Trailing ignition Modification
11-18-04, 02:58 AM
#1
Trailing ignition Modification
Well since I'm running the fisrt ever MSD-DIS on my leading side I'd just like to say how amazing it is. This thing runs so rediculasly smooth its crazy. And now its even running a little lean which means all the fuel that was previously being entered into the engine is now being fully burnt. Now I need to up the jets on the carb. So here's my question is there anything I can do to upgrade the trailing side of the ignition. I am going to be adding a better than stock coil, and I was wondering if I could just hook up another MSD to run through the dizzy, like in my past boinger experiances. Would this work? Any other ideas would be grrrrreat!
11-18-04, 04:22 AM
#2
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I think that jeff20b is more of the authority on this subject, but, IIRC there is no reason to do anything special to the trailing at all. The trail doesn't play that big a roll in the functionability of the motor.
Don't quote me on that, like I said jeff needs to chime in on this one.
Don't quote me on that, like I said jeff needs to chime in on this one.
11-18-04, 08:49 AM
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Sounds good...
Exactly what parts did you use on this installation? MSD 6A with what coil (make and part number). Are you using an ignitor, or running the MSD directly off the same signal that would have triggered a J-109?
Exactly what parts did you use on this installation? MSD 6A with what coil (make and part number). Are you using an ignitor, or running the MSD directly off the same signal that would have triggered a J-109?
11-18-04, 01:22 PM
#5
That's great that it's running well. I too noticed a lean condition after going to a direct fire ignition system. It turned out the jets in my carb were too lean. I ordered the correct size for my air bleeds and can't wait for them to get here.
Yes, my butt dyno testing and another person's actual dyno testing showed that trailing is good for only a fraction of total engine power. My butt dyno couldn't tell the difference and the real dyno results showed that without trailing functioning, the power loss is like 1HP. One measily pony! I could not justify running trailing ignition on my 20B as the parts it would require (three ignitors, three coils) could be put to better use on the leading side of my other engines. Upgrading leading is "where it's at" and upgrading trailing is like having pistons on the brain; it's thinking that each spark plug plays an equal role in the engine's power production, when on a rotary, it doesn't.
Why is trailing so incredibly weak? One of the reasons is because the trailing holes in the rotor housings are very small and there is physically no way to unshroud the spark without drivving them out, which then allows massive blowby as the trailing edge of the rotor passes over it. Because of this, trailing is forever doomed to be weak. Another reason is when in the cycle it fires. Like vipernicus42 said, it's only there to help clean up emissions. The Wankel NSU engines only had one spark plug per rotor. By the way Jon, I hooked up a switch on the dash so I could turn trailing on and off while driving. It got to the point that I had to have somebody else switch it because the act of my clicking the switch was throwing of my butt dyno. The results were too close to call. I think that's pretty funny.
Of course both of these tests were conducted on stock ignitors. Mine had DLIDFIS and the trailing sparks were routed through the leading part of the cap. The other was fully stock FB ignition. When your engine is producing around 100HP, 1HP is only 1% total engine power, so you won't feel it. Heh, my stripped down 20B will have at least 200HP (closer to 250HP NA if I set up everything right) and trailing would have only been good for about 1.5HP, I'm guessing. Either way that's less than 1%. I don't lose any sleep over this loss.
As for going with an MSD in trailing, I suppose it wouldn't hurt anything other than your pocketbook and the cap 'n' rotor. At least the sparks can take advantage of the carbon button until they burn them up, then you could move the wires to the trailing part of the cap if you didn't feel like buying a new cap and rotor right then and there. The good thing is that the compensation will be the same (this means the LT split will not vary with RPM like it does when people use an MSD on leading and leave trailing stock). Do you have a 6AL box? I can't remember.
Yes, my butt dyno testing and another person's actual dyno testing showed that trailing is good for only a fraction of total engine power. My butt dyno couldn't tell the difference and the real dyno results showed that without trailing functioning, the power loss is like 1HP. One measily pony! I could not justify running trailing ignition on my 20B as the parts it would require (three ignitors, three coils) could be put to better use on the leading side of my other engines. Upgrading leading is "where it's at" and upgrading trailing is like having pistons on the brain; it's thinking that each spark plug plays an equal role in the engine's power production, when on a rotary, it doesn't.
Why is trailing so incredibly weak? One of the reasons is because the trailing holes in the rotor housings are very small and there is physically no way to unshroud the spark without drivving them out, which then allows massive blowby as the trailing edge of the rotor passes over it. Because of this, trailing is forever doomed to be weak. Another reason is when in the cycle it fires. Like vipernicus42 said, it's only there to help clean up emissions. The Wankel NSU engines only had one spark plug per rotor. By the way Jon, I hooked up a switch on the dash so I could turn trailing on and off while driving. It got to the point that I had to have somebody else switch it because the act of my clicking the switch was throwing of my butt dyno. The results were too close to call. I think that's pretty funny.
Of course both of these tests were conducted on stock ignitors. Mine had DLIDFIS and the trailing sparks were routed through the leading part of the cap. The other was fully stock FB ignition. When your engine is producing around 100HP, 1HP is only 1% total engine power, so you won't feel it. Heh, my stripped down 20B will have at least 200HP (closer to 250HP NA if I set up everything right) and trailing would have only been good for about 1.5HP, I'm guessing. Either way that's less than 1%. I don't lose any sleep over this loss.
As for going with an MSD in trailing, I suppose it wouldn't hurt anything other than your pocketbook and the cap 'n' rotor. At least the sparks can take advantage of the carbon button until they burn them up, then you could move the wires to the trailing part of the cap if you didn't feel like buying a new cap and rotor right then and there. The good thing is that the compensation will be the same (this means the LT split will not vary with RPM like it does when people use an MSD on leading and leave trailing stock). Do you have a 6AL box? I can't remember.
11-18-04, 08:26 PM
#6
Nope just a 6a box. I didn't realize that the split changed using an MSD. Explain this. Also I was at racing beats web site looking at plugs and they recomend using NGK the iridium plugs and while at GI Joes I noticed they have the same ones there for $3 cheaper and was thinking about running the 8's in the leading and the 9's in the trailing. Is this a worth wile investment or should I stick to the stock replacement FC plugs. When I supercharge I figure I'll run 9's all around, but will the stock trailing ignition be able to, or rather benifit from the firing the iridium plugs? Cause they're the same price as the stock second gen plugs.
Last edited by Hyper4mance2k; 11-18-04 at 08:31 PM.
11-18-04, 08:47 PM
#7
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I see your only running 3 plug wires...I think this answers one of my questions in a post today. I see that trailing is not neccessary? and your not running anything to either position! Is this correct? I got this info from your cardomain site in your signature.
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11-18-04, 09:04 PM
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Im staring at your cardomain site HYPER and im baffled.
Im looking at your engine pictures and it shows your T1 T2 plug wires going to the L1 L2 SPark plug. Am I seeing this right? And your trailing coil going to T on dist. cap? Im going crazy I think
Im looking at your engine pictures and it shows your T1 T2 plug wires going to the L1 L2 SPark plug. Am I seeing this right? And your trailing coil going to T on dist. cap? Im going crazy I think
11-19-04, 05:33 AM
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Hyper, I'm not running MSD, but I am using the 2nd gen direct fire. I have noticed that using BUR7EQ in the lead and up until recently BUR8EQ in the trail that the engine ran extreamly smooth. Better IMO than with the 9's in the trail or 9's all the way around. Unfortunatly I can no longer get the BUR8EQ. Therefore I was left with the BUR9EQ instead of the BUR9EQ-14's. I have not yet brought myself to put them in the trail. I guess that after hearing Jeffs' opinioun that I am not ready to sacrifice my ignitor. At any rate if you can find the 8's I think that you will enjoy the way the motor runs and performs with the 7's instead of runnning the 9's.
11-19-04, 07:01 AM
#14
Would it be possible, or even worth it to drill out (during rebuild obviously) the shroud, or whatever it is that covers up most of the spark plug end inside the trailing mounting holes? Like, when you look in the holes and the leading is wide open but the trailing is not. Could you make it to where they were both the same and would that help any? I always wondered why it was there and what the actual use is. May be a safety thing so you cant put those in too far??? Someone who knows, please answer. Sorry to thread jack, but it kind of went along with what was being discussed.
Ian
Ian
11-19-04, 01:07 PM
#15
Hyper4mance2k, the compensation is a built-in feature of any so-called 'smart' ignition module which has a dwell function. As RPMs climb, the timing will get progressively more retarded. At or near redline, the difference between an MSD and a J-109 can be quite a lot. Even at idle, I noticed a difference which was enough to prompt me to have to reset my timing after installing the MSD, and then reset it again after removing it. I was like dubya tea yeff. I think only the higher-end MSDs' compensation is adjustable.
I don't have much of an opinion on the iridium plugs. You probably shouldn't use 9 in all four holes. Even the T2 and 3rd gens use L7 and T9. Since you already have a direct fire leading ignition system, and you plan on getting an MSD for trailing, why not get a set of platinum plugs like what the 3rd gen has? BUR7EQP and BUR9EQP.
MountainDew67, keep learning. Your rotary VW project is a great example of a cool rotary project. Try to learn all the cool tips and tricks that we often talk about on this forum. I don't even have a 1st gen, but I've got some parts on my older rotaries, such as 1st gen ignition stuff, that keeps me coming back to this forum more than any other on this site. It's not because the parts are complicated or anything, it's because I like to share the knowledge I've gained from working with them.
Brianhsval, BUR8EQ was the stock trailing plug of a 20B and 13BRE. My engine actually had a set of 2nd gen plugs in it which were one heat range too cold. It was full of carbon (luxury car engines get this way lol). So where did you try to purchase some BUR8EQs from? It might be good if we can find a reliable source for these plugs.
By the way, what is BUR9EQ-14's? What do you mean sacrifice the ignitor? Is it something I said would happen? If you're trying to use a direct fire plug in a cap and rotor ignition system, it's more difficult to jump the gap, and they may misfire more often than a BR8EQ-14 would have. Of course if trailing misfires from time to time, you'd probably never notice it. I don't think it would burn out the ignitor, but it is possible. On that note, my friend's REPU with a set of 2nd gen plugs and a cap and rotor (stock FB) ignition system burned out the coil I'm assuming from the increased resitance.
It's best to choose plugs which match your ignition system. This is why I often recommend BUR7EQ in leading and BR8EQ-14 in trailing. The leading plugs always wear faster due to being less shrouded, and as my older DLIDFIS projects age, I'm going to inspect the plugs from time to time and eventually change out the BR8EQ-14s in leading for a new set of BUR7EQs and probably leave the trailing plugs alone if they look good. BR8EQ-14s aren't sold at my local auto parts store anymore. Good thing the trailing plugs don't wear very quickly, huh?
IanS, as I said earlier, the reason why you don't want to go drilling (I mispelled the word in my post above) out the trailing holes is because you'd get massive blowby as the apex seals travel over the trailing holes. As they pass the trailing holes, the AF mixture has already been ignited and is in the process of burning. A little leaks past the stock sized trailing holes already. The 787B had late-trailing holes that were the same size as the regular trailing holes and it caused enough blowby that the torque of the engine did not increase, even though it had a third set of spark plugs! Or maybe it was the gas mileage? I think gas mileage was a factor. If you're interested, you can PM Evil Aviator for more info on the 787B as he always has lots of links handy.
I don't have much of an opinion on the iridium plugs. You probably shouldn't use 9 in all four holes. Even the T2 and 3rd gens use L7 and T9. Since you already have a direct fire leading ignition system, and you plan on getting an MSD for trailing, why not get a set of platinum plugs like what the 3rd gen has? BUR7EQP and BUR9EQP.
MountainDew67, keep learning. Your rotary VW project is a great example of a cool rotary project. Try to learn all the cool tips and tricks that we often talk about on this forum. I don't even have a 1st gen, but I've got some parts on my older rotaries, such as 1st gen ignition stuff, that keeps me coming back to this forum more than any other on this site. It's not because the parts are complicated or anything, it's because I like to share the knowledge I've gained from working with them.
Brianhsval, BUR8EQ was the stock trailing plug of a 20B and 13BRE. My engine actually had a set of 2nd gen plugs in it which were one heat range too cold. It was full of carbon (luxury car engines get this way lol). So where did you try to purchase some BUR8EQs from? It might be good if we can find a reliable source for these plugs.
By the way, what is BUR9EQ-14's? What do you mean sacrifice the ignitor? Is it something I said would happen? If you're trying to use a direct fire plug in a cap and rotor ignition system, it's more difficult to jump the gap, and they may misfire more often than a BR8EQ-14 would have. Of course if trailing misfires from time to time, you'd probably never notice it. I don't think it would burn out the ignitor, but it is possible. On that note, my friend's REPU with a set of 2nd gen plugs and a cap and rotor (stock FB) ignition system burned out the coil I'm assuming from the increased resitance.
It's best to choose plugs which match your ignition system. This is why I often recommend BUR7EQ in leading and BR8EQ-14 in trailing. The leading plugs always wear faster due to being less shrouded, and as my older DLIDFIS projects age, I'm going to inspect the plugs from time to time and eventually change out the BR8EQ-14s in leading for a new set of BUR7EQs and probably leave the trailing plugs alone if they look good. BR8EQ-14s aren't sold at my local auto parts store anymore. Good thing the trailing plugs don't wear very quickly, huh?
IanS, as I said earlier, the reason why you don't want to go drilling (I mispelled the word in my post above) out the trailing holes is because you'd get massive blowby as the apex seals travel over the trailing holes. As they pass the trailing holes, the AF mixture has already been ignited and is in the process of burning. A little leaks past the stock sized trailing holes already. The 787B had late-trailing holes that were the same size as the regular trailing holes and it caused enough blowby that the torque of the engine did not increase, even though it had a third set of spark plugs! Or maybe it was the gas mileage? I think gas mileage was a factor. If you're interested, you can PM Evil Aviator for more info on the 787B as he always has lots of links handy.
Last edited by Jeff20B; 11-19-04 at 01:20 PM.
11-19-04, 05:31 PM
#16
What benifits do platinum plugs offer over regular plugs? And what's the big deal with iridium plugs. The ones I found are the ones Racing beat recomends and sells for $9 each; I found then for $5 each the same as they sell the stock FB plugs for and the stock FC plugs are $6 each so I'm thinking of going iridium, but whats the big deal with exotic metals in the engine. Is it just the bling factor comming in?
11-19-04, 07:50 PM
#17
You can find out lots of great info about spark plugs like "What makes platinum and iridium better than regular plugs" at www.sparkplugs.com , through their FAQ.
For Iridium, in the Canadian section they were saying that someone was using BR8EIX Iridium plugs from NGK on their 2nd gen, the benefit of the plugs being that a) they worked and b) they were cheap because they are used for other applicaitons. $11/ea Canadian here and available straight off the shelf at the local part store. Now I know that they don't protrude too far ('cause 13b and 12a have the same plug depth), but I don't know how well they'd work in the 1st gen's distributor cap ignition system vs. the 2nd Gen direct fire. If you switch to DLIDFIS or 2ndGen coil I would say that they're worth running.
Heck, for only $11 (when my BR8EQ-14s are the same price) I'd try 'em anyway! And I will in the spring, so if you wanna know how that goes, somebody ask me in late May
The Platinum and Iridium are there because a) they're as good or better conductors b) they are stronger metals which can be machined into thinner centre posts for better flame front c) they are stronger metals which will last longer. More details on sparkplugs.com
Jon
For Iridium, in the Canadian section they were saying that someone was using BR8EIX Iridium plugs from NGK on their 2nd gen, the benefit of the plugs being that a) they worked and b) they were cheap because they are used for other applicaitons. $11/ea Canadian here and available straight off the shelf at the local part store. Now I know that they don't protrude too far ('cause 13b and 12a have the same plug depth), but I don't know how well they'd work in the 1st gen's distributor cap ignition system vs. the 2nd Gen direct fire. If you switch to DLIDFIS or 2ndGen coil I would say that they're worth running.
Heck, for only $11 (when my BR8EQ-14s are the same price) I'd try 'em anyway! And I will in the spring, so if you wanna know how that goes, somebody ask me in late May
The Platinum and Iridium are there because a) they're as good or better conductors b) they are stronger metals which can be machined into thinner centre posts for better flame front c) they are stronger metals which will last longer. More details on sparkplugs.com
Jon
11-20-04, 02:06 PM
#18
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Originally Posted by Jeff20B
Brianhsval, BUR8EQ was the stock trailing plug of a 20B and 13BRE. My engine actually had a set of 2nd gen plugs in it which were one heat range too cold. It was full of carbon (luxury car engines get this way lol). So where did you try to purchase some BUR8EQs from? It might be good if we can find a reliable source for these plugs.
By the way, what is BUR9EQ-14's? What do you mean sacrifice the ignitor? Is it something I said would happen? If you're trying to use a direct fire plug in a cap and rotor ignition system, it's more difficult to jump the gap, and they may misfire more often than a BR8EQ-14 would have. Of course if trailing misfires from time to time, you'd probably never notice it. I don't think it would burn out the ignitor, but it is possible. On that note, my friend's REPU with a set of 2nd gen plugs and a cap and rotor (stock FB) ignition system burned out the coil I'm assuming from the increased resitance.
It's best to choose plugs which match your ignition system. This is why I often recommend BUR7EQ in leading and BR8EQ-14 in trailing. The leading plugs always wear faster due to being less shrouded, and as my older DLIDFIS projects age, I'm going to inspect the plugs from time to time and eventually change out the BR8EQ-14s in leading for a new set of BUR7EQs and probably leave the trailing plugs alone if they look good. BR8EQ-14s aren't sold at my local auto parts store anymore. Good thing the trailing plugs don't wear very quickly, huh?
So, are you saying that the coil is what could could go with the BUR9EQ? Not the ignitor? If that is the case I will install the 9's that I have and get back with you in about a month and let everyone know if they are working well. I don't mind losing a coil for this. I just don't want to chance the ignitor.
11-20-04, 02:22 PM
#19
Oh, I see you meant to say BR8EQ-14, and not the stock trailing plug of JC Cosmo engines. There's no U in 1st gen NGK plugs. 
As for cleaning them with gas, I've done it before and it gets rid of all the oil that may be sitting on and within the plug. It makes cleaning carbon and other deposits from the electrodes really easy with a wire brush or wheel as the carbon dust/particles won't stick.
Yep, the coil burned through the long insulator and started arcing to one of the terminals. The ignitor lived through it just fine. He swapped the coil and ran the REPU for another year or two without any problems other than misfires. I installed DLIDFIS in it this summer and left the BUR9EQs in trailing; so far, so good. Go for it.
As for cleaning them with gas, I've done it before and it gets rid of all the oil that may be sitting on and within the plug. It makes cleaning carbon and other deposits from the electrodes really easy with a wire brush or wheel as the carbon dust/particles won't stick.
Yep, the coil burned through the long insulator and started arcing to one of the terminals. The ignitor lived through it just fine. He swapped the coil and ran the REPU for another year or two without any problems other than misfires. I installed DLIDFIS in it this summer and left the BUR9EQs in trailing; so far, so good. Go for it.
11-21-04, 05:09 PM
#22
Well i put in the br8eix in the leading and noticed verry little difference only thing it did was smooth out the top just a little bit more. Caution: you need a thin walled socket to put these in. I wish I would've known thank god I've got strong hands. I hand tightened them and they seem fine. I'm going to have to grind down my socket soon just to be safe.
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