Ford F834 Posted January 8, 2018 Author Share Posted January 8, 2018 Bill - That's a very good point about the balancer slipping. It is not unusual at all with these old engines. It was either Dad's or Rusty's 351M that had the balancer's outer ring slipped and cocked slightly sideways. But they don't always give any external indications of having slipped, so need to be checked. Thanks guys for the great information that keeps pouring in. I am starting to get a little bit better picture of this whole process now. On the carb, I looked at that baseplate number, but I could not find it on the charts that David sent me for YF identification: I don't know if I stated this explicitly anywhere, but on my truck the EGR system has been removed and the catalytic converters deleted. I have heard about slipping harmonic balancer problems with the IDI, but I wasn't aware that the 300 balances did it. I guess it's worth checking. What is the best way to do this? I've found time via a screw driver in the spark plug hole method on the 240 with a broken distributor shear pin but that does not seem super accurate for checking the balancer notch. Also, my balancer had two notches in it... any idea what the other one is used for? Link to comment Share on other sites More sharing options...
PetesPonies Posted January 8, 2018 Share Posted January 8, 2018 Thanks guys for the great information that keeps pouring in. I am starting to get a little bit better picture of this whole process now. On the carb, I looked at that baseplate number, but I could not find it on the charts that David sent me for YF identification: I don't know if I stated this explicitly anywhere, but on my truck the EGR system has been removed and the catalytic converters deleted. I have heard about slipping harmonic balancer problems with the IDI, but I wasn't aware that the 300 balances did it. I guess it's worth checking. What is the best way to do this? I've found time via a screw driver in the spark plug hole method on the 240 with a broken distributor shear pin but that does not seem super accurate for checking the balancer notch. Also, my balancer had two notches in it... any idea what the other one is used for? The key on the crank snout will be at 12:00 when the engine's #1 cylinder is at TDC. But there are two times in the cycle that this happens. You need to find the correct one. I always use a small piece if toilet paper or light paper towel. I remove the plug and push the paper into the hole slightly. Crank the engine around by hand, the paper will shoot out on the compression stroke. Then move the engine slightly to align your timing marks at TDC or zero. When you have that done, remove the balancer bolt and see if the key is straight up and down. If it is not, your balancer has shifted or you are using the wrong timing marks. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 8, 2018 Share Posted January 8, 2018 The key on the crank snout will be at 12:00 when the engine's #1 cylinder is at TDC. But there are two times in the cycle that this happens. You need to find the correct one. I always use a small piece if toilet paper or light paper towel. I remove the plug and push the paper into the hole slightly. Crank the engine around by hand, the paper will shoot out on the compression stroke. Then move the engine slightly to align your timing marks at TDC or zero. When you have that done, remove the balancer bolt and see if the key is straight up and down. If it is not, your balancer has shifted or you are using the wrong timing marks. I use a method similar to Pete's. Once the paper has blown out, assuming you aren't going super fast when cranking, I then stick a straw or something soft in. Crank the engine further, slowly, and find the spot that has the most of the straw out. That will be TDC or close. But, the best way is with a piston stop. It is an adjustable bolt with a rounded head that screws into the spark plug hole. With trial and error you adjust it so that the piston stops close to TDC. Let's say 10 degrees, although how much doesn't really matter. You then turn the engine back the other way and gently come up against the stop again. Exactly 1/2 of that is true TDC. You can mark the balancer with a sharpie and if the mid-point is under the TDC mark the balancer hasn't slipped. You don't have to be super accurate as if it slips it usually slips a lot. Link to comment Share on other sites More sharing options...
85lebaront2 Posted January 8, 2018 Share Posted January 8, 2018 Thanks guys for the great information that keeps pouring in. I am starting to get a little bit better picture of this whole process now. On the carb, I looked at that baseplate number, but I could not find it on the charts that David sent me for YF identification: I don't know if I stated this explicitly anywhere, but on my truck the EGR system has been removed and the catalytic converters deleted. I have heard about slipping harmonic balancer problems with the IDI, but I wasn't aware that the 300 balances did it. I guess it's worth checking. What is the best way to do this? I've found time via a screw driver in the spark plug hole method on the 240 with a broken distributor shear pin but that does not seem super accurate for checking the balancer notch. Also, my balancer had two notches in it... any idea what the other one is used for? Great pictures! On the vacuum ports, the one on the side the number is on was probably for the EGR system, it was used to operate a vacuum amplifier as it probably goes into the venturii for a very low vacuum signal, the one on the throttle body should be for the distributor vacuum. Carburetor is probably from the mid 70s (sort of looks like the one my 1977 F150 300 had on it). 7388S is a Carter ID number, now if someone has a good carburetor PN listing for the YFs maybe you can pin it down. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 8, 2018 Share Posted January 8, 2018 Great pictures! On the vacuum ports, the one on the side the number is on was probably for the EGR system, it was used to operate a vacuum amplifier as it probably goes into the venturii for a very low vacuum signal, the one on the throttle body should be for the distributor vacuum. Carburetor is probably from the mid 70s (sort of looks like the one my 1977 F150 300 had on it). 7388S is a Carter ID number, now if someone has a good carburetor PN listing for the YFs maybe you can pin it down. How’s this: http://www.carburetion.com/CarbNumber.asp?Number=7388S Link to comment Share on other sites More sharing options...
85lebaront2 Posted January 8, 2018 Share Posted January 8, 2018 How’s this: http://www.carburetion.com/CarbNumber.asp?Number=7388S Gee, talk about luck, he actually has the correct application carburetor for his truck. Link to comment Share on other sites More sharing options...
Ford F834 Posted January 9, 2018 Author Share Posted January 9, 2018 How’s this: http://www.carburetion.com/CarbNumber.asp?Number=7388S Thanks Gary! That's great! And it is luck that it's the right one for the application. Mine does not have the bowl vent, shown in the picture, but otherwise seems accurate. This will help make sure I get the right rebuild/seal kit 🙂 Link to comment Share on other sites More sharing options...
85lebaront2 Posted January 9, 2018 Share Posted January 9, 2018 Thanks Gary! That's great! And it is luck that it's the right one for the application. Mine does not have the bowl vent, shown in the picture, but otherwise seems accurate. This will help make sure I get the right rebuild/seal kit 🙂 Don't go by the picture, it is a later model than 1981, probably a non-feedback 1985 or 1986. Link to comment Share on other sites More sharing options...
Gary Lewis Posted January 9, 2018 Share Posted January 9, 2018 Thanks Gary! That's great! And it is luck that it's the right one for the application. Mine does not have the bowl vent, shown in the picture, but otherwise seems accurate. This will help make sure I get the right rebuild/seal kit 🙂 Jonathan - It was the right carb for the application. But with the EGR blocked it isn't. Bill - What typically needs to be done to dial an EGR carb in when the EGR has been deleted? Link to comment Share on other sites More sharing options...
85lebaront2 Posted January 9, 2018 Share Posted January 9, 2018 Jonathan - It was the right carb for the application. But with the EGR blocked it isn't. Bill - What typically needs to be done to dial an EGR carb in when the EGR has been deleted? If everything else is still the original, specifically timing, you would need to lean the main jet slightly. That being said, first I would look at the plugs and second if it needs "tweaking" there should be a small aluminum plug, like a miniature freeze plug in the top of the carb where the air filter sits (BTW, that air filter is cute, but even for a one barrel is too small), under that plug is a hole down to the small Philips head screw on the metering rod hanger, clockwise is richer, counterclockwise is leaner. Since the YF metering rod is similar to the older carburetors it has both a vacuum and mechanical control. At cruise the mechanical linkage limits the down travel so the mixture is partially dependent of throttle opening. Link to comment Share on other sites More sharing options...
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