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Discussion Starter · #1 ·
hi folks,

a while back we rebuilt the heads on my 94LS, and put new piston rings on the pistons. when we got it all back together there was very low oil pressure. i drove the car anyways and eventually there was a horrendous noise coming from the engine. this weekend we got around to taking the engine out of the car. took about 4 hours to remove it, and about 2 hours to figure out how to use the engine stand and get the oil pan off. here is what we found.

the rod bearing closest to the crank pulley was whittled away into almost nothing on the oil pan side and was totally disintegrated on the rod side. the crankshaft had a notch in it as u can see in the photo right next to the oil hole. this notch was there when my dad pulled the engine the first time and redid the heads. he believed for some reason that the notch was supposed to be there. my guess is that the oil was leaking through the notch and voila, low oil pressure. the crankshaft is now about 1/8 of an inch thinner in the area where the bearings for that rod go.

is this crankshaft toast? is that where the oil pressure was going? i say yes to both of these questions. what do you think?

am i going to need a new connecting rod, because the crankshaft whittled it down as well as it whittling the crankshaft down?

I have other engines lying around. 2 164S engines and 2 164L engines. are these crankshafts the same as the one for the 164LS. if not does anyone know where to find a crankshaft for a 1994 164LS?

i added pictures as attachments so hopefully this works.

thanks

Pete
 

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Moderator
2015 Chevy (Holden) SS, 1989 Milano (Shankle Sport), 1991 164S
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Yowee. That hurts. Sorry it happened. Guess we better not run an 24v car if it has low oil pressure. Expensive lesson I guess.

What was the average oil pressure at say 2500-3000 rpm cruising? What oil brand and grade were you using?

Have not looked closely at a 24v crank, but it is possible that the notch you see on that throw was as stock. That is done sometimes to enable oil to flow to more regions of the bearing surface. Usually, though you see a groove in the bearing shell inner surface instead. That groove looks too clean and straight to be caused by severe wear. Looks machined. Could be wrong, though. I'm certain others who have had these apart would be able to tell you for sure.

Don't know why you would have had low oil pressure after the rebuild. I wonder if the bearing shell there was not properly centered/aligned upon reassembly and spun from the get go, and then ground itself into oblivion.
 

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1991 164L
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Is this the engine where lower end bearings were not replaced when piston rings were replaced? Seems like I remember you saying that sometime ago.

Jason what is the difference in a 24v 96412842 CRANKSHAFT? I think earlier crankshaft could be used.

ARI-Orlando web site states it can 00964120920000 CRANKSHAFT 3.0 Superseded by 00964128420000


Also ePER data looks like Milano and 164 12v cranks was replaced by 24v part number one. The one definite difference between Milano 3.0L and earlier 164 and later ones was thread pitch of flywheel bolts but otherwise maybe cranks are interchangeable are long as you have correct coarse threaded bolts for flywheel and correct length ones for either 5-speed or A/T flywheels.

Product previously in use for: 96412092 CRANKSHAFT

Substituted Substitutes
96412068 CRANKSHAFT - Replacement date:12/1993
IF REQUESTED FOR 164 3.0 6 CIL. AUTOMATIC TRANS.
Prod. code Desc. Min. qty Repl. Ratio
60579166 SCREW 8 1/1
96412092 CRANKSHAFT 1 1/1
Substituted Substitutes
96412068 CRANKSHAFT - Replacement date:12/1993
IF REQUESTED FOR 164 3.0 6 CYLINDER MECHANICAL TRANS.
Prod. code Desc. Min. qty Repl. Ratio
60579167 SCREW 8 1/1
96412092 CRANKSHAFT 1 1/1
Substituted Substitutes
96412068 CRANKSHAFT - Replacement date:12/1993
IF REQUESTED FOR FOR 75 3.0 6 CYLINDER
Prod. code Desc. Min. qty Repl. Ratio
60577457 SCREW 8 1/1
96412092 CRANKSHAFT 1 1/1
Substituted Substitutes
96412475 CRANKSHAFT - Replacement date:12/1994
Prod. code Desc. Min. qty Repl. Ratio
96412092 CRANKSHAFT 1 1/1


Comprehensive replacement list for:
96412092 CRANKSHAFT - Subst. Date02/2000


96412831 (05/2000) CRANKSHAFT

96412842 CRANKSHAFT


Replacements for: 96412092 CRANKSHAFT - Subst. Date : 02/2000

Prod. code Desc. Min. qty Repl. Ratio
96412842 CRANKSHAFT 1 1/1
 

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It's hard to tell from the pics exactly how bad the crank is. I see a lot of babbet from the bearing shell deposited on the crank, but can't see any scoring or discoloration from over heat. Maybe it will clean up if it is polished. Although, with that much bearing wear, it's pretty hard to believe the crank is not damaged. I can't comment on the groove, but have to agree with Del, it looks machined from the pics.
 

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Discussion Starter · #6 ·
Yowee. That hurts. Sorry it happened. Guess we better not run an 24v car if it has low oil pressure. Expensive lesson I guess.

What was the average oil pressure at say 2500-3000 rpm cruising? What oil brand and grade were you using?

Have not looked closely at a 24v crank, but it is possible that the notch you see on that throw was as stock. That is done sometimes to enable oil to flow to more regions of the bearing surface. Usually, though you see a groove in the bearing shell inner surface instead. That groove looks too clean and straight to be caused by severe wear. Looks machined. Could be wrong, though. I'm certain others who have had these apart would be able to tell you for sure.

Don't know why you would have had low oil pressure after the rebuild. I wonder if the bearing shell there was not properly centered/aligned upon reassembly and spun from the get go, and then ground itself into oblivion.
Del

avg oil pressure at 2500 to 3500 rpm when hot was about 15 to 20 psi. i used 20w 50 oil.

there are definitely grooves in the inner shells of the bearings. the groove shown in the pic is strange because it is only on that one rod bearing. none of the other bearings have that corresponding groove on the crankshaft.

my thought was that oil was leaking out of that groove when the engine heated up and the oil thinned. it is also possible that the corresponding bearings were slightly worn, because they were not checked with plastigage.

the timing belt tensioner broke on that engine before the rebuild of heads and ring replacement . maybe a small chunk of something shot out of the oil hole on the crank and dug into the crank as the engine screeched to a halt and formed that groove. who knows?

pete
 

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Discussion Starter · #7 ·
Is this the engine where lower end bearings were not replaced when piston rings were replaced? Seems like I remember you saying that sometime ago.

Jason what is the difference in a 24v 96412842 CRANKSHAFT? I think earlier crankshaft could be used.

ARI-Orlando web site states it can 00964120920000 CRANKSHAFT 3.0 Superseded by 00964128420000


Also ePER data looks like Milano and 164 12v cranks was replaced by 24v part number one. The one definite difference between Milano 3.0L and earlier 164 and later ones was thread pitch of flywheel bolts but otherwise maybe cranks are interchangeable are long as you have correct coarse threaded bolts for flywheel and correct length ones for either 5-speed or A/T flywheels.

Product previously in use for: 96412092 CRANKSHAFT

Substituted Substitutes
96412068 CRANKSHAFT - Replacement date:12/1993
IF REQUESTED FOR 164 3.0 6 CIL. AUTOMATIC TRANS.
Prod. code Desc. Min. qty Repl. Ratio
60579166 SCREW 8 1/1
96412092 CRANKSHAFT 1 1/1
Substituted Substitutes
96412068 CRANKSHAFT - Replacement date:12/1993
IF REQUESTED FOR 164 3.0 6 CYLINDER MECHANICAL TRANS.
Prod. code Desc. Min. qty Repl. Ratio
60579167 SCREW 8 1/1
96412092 CRANKSHAFT 1 1/1
Substituted Substitutes
96412068 CRANKSHAFT - Replacement date:12/1993
IF REQUESTED FOR FOR 75 3.0 6 CYLINDER
Prod. code Desc. Min. qty Repl. Ratio
60577457 SCREW 8 1/1
96412092 CRANKSHAFT 1 1/1
Substituted Substitutes
96412475 CRANKSHAFT - Replacement date:12/1994
Prod. code Desc. Min. qty Repl. Ratio
96412092 CRANKSHAFT 1 1/1


Comprehensive replacement list for:
96412092 CRANKSHAFT - Subst. Date02/2000


96412831 (05/2000) CRANKSHAFT

96412842 CRANKSHAFT


Replacements for: 96412092 CRANKSHAFT - Subst. Date : 02/2000

Prod. code Desc. Min. qty Repl. Ratio
96412842 CRANKSHAFT 1 1/1
steve

thats the same car. hopefully no damage was done to the freshly rebuilt heads or the connecting rod or piston of corresponding damaged bearing, and we can just replace bottom end bearings and crank without taking heads off.

pete
 

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Discussion Starter · #9 ·

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Looks like Jason's pic shown a groove on the 1st rod also.
Maybe you have an oil pump problem.
 

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Richard might be right. I've had a similar problem on my Fiat when oil pump went bad and lost oil pressure quite quick. It happened on a highway and by the time I stopped, damage was already done. I couldn't find any particles that could cause oil pump to fail. I ended up replacing rods, crank and pump. I think bad oil caused an event in my case.
 

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That groove on the journal is ABSOLUTELY there for a reason and part of all of these cranks. Whey was this motor pulled before? Did it have similar damage once before?

When you start to spin one bearing, there is a bit of a cascading effect as oil-access to the next bearing inline is also blocked and so forth!

This crank can definitely be saved! In fact, consider off-setting the rod journals as part of the cutting and polishing to create more stroke (slightly larger displacement) and higher compression for some extra performance. We do it all of the time! I can help you with it. And yes, you have to re-nitrate the crank.

You could also keep the stroke stock, but bump compression by modifying the rods and pistons to take compression up and get some "punch" value out of the required work! Could be fun! Buzz me and I'll give you some tips - no charge! ([email protected] or buzz me via 425.766.4278.)

I also use a different crank main journal bearing cross-over from another brand of car completely to achieve significant under-sizing of those journals if needed! As far as the rods, if needed you can just replace one rod, but you may need to re-bore / re-size the journals. By then you could just go with a set of forged steel chrome molly connecting rods for future performance increases! I would also do a full balancing - nice bump in performance!

Now, here's the BIG ONE; I'm giving you pearls here -
Behind the water-pump on the front and then at the other end of the block on the back (ahead of the flywheel), there are these two brass plugs about the size of a quarter. When the block is COMPLETELY disassembled and tanked and machined and just when you think that you are done-done, take those two plugs out! There will be a palm-full of metal shavings in there!

Those two plugs access the main oil-feed galley straight down the center of the motor and that feed is POST oil filter. So, upon first starting this baby back up, you will push that crap straight back to the bearings! You HAVE to clean that main galley out! :hammer:

Also, while I'm at it - may as well mention that it would be a great idea - again once fully disassembled and back on the engine stand - ready for reassembly - to take a compressed air nozzle to those 6 block squirters from the piston-side down and out to the crank side - as well as air to all of the crank journal oil-feeds! You won't believe the amount of crap that ends up throughout little spots like these from a bearing failure!

Hope this helps!
 

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1991 164L
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steve

thats the same car. hopefully no damage was done to the freshly rebuilt heads or the connecting rod or piston of corresponding damaged bearing, and we can just replace bottom end bearings and crank without taking heads off.

pete
I did a crank and bearing change to Old Nero's 164L engine few years ago and test ran the engine on my garage floor. The engine is now purring along in Rai's 164L in FL and he is loving the car.
 

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I have an OEM new oil pump in an Alfa plastic bag if needed.
 

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It is also strongly advised that you service the hydraulic lifters and tank those heads real well! At this point, assume that bearing material is everywhere!

Remember that the oil supply goes to the sub-assembly FIRST! Crank and rods and then up to the heads. Contaminated oil from a spun bearing is supplied to the rest of the motor during a bearing failure! The holes in the lifters are tiny! (So too the block squirter jets...)

I even find the **** in the little mounting hole behind the oil pressure sender on some motors I take apart. It doesn't have anywhere to go at that point, but still...
 

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2015 Chevy (Holden) SS, 1989 Milano (Shankle Sport), 1991 164S
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Yup, that groove looks to be OEM. I suspect Alfa detected an oil pressure problem there, so put in the groove to enable better oil flow on that throw. I guess, especially in this 24v engine, low oil pressure is not it's friend.

I'd be surprised if the crank throw is damaged, as nitrided cranks are incredibly hard and resistant to wear.

In my highly modified Downton Engr 1967 Mini Cooper S with a nitrided crank, the rod bearings would wear down to the steel backing of the shell. Absolutely no damage to the crank throw at all. Every 5000 miles I could just shine up the crank and replace the rod bearings with new standard thickness bearings. I was amazed.

So, maybe when cleaned up, the crank might be almost as new.
 

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I have new in stock and good used -$600.00 without bearings.
New crank(including rod and main bearings) in stock $1,900.00. :O 12V and 24V are interchangeable. Except for the fine thread, course thread flywheel bolts.
 

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Also, what you want to do FOR SURE is remove the crank-plugs and clean the sludge-traps! Run pipe-cleaners through all of the holes and clear out to the crank journal oil-feed holes!

Might be why you spun a bearing to start with...?

The NEW plugs should be staked back in AND a spot-weld is recommended before then re-balancing the entire setup!
 

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What type of use does/did this car get? Daily driver, running to the store, garage queen, track use? How many miles does it get put on it a year? It might make a difference to how much you want to do to it. Certainly a through cleaning of all oil passages would be in order given the bearing failure.
 
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