walt evans

Timing a Dodge Brothers 27 roadster has me on the ropes

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Maybe someone can tell me what I'm doing wrong.  I have a 27 Dodge Brothers Roadster. I've tried to time it to the book, but it's very confusing.

I consider myself pretty good with engines, but this just isn't working.  After doing what I think they are saying, it run's but sluggish as hell with little or no power. While its running I loosened the dist. and turned to the left (CCW) and it increased in rpm and power. I must have moved it 20 degrees or so. Now it's peppy and has quick acceleration.It's obvious I am doing it wrong, but what part of the procedure am I not understanding?

I'd appreciate any input on this.

Thank you.

 

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It's not the fast four. Seems the models were changing around this time. Engine #D936-xxx.

The distributor is lower right, front, driven off water pump shaft

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Hi Walt,  are you following the Mechanics Instruction Manual for setting static timing?  I'm not sure if procedure in my '25 manual will be correct for your engine but I'll scan in and post the pages if you like.  It sounds as if the distributor is in same place as on a '25 motor.

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I Have a D938-120 engine in my 27 sedan. Very close to yours. I used a timing light and the marks on the fly wheel to get it close and then just tweaked it from there. It is the engine I’m going to pull apart shortly and balance. It runs nice but the vibration makes it horrible. 

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Mike and Matt,

I've tried multiple times and it doesn't make sense. That my problem.

As far as the timing light, can't seem to find the mark in the window anywhere. (I've even highlighted it with a big white dot.

The time light alone is not the problem, It's how am I reading the procedure wrong?

I don't understand that in all the illustrations of the distributor, it shows the finger of the points on the back side of the lobe with the rotor spinning clockwise, this would relate to the points closing not opening when the spark happens.  Guess maybe that "close" point is just the reference that they use back then.

I still don't get it.

Oh well.

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Electrically you need the points to open to make the spark happen, pure physics there!  Sounds like you might have some excess lash in the distributor or it’s drive that forces the timing when running to be off and need extra advance.

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Walk away from it and reread the directions in your mind. I know someone that read the same directions for a DA. It said turn the distributor one way and I, I mean he was turning it the other way. When done correctly it worked and ran. 

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The picture that is shown with the procedure is usually this one. But it's confusing cause with the rotor turning clockwise, this is where the points close, not where it's firing.   Maybe I'm just assuming that's where I should be, but I should be on the other side of the lobe.That would make sense to where I turned it.

For all you who did this and it worked, where you like the Picture, or where the point fire?

Thanks

dist.PNG

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Hi I have 18 4 cylinder had some what the same problem I called a DB brother told him the eng was lazy first question he ask was the carburetor throat wet with condensation  (Yes it was ) his answer was its very slow in timing ( loosen the cam screw advance the rotor some and sneak up on the optimum timing then back off a little) boy what a difference it made I don't know what the actual timing is but it runs smoothly and very cool temp.  Hope this helps    mike

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Mikefit,

Thanks.

I guess that's kind of what I did. Just that it seemed quite alot  of movement.

Guess the point of this thread is wondering why I had to move it so much.

Bottom line is that It runs  so much better now, I'm happy.

  • Thanks 1

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Wouldn't condensation on the intake singlefold (it's not a manifold) be more an indicator of water vapor in the air?  The fuel has been introduced to the air  at this point and I would think some  cooling effect is normal.  I didn't think the condensation was unusual and mine seem to run fine (although I don't have anything to compare it to).

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Mike,

Any time you have rapid expansion of air, like when air/fuel goes through the carb venturi, the temp drops. So it's like a cold glass of beer with condensation on the outside.  That is not necessarily a bad thing except in flying. That's why small piston airplanes have a Carb heat control to put hot air into the carb when slowing the engine which brings the vacuum up.  The planes will actually freeze up and quit.  And it actually happens more in the warm weather when the moisture is high.

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That makes sense Walt.  I forgot about carb heat on small aircraft.

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Yes Walt  we lost 2 pilots here about 2 yrs ago small plane not property warmed up went to full throttle iced up went in the lake   I don't understand why the D/B brother ask if it had condensation on it but ?????? Mike

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Think it's one of those things that you never notice till you're looking for something else and the condensation stands out as being odd.

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Condensation is a symptom of carb. icing. My Dodge 8 gets it when the temperature is below about 12 oC. During warmup you can feel the cold on the neck of the intake below the carb. That is why they had manifold heat flaps, to put exhaust up around the intake during warmup. Nothing to do with tune, just means cold.

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