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Old 02-04-2009, 10:17 AM
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Straight 8 questions

Hello all -

Engine in question is a 36 240 cid Olds. Currently running 6 Volt ( I am converting to 12V when the temp is over freezing ) Carter WDO 2 Barrel Carb.

Quick recent history for background. Over the last 2 summers I have simply driven the car (roughly 1500 miles) and it runs ok. The carb has been rebuilt several times due to hesitation. The first couple of times I rebuilt it myself and then sent it out the last time as I had become convinced I was doing something wrong. The engine will hesitate sharply on acceleration when the choke is open. However, the hesitation dissapears when the choke is set to roughly 60% closed, and the engine runs fairly well.

As last summer progressed the car had become increasingly difficult to start. The timing is good, the plugs are good, the points appear fine (though I will replace this spring to be sure - along with condenser,) I cannot locate a vacuum leak. While I am on the topic - does anyone know of a cross reference for points and condenser - and will this need to be changed when I convert to 12V?

Am I missing anything? My first instinct is to replace the accel pump, but am gunshy at opening the carb up again. I by no means would consider myself a mechanic - but am no idiot either (though some might disagree) and am not afraid to get my hands dirty.

The other change I have planned to make is convert the car to 12V - as it starts far better when the hand crank is used in comparison to the starter.


I am certainly open to suggestions! I also know that this is a less common engine - but its different and I like it - and on top of it the car orginally belonged to my great grandfather...


Thanks in advance for any thoughts! I will try to provide as much information as I can!


36oldseight

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Old 02-04-2009, 12:00 PM
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Remove the air cleaner and get some light in the carb. Move the accelerater slowly and watch the pump shot. It should spray fuel the instant you move the throttle, if it passes that test next I would move the throttle quickly and be sure it does the same thing as in the past when the throttle is moved slowly no hesitation and a full pump shot, move it quickly the pump shot would delay. If this is the case then there`s a issue with the acc. Pump. Being it doesn`t hesitate with the choke half closed indicates it`s lean, as it`s limiting the amount of air and increasing the amount of fuel.
As for converting to a 12V the points must remain on a 6 volt supply. However I would switch over to a electronic ignition if anyone makes a kit for it as the best place for points is the trash.
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Old 02-04-2009, 03:53 PM
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Quote:
Originally Posted by 36OldsEight
Hello all -

Engine in question is a 36 240 cid Olds. Currently running 6 Volt ( I am converting to 12V when the temp is over freezing ) Carter WDO 2 Barrel Carb.

Quick recent history for background. Over the last 2 summers I have simply driven the car (roughly 1500 miles) and it runs ok. The carb has been rebuilt several times due to hesitation. The first couple of times I rebuilt it myself and then sent it out the last time as I had become convinced I was doing something wrong. The engine will hesitate sharply on acceleration when the choke is open. However, the hesitation dissapears when the choke is set to roughly 60% closed, and the engine runs fairly well.

As last summer progressed the car had become increasingly difficult to start. The timing is good, the plugs are good, the points appear fine (though I will replace this spring to be sure - along with condenser,) I cannot locate a vacuum leak. While I am on the topic - does anyone know of a cross reference for points and condenser - and will this need to be changed when I convert to 12V?

Am I missing anything? My first instinct is to replace the accel pump, but am gunshy at opening the carb up again. I by no means would consider myself a mechanic - but am no idiot either (though some might disagree) and am not afraid to get my hands dirty.

The other change I have planned to make is convert the car to 12V - as it starts far better when the hand crank is used in comparison to the starter.


I am certainly open to suggestions! I also know that this is a less common engine - but its different and I like it - and on top of it the car orginally belonged to my great grandfather...


Thanks in advance for any thoughts! I will try to provide as much information as I can!


36oldseight
The hesitation is lean drop and was very common upon opening the throttles in these old engines.

It's often due to the lack of a transition circuit in these carbs between idle and main metering. It can be hidden to some extent with greater accelerating pump discharge. But if this old Carter lacks a transition circuit, then it pretty much is what it is.

However, if the Carter has a transition circuit, then careful tuning of the idle so as to get the engine to tick over nice with the top of the throttle plate just under the bottom of the transition hole or slot will help.

Another trick is to kick the base timing up a few degrees, these old low compression engines can take a lot of low speed advance today. They didn't use it back when because the fuels of the day had octane ratings in the 50s and 60s so they knocked with 6.5 to 1 compression. Even today's unleaded regular brings 87 octane to the table so you can push on the advance without problems. This gives these low density mixtures a longer time to burn.
Actually if your converter to 12 volts, hiding an MSD multiple spark box will help also as it improves getting the burn going at all, reducing missfires and late burns.

Bogie
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Old 02-05-2009, 11:20 AM
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Bogie and Double Vision -

Thank you both for your replies - I plan to fire the car up this weekend as the weather might just cooperate enough to be outside for an extended period of time. I will take a look at what you both mentioned - though I will admit that I haven't even looked into electronic ignition at this point.

Chris
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