Pony plugs

Hilltopper · Jan 17, 2013

I have problems starting the pony on my 58 720d.
I put a new set of Autolite 303 in it and it seems worse. It always fuel fouls the plugs when attempting to start it after it sets a few days.
I checked an autolite plug chart and it shows these to be resistor plugs. The chart shows a 458/258 non resistor.I have solid core wires and the distributor is good. I put new float valve and gaskets in carb. What do you use?

Rwolfejr · Jan 18, 2013

Myself... I don't think it really matters much what plugs you use. I've had best performance out of low octane gas (easier to ignite) and you probably just need to close the gap on your plugs a little bit. I had issues with an R I had and it'd fire fine with the plugs out. When put under compression it's harder for the spark to jump the gap. Closed them up and Voila!! Same thing on my 820's little V4. They like to be closed more than book says.

Try about .02 gap and so long as the rest of your electricals are O.K. you should be good. Also use low octane. It's easier to light.

jd2cylman · Jan 18, 2013

I used AC 45M plugs. A little hard to find, but they worked great. I still have one set left in case I ever get another pony.

Adrian

Dan in Ohio · Jan 18, 2013

That is interesting , I agree the type of plug makes little
difference as I use the (Clooney recommended) J8C in all four
of my cranking engines. Have also used auto lite plugs and
saw no difference. Next time I change plugs I will try
shortening the plug gap (just wish the back two were easier to
reach).

Hilltopper · Jan 18, 2013

Thanks for the replys. I use 87 octane fuel. I will try the closer gap.

buickanddeere · Jan 18, 2013

Autolite 437 non resistor . Plugs won't foul if the mixture is correct . Lube oil should be a low ash SF-2 40wt such as Shell Rotella T1.
We use 100LL in three starting engines here with excellent results. No gummed up fuel system components.
Have you installed matching wires for the starting engine coils? There are two distinct different types.

BushogPapa · Jan 18, 2013

B&D..I am sure my Manual calls for 10 WT in my Pony..'58 720 D...

Are you suggesting to use 40 Wt.??

Thanks..
Ron..

buickanddeere · Jan 18, 2013

There will be enough wear and extra clearance in the mains and rod that 40wt will be fine. The engine will smoke less too.
Any engine that is an oil burner will foul less with SF-2 oil or the engine oil for post 2007 diesel pickups.
Unless engine needs extreme pressure wear protection that most low ash oil struggles to provide.

730d se · Jan 18, 2013

"Use the same type of oil in the pony as used in the diesel."

Blksmok · Jan 18, 2013

Hilltopper...I'm normally not a fan of Champion spark plugs in cars and trucks, but I use JC8's in my pony motors and haven't had many spark plug fouling problems. The next time it balks when you try to start it ..run a jumper wire from the hot post of the starter to the terminal on the side of the coil box. The ignition switch contacts gets corroded and the resistor may be wrong so the coils don't see a full six volts on the starting mode. I use straight 30 weight non-detergent oil in the crankcase.

gtx1967jewison · Jan 19, 2013

I use shaeffers 20w-50 semi synthetic racing oil. It has lots of extra zinc (allowed by the dictatorship because its offroad motorsport oil) . It stopped my R pony from smoking &a it keeps the oil pressure higher than straight 30w. Non detergent oil should NEVER be used in an internal combustion engine!

Earl-IL · Jan 19, 2013

Repair your fuel system.

Hilltopper · Jan 19, 2013

I got a set of j8c plugs today and set them at .023. I was able to get the pony started. I will try it again Monday and see how it does. Thanks guys

Pony plugs

Hilltopper

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Rwolfejr

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jd2cylman

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Dan in Ohio

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Hilltopper

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buickanddeere

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BushogPapa

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buickanddeere

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730d se

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Blksmok

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gtx1967jewison

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Earl-IL

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Hilltopper

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