Big_T112
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posted February 12, 2011 12:55 PM
Checking Rod Bearings with Plastigauge
Still waiting on a few more pieces before I can assyemble my turbo motor. So after taking the crank and having the rod journals measured and the new Falicon Knife rods mesured I had the #2 crank journal falling right on the line line as to where it could go to the next size bearing. So I ordered one extra set of the next size bearing halfs just in case. Lucky I did because it needed it. Here are a couple of pics of the process. First clean the journals really well. buy some Plastigauge from your local autoparts store. Cut it to length and place it on the journal away from the oil hole
Put the rod cap on and do not use the bolts to pull it down. tap it down with the wooden end of a hammer or a soft mallet. Torque the bolts to spec in a couple of stages. Do not let the crankshaft turn. It will ruin your reading. use the supplied gauge to measure.
I was looking to have close to .002" on mine.
#2 rod and journal required the next size bearing to get the clearance I needed. This is why it is so important to check.
Now that I have all of the bearings they way I want them I am taking everything back apart and start cleaning the motor parts up and getting it ready to go back together. The local track starts back racing season on March 5th. As soon as the last couple of parts come in from Schnits Racing I will be ready to put it all together.
  
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Big_T112
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posted February 12, 2011 12:57 PM
The second pic has the gauge on the MM side. DUH! It's still what I wanted.
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Darkforce
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posted February 12, 2011 03:53 PM
 Edited By: Darkforce on 12 Feb 2011 23:55
r those stock bearings?
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Big_T112
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posted February 12, 2011 07:06 PM
Yes they are. I have never used any other than stock.
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Darkforce
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posted February 13, 2011 03:11 PM
quote:
Yes they are. I have never used any other than stock.
cool, wasnt aware that u could get the stock bearings n different sizes.
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Big_T112
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posted February 14, 2011 06:45 PM
They are color coded. Each color is a different size. you are suppose to get the mark off the rod and the mark off the crank. cross them in the service manual and it tells you the color you need. But if your smart you will check them. If I had used the bearing the book said I would have a tight - .001" clearance. It would have spun a rod bearing in no time. Check to be sure.
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Darkforce
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posted February 15, 2011 09:01 PM
quote:
They are color coded. Each color is a different size. you are suppose to get the mark off the rod and the mark off the crank. cross them in the service manual and it tells you the color you need. But if your smart you will check them. If I had used the bearing the book said I would have a tight - .001" clearance. It would have spun a rod bearing in no time. Check to be sure.
so does this apply 2 determining bearings 4 a stroker also?
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LAB3
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posted February 16, 2011 04:03 AM
Edited By: LAB3 on 16 Feb 2011 12:06
quote:
quote:
They are color coded. Each color is a different size. you are suppose to get the mark off the rod and the mark off the crank. cross them in the service manual and it tells you the color you need. But if your smart you will check them. If I had used the bearing the book said I would have a tight - .001" clearance. It would have spun a rod bearing in no time. Check to be sure.
so does this apply 2 determining bearings 4 a stroker also?
YES any engine that has split bearings for the crank and rods should be checked this way.
Do not rotate the crank when doing this. Make sure all oil is off the crank and block when doing this clearance check for accurate readings.
If I was Big I would recheck again after cleaning everything before reassembly.
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Big_T112
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posted February 16, 2011 07:21 PM
I did clean the rod journals before checking them. I did not clean anything else though. I am still waiting on a few parts before I have everything I will need to put it back together. Then I will clean up the rest of the parts.
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LAB3
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posted February 16, 2011 07:39 PM
Figured you did. Just sayin........ :-) I use to build small block Chevy's in my younger days.
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ZX14Mike
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posted February 16, 2011 08:39 PM
Why would the bearings vary or change in size?
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LAB3
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posted February 17, 2011 03:54 AM
Several reasons............... when the crank was finish ground on O.D. Grinder Machinist needed to dress the wheel and and the jounal was a liitle larger. The person putting the slpit bearings in the boxs to send to the Dealers drops the wrong colored bearing in the wrong box.............. checking clearnce wet and dry will give you different specs. Lot of ways things can go wrong on mass made close tollerence parts.
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1badzx12r
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posted March 07, 2011 05:34 AM
Edited By: 1badzx12r on 7 Mar 2011 13:41
did a zx14 motor yesterday ..crank from flywheel .002 .0015 .0015. 0015 .002
rods all .002
also installed the connie transmission 1st thru 5th gears ... now i got to find a rolling chassis ..may make me a go-kart or something of the likes http://houston.craigslist.org/mcy/2247867472.html
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Big_T112
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posted March 07, 2011 09:29 AM
I know a lot of dealers take the color codes as gold and just assy. without checking. But I would hate to have to pull a motor back out, take it back apart just because I didn't check a simple bearing clearance. It's happened I am sure.
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1badzx12r
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posted March 07, 2011 09:58 AM
quote:
I know a lot of dealers take the color codes as gold and just assy. without checking. But I would hate to have to pull a motor back out, take it back apart just because I didn't check a simple bearing clearance. It's happened I am sure.
that makes two of us .. when i split the cases the bearing had some fine scratches dug into them and i wanted to know what i had after installing new bearing .. i didnt do the old bearings ..maybe i should had to compare wear .. but i really didn't know the history on that motor except the oil never got changed .,. and it ran really rich . and the clutch pack look great ..
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Big_T112
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posted March 07, 2011 11:05 AM
I don't check the old ones either. the bearings are softer then the crank so that's where your wear should be. Check the new ones though.
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billeason
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posted March 07, 2011 05:29 PM
quote:
did a zx14 motor yesterday ..crank from flywheel .002 .0015 .0015. 0015 .002
rods all .002
also installed the connie transmission 1st thru 5th gears ... now i got to find a rolling chassis ..may make me a go-kart or something of the likes http://houston.craigslist.org/mcy/2247867472.html
What color were the rod bearings ?
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bill eason
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1badzx12r
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posted March 07, 2011 05:38 PM
all blue
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billeason
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posted March 07, 2011 05:58 PM
I just pulled one that called for all black rods ( small journal,small big end ) but had all blue bearings, and barely had .001-.0015 clearance.
Its amazing it didn't take out a bearing or worse ............
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bill eason
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Y2KZX12R
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posted March 08, 2011 03:58 AM
I recommend using a bore gauge and a 1"-2" mic instead of plastigauge.
You will actually know what the bearing clearances are. Also and more importantly you will be able to detect any journal wear and rod big end out of roundness.
Rod big end out of roundness is very common and is the cause of most bearing failures. But if you use plastigauge to just measure the oil clearance top and bottom you will never detect it.
A micrometer that reads 1"-2" needs to read .0001" as does the bore gauge. The mic can be had for about $50-$75 and a bore gauge is about $180-$250.
If you are replacing the rod bolts you should have the rods resized for sure.
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Y2KZX12R
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LAB3
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posted March 08, 2011 05:46 AM
I agree, being a retired Tool&Dire Maker I have some very expensive mic's etc. Carbide tiped O.D. mic's and friction wheels for a better "Feel" when measureing. Most don't own these tools so plastic gauge is the next best thing. Brown&Sharpe makes a Intra Mic for measuring I.D. if you are really serious about your clearances on the rods. What about measuring the rod bolt length after you have torqued them? Some builders only use the rod bolts one time. Really picky there. Do you have a Dial Bore gauge(checking taper in cylinder bores) and "Jo" Block set for setting your mic's to "Zero" looking for 1/10's with hand mic's takes a lot of practice and everyday use.
I ran a I.D./O.D. centerless grinder in a 72 degree controlled Air Craft Machine Shop for years. You do good work Jim, great job on my ZX-12 CCT you machined to fit the ZX-14.
Louis
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billeason
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posted March 08, 2011 05:59 AM
Edited By: billeason on 8 Mar 2011 14:07
I always mic. it all'' then plastic gauge on final assemble just to back it up!
May be overkill but i had a funny reading on a crank one time that this caught .
The machine shop that fluted the journals got carried away and the journals had low spots.
I have also found that carillo rods with low miles seldom need much attention, but i still check them. The only reason i mention in the post above was whatever shop put this motor together either never mic'' the rods or anything else because Kaw called for black bearings but it still got all blue, that with the small journal and small big end ( carillo ) calls for black so had it been mic, it would have had correct bearings installed. Im still amazed it didnt sling a rod out at .001 clearance it was tighter then kaw sits the rods up oem and i still think this is a lot of why the 14 eats rod bearings.............
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bill eason
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Big_T112
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posted March 08, 2011 08:43 AM
You platigauge after you have everything mic'ed. The platigauge just lets you know that the bearings you selected are what you need. Bearings vary slightly even in the same color code. It would be a finishing touch not the only one.
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1badzx12r
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posted March 08, 2011 09:38 AM
engines blow other wise these engine builders would warranty what they build like the factory does .. not hating just how it is .i've seen $20,000.00 built motors pop faster than $2,000.00 used stock motors .. end result was how much money you put into it
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LAB3
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posted March 08, 2011 10:37 AM
quote:
You platigauge after you have everything mic'ed. The platigauge just lets you know that the bearings you selected are what you need. Bearings vary slightly even in the same color code. It would be a finishing touch not the only one.
Not a bad idea. After everything is torqued in place and the T.I.R. on each rod bolted to the crank is what it is now from all the bearings seated. Easy to misfigure with so many measurements.. The more I think about it Good idea to double check.(Getting older) Down side some builders don't like to retorque the rods bolts again as they tend to "Grow" a little each time.......................... Another story :-)........... for point counter point.
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