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TD 6, When TDC is not TDC


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I'm adding a post, to update my "TD6 won't start" earlier post, because I'm afraid this won't get seen.  After everything previous I still have no spark.  I removed the breaker cover and set the engine to TDC on the compression stroke, (heard the impulse drive kick over), when I look at the distributor lobes the rubbing block is not on the high point of the lobe.  The points are open but it seems the rotor is not quite at the #1 wire. Can the distributor be out of adjustment? Gap on the points is .013 when fully opened.

I am used to older gas engines where I could rotate the distributor a little for optimum spark.  I don't see any means to do that on the TD6 mag/distributor. Or could there be a timing mark on the crankshaft pully that I'm not seeing? I placed it at a definite mark on the pully. 

Hoping someone understands this better than I do.  It was running when I shut it down at the end of January due to COVID knocking me down.

Thanks for the assistance,

Tracksbeatwheels

Damascus, Oregon

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Hi Mmi, it is a magneto distributor. I disconnected the grounding wire to be sure that it would fire.  I have tried resetting the points, but have not removed the mag or distributor.  I don't understand why at (supposedly) TDC the rubbing block is not on top of the distributor lobe.

Thanks for your reply

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The magneto shouldn’t be tripping at TDC it should be doing so at the M mark which is about 12mm after the TDC mark, that is the mark where the points should open, the points cam lobes can be timed , as they are a press fit onto the magneto shaft and can be rotated, as the points block that rides on the cam lobes wears away it changes the points opening timing , if you see my thread about TD6 won’t start on petrol, I explain where the points should open in regards to the magnet orientation when it’s held by magnetism between the air gap of the magneto .

reg

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5 hours ago, reggievonruffnut said:

The magneto shouldn’t be tripping at TDC it should be doing so at the M mark which is about 12mm after the TDC mark, that is the mark where the points should open, the points cam lobes can be timed , as they are a press fit onto the magneto shaft and can be rotated, as the points block that rides on the cam lobes wears away it changes the points opening timing , if you see my thread about TD6 won’t start on petrol, I explain where the points should open in regards to the magnet orientation when it’s held by magnetism between the air gap of the magneto .

reg

Very true the information given, there are two different timing marks on the flywheel, one for pistons, the other for ign timing.  The above poster has great information on this subject 

Mark

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Hi Mmi, it is a magneto distributor. I disconnected the grounding wire to be sure that it would fire.  I have tried resetting the points, but have not removed the mag or distributor.  I don't understand why at (supposedly) TDC the rubbing block is not on top of the distributor lobe.

Thanks for your reply

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Hi Reg, It makes sense even though I can't find an "M" on the crankshaft pulley. When I move it to about that position the rubbing block is on the lobe.... I'll check to see when the impulse drive trips exactly.  I'll go back to your post about not starting on Petrol and see what you have there.  Thanks everyone.  I hope I don't have to take the mag off the machine. It's alien to me at this point.  Thanks everyone, send more ideas as you have them.  

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if engine was not factory mag it may not have an "M"

go thru reggs info,   from here suspect you or time have disturbed grounding,connections /un connections at the proper times . check coil that is rare but common and for $85 most hack in a $20 12v   . then the slim chance of lost magnetism.

KISS, this is where I swap in running 5 min ago parts,

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Good News!  After watching a lot of you tube videos about rebuilding the H4 magneto, I decided to try something to test the coil.  I inserted my spark tester into the coil terminal and grounded it. then I cranked the engine and behold! there was spark!  so now I know that then problem is in the distributor.  Another video showed me that I can adjust the distributor by undoing two bolts and moving the distributor back and forth slowly to get the timing right.  I may be very close to having success, but its raining now and I have to wait for the sunshine. I can see the light of day.

TRACKSBEATWHEELS

Damascus, Oregon

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9 hours ago, Tracksbeatwheels said:

Good News!  After watching a lot of you tube videos about rebuilding the H4 magneto, I decided to try something to test the coil.  I inserted my spark tester into the coil terminal and grounded it. then I cranked the engine and behold! there was spark!  so now I know that then problem is in the distributor.  Another video showed me that I can adjust the distributor by undoing two bolts and moving the distributor back and forth slowly to get the timing right.  I may be very close to having success, but its raining now and I have to wait for the sunshine. I can see the light of day.

TRACKSBEATWHEELS

Damascus, Oregon

Crikey! I was working on the assumption you had already tried the range of magneto adjustment provided by the bolts, so what you need to do is loosen the magneto bolts and pull the mag to you as far as it can go, then rotate the engine in the correct direction to TDC on the compression stroke, then rotate past that point by 12 - 15mm, the go back to the magneto and slowly push it away until the magneto gives a distinctive throwing click, tighten the mag bolts & it will be correctly timed.

reg

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2 hours ago, reggievonruffnut said:

Crikey! I was working on the assumption you had already tried the range of magneto adjustment provided by the bolts, so what you need to do is loosen the magneto bolts and pull the mag to you as far as it can go, then rotate the engine in the correct direction to TDC on the compression stroke, then rotate past that point by 12 - 15mm, the go back to the magneto and slowly push it away until the magneto gives a distinctive throwing click, tighten the mag bolts & it will be correctly timed.

reg

Hi Reggie, Thanks for the update, I didn't realize that I could "time" the magneto simply as you said.  That makes a lot of sense. As you and others have said the Impulse drive reacts not at TDC but at 12-15mm "after TDC" I found this out myself by had turning the crankshaft, however the only mark I have on my Crankshaft is the TDC mark. Just to be sure, its 12 - 15mm, not 12 - 15 degrees right?  I'm going to check it as soon as we get a dry day, This is Oregon and my 6 is covered with a tarp except when I'm working on it or using it.  Thank you for sharing your knowledge with those of us who aren't educated yet.

ron

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Well, at this point it's just throwing ideas out there, when I rebuilt my 9, I had the wires setup for incorrect rotation of the distributor.  In your first post you said the wires were wrong, and very possibly so.  I am looking through and old manual, and it is saying there is right hand rotation mags, and left hand rotation. When you routed the wires, you are sure which direction yours is turning?  I went by the manuals and what I understood, but untill I pulled the cap and watched while cranking, I was backwards. I had no fire at all on a new motor, untill I got that straightened out. You might be right, I'm just throwing out there what happened to me. 

Mark

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On 4/1/2022 at 1:23 AM, Tracksbeatwheels said:

Hi Reggie, Thanks for the update, I didn't realize that I could "time" the magneto simply as you said.  That makes a lot of sense. As you and others have said the Impulse drive reacts not at TDC but at 12-15mm "after TDC" I found this out myself by had turning the crankshaft, however the only mark I have on my Crankshaft is the TDC mark. Just to be sure, its 12 - 15mm, not 12 - 15 degrees right?  I'm going to check it as soon as we get a dry day, This is Oregon and my 6 is covered with a tarp except when I'm working on it or using it.  Thank you for sharing your knowledge with those of us who aren't educated yet.

ron

It is millimeters not degrees, I’ll try and post the H4 manual in the next day or so.

Reg

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If the mag base is 4 1/2" diameter a degree and a millimeter is the same thing 🤔

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22 hours ago, hardtail said:

If the mag base is 4 1/2" diameter a degree and a millimeter is the same thing 🤔

The distance is on the harmonic balancer/ belt drive at the front of the engine, the M mark is exactly 10mm after the TDC mark.

reg

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On 3/31/2022 at 4:13 AM, reggievonruffnut said:

Crikey! I was working on the assumption you had already tried the range of magneto adjustment provided by the bolts, so what you need to do is loosen the magneto bolts and pull the mag to you as far as it can go, then rotate the engine in the correct direction to TDC on the compression stroke, then rotate past that point by 12 - 15mm, the go back to the magneto and slowly push it away until the magneto gives a distinctive throwing click, tighten the mag bolts & it will be correctly timed.

reg

Reg,  Thanks, I did like you said, at the point that the impulse drive, "snapped" I locked the bolts down, then hooked up number one plug via my spark tester, but no spark.  I connected the spark tester to the coil output and cranked it over. Lots of spark!  For some reason the spark is not being delivered to the distributor or the rotor and the distributor are still not where they should be. Taking the cap off it looks as though they are where the should be, number one at about two oclock.  We're getting closer, but still no ceegar. I really appreciate all the advice you and others have given me. Oh, By the way, the cap and rotor are relatively new still shiney brass inside.

Ron

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Leave the cap off and see if your points are arcing when it trips

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Thanks everyone for your comments, As soon as it quits raining I'll check the rotation again, (I'm sure I did already. the engine turns clockwise and the H-4 Mag turns counter clockwise, but I'll double check.  I will also take a closer look at the cap contacts and the rotor.  The mag has not been removed from the engine. I took the distributor down to the points to make sure they were adjusted correctly.  I'm also convinced that it is something simple and I will kick myself for later, but I am really perplexed.  Thanks reggie for the Mag rebuild pages. I have tried printing one and will check it later today.  Hey reg, do you live in the city or in the bush? Many years ago while in the Marines, I met some Aussies who took me aboard their ship, The Ark Royal in the Philippines. We had a great time, then I screwed up and said something like, "You limeys really know how to have a good time." to which my friend exploded with, "Limey, I ain't no bloomin limey, I'm Australian!"  I will never forget that.

ron

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On 4/3/2022 at 11:36 PM, Tracksbeatwheels said:

Thanks everyone for your comments, As soon as it quits raining I'll check the rotation again, (I'm sure I did already. the engine turns clockwise and the H-4 Mag turns counter clockwise, but I'll double check.  I will also take a closer look at the cap contacts and the rotor.  The mag has not been removed from the engine. I took the distributor down to the points to make sure they were adjusted correctly.  I'm also convinced that it is something simple and I will kick myself for later, but I am really perplexed.  Thanks reggie for the Mag rebuild pages. I have tried printing one and will check it later today.  Hey reg, do you live in the city or in the bush? Many years ago while in the Marines, I met some Aussies who took me aboard their ship, The Ark Royal in the Philippines. We had a great time, then I screwed up and said something like, "You limeys really know how to have a good time." to which my friend exploded with, "Limey, I ain't no bloomin limey, I'm Australian!"  I will never forget that.

ron

I live in the bush, you would have been confused, the Ark Royal was a British ship.

reg

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Hi Reg, Yes it was, but for some reason there were Aussies aboard. It was a grand ship. Now that we are talking about Australia, what's the difference between the Outback and the Bush.

I still have no spark to the distributor. The impulse drive snaps perfectly at the right moment. I set the engine at TDC, then advance it ten mm with the Mag loosened and pulled toward me as far as it will go.  With the engine at that mark, I slowly push the Mag away from me and lock it down when the impulse drive "snaps", then I lock it down and try to start it but no spark at the distributor.  I am going to recheck the points once more.  Should I set the points at TDC or at the "M" mark, (which I don't have)?  I'm "assuming" that I should set them with the rubbing block on the highest point of the lobe. I cleaned the rotor and the cap the contacts inside are bright and shiny.  Oh! One more thing.  I shorted the coil to number one plug, but it didn't spark then either, so its back to the points. Maybe the spark isn't strong enough to jump the plug?

Maybe I should replace the condenser? I know the coil functions, but if the condenser is weak maybe it would not give a strong spark.

I'm learning a lot, surprising how many diesel people have never heard of the IH Gas/Diesel engine.  I tried explaining it to a Cat guy and he said I meant "Pony Motor", nope, I told him, starts on gas and runs on diesel,  He said "unbeliefvable"  LOL

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The condenser could be a problem  Make sure it is not grounded.  When replacing it make sure the new condenser fits the hold down strap.  I replaced the condenser on my Oliver 77 and just slid it into the old strap and tightened the screw.  It kept cutting out at odd times when I would drive it around.  Turned out the new condenser was not quiet as big around as the old one and the condenser was moving under the strap and shorting out when I ran the tractor.  I used the new strap that came with the new part and the problem was solved.

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One should try to find a good old condenser or take a chance with a Chiny model though they are not very reliable.  I had trouble with my TD14A and got a replacement condenser that was too short and tried to make it work, but no go.  I finally found that the coil was defective and solved my problem.  

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On 4/7/2022 at 3:52 AM, Tracksbeatwheels said:

Hi Reg, Yes it was, but for some reason there were Aussies aboard. It was a grand ship. Now that we are talking about Australia, what's the difference between the Outback and the Bush.

I still have no spark to the distributor. The impulse drive snaps perfectly at the right moment. I set the engine at TDC, then advance it ten mm with the Mag loosened and pulled toward me as far as it will go.  With the engine at that mark, I slowly push the Mag away from me and lock it down when the impulse drive "snaps", then I lock it down and try to start it but no spark at the distributor.  I am going to recheck the points once more.  Should I set the points at TDC or at the "M" mark, (which I don't have)?  I'm "assuming" that I should set them with the rubbing block on the highest point of the lobe. I cleaned the rotor and the cap the contacts inside are bright and shiny.  Oh! One more thing.  I shorted the coil to number one plug, but it didn't spark then either, so its back to the points. Maybe the spark isn't strong enough to jump the plug?

Maybe I should replace the condenser? I know the coil functions, but if the condenser is weak maybe it would not give a strong spark.

I'm learning a lot, surprising how many diesel people have never heard of the IH Gas/Diesel engine.  I tried explaining it to a Cat guy and he said I meant "Pony Motor", nope, I told him, starts on gas and runs on diesel,  He said "unbeliefvable"  LOL

The bush is greener and rugged, the outback is dry, desolate, unforgiving and the crows fly backwards to keep the dust out of their eyes.

you said you were getting a good spark out of the coil wire that leads to the distributor cap, that means the points are working ok, that means the problem should be beyond that point, which could be the distributor cap, the rotor button, the leads or the plugs.

reg

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