Con Rod Bearing Selection

[scrappy]

I decided to start a new post to keep from confusing people from my last post.

I am about to ask questions for connecting rod bearing measurements. Please keep to the topic. This is not for main bearing sizing..

This is for an 06 busa, using Carrillo H-beam rods (OEM Suzuki length), stock crank with 25k miles (no modification to crank). I am trying to find new con rod bearing sizes for a force induced application.
If you have a Haynes manual or equivalent this may help, if not see pictures below this forum post and bearing selection chart below.
This picture is from APE's tech page which can be found here Hayabusa Crank Specs

All measurements will be shown in inches (")

Haynes Manual Bearing Selection chart typed below (i only listed the table for con rod code 1 since the carrillo rod falls into that category)

_______________________|_Connecting Rod Code __|
CrankPin Journal Code___|_1 - (1.6142" to 1.6145")|
1 - (1.4957" to 1.4961") _| Green - 0.0583 to 0.0584_| bearing selection
2 - (1.4954" to 1.4957") _| Black - 0.0584 to 0.0586_| bearing selection
3 - (1.4951" to 1.4954") _| Brown - 0.0586 to 0.0587_| bearing selection
I happened to have a brand new yellow bearing set (0.0587 to 0.0589) that i did a test measurement with. When i applied plastigage to the crank and rod, the measurement came out to .001" and since plastigage has poor measurement tables, it is difficult to see exact clearance with the naked eye. I did this to pins 2 and 3 allowing me to see if their was a difference between the two crank pin sizes according to the rods crank pin codes. See pictures below this forum post. The blurry pic is of pin 3 and the non blurry pic is of pin 2.

(I know different measurements may be caused by tools, the person using the tools or both)

Ok, today I had 2 different machine shops measure the diameter on the Crank pins. Machine shop one and two both said that the crank pins were extremely close to the same size..

Machine shop one came up with 1.4951" all four crank pins - Pin Code 3 (low side of crank pins being in spec) / see chart above
Machine shop two came up with 1.4949" all four crank pins - (No crank pin code - technically crank pins would be out of spec)
I figured 1.4950" (middle number between 1.4949" and 1.4951") (No crank pin code - technically crank pins would be out of spec)
Crank pin Code STAMPED ON THE CRANK FROM FACTORY shows pins 1 & 3 are sized 1.4954" to 1.4957" - Pin Code 2 / see chart above
Crank pin Code STAMPED ON THE CRANK FROM FACTORY shows pins 2 & 4 are sized 1.4951" to 1.4954" - Pin Code 3 / see chart above
RODs: The spec card for Carrillo H-Beams Big End bore size 1.6144". Con Rod Code 1 / see chart above
Con rod oil clearance is supposed to be between 0.0013" and 0.0022"

(Rod diameter) minus (crank pin diameter) = X ----(crank pin diameter is based on machine shops numbers given to me, crank pin code 2 is not listed here, see my question below to find out why)
1.6144" minus 1.4951" = 0.1193"
1.6144" minus 1.4950" = 0.1194"
1.6144" minus 1.4949" = 0.1195"

Bearing selection is bearing size multiplied by 2 (2 bearings halves make up one bearing size)
Example: Green bearing is shown as 0.0583" to 0.00584" (this is for 1/2 of the total thickness of the bearing size). Total thickness for the green bearing would be .1166" to .1168". If i used this bearing with my current (guessing at) .1194 measurement I would be at oil clearance 0.0028 to 0.0026 exceeding the specified clearance listed above.

Question : Should i go with machine shop calculations and size my bearings for crank pin codes 3 (all four pins) or use the crank pin codes stamped on the crank, codes 2 & 3? I was told that Suzuki when selecting bearings would try to find exact middle oil clearance (0.0013 to 0.0022) which would be roughly 0.0017" to 0.0018". Does anyone know if this is true? Since i am building this machine for racing applications wouldn't i want to go with more clearance such as 0.0020" to 0.0022" ?

 

[scrappy]

Pictures would not load.. here they are

 

[cdhoroho]

I went with .0015 clearance on my build
Prostreet and 600hp capabilities

 

[scrappy]

Posted via Mobile Device

 

[scrappy]

Cool, but my most important question would be, should I trust the machine shop calculations or go with what is printed on the crank. The crank does not have any signs of damage or wear (synthetic oils been used after initial break in). My bearings I took out also looked good but I want to replace them anyways as a precautionary measure.
Posted via Mobile Device

 

[scrappy]

Does any one know what plastigage goes down to the 0.0013 to 0.0022 measurement? I can't seem to find any on the plastigage website
Posted via Mobile Device

 

[cdhoroho]

the green plastigauge is what i use
also it seems the call out is 2 black and 2 brown bearings
and being im a tool maker i will tell you this
more people then not over tighten the mics when checking and could be up to .0005 off on measuring
best to check mics to a set of gauge blocks by same person checking crank measurements

 

[scrappy]

Ya the crank calls for 2 black and 2 brown bearing sets. This is why I wanted to know if I should go with the machine shop mic specs or the codes stamped on the crank from factory. The machine shop said to go with one color for all the bearings I believe he wanted me to go with black, based on his measurement of 1.4949, but the brown seems like it would be a better fit if I did that.
Posted via Mobile Device

 

[cdhoroho]

id follow the book if everything looks to be close to factory specs

 

[scrappy]

I'm leaning towards that too, fricken bearings are expensive, and the stealership has a no return policy on "special order" parts
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[scrappy]

Thanks to one of the members here on the .org i learned that the Gen2 bearings can be used on the Gen1 crank and they offer better lubrication than the Gen1 bearings... something to keep in mind next time you order your bearing sets for the Gen1

 

[2wicked]

Thanks to one of the members here on the .org i learned that the Gen2 bearings can be used on the Gen1 crank and they offer better lubrication than the Gen1 bearings... something to keep in mind next time you order your bearing sets for the Gen1

Gen 1 and Gen 2 rods bearings are identical, they do not offer any better lubrication as they are the same. Your information is incorrect,

Richard

 

[scrappy]

Gen 1 and Gen 2 rods bearings are identical, they do not offer any better lubrication as they are the same. Your information is incorrect,

Richard

Are you sure?

Gen2 main bearings oil the crank better than the gen1 bearings and can be used in either gen1 or gen2.

Because i was told this by a .org member and then by a sales member at a respectable parts store..

 

[cdhoroho]

yes mains are different but should be used on a gen 2 crank because of the bearing surface on crank
the rod bearings are the exact same as the gen1

 

[2wicked]

Are you sure?

Gen2 main bearings oil the crank better than the gen1 bearings and can be used in either gen1 or gen2.

Because i was told this by a .org member and then by a sales member at a respectable parts store..

100% sure, and the main bearings do not oil the crank any better either, the Gen 2 crank has an oil relief groove in the mains on the crank. So be careful with the info you are recieving, it is not the bearings that are inscreasing the oil to the mains on the Gen 2s, its the crank itself.

Richard

 

[cdhoroho]

exactly
also dont go using the gen 2 mains on a gen 1
id keep the generations to their respective year cranks IMHO

 

[mountainmotor]

Ditto - use the gen 1 main bearings in it.

 

[scrappy]

ok, i shall keep that in mind.

 

[mountainmotor]

Gen2 main bearings oil the crank better than the gen1 bearings and can be used in either gen1 or gen2.

Grooved main bearings lessen the bearing load area and resultant oil cushion. Engines in the past used grooved mains in the upper half of the main web because it "bearing" see's lower load. That in itself is not necessarily the best thing but it was used for reason.

Suzuki went a step further and grooved the crank and used grooved bearings upper and lower. The groove in the crank requires no further oil cushion for support and as the bearing groove grows in length or diameter, so does frictional HP loss . Back to the groove in the crank again which also breaks up the oil tension helping move it on out of the bearing for cooling.

The real reason for any of this is to supply the rods with plenty of oil . The grooved crank has to be an engineering compensation for the lessened load area , oil film and higher frictional losses vs non grooved crank.

 

[mountainmotor]

The grooved crank has to be an engineering compensation for the lessened load area , oil film and higher frictional losses vs non grooved crank.

To be a bit more clear , that is higher frictional losses with grooved bearings running on a non grooved crank. I got that info from a Clevite bearing test pdf some time back but could not find it again to post so going off memory. The the more the diameter " length" of the groove, the less HP. The article did not speak about a groove in the crank journal though. It was a good read but now seems long gone.