Bad main bearing? PICS
Thread Starter
Burning Brakes
Joined: Oct 2008
Posts: 955
Likes: 50
From: Jersey Shore
Bad main bearing? PICS
Continuing my search to find my low oil pressure only under load problem, I pulled the main caps off of the motor tonight. Tell me what you think. I know they dont look good, but would this cause a low oil pressure? Would you pull the motor after seeing this? I only pulled 2 so far. This was the worst one.
Racer
Joined: Jan 2011
Posts: 266
Likes: 0
From: York Pa.
Well its hard for me to tell if you are thru the babbit material..is it dark or is it just the way the picture took..the small pits are from sitting..looks like some gauging also..if the crank looks clean try some plasti gauge and see what clearance you have..that's a start..maybe oil pump issue..have you checked.pressure with a real gauge?
Last edited by Chromie69; Feb 18, 2011 at 08:03 PM.
Drifting
Joined: Dec 2009
Posts: 1,349
Likes: 34
From: Porterville Ca
The grooves are a bad sign, it has significant wear. I'll bet the rods are even worse, mains usually aren't this bad. You need to inspect all the crank and rod journals, bearings and thrust bearing surface. Make certian you plasigage all crank surfaces before reassembly, with or without machining the crank. How many miles does the motor have?
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Scoring like that is not good. Take some pics of the crank journals in the same detail. I do not want to step on anyones toes but a plastigauge measurement is not worth the price of of the plasticgauge itself. There are some good boregauges that can be had for very little investmemt these days and if you want to build a motor properly that is the way to go 
Racer
Joined: Jan 2011
Posts: 266
Likes: 0
From: York Pa.
So we are now building a race engine and not just checking what the average clearance is..plastigauge has been used since these motors were new and is still used per new auto manufactures ..I've been on this forum now for maybe 3 weeks and have never met so many combative people in my life..I know this is way off topic and may start a thread asking just that WTF? There's always someone to put down what someone else has to say..is it me or does everyone on this forum fix cars for a living or what?
Racer
Joined: Feb 2008
Posts: 497
Likes: 0
From: Streator Illinois
So we are now building a race engine and not just checking what the average clearance is..plastigauge has been used since these motors were new and is still used per new auto manufactures ..I've been on this forum now for maybe 3 weeks and have never met so many combative people in my life..I know this is way off topic and may start a thread asking just that WTF? There's always someone to put down what someone else has to say..is it me or does everyone on this forum fix cars for a living or what?
Terry
Racer
Joined: Jan 2011
Posts: 266
Likes: 0
From: York Pa.
Saying that a plastigauge measurement isn't worth the money spent on it is an opinion that makes no sense..its obvious this OP has a severe problem with lack of lubrication..so why go crazy on it and just get a general idea of how bad it is..I have watched more than posted here and it really seems like some people get all cranked up on how much they can up the next guy..if there really is something posted that really is wrong then by all means correct..if not then maybe approach or forum tact is something I need to work on..and I will just have to get used to it.
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Drifting
Joined: Jun 2010
Posts: 1,781
Likes: 15
From: Oxford Ohio
Go to a bearing companies web site. They normally have pics of different degrees of wear, and will inform you what the issue probably is.
How many miles on your motor?
Just guessing, but it looks like it may have debris going through the oil system.
How many miles on your motor?
Just guessing, but it looks like it may have debris going through the oil system.
Le Mans Master
Joined: Oct 2010
Posts: 6,938
Likes: 848
From: melbourne florida
2023 C3 of the Year Finalist - Modified
plastiguage is a perfectly acceptable means of checking. its kind of hard getting a dialbore gauge into a rod in an assembled motor in a car.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
For what it's worth...
An "open" discussion forum is just that--a place where anyone can offer 'input'. Sometimes that input is useful; sometimes it's not. You just have to let it come in, then ignore the cr@p. The only thing that bothers me is when someone makes a direct attack/confrontation with what someone else says, rather than merely offering their viewpoint.
So, don't take anything too seriously; just sift through the rhetoric and learn what you can. Dump the rest.
An "open" discussion forum is just that--a place where anyone can offer 'input'. Sometimes that input is useful; sometimes it's not. You just have to let it come in, then ignore the cr@p. The only thing that bothers me is when someone makes a direct attack/confrontation with what someone else says, rather than merely offering their viewpoint.
So, don't take anything too seriously; just sift through the rhetoric and learn what you can. Dump the rest.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
For what it's worth...
An "open" discussion forum is just that--a place where anyone can offer 'input'. Sometimes that input is useful; sometimes it's not. You just have to let it come in, then ignore the cr@p. The only thing that bothers me is when someone makes a direct attack/confrontation with what someone else says, rather than merely offering their viewpoint.
So, don't take anything too seriously; just sift through the rhetoric and learn what you can. Dump the rest.
An "open" discussion forum is just that--a place where anyone can offer 'input'. Sometimes that input is useful; sometimes it's not. You just have to let it come in, then ignore the cr@p. The only thing that bothers me is when someone makes a direct attack/confrontation with what someone else says, rather than merely offering their viewpoint.
So, don't take anything too seriously; just sift through the rhetoric and learn what you can. Dump the rest.
That can be applied below.
Continuing my search to find my low oil pressure only under load problem, I pulled the main caps off of the motor tonight. Tell me what you think. I know they dont look good, but would this cause a low oil pressure? Would you pull the motor after seeing this? I only pulled 2 so far. This was the worst one.
Check the numbers on the back, probably standard size, just get a new set of main and rod bearings (cheap anyway), forget measuring anything, clean the debris out of the pan, a new 40 buck oil pump and you're good for at least another 5,000-10,000 miles with some oil pressure.
Race Director
Joined: Dec 1999
Posts: 11,096
Likes: 990
From: Sierra Foothills CA
Looks like you're thru the bearing to me.
Check the numbers on the back, probably standard size, just get a new set of main and rod bearings (cheap anyway), forget measuring anything, clean the debris out of the pan, a new 40 buck oil pump and you're good for at least another 5,000-10,000 miles with some oil pressure.
Check the numbers on the back, probably standard size, just get a new set of main and rod bearings (cheap anyway), forget measuring anything, clean the debris out of the pan, a new 40 buck oil pump and you're good for at least another 5,000-10,000 miles with some oil pressure.
Le Mans Master
Joined: Dec 2006
Posts: 5,557
Likes: 9
From: Oquirrh Mountains
St. Jude Donor '09
There's been a lot of trash go through that engine. A complete rebuild is in order. I wonder if it was put together without the block being washed. That, or something came apart. What do the oil pump gears look like? It sure looks like there's a lot of iron particles embedded in those bearings.
Going to have to disagree w/ya on the plastigauge MH. Though not as good as a bore gauge, it is reasonably accurate if used correctly.
Going to have to disagree w/ya on the plastigauge MH. Though not as good as a bore gauge, it is reasonably accurate if used correctly.
Last edited by Ben Lurkin; Feb 19, 2011 at 01:43 AM.
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
Naturally a set of 'Mikes is the best way to check the crank and bearings....but not everyone has that in their tool assortment....Therefore a simple method is to drag your fingernail across the crank bearings surface...the test is if your nail catches groves then it should come out and be replaced...as simple as that....You can check the ware on the bearings with a 'Ball mike...You would need the specifications from a bearing catalogue...
By the looks of the pictured bearings, the crank is history or dead
By the looks of the pictured bearings, the crank is history or dead
Thread Starter
Burning Brakes
Joined: Oct 2008
Posts: 955
Likes: 50
From: Jersey Shore
Thanks for the responses guys 
I ended up pulling the motor. Its going for a rebuild and some other "while im at it" upgrades (thermostatic oil cooler, 7 qt road race pan, and a Lakewood scatter shield)
I bought the car with a wiped out cam. I put a new top end on the shortblock about 4 years ago without doing anything to it. I guess thats what went through the motor. I have no idea how many miles are on it. All I know is that it was rebuilt in 1990.
I tried the plastigauge, but I couldnt get an accurate reading from it. The crank looks far better than the bearings, no scoring or pitting.
It ran great right up to when I tore it down. I gave it a final burnout sitting on the rev limiter. Motor took it like a champ
I ended up pulling the motor. Its going for a rebuild and some other "while im at it" upgrades (thermostatic oil cooler, 7 qt road race pan, and a Lakewood scatter shield
)I bought the car with a wiped out cam. I put a new top end on the shortblock about 4 years ago without doing anything to it. I guess thats what went through the motor. I have no idea how many miles are on it. All I know is that it was rebuilt in 1990.
I tried the plastigauge, but I couldnt get an accurate reading from it. The crank looks far better than the bearings, no scoring or pitting.
It ran great right up to when I tore it down. I gave it a final burnout sitting on the rev limiter. Motor took it like a champ
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
There's been a lot of trash go through that engine. A complete rebuild is in order. I wonder if it was put together without the block being washed. That, or something came apart. What do the oil pump gears look like? It sure looks like there's a lot of iron particles embedded in those bearings.
Going to have to disagree w/ya on the plastigauge MH. Though not as good as a bore gauge, it is reasonably accurate if used correctly.
Going to have to disagree w/ya on the plastigauge MH. Though not as good as a bore gauge, it is reasonably accurate if used correctly.
Walk into any good engine shop and ask them if they use plastgauge when building a motor. I happen to be the one offended here, do some homework and you will find the answer instead of attacking me
Burning Brakes
Joined: Jan 2007
Posts: 1,057
Likes: 4
From: Concord Calif
Go to a good machine shop, ask someone there that's been building motors for more than a year what his opinion is on plastigauge. I was not attacking anyone just trying to help. Like I said bore gauges are inexpensive now a days and I check rods with mine no problems. Seems like you try to give advice that any engine builder would agree on and all of sudden it's taken the wrong way,
Walk into any good engine shop and ask them if they use plastgauge when building a motor. I happen to be the one offended here, do some homework and you will find the answer instead of attacking me
Walk into any good engine shop and ask them if they use plastgauge when building a motor. I happen to be the one offended here, do some homework and you will find the answer instead of attacking me
Your right about the plasta-Gage for the most part, it does have a place but it is more of a go/no go type Gage. Seems the OP did the right thing and pulled the motor and he probably is correct in what happened to his engine also. As far as some others comments, well just can't say here what I really think on this site, but that stuff has NO business on this site. I see NP with what you said at all.
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
What did the rod bearings look like?
Time to freshen her up and do a little modding while youre in there....Might as well so you can justify the tear down.... Thats what I always tell myself....
Time to freshen her up and do a little modding while youre in there....Might as well so you can justify the tear down.... Thats what I always tell myself....