Honda engine bearings......OEM versus ACL?
01-23-2007, 07:39 PM
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Honda engine bearings......OEM versus ACL?
Wanted to get some opinions about which bearings to use.
I will use an OEM LS crankshaft that will probably mic out at the proper specs, meaning no previously spun bearings and the journals never turned.
I have been told that OEM Honda bearings have different color codes to specify the different tolerances.........but most of the time, the green color code is used. I've also been told that ACL bearings are just as good, but are always a standard tolerance that matches the OEM green tolerance. I need to know if this is a correct statement. If correct then continue reading. If not correct, then what would be the correct statement?
If my crankshaft mics out properly to meet the OEM "green" tolerance, then which bearing would you use? ACL bearings are about half the price of Honda bearings. Are ACL bearings the same quality as OEM Honda?
I will use an OEM LS crankshaft that will probably mic out at the proper specs, meaning no previously spun bearings and the journals never turned.
I have been told that OEM Honda bearings have different color codes to specify the different tolerances.........but most of the time, the green color code is used. I've also been told that ACL bearings are just as good, but are always a standard tolerance that matches the OEM green tolerance. I need to know if this is a correct statement. If correct then continue reading. If not correct, then what would be the correct statement?
If my crankshaft mics out properly to meet the OEM "green" tolerance, then which bearing would you use? ACL bearings are about half the price of Honda bearings. Are ACL bearings the same quality as OEM Honda?
01-23-2007, 08:26 PM
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Assuming none of the journals need anything besides the standard size bearing, ACL makes quality bearings that many guys use for their motor builds.
Personally, I would use OEM bearings.
h:
Personally, I would use OEM bearings.
h:
01-24-2007, 12:06 AM
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Your information on ACL bearings is correct, I just went through this about 2 months ago. If you are taking measurements yourself, be sure you have a micrometer that is accurate between ten-thousandths and one hundred-thousandths of an inch. Most commercially available micrometer's aren't accurate to this degree of precision. I got mine for $220 a piece. Link: http://www.mytoolstore.com/starrett/microndx.html
After lots of thought, measuring, and talking to various builders, I decided to stick with OEM only. I am sure ACL makes quality engine bearings, but unless you have your crankshaft precisely ground to mate with "green" bearings, they aren't up to par with OEM.
I have yet to see a "virgin" Honda crankshaft with identical measurements all the way across, calling for "green" bearings. Depending on the measurement variance (between journals), using the same size bearing on all can result in a variance oil pressure. I just feel that Honda must have fine tuned everything for a reason. 8500 +/- RPM's isn't something to underestimate.
After lots of thought, measuring, and talking to various builders, I decided to stick with OEM only. I am sure ACL makes quality engine bearings, but unless you have your crankshaft precisely ground to mate with "green" bearings, they aren't up to par with OEM.
I have yet to see a "virgin" Honda crankshaft with identical measurements all the way across, calling for "green" bearings. Depending on the measurement variance (between journals), using the same size bearing on all can result in a variance oil pressure. I just feel that Honda must have fine tuned everything for a reason. 8500 +/- RPM's isn't something to underestimate.
IMO, you shouldn't cut corners on bearings for anything other than an economical box. With the amount spent already, I doubt the extra cost for OEM will brake the bank.
In the end, I doubt you would have any major issues with ACL bearings as they have been used countless times.
This is just my opinion, take it or leave it.
Main Bearing thickness by color
Blue 2.013-2.010 mm 0.0793”- 0.0791”
Black 2.010-2.007 mm 0.0791”- 0.0790”
Brown 2.007-2.004 mm 0.0790”- 0.0789”
Green 2.004-2.001 mm 0.0789”- 0.0788” <- ACL Size
Yellow 2.001-1.998 mm 0.0788”- 0.0787”
Pink 1.998-1.995 mm 0.0787”- 0.0785”
Red 1.995-1.992 mm 0.0785”- 0.0783”
Rod bearing thickness by color
Blue 1.510-1.507 mm 0.0594”- 0.0593”
Black 1.507-1.504 mm 0.0593”- 0.0592”
Brown 1.504-1.501 mm 0.0592”- 0.0591”
Green 1.501-1.498 mm 0.0591”- 0.0590” <- ACL Size
Yellow 1.498-1.495 mm 0.0590”- 0.0589”
Pink 1.495-1.492 mm 0.0589”- 0.0587”
Red 1.492-1.489 mm 0.0587”- 0.0586”
This is just my opinion, take it or leave it.
Main Bearing thickness by color
Blue 2.013-2.010 mm 0.0793”- 0.0791”
Black 2.010-2.007 mm 0.0791”- 0.0790”
Brown 2.007-2.004 mm 0.0790”- 0.0789”
Green 2.004-2.001 mm 0.0789”- 0.0788” <- ACL Size
Yellow 2.001-1.998 mm 0.0788”- 0.0787”
Pink 1.998-1.995 mm 0.0787”- 0.0785”
Red 1.995-1.992 mm 0.0785”- 0.0783”
Rod bearing thickness by color
Blue 1.510-1.507 mm 0.0594”- 0.0593”
Black 1.507-1.504 mm 0.0593”- 0.0592”
Brown 1.504-1.501 mm 0.0592”- 0.0591”
Green 1.501-1.498 mm 0.0591”- 0.0590” <- ACL Size
Yellow 1.498-1.495 mm 0.0590”- 0.0589”
Pink 1.495-1.492 mm 0.0589”- 0.0587”
Red 1.492-1.489 mm 0.0587”- 0.0586”
02-14-2007, 06:17 PM
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No matter what bearings you use, you really, really, really should plasti-gage them to make sure your tolerances are correct when the main caps are torqued.
Given the relatively cheap price of bearings, you can take your time and order several sizes to match up the sizes you need, checking and re-checking with plasti-gage.
In the process of building engines, crank and rod bearing sizing is one of, if not THE most critical steps you need to take. If you want to try a different brand of bearing, just take your time, and do it right. I typically measure and torque the main caps 2-3 times when guaging the bearings before finally lubing them up and leaving the lower end assembled.
Given the relatively cheap price of bearings, you can take your time and order several sizes to match up the sizes you need, checking and re-checking with plasti-gage.
In the process of building engines, crank and rod bearing sizing is one of, if not THE most critical steps you need to take. If you want to try a different brand of bearing, just take your time, and do it right. I typically measure and torque the main caps 2-3 times when guaging the bearings before finally lubing them up and leaving the lower end assembled.
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02-17-2007, 12:33 AM
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But they only offer one standard size, and a few over/under size bearings. The over & under sizes are intended for use on a crank that has been "turned" or a block that had the main's "line honed". With most engine manufactures, this is common practice. Honda, however, chooses to run more precisely specified oil clearances.
Take this for instance...
Say you purchased ACL Standard bearings, for a Virgin, OEM Crankshaft & block. (Bearing surfaces are still original, Never line honed etc.) When you test fit & plasti-gauge, main #2 and rod #4 are out of tolerance by .00xx". What do you do then?
The only options I see are:
Order the next step "oversize" main's, and have the entire block "line honed".Then order the next "undersize" rod bearings, and have the rod journals turned. And after all this, you probably still wont have even clearances on every journal.
At that point, you've already bought 2 sets of ACL's, paid for a crank resurface and main "line bore/hone". By then you have exceeded the cost of OEM bearings anyway. Honda OEM bearings are available individually, and give you the option to fine tune at each individual journal. You can even use the "half step" method, which is 2 different colors on the same journal.
Ok, i'm officially done trying to persuade people to use Honda Engine Bearings. Sorry to sound like a broken record, maybe I am just too picky.