Author Topic: Injection Timing Method  (Read 13032 times)

bob b

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Re: Injection Timing Method
« Reply #15 on: October 27, 2014, 03:52:14 AM »

    Was hoping some twin owners would comment on my running video. Oh well.
  Maybe its because they run so well there is no need to come here for counsel ;D OR they all blew up.

   To me my #2 sounds fat and powerful whereas my #1 sounds wheezy and ball-less. #2 spill time checked at 24 degrees with exhaust opening at 48. #1 spill was 20 BUT exhaust opening is 43 so I don't know what to think.  I have never heard a good running 12/2 so I really don't know. Can anyone post a link for a good running 12/2 coming up to speed? 1 cylinder at a time would be awesome. I posed this question in my other thread but, does anyone know what the reason is for the different exhaust timing in COV versus non COV engines? My non COV 12/2 came with a COV timed exhaust event. Unfortunately the 2 exhaust lobes are at both ends of the spec tolerance (43 and 48). Should I put the 55 back in? 

    I also learned that there are TWO places where fuel will shut off when spill timing. My theory is that instead of being between the inlet and the helix, I was so loose I was on the other side of the inlet groove. That'll throw off your timing efforts. Does that make sense?

   Its been raining here for most of a week. My engine is under a roof but the mechanic isn't and I aint that hardcore. I did get a few hours in here and there. I got an Iphone app called slopro. Claims to be 1000fps capable. It doesn't seem anywhere near that but,  at 500fps I'm able to crank and see/hear 1 frame per degree of revolution. Initial results seem promising.  I have an old 5.6kw duct heater with three switches so I should be able to do some decent empirical testing. I spent a couple of hours on the interweb and it seems that slow running IDI engines are typically between 0 and 5 advanced. Going to make timing changes (+2,0,-2,-4) with the camera as it will go much faster. If its an epic fail, I'll come back and tell y'all. The camera should help with recording performance results as well.  I would definitely recommend to anyone else, spill time it FIRST. I wouldn't even try this if I was cranking by hand either.

  I also made a wrench. Looks like a crowfoot with a piece of 1/2 X 1/4 welded on at a 45 degree angle. Helps a lot. I should have plate sanded the mating surfaces between the locknut and the roller. I think that would help expedite things as well. 
   
  @Ronmar. I was going by Radio Shack the other day and figured what the hell. Every time I go in Radio Shack stores now I weep a little. I swear that there is one less component cabinet  each and every time. HOWEVER they had both parts! So I bought them. I think your doohickey and my thingamabob are going to be pretty close to each other.

   Now that I've written all of this, does anyone think I am wasting my time or might hurt my engine? Thanks for any advice you can give me. Please and thank you.

 
 

38ac

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Re: Injection Timing Method
« Reply #16 on: October 27, 2014, 12:56:33 PM »

    Was hoping some twin owners would comment on my running video. Oh well.
  Maybe its because they run so well there is no need to come here for counsel ;D OR they all blew up.

 
 
 

Neither in my case, its because I am so deaf that that I couldn't tell if it was running perfectly or crap from a video.  The twins will never be smooth like a well tuned and balanced single because of the uneven firing sequence and what is called "crankshaft rocking couple".  I wont expand on that here punch it into Google if your curious.

As for your timing variances side to side. The Indian cams are less than precise for sure but I have yet to see one so far off that it could not be "tuned around".  If you want to make science out of cam timing have fun, but it isn't necessary to get the engine running nicely. If you want the valves opening and closing at the same crank position vary the lash to accomplish it and record the settings for future use. "Well ya know it all but what about the lift you just changed???"  you might ask next? Well to that I say if you had  ever checked the total lift AT THE VALVES you would know it isnt the same anyway even with the lash set to the book  :o  This due to the rocker ratios and cam lobes being different due to poor machining and the way each of the long push rods flex differently. It just plain isnt easy to make a F-1  engine out of a Listeroid without reinventing the wheel  is my bottom line here. If you wish to both worry about and correct the tming remove the cam, correctly reset the lobes on a good shaft and then send it out to a cam grinder to have the lobes precisely ground and while at it also sent them the rockers to thave the ratios corrected and equalized and have two push rods custom made that will (hopefully) flex more or less equally.

If you just want the engine running as nice as any twin will run. By FAR the biggest influences upon it in my experience are two fold.
1. first thing is;  Getting ALL the air out of the #2 cylinder fuel lines is a PITA. This is due to the shape of the line feeding the #2 pump. It will NOT bleed totally out at idle or no load in my experience. What I do is loosen the line nut at the #2 injector and then pull the pin out out of the fuel pump linkage and pull the pump rack wide open while running on #1. Ya, big mess.
2 Once you have it bled out you need to set the linkage that comes across from #1 so that #2 has an equal amount of load WHEN UNDER LOAD. Several ways to do this. load the engine enough to get smoke and set by eyeballing the exhaust.  Exhaust temp is best way with cheapo harbor freight infrared heat gun. You can also do it by touching the mufflers,,, Once set under load this often this means that at idle or no load that the cylinders will not be firing equally, thank India again for poor workmanship or watch what is going on with the linkage and correct it. I have seen two of the pump mount housings for the #2 side that were not machined correctly for the arm that pins to it and you could not make the governor work both pumps work together. One was welded and remachined the other was so bad it was trashed and replaced.
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dieselgman

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Re: Injection Timing Method
« Reply #17 on: October 27, 2014, 03:22:28 PM »
Not a very large number of twins out there... We sell about 50 to 1 in favor of singles.

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