Bitter learning curve. Absolutely DONE with carburetors!!!

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So far, I see nothing to blame the carburetor for.

You sure it's not a bad fuel pump?



LOL
 
A carb dumping 2 quarts of gas into the oil seems highly unlikely, that's a lot of gas tor a carb to leak down into the oil! I suspect the pump as well!!
 
My Imperial's 440 is waiting for me to take the time to change the pump - it leaks into the crankcase too. **** happens.
My rule of thumb on a new engine is noises are not a big deal coming and going. But if the oil pressure changes either at idle or above idle - pull it and inspect. Waiting just lets the problem get worse. Catching it early enough means little to no machining. I would check the crank end play first, you might have a thrust going bad, but I'd be figuring on pulling it at this point.
 
PhillH said:
Also the oil pressure is low, 5 pounds at idle after warm, 23 at 2k rpms, 32 at 3k rpms.
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this may be enough oil pr to keep it from flying apart but this is not acceptable .what was your psi at first start up warn and cold . are you using arp main studs by any chance ?
 
Valley oil plug is definitely in, checked over and over during build. Oil pressure is about 40 at startup with 10/30 oil. I did do the oil mod by drilling tiny hole in plug to oil the distributor drive. Maybe I'm being to hard on the carb, could be the fuel pump but that still doesn't fix the issue. I will take post a YouTube video this weekend so i can get better opinions. Rusty, it might be the fuel pump, LOL!!!
 
It put about 2 quarts of fuel in the oil in the 20 mile break in, then oil change. Now it has about 300 miles on it and the oil level is fine?
 
As a reference, our new build with new HV oil pump has 65+ psi cold start with 10W30. Startup temps here have been 40F or so. I doubt the oil mod you did would lower pressure more than a psi or 2; it is waaaay at the far end of the oiling chain.

Were your 'lower than average' oil pressures there all along or has it has it gotten lower after the '2 extra quarts in the pan' situation? AM I correct in assuming that the oil reeked of gas when you changed it?
 
Pull the filter and cut it open, if you don't see any bearing material you will know then.
 
Never seen the pump leak into the crankcase. Where does the gas shoot out of
 
Where the arm comes out. There's a vent hole on the outside of the pump that when the diaphragm ruptures it supposed to leak out of there also.
 
Just a couple of thought from me, The engine would not run with that much extra fuel going into the cylinders.
Take the oil filter off and cut it open check in the folds of the filtering material for metal. that';s where your bad bearing will show up real quick.
Good luck I hope the crank isn't toast.
 
No the main studs are not arp, but the rod bolts are. The reason the oil level is fine and why I blame the carb, I believe the bowl would drain into the manifold, the plugs were way rich and as I discovered that the oil was full of fuel I rebuilt the carb, so now the oil level is fine.
 
I'll take a video this weekend before I start pulling anything apart, this way you guys will be able to see and hear what's going on.
 
PhillH said:
No the main studs are not arp, but the rod bolts are. The reason the oil level is fine and why I blame the carb, I believe the bowl would drain into the manifold, the plugs were way rich and as I discovered that the oil was full of fuel I rebuilt the carb, so now the oil level is fine.
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the reason I asked this is there 3 or 4 members had oil ps problems lately because the arp studs were interfering with the oil pump not letting it seat properly causing pressure leakage . :)
 
jimjimjimmy said:
the reason I asked this is there 3 or 4 members had oil ps problems lately because the arp studs were interfering with the oil pump not letting it seat properly causing pressure leakage . :)
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Hear-say to me there has been issues with pump casting clearances on some pumps. Never seen it though.
 
I had a simular noise as you are describing on a fresh 340. What I found was the crank thrust bearing wore and the crank counter weight would move against the block. It was getting worse that is why it came to the shop.

We tore it out and found the rest of the bearings were fine. The knocking was a slug of heavy metal that was used to balance it. The weld was protruding from the side of the counter weight. As the oil got thin the crank would move causing the slug to hit the block every time around.

Grab the front of your crank and see how much play it has front to back using a dial intcator. Take the plugs out and turn the crank pushing front and then pushing rear. You should be able to feel it hit in one of these directions turning the motor by hand

We grund the weld and installed a new thrust bearing. Noise was gone
 
Marcohotrod said:
except in this case Phil never mentioned any symptoms of a lean condition, then 4 plugs way rich:D
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interesting concept
4 out of 8, that is exactly half (public school math at its best)
is there by any chance a dual plane manifold on that engine?
and how do the 4 rich plugs relate ?
are the all on the same bank?
or would they by any chance all be on the same plane of the intake?

and the other 4 plugs, did they look good, decent, lean or...?
 
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