posts: 202
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340 Vibration Testing
Jimmy Tubbs responded to my email regarding strain gauge testing from last week with the following response, posted with his permission.
Quote:
Rhonda: Good to hear from you. How is Monty? In answer to your question, we have conducted vibration testing, and the 340 engine balances out with almost no balance washers. We have run-in a number of them on the test stand, and also on airplanes, and the effort to balance is almost nil. The smoothness of the engine in the test cell and in the air is very noticeable, but that is not scientific!
We are conducting more sophisticated instrumented vibration testing, and I will let you know when that is completed and what we find.
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This is prop balancing, not strain gauge testing. The washer corrections deal with the fundamental frequency or 1 per rev. Strain gauge testing measures the torsional inputs between the engine and prop. Strain gauge testing as required by the FAA for certification is generally considered a minimum test of torsional stress by most "think tank" engineering standards. The gauge is placed forward of the slinger. This is not really an ideal location because this area is not nitrided and is more ductile than the rest of the crankshaft. As you move further down the crank, the crankshaft becomes more rigid. This is why counterweights are put at the end of the crankshaft. Editing note: I should have said this is why they use dampeners on the crankshaft - to reduce twist.
As a side note, you will not feel how smooth an engine is relative to crankshaft vibration during flight. C/S vibration/twist occurs at the sixth order, meaning that it is at 6 times the engine speed. So for easy math sake, let's say you're spinning the crankshaft at 2000 rpm, that means the vibrations would occur 12,000 times per minute, and no one will feel that.
__________________
Rhonda Barrett-Bewley
Last edited by rgbewley : 03-11-2008 at 09:04 AM.
Reason: clarification re: ct'wts
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03-11-2008, 09:22 AM
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Join Date: May 2005
Location: Tuttle, Oklahoma
Posts: 2,563
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Quote:
Originally Posted by rgbewley
Jimmy Tubbs responded to my email regarding strain gauge testing from last week with the following response, posted with his permission.
This is prop balancing, not strain gauge testing. The washer corrections deal with the fundamental frequency or 1 per rev. Strain gauge testing measures the torsional inputs between the engine and prop. Strain gauge testing as required by the FAA for certification is generally considered a minimum test of torsional stress by most "think tank" engineering standards. The gauge is placed forward of the slinger. This is not really an ideal location because this area is not nitrided and is more ductile than the rest of the crankshaft. As you move further down the crank, the crankshaft becomes more rigid. This is why counterweights are put at the end of the crankshaft. Editing note: I should have said this is why they use dampeners on the crankshaft - to reduce twist.
As a side note, you will not feel how smooth an engine is relative to crankshaft vibration during flight. C/S vibration/twist occurs at the sixth order, meaning that it is at 6 times the engine speed. So for easy math sake, let's say you're spinning the crankshaft at 2000 rpm, that means the vibrations would occur 12,000 times per minute, and no one will feel that.
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This is interesting. Thanks for the input.
So to address the issue of anyone stating their 320 is smoother than another guy's 320, we can infer that any comments are going to be a subjective comment no matter which builder states it then? Or, if a stroked 340 is smoother than a comparably powered 320 or 360. If this is true, how could anyone determine with any measure of meaning whether one engine manufacturer's engine is "smoother" than another?
Of course I do understand the issue of adding more cylinders to smooth out the pulses and all that. However, the issue of comparing like to like engines, or at least engines with the same number of cylinders and similar HP ratings sounds like a marketer's statement not an engineer's statement.
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03-11-2008, 10:19 AM
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Join Date: Aug 2006
Location: Crestwood, KY
Posts: 848
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340 Stroker kit contents to convert from 320
The 340 stroker kit contents on the ECI website are as follows:
1 - Crankshaft Assy 4.125 Stroke 340 series
4 - Piston 5.125 diameter 7.2:1 Compression Ratio
4 - Connecting Rod Assy 340 stroker series
Henry - Are you sure the camshaft is different from the standard 320?
I believe the cylinders are for a narrow deck case.
You guys got me wondering if it would be worthwhile or possible to covert my 0320 D3G core over to a 340. My case is a wide deck. The piston diameter is the same though. Is it worth $4000 for 10 horsepower?
Thanks,
__________________
Mike
RV-9A Based K6I2
Flying - out of Phase 1
Building RV-12 with brother
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03-11-2008, 10:26 AM
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Join Date: Jan 2005
Location: 57AZ - NW Tucson area
Posts: 10,011
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SB-505
Quote:
Originally Posted by Fearless
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You guys got me wondering if it would be worthwhile or possible to covert my 0320 D3G core over to a 340. My case is a wide deck. The piston diameter is the same though. Is it worth $4000 for 10 horsepower?
Thanks,
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It certainly would be if your O-320 crank fails the SB-505 corrosion inspection...
gil A
__________________
Gil Alexander
EAA Technical Counselor, Airframe Mechanic
Half completed RV-10 QB purchased
RV-6A N61GX - finally flying
Grumman Tiger N12GA - flying
La Cholla Airpark (57AZ) Tucson AZ
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