What is it with the rod bearings on these cars?!?

NickM

Registered User
The original engine in my '89 expired do to spun bearings (all of them!), so I put in a little over a year ago, a '94. That engine had good bearings, no copper showing on any of them, so I put it in as is.
Last summer, I started getting some tapping under light load, which I attributed to bad lifter or lifters.
This morning, I started getting a much louder knocking, along with the squealing that the other engine did.
I have only run Mobil1 15-50 in this engine since I dropped it in.
I thought these were supposed to be strong on the bottom end. Is there any trick to making them live long-term?
5.0 is looking more tempting, or even another car.
I can't be swapping engines as an annual event-my wife would leave me!
BTW, it still has good pressure (modded stock guage).

Nick
 
For one thing, that oil is too heavy especially on a fresh rebuild. I'd be running 10W30, which I do, cause my car starts rattling and groaning and moaning with anything heavier.

Frit
 
It wasn't a rebuild. The engine was used (100 dollars), but looked to be in good shape on the bearings.
The oil weight was derived from Dave Dalke's success with bearing life.
Can't believe it lasted this long (been rattling for about 15,000).
Been chasing that noise around for a while-first blower coupler, then triple check for exhaust leaks.
Did head gaskets last summer as a preventative measure-talk about wasting money and time.

Nick
 
Did you check bearing clearances? What was your oil pressure? Sounds like you had excess clearance allowing the bearings to come under higher stress. the motors in my cars have well over 120k miles and when I pulled the bearings on the 93, they showed wear, but nothing significant.

No doubt that even if the bearings didn't show copper, they were worn.
 
It wasn't a rebuild. The engine was used (100 dollars), but looked to be in good shape on the bearings.
The oil weight was derived from Dave Dalke's success with bearing life.
Can't believe it lasted this long (been rattling for about 15,000).
Been chasing that noise around for a while-first blower coupler, then triple check for exhaust leaks.
Did head gaskets last summer as a preventative measure-talk about wasting money and time.

Nick
Does it actually have SC cast onto the front of the block near the water pump?
 
Assuming that it is an SC engine that you put in, some people miss the fact that these engines are up somewhere in the neighborhood of 15:1 comp ratio at full boost (not good on the rod bearings). With mileage they will wear out alot faster then a N/A engine.

If it where me in this situation I would do a rebuild and break the engine in with a natural 5w30 oil then go to synthetic after about 500 miles. But you can't get on it too hard till the oil type is changed. If you use good quality parts (Dave Dalke) it should last you well over 100K with proper mantinence.
 
Oil pressure is key. You need to have working 0-100psi oil pressure gauge. There are a mirade of things that could have ruined the bearings. Trash in the motor from when it was apart, detonation from a bad tune, etc. You can't assume all is well just because the stock (or modified) gauge says so. I'm very sorry this happened but it's not normal. There was a cause for it.
 
Oil pressure is key. You need to have working 0-100psi oil pressure gauge. There are a mirade of things that could have ruined the bearings. Trash in the motor from when it was apart, detonation from a bad tune, etc. You can't assume all is well just because the stock (or modified) gauge says so. I'm very sorry this happened but it's not normal. There was a cause for it.

I agree. This guy seems to know what he is talking about.
 
Oil pressure is key. You need to have working 0-100psi oil pressure gauge. There are a mirade of things that could have ruined the bearings. Trash in the motor from when it was apart, detonation from a bad tune, etc. You can't assume all is well just because the stock (or modified) gauge says so. I'm very sorry this happened but it's not normal. There was a cause for it.


I'll agree with you there on the not normal part. It started making noise after a clogged cat incident-related? Maybe.
It would not make any noise under acceleration or deceleration, only light load cruise.
When it was not making the noise (ie:1500 RPM) the oil pressure would be higher then when it was making the noise (ie:2000 RPM).
It also seemed that the oil had bubbles on the dipstick when checking it after the engine had been running, and no, it was not overfull.
I guess I will have a better idea once I take it apart.

Nick
 
It also seemed that the oil had bubbles on the dipstick when checking it after the engine had been running, and no, it was not overfull.


Nick

Same here...

I got mine running pretty good today....Ran it up the street with no plates to check boost levels and hear my exhaust after welding them up for the first time..SC sounded great as well..I checked the oil right away and seen the tiny bubbles popping...

I havent changed the oil since putting fresh oil in right before the head gasket change.....So Im hopein....A very very little bit of water left in system...Little fuel...Little silicone..Little brake clean....

I wanted to let my cam wear in a bit and everything else and change the oil to the good stuff...Ive got 1/4 mile driving and maybe 15 minutes of idling...So tommorow I might try the amsoil....

F1

**EDIT**

Oil is already out and draining til tommorrow....Oil was alot worse then the dipstick showed and smelt..Darker and more fuels...Also bubbles in it(mostly on surface of catch bucket)..Well my guess tad tad bit of water and fuel and cleaners from hg change...

Point learned.....Do oil changes and lots of them...High temps and pressure from boost....
 
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Bubbles on the dipstick is normal. That's a little air from the oil being whipped around by the crankshaft. With the small oil pan on the SC motor, the oil gets beaten around alot. That's why race motors run 6, 7 or 8 qt oil pans and not 4 qt pans like our SC motors.

The sounds under light load were almost certainly detonation. Light load is when the EEC has the most spark advance and least fuel in the tune. If you've played with ANYTHING (injectors, MAF, etc) and not changed the EEC, that would create detonation under light load first. Detonation is like putting a chisel on the top of the piston and hitting it with a sledgehammer. It'll destroy a piston and rod bearings in very short order. Severe detonation can bend rods if the pistons strong enough. Trust me.. I have a banana'd rod from my experiences with detonation. The rod bearing got so hot it started to peel.
 
I've got over 255k miles on my SC's original longblock. I've only done the head gaskets. Never had the oil pan off.

These motors are strong. When I hear of people breaking cranks or spinning bearings, I wonder what else was wrong with the car.
 
Well, I took the rods loose tonight

Don't have much time to work on things with a 2 year old and a wife that works too.
Drained the oil last night (came out real nasty and had just changed one week before I pulled the car off the road).
Lot of bits in the oil pan.
#6 had no bearing left (the debris in the pan).
The other five all had copper showing, and all had some peeling more or less.
All bearings also came out in pieces, but had not spun.
At this point, I have five good rods, one that might be slavageable, and a crank that is likely toast (I will let a machinest make that call), and no idea what happened to cause this.
The only mod I have is a 73 mm C&L with a clear tube, but this started long before I swapped meters.
I figure that I will fix the bottom end (is it possible to pull and replace pistons from the bottom?), and sell the car.
I consider myself fairly competent, but pulling the engine really should not be some kind of annual event-repairs have pretty much killed any mod budget I might have, and that has made it less than fun.
I realize that a lot of the problems were inherited from the last owner's lack of knowledge and his friend's lack of knowledge that worked on it for him, but I think I am through with SC's.

Nick
 
if you need rods, post in wanted to buy. Folks have take out parts that can be reused.

if you can grind down to .010 on the crank, you'll be good to go. Anything more and throw it.
 
Don't have much time to work on things with a 2 year old and a wife that works too.
Drained the oil last night (came out real nasty and had just changed one week before I pulled the car off the road).
Lot of bits in the oil pan.
#6 had no bearing left (the debris in the pan).
The other five all had copper showing, and all had some peeling more or less.
All bearings also came out in pieces, but had not spun.
At this point, I have five good rods, one that might be slavageable, and a crank that is likely toast (I will let a machinest make that call), and no idea what happened to cause this.
The only mod I have is a 73 mm C&L with a clear tube, but this started long before I swapped meters.
I figure that I will fix the bottom end (is it possible to pull and replace pistons from the bottom?), and sell the car.
I consider myself fairly competent, but pulling the engine really should not be some kind of annual event-repairs have pretty much killed any mod budget I might have, and that has made it less than fun.
I realize that a lot of the problems were inherited from the last owner's lack of knowledge and his friend's lack of knowledge that worked on it for him, but I think I am through with SC's.

Nick

You can't really expect to buy a $100 motor, install it and drive the car for several years without any problems. No you can't change the pistons without pulling the heads.

David
 
You can't really expect to buy a $100 motor, install it and drive the car for several years without any problems. No you can't change the pistons without pulling the heads.

David

The reason I am so surprised on this, was that before I put this engine in, I pulled the pan, and pulled both rods and mains, intending to replace the bearings (no, I didn't mix them up), and discovered, to my surprise, bearings that looked in very good shape, and were original size Ford factory.
Based on that, I buttoned it back up and dropped it in my car.
This last summer, I had the heads from the original ('89) motor rebuilt and replaced the head gaskets-trying to do it BEFORE I had blown gaskets and coolant in the oil.
After I dropped the engine in and started it, I had evidence of water in the oil (milkshake), but it cleared up after about 20 minutes (no coolant at exhaust).
My guess was that the engine had condensation from sitting, and it burned off-this was borne out by it never using any coolant, except for a leaky stat housing which I eventually fixed.
One other possibility, my IRCM was bad, only activating the overheat fan, until it was replaced late last summer-could the damage have been doone always running around 228 or so?

Nick
 
I would think it would be experincing a lot of detonation at 228 degrees, and that could have contributed the premature bearing wear/failure. There may have been some pitting to the crank from sitting for however long before you bought the motor and the bearings could still look good, because the motor had not been ran yet.

Were you using 91 or higher octane ?

David
 
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Yep, I have always run premium in this car.
I didn't SEE pitting on the journals, but that does not mean none was there.
I didn't hear any detonation, and never have, unless that is the noise it has been making the whole time-but if this has been detonating like that, it would be on a stock tune and stock hardware.
I have run an EGR block off since the beginning, since the tube was rotted through, which would raise the burn temp somewhat.
Plugs look normal, except the platinum on the side electrode is gone-center electrode looks fine.
In my original post, I stated that the indicated oil pressure was higher at ~1500 rpm than it was at ~2000, when it would be making the noise.
My main hope at this time is that I don't fix this, without fixing the cause-I certainly don't want to sell a time bomb to the next guy like the po did to me-and no, I don't intend to part it out-there are less of these cars every day and I don't want to make it one more.
Edit-the first engine also did the same thing, but much worse. I suspect losing the inner input shaft on my AOD (at the time) at ~80 may have had a hand in that.

Nick
 
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A little follow up

I think I may have found the underlying cause of the carnage.
As I tore the motor down, I found that number one piston had lost one of the pin retainers at some point in the past.
That did not seem overly significant at the time, as I was in the middle of picking up a replacement car ('03 Stang GT-I know....sellout).
When I got around to flipping the block over, I discovered that the pin had worn a groove in the cylinder wall-need at least .020 to clean that one up.
I have known for a while that every oil change, the oil was what I would consider excessively dirty for the time interval (3000) and smelled like unburned fuel.
My hypothesis is that the oil was quickly contaminated by metal and diluted by fuel to the point of not giving good lube to the bottom end.
As to why the retainer parted company? I have no clue, but this has convinced me that maybe floating wrist pins aren't all that for a stock app that does not get regularly torn down and inspected.
Any comments or theories?

Nick
 
hmmm, factory pins are full floating in the 94/95. Retaining clips shouldn't come loose if the proper retainers are used in the proper pistons with the proper pins. and are installed properly. Were they spiral locks?

I took a lot of care installing my pin retainers and made sure they were in their channel and not going to come out.
 

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