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Discussion Starter · #1 ·
Thought I'd share these pics with everyone.

Engine was pulled last month and torn down two weeks ago. Never did I imagine the severity of what we found. She (engine) is a 1990 120K mile donor that was completely and professionally rebuilt 3311 miles ago. Last fall she went kaput on me although little did I realize she was internally wounded many miles before finally having to put her to rest. I realize that it is sometimes a near impossibility to conclude what the root cause of these failures types are. We sort of suspect what may have happened but that is only it ... suspect.


(Main and rod bearings. Sorry for the shadow)


(Main bearings)

Although having a MAP sensor issue from the get go, (that wasn't truly resolved until last June week before the Fling), FFR#2625 ran pretty good for about her first 1800-2000 miles. Around this time she started to develop a slight vibration at 2200 rpm. I chased the vibration for well over a year never thinking it may be engine related. I checked every nut and bolt on the car three times over never finding a darn thing loose. Always felt that my wind screen was coming loose. Vibration kept getting worse little by little until last summer it got pretty annoying. Also those darn SW gauges are sometimes more trouble having them than not. To make matters worse very early on FFR2625 developed an oil pressure gauge issue that I tinkered with on and off but never did completely resolve. I finally concluded, and still believe today, that the gauge is defective and requires replacing. Proved it with a mechanical gauge before I pulled the engine. Although I had gauge issues little did I realize that the stupid defective gauge was also intermittently hinting to me that I had a potential problem going on. Completely my fault for not paying closer attention.


Here's a pic of the main bearing journal. Completely shot. Hope you can see this...if you look closely enough you will see deep shoulders worn into the journal the width of the bearing. Worn so much so that the crank can not be refurbished.



Well, what we believe may have cause this failure is this.....that MAP sensor problem I was having from day one up until last year made the car run very rich at times, especially early on in FFR#2625's life. I did a 3 MAP sensor swaps w/ used sensors and each time I pilled codes I'd get errors. Last summer I put a new sensor in which resolved the problem. We believe this caused excess fuel to leak/dump pass the rings and into the oil thus thinning it out enough to demish it's lubricity. This probably happened within the first 500 miles of driving time. Although quite some time ago and several oil changes later I never recalled the oil smelling like fuel but then again maybe I just failed to notice and never caught it. The excessive fuel in the oil caused excessive bearing wear (probably starting out with the rear main) and ultimately causing the rest to wear excessively.

Of course one can never rule out a balance issue, poor assembly technique, or lack of cleanliness during assembly rebuild?!?!? Guess we'll never really know.

Note: balancer is stock and doesn't appear to have slipped. No signs of oil starvation on bearings. CAM bearings look absolutely fine with no wear. Pistons, rings, and rods look in good shape.

Doug
FFR2625
 

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Damn, dude. Those are some ugly bearings. :(

If the car was dumping enough fuel to thin your oil, I think you'd hardly be able to drive it for all the black smoke! I'd bet the problem lies elsewhere. Maybe the wrong size bearings?
 

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I see one of 2 possible problems. 1 is a bent crank. The other is the possibilty of the oil lines to the remote filter being hooked up backwards. I tend to think a bent crank.
 

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Discussion Starter · #5 ·
Wade - this one's got me stumped. Bearings were Clevite 77 and were the correct size. No excessive black smoke but early on, at times, it ran rich, and I had some drivability issues that were MAP sensor related.

Hank - I check the run out. Crank is stock cast.

Gordon - Crank was polished and balanced upon rebuild. Ran good, other than MAP sensor issues, for first 1800 miles. No real signs of oil starvation and oil lines were routed correctly. Double checked many time over.

The one other thing that was found when the engine was dismantled was that it never was Aline honed when in fact I was charged for it. I've since resolved this the $$ issue with the builder.

Doug
FFR2625
 

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If you were dumping fuel that badly the rings/cyl walls would have been shot too. What do those look like?
 

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The assembly may have been balanced but that doesn't mean the crank is straight. If the machinist, assembler, shop pion, etc.. knocked the crank over, it can be bent. Most of the time you wouldn't even know unless the run out was specifically checked. I did learn this the hard way and always have all of my parts checked, be it new or rebuilt.
 

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Never saw worse in a running engine. The oil system was dry as a chip, when it ended and the bearings were hot as He!!. With the consistant problem thru out the engine, I think it was an oil problem. ... didnt the hyd lifters rattle?

I vote against the fuel issue killing the bottem end. If you have a fuel problem so bad that it would destroy the bottem end the engine would have to been making oil.

I saw a 1.6 toyota once that developed a leak in the fuel pump. Pumped the engine PLUMB FULL of gasoline till it squirted out the oil filler hole. THe owner drained gallons out of it. replaced the fuel pump, put 4 quarts of good oil and a filter in it and DROVE ON. (it was never quite the same tho) :D :D

The way he found out there was a problem was, it left a huge trail of oily gasoline on the driveway when he backed it up the drive way to go to work. :D :D

earl

[ March 09, 2004, 08:07 PM: Message edited by: CobraEarl ]
 

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If you want to go through the expense, mag the crank. You will most likely find that it is cracked and flexing/twisting and that is taking out the bearings. Make sure you examine the main bearing webs in that block if you are going to re-use it (block)...

You were lucky that you disassembled the engine rather than having it disassemble itself!
 

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Originally posted by Mike D:
If you were dumping fuel that badly the rings/cyl walls would have been shot too. What do those look like?
This is the same thing I was thinking.

Now you guys have me wondering....Is my new crank straight?
Did the UPS man use it as a wheel chock?

[ March 09, 2004, 08:25 PM: Message edited by: Knight ]
 

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Discussion Starter · #12 ·
Cylinder walls are in good shape. I had a few advise that if it were gasoline leaking into the oil that it really doesn't take much gas to kill lubricity of 5 quarts of oil. Also if it were gasoline leaking into the oil most, if not all, of the gasoline would quickly evaporate off due to the level of heat. A bearing or bearingss could start to go within the first 100 - 200 miles driven with washed down oil. Really at no time did I have black smoke coming out of the pipes.

Guess it could possibly be a bent or cracked crank but I'm not going to waste the time nor money to find out.

Earl - no ticks or rattles from the lifters or any other part of the engine. Other than my sensor issue the car (engine) ran fast, furious, and strong until she started vibrating. The car just started to vibrate at or around 1800-2000 mile mark but I never could tell that it was coming from the engine0. The Vibration gradually got worse until finally one day in August the engine started to knock from deep within. That's when I shut her down for good.

CAm bearings are still in good shape.

Doug
FFR2625
 

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I have had these bearings in my hand. It is hard to see from the pictures but the wear is smooth so to speak. When they go dry they weld together. These bearings are worn ALOT but smooth wear. Not that welded completely tore up look. It makes sense to me that the oil was there but thinned with fuel. It had enough lub to not lock up but not enough to keep it from doing damage. I have no idea what a bent crank will make the bearing look like. Doug didn't have a problem for the first 1800-2000 miles maybe the crank is cracked and the last 1000 miles it was flexing.
Jeff Hamilton
 

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Hi Doug,
My thoughts are an internal oil eak. How many miles, what engine & year, was it rebuilt, does it have all of the galley plugs in, how about the plug in the lifter valley or plugs behind the timing sprocket. How was the oil pressure when cold & then hot? These are a group of clues to find the answer to the problem. These bearing aren't just bad, it's how & why we all need. Call me with some answers and I hope to give an answer.
Mike Forte
781-273-9900
cell 248-8946
 

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If the builder charged you for honing that was not done, what else didn't he do?
 

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I'm with Earl, if they forgot to hone it, they probably didn't do a good job cleaning out the crank holes. It wouldn't take much. I'm betting you're the one that noticed that it wasn't honed.

Jimbo2
 

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grit and crap left in the oil passages usually puts a few deep scores around the circumference of the journals and bearings, then it ends up in the oil filter. Given that the wear was described as "smooth", I doubt it was dirty oil passages.
 

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Originally posted by Wade Chamberlain:
grit and crap left in the oil passages usually puts a few deep scores around the circumference of the journals and bearings, then it ends up in the oil filter. Given that the wear was described as "smooth", I doubt it was dirty oil passages.
To me, the charring appearance of some of the mains tells me there was intense heat going on. I think that there was NO oil on the crank at the end.

Did the oil gauge indicate that there was oil pressure?? was it dropping as the problem intensified??

If the gauge showed oil pressure, then something was blocked.. Like the old reversed lines to the oil filter problem or a blocked oil passage.

If an internal oil passage plug were out, there would have been no signifficant oil pressure showing at the gauge.

One other thing.. most folks are not talking about the rod bearings. To me, a broken crank/bent crank would not harm the rod bearings.

Can you put the bearings in one of these engines wrong?? so the oil passage holes are not lined up with the oil hole in the bearing?? you might get enough oil flowing around the bearings for it to run for a while.... which it did. and you would have EXCELLENT :D :D oil pressure (showing on the gauge).

Main bearings gone.
Rod bearings gone.
Cam bearings fine,
Cylinder walls fine.

Do the cam bearings get oil first or last?

Since this is a rebuilt engine, we can assume that no oil passages were left out in manufacture.

What ever it is, i hope we figure it out.. Id like to know so Id never make this mistake. :D :D


earl


[ March 10, 2004, 10:55 AM: Message edited by: CobraEarl ]
 
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