^^^ that is what I was thinking, the crank needs to come out and be checked, not sure one could check it in the the block.
You might be able to test it in the engine... Perhaps a dial indicator (better yet with a test indicator - last word) with a mag base and being careful to gently rotate the crank (hopefully without causing any deflection) after pulling all the plugs.
Out of curiosity, what year is the block, what brand is the crank, and was the crank checked for straightness prior to being balanced?
Even though it may be a faulty bearing that just lost it's babbit. I'd be wanting to pull and mike the crank to make sure it was right. With no marks on the journal and the bearing worn evenly all around the babbit may have just gone away with premature wear. That bearing looks like one that came out of an engine with mega miles. Engines that have sat for years with old dirty oil in them will often have the babbit flake off the bearings when someone starts driving it as the acid in the oil ate into the babbit.
The block is a 5.0 out of a 88 foxbody, crank is a steel scat( brand new), bearing are clevite 77s, all new stuff. Block was line bored and rods were resized. Built and assembled by a Reputable machine shop. The Babbitt polished off the journal pretty easy. Ya out of round could be the problem
Also, the car did sit all summer, to hot in south Florida. The oil pressure dropped the same time when the front main seal started dripping, related seems weird. What if the pump bled off and got dry? Even old out of round cranks don’t destroy bearings that fast! Sent from my iPhone using The H.A.M.B. mobile app
Well,,, a new out of round might . They did mention that some Scat cranks were like that. You could easily put a dial indicator on a mag base on the pan rail,,,and then indicate over to the journal. Spin the crank gently by hand and read the runout. It would be worth a try I think. The more I read ,,the more I suspect the journal. Mic the bad bearing and compare to the good one from the #2 main,,,that will tell you a little info also. Tommy
The semi-finished forgings are shipped from China and the final machining is done in the US. I guess it could be one that missed getting checked, but unlikely. Whatever happened it went south pretty quick so I would check and see if that bearing is getting any oil.
Was the block magnafluxed? Why was the factory crank not used? Ford lightened the block and crank ~'80 This saved a bit of weight(good) but at the cost of structural integrity(bad). 50oz balance on the later 5.0 cranks causes the crank to whip more than with the older 28oz 302s. Cranks are lighter and in total are still balanced, but the balance weights are at either end of the crankshaft. Imagine a length or rope or chain, if you have ever whipped it around in a circular motion that is what an external balance crankshaft is doing. The more external weights, or faster crankshaft speeds, the more the crank will whip. There is nothing that will prevent this. This whipping will damage the blocks as it pulls on the mains, a visual inspection will not reveal any cracks as the splitting varies from block to block but usually it is a crack that goes up through the mains, through the camshaft gallery and then splits the block itself down the middle. Early signs of a whipping crank are fretting of the mains on the block. Usually people blame the 'weak' two bolt mains, 'weak' factory main bolts, or any number of things. The common belief 'fix' is to install a girdle to 'strengthen' the mains. Only thing a girdle really does is help prevent the block from totally splitting apart and scattering when it does shit the bed. The only things that are keeping the block together at this point are the front timing cover, oil pan, mains, intake manifold and bellhousing. And it's not really the blocks fault, all a block is designed to do is be a structure to hold a rotating assembly, not a whipping one. Cast iron is not the best at flexing so the mains usually crack or split. If the original crank was replaced because it was cracked or broke, that is also the death knell for the block. Telltale signs are usually unusually low oil pressure at idle and low or erratic oil pressure as rpms increase. Look for any signs of cracking or oil seepage near the distributor mount.
If the pump did in fact “bleed off”, and I very seriously doubt this happened, I would think that the rear bearings would have failed first because they are the farthest away from the oil pump. Sent from my iPhone using The H.A.M.B. mobile app
And along that line of thought, the rear of the crank is supported by the transmission, be it the pilot in an MT or the TC/pump in an AT. Usually the front snout is what snaps off in a 'minor' crank failure. Check your harmonic damper ring has not slipped as well.
How that we know more ,was the crank checked for being straight or the line bore. Every engine I build I start with the middle main and check the torque to turn the crank. As I do each main cap I check the torque again any big jumps is a warning sign. With the engine that far together a difference might be hard to tell but find a beam or dial torque wrench and check the torque to turn it over then install a new bearing and try it again That first bearing went south quick.
Great advice, I’ll run dial on it to check the runout before I install the new bearings. I’ll check the torques and keep a eye on it. Also a cracked block could be the cause the more I think about it. Low oil pressure especially as it gets hot. A new short block may be in the future. Best case it could just be the front main was just dry from the beginning and just started showing signs after a 1000 miles. Thx and I’ll keep ya up to date Sent from my iPhone using H.A.M.B.
I started it this morning and the oil pressure jump right up at 55 and 40 hot at idle. Oil looks clean and sounds good. Going to run it a little, drain the oil and cut the filter open. Hoping it looks clean. Hopefully just a bad bearing install or defect in the bearing. Thx Sent from my iPhone using H.A.M.B.
Also noticed some moisture in the pickup tube. Again the car sat all summer in south Florida(high humidity). That could of been enough to wash out the bearing. Sent from my iPhone using H.A.M.B.
Calm down a little. That is the least of his problems,,,,if this doesn’t fix it,,,it will be right back down anyway. And besides,,,the Babbitt layer is super soft,,,it should come out with the filter element. If it is the journal,,,it should do as before and after a while start leaking around the front seal,,,,then he will know for sure. I say run the day lights out of it,,,,,and then do whatever the results are! Tommy
That’s my plan tommy. If its got to come out after not time involved not a real big deal at this point. Besides I really don’t like the cam that much anyway. Thx and good reply Sent from my iPhone using H.A.M.B.
There used to be some special timing chain/gear sets available for engines that had been line bored. They were made to reduce the chain slack. Fairly hard to find these days, used mostly by bulk rebuilders. I have seen a water pump break the shaft and the front main wiped out on a small block Chevy from too tight a belt. The owner was removing the alternator belt when at the drags and running a belt looped over just the water pump and crank. Threw the upper pulley and fan through the radiator at the top end. On tear down, the front main was found to be wasted, also.
@stegman Have you thought about 28oz. vs. 50oz. flywheels/flexplates and harmonic balancers? I’m just figuring out my engine now and have read if you have the wrong parts installed, bad things will happen. Maybe this was already mentioned??? I didn’t feel like reading every word of every previous post.
Yes, you can. (one can) Just install the rest of the main caps, leave #1 cap OFF. Set up a solid dial indicator on #1 crank main journal. Crank the engine. Out of round journal will 'talk and admit'. (if out of round) I'd be looking for diet and metal particles. JEESH!
Just me , but it would be out and apart before it ever got started again. Some people get chicken salad from chicken shit . Good luck .
Only bearing failures Ive ever had where from new or freshly turned cranks. go get a used crank and the harmonic balancer and flywheel that came with it. put it together with a stock oil pump. If you have 10 psi for every 1000 RPM that's plenty. High oil pressure doesn't translate to long engine & bearing life. all a high volume high pressure oil pump does is pump the oil to the top end at high RPM and starve the bearings. I can show you lots of engines with a few hundred thousand miles and a stock oil pump. Very seldom will a engine with a high oil pressure pump last very long. On Cummins 855diesels they had a oil pump that put out variable oil pressure 60 PSI wasn't uncommon. And about every 250 thousand miles the rod and main bearings had to be changed. Then the Big cam 855 came out and it made a steady 40 PSI no matter what. and a million miles on a set of bearings wasn't unheard of.
I havent been in a SBF in 40 years,but as I recall the oil pump,and distributor have a hex shaft that drives them.I would look at that shaft for signs of rounding off on the ends,or twisting.Plastic gauge the bearing/ journal in question to check clearances.
Incorrect imbalance would show up pretty quick. Your teeth chattering would let you know, if not that the exponentially greater vibration of the engine as rpm increased would. If you have ever had an engine chuffing away because of some fuel or ignition issues, imagine that but rather than hearing it you feel it through the rev range.
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