Spun Bearings

birds4us

Registered User
It seems that some of the earlier SC's like to spin bearings. Is there a reason for this and is there a cure? Is there a good aftermarket crank kit available? Any other suggestions? Thanks.
 
They don't like to spin bearings, people just beat them up. ;)

Ford uses very tight bearing clearances on the original engine. Usually about .001", sometimes apparently less. This is very tight for an American engine and is the basis for the recommended 5W30 oil.

However, life is not kind to these motors and most bearings open up to a more reasonable (for an American engine) .002-.0025" with use. Unfortunately this also involves a wearing away of the babbit bearing material leaving copper exposed. Once copper has been exposed the bearing becomes more likely to turn due to friction if the crank ever contacts the bearing under load.

Therefore it is my recommendation to run a heavier oil in your SC motor if it has many miles on it or you plan to run it hard. I have run Mobil 1 15W50 successfully in my SC for many years while subjecting it to high levels of boost, rpm, cylinder pressure and general abuse. I have never experienced a bearing failure.

As far as a crank kit, all you can get is a standard .010" under no matter where you go. It's all the same stuff and you'll end up with the clearances between .0008-.0014 in most cases. This is fine for a basic rebuild but I feel it is too tight for a performance SC application. I have all my cranks custom ground for an extra .0005" or so clearance depending on block housing dimensions. This is also one reason why I will never use a reman engine. I feel the clearances on those motors are too tight for performance use.

Unfortunately there are no .001" undersize bearing options for the SC so you can't "blueprint" a crank once it has been ground. You must do your blueprinting before grinding the crank so that it can be finished to your specs.
 
What I thought might be a contributing factor is when a head gasket goes south and it owner just keeps diving the car with anitfreeze in the oil the dammage is done. The gaskets get replaced as with new oil but the time that it sits can also cut down on the life of the bearings. I never liked to have a cut crank in these engines so I would find a used one in good shape and have it polished and replace bearings. Seems like this always gave me that extra oil clearance I was looking for.
 
It is a good recommendation to use 15W-50 on a high mileage motor. Even on a rebuilt motor it is wise to use 10W-30 for winter and 15W-50 for summer use.
 
Dealing with spun bearings now!

I pulled the Ford REMAN motor with 35,000 miles on it out of my 94 SC after I heard the distinct rod bearing knock. Took it apart and found all of the mains were down to the copper and 4 of the 6 rods were down to the copper with #3 and #6 rod bearing just about gone. #1 and #4 rod bearings were the only ones still in tact. So I pulled everything apart and had the block boiled and the cylinders ball honed. No wear on the cylinders at all. I attribute that to the 15W-40 synthetic oil. I don't know what caused this bottom end melt down unless it is what XR7 DAVE said about a FORD REMAN and very tight clearances or the 15,000 miles the previous owner put on the REMAN motor before I bought the SC. I'm now trying to get a NAPA crank kit to fit and am not having much luck. I installed it with plenty of assembly lube and with just 60 lbs-ft of torque on the bearing caps with ARP studs installed. This was just to pre-stretch the ARP studs per their directions. Now I can't turn the crank by hand or using a strap wrench on the harmonic balancer. So I took the caps off and all of the assembly lube on the front 2 bearing appeared to be squeezed out. The thurst bearing and rear bearing looked fine. So I put the caps back on and just slightly tightened the bolts. I could turn the crank but it was very difficult. However, it would turn and not bind so that made me believe the crank is not bent. I have not plastic gauged the bearings. Ran out of time last night. I believe before I plastic gauge I'm going to install the bearing caps one at a time starting with the rear to determine which bearing or bearings are binding the crank and plastic gauge them first. I suspect #1 and #2 are the culprits.

XR7 DAVE - any guidance would be appreciated.

Ed Springer

94 Red SC Auto: 70mm TB, Fresh Air Intake, Stock 90 SC Pulley, Accel 36# injectors, Scorpian 1.73 Rockers, ARP Head Studs, 190 l/h fuel pump, Raised SC Top, Headers, Raven Muffler (no cats) with stock resonators, 3:73 Gears, 76 C&L MAF (Gold Tube), MSD DIS-4 + Ignition Box, TRANSGO Shift Kit, Haydon Auxiliary Transmission Cooler, Pro-Torque 2500 TC, Tokico Struts & Shocks, Royal Purple Synthetic Lubricants, Optima Yellow Top Battery, American Racing 17” Sniper Wheels, Michelin Pilot Sport A/S, COMMANDO Alarm and Remote Starter and Autometer A/F Ratio and Transmission Oil Temperature Gauges.
 
Mike8675309 said:
Did you make sure to put the right bearings in the right places? #4 is a different size.

I agree...in my reading while doing the rebuild on my 89 i ran into this many times. There are tons of threads where people put the bearings in the wrong spot and they cant turn the crank. Double check the position of the bearings and hopefully that will fix the issue.

As far as oil goes, is it really recomended to run such thick oil? In my rebuild I ran clearances just as specified in the hayes manual and im running 5w-30. I was told just to use this regular oil since its a rebuild and the car will be a street car with your usual time at the track (not race-only). If I can do something to slow down bearing wear in my engine, i'd do it. Out of 4 sc engines in my back yard, all of them have had the bearings worn at some point to the copper. Actually the crank that came out of my rebuild engine is toast with a damaged journal, so i had to get another one.
 
If the motor has tight clearances you must run a thin oil. If an SC motor has lots of miles on it, it will be loose and will benefit from heavier oil. When I build a motor I design in more clearance so that heavier oil is used from the start. If you already have the motor in the car I would check oil pressure and determine what to do after taking some readings. I would not guess about oil and oil pressure.

Having said that, yes, check the bearings and make sure that you don't have them in the wrong place. I am assembling a shortblock right now and with everything torqued and all pistons in place it takes about 20ftlbs to spin the motor.

It is also possible that your new crank isn't going to work. Due to tight housing bores I've seen cranks come in with NO clearance. It happens. This is why I will never use a crank kit in an SC motor. You want to get a stock un-turned crank and then machine it to fit. That's the only way to do it IMO.

Let us know what you find out with the bearings.
 
XR7 Dave said:
If the motor has tight clearances you must run a thin oil. If an SC motor has lots of miles on it, it will be loose and will benefit from heavier oil. When I build a motor I design in more clearance so that heavier oil is used from the start. If you already have the motor in the car I would check oil pressure and determine what to do after taking some readings. I would not guess about oil and oil pressure.

Having said that, yes, check the bearings and make sure that you don't have them in the wrong place. I am assembling a shortblock right now and with everything torqued and all pistons in place it takes about 20ftlbs to spin the motor.

It is also possible that your new crank isn't going to work. Due to tight housing bores I've seen cranks come in with NO clearance. It happens. This is why I will never use a crank kit in an SC motor. You want to get a stock un-turned crank and then machine it to fit. That's the only way to do it IMO.

Let us know what you find out with the bearings.

Dave,
I Just blew a HG today, do you know what the time limit is as far as me draining the coolant/oil and re filling/flushing the crankcase with new oil?
Do I have a couple days?
A week?
24 hours?
Please let me know, as free time is a huge deal for me lately....

paul:(
 
It's fixed but I don't know why!

Well, after reading Mike's response that got me to thinking. So I pulled the caps and all the bearings out and checked the journals with a straight edge. No problem there. So I rechecked the bearings to be sure they were all the same size and they were all labeled 25mm. Now all of the upper bearings are notched the same so I don't know why #4 would be different as Mike suggested. So I put them back in and when I laid the crank on the bearings, the crank pivoted on the #2 bearing. That was the bearing that squeezed out all of the assembly lube when I initially installed the crank. Ahha, there is the problem but why? So I pulled the crank and bearings out again, numbered them as I did, rechecked the journals again, reinstalled the upper bearings, except I swapped #2 and #4 (what the hell, I would give it a try), put the crank in and no tilt. Hmmm, that is interesting. I should have swapped #2 and #4 back to see if the pivoting was still there but I was SOOOOO happy that it did not pivot I left it alone. So I put the caps back on and just snugged them down. Crank spun nice and smooth. So I torqued them down to 60 lbs-ft and SWEET. Crank needed a little more effort to turn but still was nice and smooth with no binding. I then applied the ARP moly to the ARP studs and torqued them to spec. SWEET, crank still turns nice and smooth. I would expect the 20 lbs-ft of torque that Dave said he needed to turn over an assembled short block will be right in the ballpark. I put the oil pump pickup support on the #3 bearing UNDER the ARP nut and washer after I drilled the hole just big enough to go over the ARP stud. There just was not enough thread on the stud to hold the support bracket in place on top of the ARP nut. That bracket is a pretty stout piece of material. I did not put the windage tray back on since Bill Evanoff told me that only the 94/95 SCs had windage trays. I had to remove the #1 bearing ARP studs since the oil pan would not fit with them installed. I'm contemplating drilling out about .375 inches of journal thread so the stud will go furhter down into the block. I have to look into and think about that a little more. Bill's main bearing ARP stud kit leaves a little bit to be desired. He should have 2 shorter studs for the #1 bearing and 1 longer stud for the #3 bearing to support the oil pump pickup support bracket especially when I'm paying that kind of money for the kit. Thanks for all of the help and if you think I'm doing something stupid, please respond.

Ed Springer

94 Red SC Auto: 70mm TB, Fresh Air Intake, Stock 90 SC Pulley, Accel 36# injectors, Scorpian 1.73 Rockers, ARP Head Studs, 190 l/h fuel pump, Raised SC Top, Headers, Raven Muffler (no cats) with stock resonators, 3:73 Gears, 76 C&L MAF (Gold Tube), MSD DIS-4 + Ignition Box, TRANSGO Shift Kit, Haydon Auxiliary Transmission Cooler, Pro-Torque 2500 TC, Tokico Struts & Shocks, Royal Purple Synthetic Lubricants, Optima Yellow Top Battery, American Racing 17” Sniper Wheels, Michelin Pilot Sport A/S, COMMANDO Alarm and Remote Starter and Autometer A/F Ratio and Transmission Oil Temperature Gauges.
 
thirdbird said:
Dave,
I Just blew a HG today, do you know what the time limit is as far as me draining the coolant/oil and re filling/flushing the crankcase with new oil?
Do I have a couple days?
A week?
24 hours?
Please let me know, as free time is a huge deal for me lately....

paul:(

The bearings and journals will not rust, oil turns to margarine when mixed with water. The rotating parts will not rust but the cylinders will. Drain the antifreeze from the motor completely and run the motor for about a minute to get all the moisture out of the cylinders. Then spray a good bit of WD40 into the cylinders through the spark plug holes.
 
Ed: Just cut the ARP studs off flush with the tops of the nuts and recheck clearance. You should be OK.
 
edspringer said:
Well, after reading Mike's response that got me to thinking. So I pulled the caps and all the bearings out and checked the journals with a straight edge. No problem there. So I rechecked the bearings to be sure they were all the same size and they were all labeled 25mm. Now all of the upper bearings are notched the same so I don't know why #4 would be different as Mike suggested. So I put them back in and when I laid the crank on the bearings, the crank pivoted on the #2 bearing. That was the bearing that squeezed out all of the assembly lube when I initially installed the crank. Ahha, there is the problem but why? So I pulled the crank and bearings out again, numbered them as I did, rechecked the journals again, reinstalled the upper bearings, except I swapped #2 and #4 (what the hell, I would give it a try), put the crank in and no tilt. Hmmm, that is interesting. I should have swapped #2 and #4 back to see if the pivoting was still there but I was SOOOOO happy that it did not pivot I left it alone. So I put the caps back on and just snugged them down. Crank spun nice and smooth. So I torqued them down to 60 lbs-ft and SWEET. Crank needed a little more effort to turn but still was nice and smooth with no binding. I then applied the ARP moly to the ARP studs and torqued them to spec. SWEET, crank still turns nice and smooth. I would expect the 20 lbs-ft of torque that Dave said he needed to turn over an assembled short block will be right in the ballpark. I put the oil pump pickup support on the #3 bearing UNDER the ARP nut and washer after I drilled the hole just big enough to go over the ARP stud. There just was not enough thread on the stud to hold the support bracket in place on top of the ARP nut. That bracket is a pretty stout piece of material. I did not put the windage tray back on since Bill Evanoff told me that only the 94/95 SCs had windage trays. I had to remove the #1 bearing ARP studs since the oil pan would not fit with them installed. I'm contemplating drilling out about .375 inches of journal thread so the stud will go furhter down into the block. I have to look into and think about that a little more. Bill's main bearing ARP stud kit leaves a little bit to be desired. He should have 2 shorter studs for the #1 bearing and 1 longer stud for the #3 bearing to support the oil pump pickup support bracket especially when I'm paying that kind of money for the kit. Thanks for all of the help and if you think I'm doing something stupid, please respond.

Ed Springer

The problem is that ARP does not make the right bolts. You can't just walk up to them and ask for custom bolts. You kind of have to take what you get which is just the use of another application that is close to what we need.

Plain and simple, the windage tray was worth more to you than the ARP studs are. Unless you are building an all-out motor the ARP studs are a waste of effort and money. On the other hand a windage tray has real value (HP).
 
edspringer said:
Well, after reading Mike's response that got me to thinking. So I pulled the caps and all the bearings out and checked the journals with a straight edge. No problem there. So I rechecked the bearings to be sure they were all the same size and they were all labeled 25mm. Now all of the upper bearings are notched the same so I don't know why #4 would be different as Mike suggested.

Yes, the #4 Journal on the crank is .010 undersized at the factory so that the cast crank wouldn't fit in a SC block. Thus the #4 bearings are bigger. #1, #2, #3 journals are 2.519". #4 Journal is 2.509.

Glad you found the solution.


Duffy pointed it out here(member area):
http://www.sccoa.com/forums/showthread.php?t=31628&highlight=crankshaft+journal+cast
 
That Works!

SCrazy said:
Ed: Just cut the ARP studs off flush with the tops of the nuts and recheck clearance. You should be OK.

Brian........thanks for the info. I cut them but I also had to remove the ARP washers because the nuts would still not let the pan go on all the way. After I did that, the pan fits fine.

Ed

94 Red SC Auto: 70mm TB, Fresh Air Intake, Stock 90 SC Pulley, Accel 36# injectors, Scorpian 1.73 Rockers, ARP Head Studs, 190 l/h fuel pump, Raised SC Top, Headers, Raven Muffler (no cats) with stock resonators, 3:73 Gears, 76 C&L MAF (Gold Tube), MSD DIS-4 + Ignition Box, TRANSGO Shift Kit, Haydon Auxiliary Transmission Cooler, Pro-Torque 2500 TC, Tokico Struts & Shocks, Royal Purple Synthetic Lubricants, Optima Yellow Top Battery, American Racing 17” Sniper Wheels, Michelin Pilot Sport A/S, COMMANDO Alarm and Remote Starter and Autometer A/F Ratio and Transmission Oil Temperature Gauges.
 
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