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HT leads

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mark.j(at)yakuk.com
Guest

Posted: Sun Mar 26, 2006 4:08 am Post subject: HT leads

Gents, I read with interest about this subject.   

   

“Experimental” allows you chaps in USA to do as you like, for example – experiment with fitting new non OEM parts or experiment to see how long “it” lasts without preventative maintenance.   

   

The experiment to see how long the Russian HT wire lasts seams to have a consensus to be approx 15 years +/- . You know when its starting to fail as you get intermittent rough running and poor starting, as the HT wire cracks and lets the sparks out and the moisture in. On some days it does and others it does not. Storage conditions of the a/c will affect the times.   

   

A very cost effective fix to not overhauling the engine at the OEM calendar times is to only fit a new HT lead set. The HT leads being used now will most likely last longer than Russian materials. The plugs are certainly cheaper.   

   

While your at it don’t forget to change the HT lead for the booster coil, this is the most critical part to aid starting. Very few mags have sufficient energy to start the engine at the speeds of air propping a cold engine.   

   

Engine reliability is a “J” curve against calendar/TTSN vs. failure. 750 hrs on new engine and 500 on overhauled. But we all know they go to 1000hrs but with the odd valve blowing or compressor change etc.  

   

Its my opinion that Dennis very good HT fix using local parts is no better or worse than an engine that’s had a proper OEM overhaul fitted with new plugs, wires and OH mags. Either will fix the problems equally as well as each other.   

   

So why go “local” when, Plugs available new - Chinese have never blown in my experience yet in M14P. Termikas advise that new Russian plugs do fail under pressure test. They have not found a Chinese one do so yet out of 500 tested.  

   

Packard or any other aviation HT wire available new  

   

Mags we hope to have new coils made very soon.   

   

Mag caps and rotors , same as on Housie engine – available.   

   

That leaves points, simple fix is to have the existing springs re tipped.   

   

I think that takes care of HT problems.   

   

Take care.   

mj

brian

Joined: 02 Jan 2006
Posts: 643
Location: Sacramento, California, USA

Posted: Sun Mar 26, 2006 9:48 am Post subject: HT leads

Mark Jefferies YAK UK Ltd wrote:

 	  Quote: 	
		   Gents, I read with interest about this subject.

 

  

 

 “Experimental” allows you chaps in USA to do as you like, for example – 

 experiment with fitting new non OEM parts or experiment to see how long 

 “it” lasts without preventative maintenance.


	


Mark, I beg to differ. The purpose of the new and different HT wiring is 

not to see how long things last but to actually improve the system from 

both a reliability and maintainability point of view. Dennis' HT wiring 

system using modern automotive materials is likely to last longer and 

give less trouble than will the stock Russian HT wiring system.



Modern resistor wires are extremely reliable and eliminate the need for 

shielding. Eliminating the shielding also reduces the capacitance of the 

wire thus allowing for a faster rise-time of the voltage. This improves 

spark timing and spark voltage as less of the energy goes into charging 

the center-conductor-to-shield capacitor. You can get away with a larger 

gap and get more reliable firing of the cylinder.



This is not a "hack" or a "band aid" but an actual systems improvement. 

In this it is like installing a modern alternator in place of the old 

Russian generator. It will last longer and exhibit fewer failures than 

will the older Russian systems.



 	  Quote: 	
		   While your at it don’t forget to change the HT lead for the booster 

 coil, this is the most critical part to aid starting. Very few mags have 

 sufficient energy to start the engine at the speeds of air propping a 

 cold engine.


	


And I would much rather see someone adapt something like the Slick-start 

"shower of sparks" module to the Chinese centrifugal-advance mags (it 

should be a bolt-on modification) and eliminate the booster coil all 

together. (You can't do it with the Russian mags as they have fixed 

timing.) The whole boost-coil starting system is a bad hack with the 

distributor providing spark timing during start. This is just butt-ugly 

bad engineering. Sure it works but it is amazing just how many bad 

things work.



 	  Quote: 	
		   Engine reliability is a “J” curve against calendar/TTSN vs. failure. 750 

 hrs on new engine and 500 on overhauled. But we all know they go to 

 1000hrs but with the odd valve blowing or compressor change etc.


	


Perhaps. On the other hand, our lubricants are superior to what the 

Russians were using when they determined wear rates and therefore 

overhaul intervals. Modern US oils combined with good oil filtration 

should reduce wear in the engine by a significant margin. This should 

result in an increase in TBO. It would be good if people did this to 

their engines and then measured wear patterns against time-in-service at 

overhaul time. That would allow us to determine what the real TBO 

intervals should be. If we could increase the length of the bottom of 

the "J" curve (we call it the "bathtub" curve over here as it looks more 

like the contour of a bathtub) then we can safely increase the 

recommended TBO without increasing the risk of systems failure.



 	  Quote: 	
		   Its my opinion that Dennis very good HT fix using local parts is no 

 better or worse than an engine that’s had a proper OEM overhaul fitted 

 with new plugs, wires and OH mags. Either will fix the problems equally 

 as well as each other.


	


IMHO it is substantially better than the stock system. With some 

measurements on both the primary and secondary sides of mag; e.g. peak 

voltage, rise time, spark energy, etc.; it should be pretty easy to 

prove too.



 	  Quote: 	
		   So why go “local” when, Plugs available new - Chinese have never blown 

 in my experience yet in M14P. Termikas advise that new Russian plugs do 

 fail under pressure test. They have not found a Chinese one do so yet 

 out of 500 tested.


	


It might also be interesting to see what the voltage breakdown 

characteristics are as well. We might be surprised.



Yes, the "experimental" category can be abused but it is quite useful if 

used properly. We can use it to learn how to do things better. If you 

doubt that, go to Oshkosh and look at the difference between the 

experimental homebuilts and the production aircraft. Innovation in 

aviation is almost the exclusive to the domain of the experimental aircraft.



-- 

Brian Lloyd                         361 Catterline Way

brian-yak at lloyd dot com          Folsom, CA 95630

+1.916.367.2131 (voice)             +1.270.912.0788 (fax)



I fly because it releases my mind from the tyranny of petty things . . .

- Antoine de Saint-Exupery

_________________
Brian Lloyd
brian-yak at lloyd dot com
+1.916.367.2131 (voice) +1.270.912.0788 (fax)

I fly because it releases my mind from the tyranny of petty things . . .
- Antoine de Saint-Exupery

cpayne(at)joimail.com
Guest

Posted: Mon Mar 27, 2006 3:56 am Post subject: HT leads

Brian wrote:

 >

 >On the other hand, our lubricants are superior to what the 

 	  Quote: 	
		  Russians were using when they determined wear rates and therefore 

overhaul intervals. Modern US oils combined with good oil filtration 

should reduce wear in the engine by a significant margin. This should 

result in an increase in TBO.

 Absolutely! Don't forget good air filtration to keep out silicone (dirt) from

 the engine oil. I use the 10 micron (absolute, not average) Marion filter and

 the Brackett air filter. Every oil change gets a test sample analysis. AOA runs

 a results tracking for my engine that shows very low contaminates since

 break in.

 >Modern resistor wires are extremely reliable and eliminate the need for 

 	  Quote: 	
		  shielding. Eliminating the shielding also reduces the capacitance of the 

wire thus allowing for a faster rise-time of the voltage. This improves 

spark timing and spark voltage as less of the energy goes into charging 

the center-conductor-to-shield capacitor. You can get away with a larger 

gap and get more reliable firing of the cylinder.

 These autoplug conversions use a wire superior to resistor wires,

 wires have a very fine stainless steel wire wrap around the conductor.

 Depending on the grade, from 80 - 200 wraps per inch covered by

 7mm - 10mm diameter Hyplon or similiar covering. However, spark

 plug gap should not be opened up as much as the high energy systems

 that these racing wires are intended for. Otherwise, a weaker spark will

 result in some conditions. I use .025" max for plugs on the M-14P

 Craig Payne

tomjohnson(at)cox.net
Guest

Posted: Mon Mar 27, 2006 7:15 am Post subject: HT Leads

At Reno this last  year in the Lycoming engine booth they had one of their experimental Turbo 550  motors for the NXT style aircraft.

 Surprise!  It  had the same automotive RACING ignition wire and plugs that we "chaps" are now  using.  This is a Lycoming factory OEM part.

  

 Many of the race aircraft use the system also as they can adjust plug temperature for higher output engines.

 Its such a no-brainer.  Makes maintenance a  delight, starts like a dream.



However. . . the shielding is  not as good as original.  I've flown my system about 100 hours now and when  far away from a station or picking up a weak signal a small amount of ignition  noise is now heard in the system.  And I have a new Garmin (true, its not  oem. . . ) avionics package.  Very minor though.

  

 Tj

 

---------------------------

Thomas Johnson

Airpower  Insurance, LLC

36 West Ocotillo Road

Phoenix, AZ   85013-1235

Tel:  602-628-2701

Fax:  623-321-5843

E:   tomjohnson(at)cox.net

BitterlichMG(at)cherrypoi
Guest

Posted: Mon Mar 27, 2006 3:17 pm Post subject: HT Leads

It  would be interesting to know Tom whether the noise you are hearing is coming in  via the front end of the radio (I.E. from the antenna) or as noise introduced  into the radio coupled from the actual power leads.  It's probably not very  easy to do... but if it IS possible to reach behind that Garmin and unplug the  antenna to see if that noise goes away,  I'd very much appreciate the  feedback.  Is your antenna in the same place as the original by the way,  and did you replace the Russian coax with RG-142 ??  

  

 Thanks  for the info. 

  

 Mark  Bitterlich

  

  

  

  --

bwalker11(at)charter.net
Guest

Posted: Mon Mar 27, 2006 5:46 pm Post subject: HT Leads

I also am curous about the radio noise since I'm in the  process of converting over to the new plugs and wires.  Has any body else  out there had any noise with this conversion?

  

 Also, removed the Baklan 5 from my other Yak and installed  the Becker 21/4 com/Trans combo.  I used RG 142 but wired it into the  original russian antenna by using the Russian coax fitting from the radio.   Not really sure if that was a good Idea as I get poor reception from aircraft in  the formation but excellent reception for aircraft further away.

  

 Any thoughts on the need to change to a different  antenna?

  

 BW

 [quote]   ---

jsfox(at)adelphia.net
Guest

Posted: Mon Mar 27, 2006 5:53 pm Post subject: HT Leads

On Mar 27, 2006, at 8:43 PM, Bill Walker wrote:

 	  Quote: 	
		  I also am curous about the radio noise since I'm in the process of converting over to the new plugs and wires.  Has any body else out there had any noise with this conversion? 	




So far my only noise issues are coming from my Flightsuits helmet with ANR. With my other headsets quite as a mouse.



Steve

dsavarese(at)elmore.rr.co
Guest

Posted: Mon Mar 27, 2006 6:25 pm Post subject: HT Leads

Bill,

 No one that has installed my conversion kit has  reported any extraneous noise in the radios or intercom after the  installation.  TJ's installation is not mine.  It may be Bill  Blackwell's offering.

  

 The Russian antenna has an impedance matching device on it and  I seriously doubt when connected to the Becker VHF that it will provide the best  functionality.  You should probably put a VSWR (voltage standing  wave ratio) meter on the output and see how much reflected power there is.    If it were my installation I would replace the Russian antenna with a  standard US manufactured VHF antenna.  I'll bet I know why you didn't  replace it to start with! -)  It's a bitch of a job getting back in  the fuselage to get to the antenna to remove it.

 Dennis

  

 [quote]   ---

viperdoc(at)mindspring.co
Guest

Posted: Mon Mar 27, 2006 6:44 pm Post subject: HT Leads

Wild Bill,

 Ask Dennis about using the Russian antenna with the  western radios. There is something about a significant ohm resistance in doing that. Sorry that is about all I know about this. Dennis understands it better. I entertained doing that on my 52 and he was pretty hard over on that about not doing it.

 Doc

  

 



  

 [quote] ---

viperdoc(at)mindspring.co
Guest

Posted: Mon Mar 27, 2006 6:49 pm Post subject: HT Leads

Wild Bill,

 Yeah, what he said. Maybe I should have read the last post first, huh?

 Doc

  

 



  

 [quote] ---

dandmaz(at)cox.net
Guest

Posted: Tue Mar 28, 2006 6:57 am Post subject: HT Leads

 Bill Blackwell's  installed Conversion kits  have not had extraneous noise? TJ installed he's own plug and wires  ?

  Don Andrews

 [quote]   ---

dsavarese(at)elmore.rr.co
Guest

Posted: Tue Mar 28, 2006 7:52 am Post subject: HT Leads

That's what I figured Don.

 Dennis

  

 [quote]   ---

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