05-11-2005, 12:22 AM
Alright, so I use plastigauge to measure clearances, which will tell me one of 2 things:
1. Everything is fine.
2. Clearances are out of whack.
In the first case, I install standard size bearings, no big deal.
If the clearances are way out of whack, I can now:
1. Reinstall old bearings. There is no reason to do this, as clearances will still be screwed up and the bearing will most likely spin in the near future.
2. Install the new std size bearings. This will put clearances closer to factory specs, prolonging the life of the engine.
3. Tear the engine out of the car, pull the crank, spend more money than a new motor would cost to have the said crank reground, then reinstall with oversized bearings.
1 is a stupid choice, 2 makes the most sense, 3 is impractical.
From the guy who writes most maintenance procedures for the SHO community and has over 300k miles on his motor:
"No real need to Plastigauge the new bearings. If they aren't in spec, what are you going to do? They are still much tighter than the ones you just replaced. Just make sure you torque them in stages to the proper value."
Guy with 181k on his motor:
"If you use plastigauge and find that you're the slightest bit off, what are you going to do? Grind the crank down so you can fit oversized bearings in there? If the crank journals have no damage, there's absolutely no reason to plastigauge. Put the standard bearings in and don't worry about it for 150k miles (unless you lug the engine periodically, then check them at 100k miles)"
SHOTimes opinion on the matter:
"Don't waste your time with the Plastigauge!!! It is not really meant to be used with an engine in that position (it should be on an engine stand), and if you have never used it before, it will take you more time, and probably give you erroneous results that will make you crazy. Besides, as Paul says, IF you got good results, and IF the crank was "somehow" (very, very unlikely) out-of-spec, whaddya gonna do about it? The car ran for years with standard bearings, put standard bearings in it."
I'm not using plastigauge, your opinions on the matter are well noted. It is not "incorrect" to replace standard size bearings with new standard size bearings without measuring them with plastigauge, as it is the only practical thing for me to do.
1. Everything is fine.
2. Clearances are out of whack.
In the first case, I install standard size bearings, no big deal.
If the clearances are way out of whack, I can now:
1. Reinstall old bearings. There is no reason to do this, as clearances will still be screwed up and the bearing will most likely spin in the near future.
2. Install the new std size bearings. This will put clearances closer to factory specs, prolonging the life of the engine.
3. Tear the engine out of the car, pull the crank, spend more money than a new motor would cost to have the said crank reground, then reinstall with oversized bearings.
1 is a stupid choice, 2 makes the most sense, 3 is impractical.
From the guy who writes most maintenance procedures for the SHO community and has over 300k miles on his motor:
"No real need to Plastigauge the new bearings. If they aren't in spec, what are you going to do? They are still much tighter than the ones you just replaced. Just make sure you torque them in stages to the proper value."
Guy with 181k on his motor:
"If you use plastigauge and find that you're the slightest bit off, what are you going to do? Grind the crank down so you can fit oversized bearings in there? If the crank journals have no damage, there's absolutely no reason to plastigauge. Put the standard bearings in and don't worry about it for 150k miles (unless you lug the engine periodically, then check them at 100k miles)"
SHOTimes opinion on the matter:
"Don't waste your time with the Plastigauge!!! It is not really meant to be used with an engine in that position (it should be on an engine stand), and if you have never used it before, it will take you more time, and probably give you erroneous results that will make you crazy. Besides, as Paul says, IF you got good results, and IF the crank was "somehow" (very, very unlikely) out-of-spec, whaddya gonna do about it? The car ran for years with standard bearings, put standard bearings in it."
I'm not using plastigauge, your opinions on the matter are well noted. It is not "incorrect" to replace standard size bearings with new standard size bearings without measuring them with plastigauge, as it is the only practical thing for me to do.
Why do people just post what they are thinking? Without thinking.
2012 Ford Mustang
1995 BMW 540i/A
1990 Eagle Talon TSI AWD
2012 Ford Mustang
1995 BMW 540i/A
1990 Eagle Talon TSI AWD