Engine assembly - in the cold?
Engine assembly - in the cold? Hey guys, kind of a random question but here goes.
Im going home for christmas break soon, and I have all the parts to start throwing my LS2 together. Im going to be measuring and clearance everything and this is where my concern comes up.
I'll be working out in the garage, where its likely that the environment will be a good 10 to 25 degrees F.
Im wondering, is this temperature change going to affect my bearing clearance measurements?
Moving it indoors is a no go. Cant be making a mess, and more importantly when I get it assembled there would be no way to get it back out to where it is going to be installed.
Any insight on this? Can i go at er and measure it up to the suggested specs? Or is there something i will have to do differently.
Im going home for christmas break soon, and I have all the parts to start throwing my LS2 together. Im going to be measuring and clearance everything and this is where my concern comes up.
I'll be working out in the garage, where its likely that the environment will be a good 10 to 25 degrees F.
Im wondering, is this temperature change going to affect my bearing clearance measurements?
Moving it indoors is a no go. Cant be making a mess, and more importantly when I get it assembled there would be no way to get it back out to where it is going to be installed.
Any insight on this? Can i go at er and measure it up to the suggested specs? Or is there something i will have to do differently.
Staging Lane
Joined: Jun 2005
Posts: 51
Likes: 0
Hey guys, kind of a random question but here goes.
Im going home for christmas break soon, and I have all the parts to start throwing my LS2 together. Im going to be measuring and clearance everything and this is where my concern comes up.
I'll be working out in the garage, where its likely that the environment will be a good 10 to 25 degrees F.
Im wondering, is this temperature change going to affect my bearing clearance measurements?
Moving it indoors is a no go. Cant be making a mess, and more importantly when I get it assembled there would be no way to get it back out to where it is going to be installed.
Any insight on this? Can i go at er and measure it up to the suggested specs? Or is there something i will have to do differently.
Im going home for christmas break soon, and I have all the parts to start throwing my LS2 together. Im going to be measuring and clearance everything and this is where my concern comes up.
I'll be working out in the garage, where its likely that the environment will be a good 10 to 25 degrees F.
Im wondering, is this temperature change going to affect my bearing clearance measurements?
Moving it indoors is a no go. Cant be making a mess, and more importantly when I get it assembled there would be no way to get it back out to where it is going to be installed.
Any insight on this? Can i go at er and measure it up to the suggested specs? Or is there something i will have to do differently.
Thats my thoughts, is it significant change? If i could get the block inside, i could do Cold temp measurements, then a warm temp measurement on the block so id know how much it changes (for science, i guess, because at that point id just install it inside)
I can do warm/cold measurements on all the other parts though, to see how that effects them, but differences in material will have difference in expansion/contraction?
We dont mind the cold, helps the boost numbers
lol mannnnnn thats rough... i would be more concerned about making a mistake because im too cold to think than i would be worried about clearances.. but im from california... its 75 degrees in december
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Aluminum and iron have different expansion rates with temperature changes, so the clearances you measure at 10-25 degrees may very well be different than if you measure at 65-75 degrees. The rods may not change but the mains probably will. If it were me, I'd invest in something to heat the garage.
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TECH Fanatic
Joined: Jun 2011
Posts: 1,343
Likes: 8
From: Katy, TX
You can test it yourself. Measure the ID of a rod bore in your cold garage, then take it inside (let it sit for a while), then re-measure. Post the results you get.
Maybe do the same with the crankshaft journal ODs.
Maybe do the same with the crankshaft journal ODs.
Is there any particular piece of metal on the engine that would be comparable to the block? The rods I have are comp stars, and the crank is a forged unit so im wondering how that's going to change things.
I have the original connecting rods as well, if that may be closer to the metal used in the block? I honestly have no idea.
Look on Matweb.com...if you know what alloy of metal your parts are made of you can look them up and look at the coefficient of thermal expansion and get a basic idea of how much the parts will expand in relation to each other....
I am not a metalurgist. However, no temperature tha a human can operate in is extreme fro metal components, I would not be too concerned. The car will sit at those temps and then warm into the 180-200 degree range under operation. You would be blowing motors all over the place. I would think that OEM specs for material and torque would take into account thermal expansion rates. Therefore as long as all the pats are the same temperature during assembly you should be ok. Setting specs with a 10 degree crank and 90 degree rods might be were bad things happen. Just a thought.
Beat me to it. Just be sure that ALL the parts are at the same temp before measuring and assembly. Best bet to me though would be in a somewhat controllable environment where it can stay consistent, that way as the day progresses and temps change you don't have to worry about that affecting your measurements and assembly.
Beat me to it. Just be sure that ALL the parts are at the same temp before measuring and assembly. Best bet to me though would be in a somewhat controllable environment where it can stay consistent, that way as the day progresses and temps change you don't have to worry about that affecting your measurements and assembly.
My big worry is that even though itll be consistent temperatures, if i clearance bearings to spec at 10 degrees, when they come up to room temperature (or whatever temperature a normal engine is assembled in) that the gaps will be too big.
If that makes sense?
Not sure how to explain this well. I know that engines see those temperatures just sitting outside, but they were not assembled in those conditions. They're gapped or spec'd to account for those conditions.
It will consistently be cold as.....i dont know things that are freezing cold.
My big worry is that even though itll be consistent temperatures, if i clearance bearings to spec at 10 degrees, when they come up to room temperature (or whatever temperature a normal engine is assembled in) that the gaps will be too big.
If that makes sense?
Not sure how to explain this well. I know that engines see those temperatures just sitting outside, but they were not assembled in those conditions. They're gapped or spec'd to account for those conditions.
My big worry is that even though itll be consistent temperatures, if i clearance bearings to spec at 10 degrees, when they come up to room temperature (or whatever temperature a normal engine is assembled in) that the gaps will be too big.
If that makes sense?
Not sure how to explain this well. I know that engines see those temperatures just sitting outside, but they were not assembled in those conditions. They're gapped or spec'd to account for those conditions.
In addition, what would pre or post assembly matter. Temp is temp. Cold should only matter if the material became so brittle that it broke during a torque sequence. Which most likely is so cold that there would be no way for you to be working outside.
USAF used to work on B-52's at Minot, ND in subzero temps. Lot more at stake in airplane repair.
Th rod and cap around the bearing and crankshaft in between will have come up to the same temperature and therefore (given proper material design) should have expanded at a rate that would maintain spec.
In addition, what would pre or post assembly matter. Temp is temp. Cold should only matter if the material became so brittle that it broke during a torque sequence. Which most likely is so cold that there would be no way for you to be working outside.
USAF used to work on B-52's at Minot, ND in subzero temps. Lot more at stake in airplane repair.
In addition, what would pre or post assembly matter. Temp is temp. Cold should only matter if the material became so brittle that it broke during a torque sequence. Which most likely is so cold that there would be no way for you to be working outside.
USAF used to work on B-52's at Minot, ND in subzero temps. Lot more at stake in airplane repair.
If you gap a motor at 50 degrees to 0.020
And you gap a motor at 10 degrees to 0.020
The motor gapped at 10 degrees, once it comes up to 50 degrees, will have a different gap than the motor gapped at 50 degrees.
It would be like measuring and cutting a piece of metal that's at 0 degrees, and then heating it up and remeasuring it. When its warmer, it'll be slightly longer.
It probably is minimal,and possibly negligible. I was just wondering if there were any changes id have to make in my measurements.
Currenty, in Minot, it is 12*F
Where Ill be working, its currently 8*F, and its going to be a boosted 10.5:1 motor.
Not as high stake, but I also don't have the repair budget that the USAF has if something goes wrong, so id like to be as precise as possible!
I got to looking into this to expound further, since I know there has to be some standardization for getting factory tolerances. Turns out, your mics (read quality measuring equipment) are calibrated to be used at a standardized temp, which the manual I was reading was showing roughly ~68 degrees.
Only thing I can think of is to look up the properties of the metal and see what the shrinkage would be at the temps you'd be working at. I'd guess that .001-.0015 or more wouldn't be out of the question for steel but who knows.
You might think about moving the engine inside and assembling in a kitchen or some other room where you can control and achieve consistent temps for all parts, otherwise it may be a crap shoot for your running clearances. That or talk to someone far more knowledgeable that can give you a better idea of what to shoot for.
Only thing I can think of is to look up the properties of the metal and see what the shrinkage would be at the temps you'd be working at. I'd guess that .001-.0015 or more wouldn't be out of the question for steel but who knows.
You might think about moving the engine inside and assembling in a kitchen or some other room where you can control and achieve consistent temps for all parts, otherwise it may be a crap shoot for your running clearances. That or talk to someone far more knowledgeable that can give you a better idea of what to shoot for.
Staging Lane
Joined: Nov 2010
Posts: 93
Likes: 1
EDIT: Please read post #27 for accurate numbers: https://ls1tech.com/forums/generatio...l#post18561966 5-13 microns should actually be 5-13 microinches, and a 100F change would be closer to 0.0006"/in
I figured I should chime in, since I'm a mechanical engineer and my daily job is to understand heat transfer, thermal stresses, tolerances, etc in automotive applications...and this thread is a bit depressing.
Spark notes: there is no difference to building your engine in 10°F or 100°F.
Aluminum and iron/steel have CTEs (coefficient of thermal expansion) between 5-13 microns/in-°F, and mostly in the 6-9 microns/in-°F range. In other words, even a 100°F change in temperature will only affect tolerances in the 0.0003"/in range. On any surface you can measure, it may only be 25 microns, which is orders of magnitude smaller than anything you can accurately measure at home. Eg, your calipers are, on a good day, only accurate to .001-.002".
Remember, these engines cycle hundreds of degrees during operation, which does far more to tolerance mismatch than 90°F could do while building your engine.
I figured I should chime in, since I'm a mechanical engineer and my daily job is to understand heat transfer, thermal stresses, tolerances, etc in automotive applications...and this thread is a bit depressing.
Spark notes: there is no difference to building your engine in 10°F or 100°F.
Aluminum and iron/steel have CTEs (coefficient of thermal expansion) between 5-13 microns/in-°F, and mostly in the 6-9 microns/in-°F range. In other words, even a 100°F change in temperature will only affect tolerances in the 0.0003"/in range. On any surface you can measure, it may only be 25 microns, which is orders of magnitude smaller than anything you can accurately measure at home. Eg, your calipers are, on a good day, only accurate to .001-.002".
Remember, these engines cycle hundreds of degrees during operation, which does far more to tolerance mismatch than 90°F could do while building your engine.
Last edited by iliveonnitro; Dec 8, 2014 at 07:58 AM.
I figured I should chime in, since I'm a mechanical engineer and my daily job is to understand heat transfer, thermal stresses, tolerances, etc in automotive applications...and this thread is a bit depressing.
Spark notes: there is no difference to building your engine in 10°F or 100°F.
Aluminum and iron/steel have CTEs (coefficient of thermal expansion) between 5-13 microns/in-°F, and mostly in the 6-9 microns/in-°F range. In other words, even a 100°F change in temperature will only affect tolerances in the 0.0003"/in range. On any surface you can measure, it may only be 25 microns, which is orders of magnitude smaller than anything you can accurately measure at home. Eg, your calipers are, on a good day, only accurate to .001-.002".
Remember, these engines cycle hundreds of degrees during operation, which does far more to tolerance mismatch than 90°F could do while building your engine.
Spark notes: there is no difference to building your engine in 10°F or 100°F.
Aluminum and iron/steel have CTEs (coefficient of thermal expansion) between 5-13 microns/in-°F, and mostly in the 6-9 microns/in-°F range. In other words, even a 100°F change in temperature will only affect tolerances in the 0.0003"/in range. On any surface you can measure, it may only be 25 microns, which is orders of magnitude smaller than anything you can accurately measure at home. Eg, your calipers are, on a good day, only accurate to .001-.002".
Remember, these engines cycle hundreds of degrees during operation, which does far more to tolerance mismatch than 90°F could do while building your engine.
Andrew