Hey guys, im new to this forum, but I had a question. I just started building honda engines, but I'm not yet familiar with all the main and rod bearing sizes and colors. Honda sells them by the color, but I want to know what size each color is so i can just measure them and order. Does anyone know how to decipher their color code or have a conversion chart? Maybe just a list of something like "green= 2" or whatever. Also, do ya'll think a rod bearing clearance of .016 or .017 is too small? Factory spec is like .015-.022. What clearances do ya'll recommend on main and rod? The setup is a 94 gsr block with ctr pistons, gsr rods, gsr crank. One more thing... I have a set of eagle H beam rods. I took them to the machine shop for them to install the rods into the new ctr pistons, but the pin on the ctr's was too small. like it fit "perfectly" through the rods with just a slight resistance. They are supposed to be just big enough to where you need a press to pop them through so they will stay in the rod. I figured maybe they were supposed to be heated or something, but the machine shop disaggrees, so I said forget it just use the stock rods. Any ideas?

Thanks in advance!
Jonathan

 

1.) You can't use full-floating pins (Eagle rods) with press-fit pin pistons (all OEM Honda). I'm surprised the shop couldn't figure this out just by looking at the pistons and rods.

2.) Factory main and rod oil clearance specs are:

Mains (1,2,4,5) = .0009" - .0017" (.0020" service limit)
Main (3) = .0012" - .0019" (.0024" service limit)

Rods = .0013" - .0020" (.0024" service limit)

3.) Don't forget to plastigage the new bearings before calling it a day.

Main bearing color chart - read the letters on the block (A, B, C, D) and pair with the numbers (1, 2, 3, 4) on the crank for each respective main to get the original bearing color. You can also just look at the colors on the side of the bearing (main cap-side I think) to get the original bearing color.


Rod bearing color chart - read the numbers (1, 2, 3, or 4) on the big end of the rod and pair with the letters (A, B, C, or D) on the crankshaft.


I usually try to shoot for the middle of the clearance range by swapping the bearings around to see which ones plastigage or mic in the best to my preferred goals. If they don't come up perfect, I'm not heart broken....as long as they clearance within the factory specified range, then I'll be happy enough.

With all that said, we now bring you our daily sponsors message.
Look into using ACL bearings (half the price of OEM Honda bearings, using the same quality and spec of materials), available through one of our local board vendors:
earl
2K_teg
camp1320

Also, somehow I think you'll be needing a Helm's manual. There's a lot more to building a motor than bearing tolerances and press-fit pins, and surely I don't have all the time in the world for me to keep taking pictures. Please get your own.

http://www.helminc.com


[Modified by IN VTEC, 10:49 AM 2/12/2003]

 

I believe the factory service manual lists the different clearances you should get with the different colors. At least my Honda CBR600F4i manaul lists them, I assume the car FSM does as well. Choosing the correct clearance depends on a couple factors. When the engine is running, the journal rides close to the center of the bearing suspended only by oil pressure. Heavy loads such as in super high HP applications will displace the journal away from the center and closer to the bearing surface. The bearing clearance on that side will decrease while the clearance 180 degrees from that side will increase. Also, local oil pressure on the short side will increase because the journal is pressing down on the oil while the oil pressure on the large side will decrease. Keep in mind also that large overall clearances will cause the journal to be displaced more than small overall clearances. The problem may arise in that the oil pressure on the large side may drop enough to cause cavitaion of the oil. This will quickly destroy bearings. The problem compounds itself because, as the bearings start to detroy themselves, the overall clearance increases, causing the journal to be displaced further and causing more bearing damage. So for super high HP applications, run your clearances on the small side of the factory specs.

On the flip side, small clearances heat the oil more than large clearances. They also impose more drag than large clearances, costing you some HP. So large clearances will free up a little extra hp, keep oil temps cooler but the bearings won't survive long in a very high HP motor. This may be fine for drag racers who tear their motors apart regularly and replace bearings. I dont know if you fit into this category. This also explains why drag racers generally run their bearing clearances on the large side.

Hope most of what I said made sense. It's hard to explain what happens with only words so bear with me. Stay within the factory specs and you should be okay. You didn't state how much power you expect the motor to make but you should have enough info now to decide for yourself what clearances to run.

Alin


[Modified by ProdriveWRC, 5:00 PM 2/12/2003]

 

Well I live in Mississippi where technology is limited to pushrods and APC stickers, so I wasn't surprised when they told me about the rods and had no further answers. What kind of pistons would fit on those eagle rods? they would have to have a circlip to hold the pin wouldn't they?


I understand the color code mostly, but what I really wanted was if there was a chart that told exactly what difference each bearing size was. I trust the factory, but I like to check stuff out for myself. In that chart that you put a picture of, are the greens, pinks, yellows, etc. that are shown the same sizes throughout the chart? Like all the greens are the same, all the pinks are the same etc?

 

You can use the PCT pistons, but you'll need to have the circlip retainer groove cut into the piston, otherwise, you'll have to stick with aftermarket pistons.

Each color corresponds to one size and only one size. That chart would be more confusing than useful if that wasn't a given.

I think somebody has mic'd out the difference in bearing size before and it was .0003". b/w each adjacent color. I wouldn't take that for granted tho.

 

Well, guess I'm S.O.L. on the rods, because the day that all this happened I asked if they could cut grooves for the clips, and the guy said, "no, we can't do that." So anyone want a brand new set of eagle rods? $350 OBO. shipping included. They were supposed to be one of the "best" machine shops in Jackson. MY ***...
Thanks everyone for your help!!

Jonathan