When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hey ford owners i was wondering how can you tell if a recently rebuilt engine has bad rings.
The truck was rebuilt about 10,000 miles ago.
Last few weeks i redid timing to 6 BTDC. I rebuilt the autolite 2100carb and changed plugs.
Recently it started running like crap and blowing black smoke. At first i thought it was running to rich. I adjusted the air mixture screws from factory standard 1 1/2 turns out al the way to 3 turns out (recomended by a fte user at a similar altitude) and the truck only runs for a few seconds at a time.
How could i check my rings to see if their bad?
History of the trucks engine
Truck was bought new by my grandpa in 71 after being promoted to manager of a ford dealership in golden co. After 4 years he bought a 1974 f250 highboy so he could use the 4x4 in winter. The truck was stored in a barn untill the early 2000's i believe. It was then gifted to my dad and rebuilt. Then i bought it for $500. Only engine mods i have done are a flowmaster 40 muffler.
Black smoke is gas, blue smoke is oil, white smoke is water. Not meaning to cast any bad on you, but just because you adjusted something doesn't mean that you know what you are doing. I do not, so I take mine to a guy that does.
You can do a compression check if you think your rings are bad, but you did say black smoke. Anyways good luck.
Sounds like either a sticking needle/seat (common in a fresh rebuild), incorrect float level, or bad power valve. The power valve should have been replaced during the carb rebuild, but if the engine backfired thru the intake, the PV can be damaged. Or, if it wasn't tightened down securely enough, it can back off, giving the same symptom as a blown power valve.
Try tapping on the carb horn right above the fuel line, with a screwdriver handle, while trying to start/keep the engine running. If it clears up, it's just the new needle seat sticking a bit. In this case, they will eventually seat in, but you have to repeat the tapping occasionally until they do.
If this doesn't do any good, it's time to open the carb up, and have a look inside.
Well im 15, and ive been working on cars and dirtbikes since i was 5 so i have a good grasp on things. But i may verywell be wrong.
Anyone have ideas of what i can try?
Also whenever the truck is running for 10 or more minutes then sits for a few hours the heat from the engine boiles the gas from the bowl into the carb. What is the easiest cheapest fix for that?
Well im 15, and ive been working on cars and dirtbikes since i was 5 so i have a good grasp on things. But i may verywell be wrong.
Anyone have ideas of what i can try?
Also whenever the truck is running for 10 or more minutes then sits for a few hours the heat from the engine boiles the gas from the bowl into the carb. What is the easiest cheapest fix for that?
The fuel draining from the bowl, into the engine, is another sign pointing towards a bad power valve. The PV is thing at the bottom of the fuel bowl that goes under that cover. When it's bad or not succifiently tight, fuel will leak past it into the intake, until the bowl runs dry.
When i rebuilt the carb at first it ran flawlessly. New needle. Needle seat. Power valve etc. on the 2nd day it started running badly so could the needle seat be settling in?
first of all the air screws are just for idle mixture and don't have much to do with off idle speeds. Another thing to remember is how far from the carb the filter is and the chances of crap getting in after the fuel filter when you have the system open. Just pull it back apart, you can take the top off without even removing the carb, takes just a few minutes. That way you can actually see the float level. Did you get the little wire clip back on the float pin correctly without damaging it? 99% chance it's something you did so go back over your work.
I was pretty darn handy when I was 15 too, and have gotten dumber every year for 44 years. Meaning, the more you learn, the more you realize how much you don't know.
I got the wire clip on correctly so unless it moved somehow it should be alright. Ill check needle for sticking and power valve tomorrow. Thanks for the help guys!
Ok so i got the truck running again. Dont know how but it is running. But it does seem to have alot less power. Ill give it some 91 octane. That woke it up last time
Well im 15, and ive been working on cars and dirtbikes since i was 5 so i have a good grasp on things. But i may verywell be wrong.
Anyone have ideas of what i can try?
Also whenever the truck is running for 10 or more minutes then sits for a few hours the heat from the engine boiles the gas from the bowl into the carb. What is the easiest cheapest fix for that?
Been wrenchin since you were 5. That is pretty impressive. prolly walked 4 miles each way to get to the toolbox, right?
91 octane is not a miracle drug, the truck should run just fine on the lower octane. There is more tweaking work needed.