Oil Clearance - Crank and Connecting Rod

[namyzzo]

(updated info - SKIP ahead to post on 7-21-2010 ) !!!!!





Question for all you motor rebuilders..

My crank journals for the rods are mic'ing out at 1.4952
The rods I am using belonged to this Crank, the used bearings are mic'ing out at 1.4970" .. so approx .0018" oil clearance... Book calls for .0008 - .0018 or (.0015" in one of the diff model/tech specs..??)

Anyways the used conn rod bearings are Green.. So should I choose to buy new Green Bearings because I mic'd used bearings, OR should I go another color or 2 thicker...

How does the colors work for Conn rods anyways>?

I have Green now = 1.4970"

Brown = 1.4?? ... approx so I know which way + or -

VS
Yellow = 1.4?? ...

...I already asked a guy in New York and I believe he advised on trying to reach .0015".. But not sure what color would get me closer to this..


..I will be Platigauging as well to double check my setup.. Just got the PL-X to do it..

 

[one2dmax]

I do believe the black is the thickest and each size gets a few thousands thicker. I could send a pair of a few colors if you wanted to test them (with the option to buy). We like .0015-.0020 but the HD oiling helps on the extra clearance.

Sean

 

[namyzzo]

Sean, hows that again..??

too many thickers' in the last reply I think...

Black thinnest and up the color chart to thicker or vice versa?

Thanks for the offer - I might just hook up with ya = once I get the crank bearings in my hands and check those measurements..etc.

 

[one2dmax]

Black bearings are the thickest (or blue which ever is the 01's). Pink is the thinnest.

Sean

 

[namyzzo]

..ok.. I'm a little farther into it now and have learned a little more

Yes, Blue is the thickest and pink bearings are the Thinnest....Rods/mains/Balancer...

Here's my specs and the main question ..


1986 vmax case:
>77 7576 = case#'s

1996 Vmax Crank,Rods and Balancer
>22 1322 = crank #'s
>F6 = con rod #'s
>GREEN = stock bearings installed in Con Rods
>unknown stock main bearing colors
>1.4952" = Rod Journal dimensions - AFTER the machine shop "lightly" polished the Crank
>1.4559" = Main Journal dimensions - AFTER the machine shop polished

>1.4977" = Con rods with used green bearings,torqued to 25 FTLBS.

..now using the Case #'s and the crank web #'s I purchased the corresponding bearings and here are the results.. I wonder, if my findings are right = how can you make this work right??... and be in Yamaha's specs...??
..Yamaha advises .0008 - .0018 .... (various somewhat between models/years) = for the MAINS & Connecting Rods

J1,PINK @ 1.4602" - 1.4559" = .0053
J2,BLACK @ 1.4602" - 1.4559" = .0053
J3,YELLOW @ 1.4595" - 1.4559" = .0036
J4,GREEN @ 1.4578" - 1.4559" = .0019

P1 & P2,green @ 1.4977" - 1.4952" = .0025

.... Not liking the above, I changed the positions of all the bearings and retorqued the cases back together..
J1,YELLOW
J2,PINK
J3,GREEN @ 1,4592" - 1.4559" = .0033
J4,BLACK @ 1,4578" - 1.4559" = .0019

....Not much of a change..Different factors I would assume could affect these alternate findings....Rods being hot from sitting in truck all day...Mic being cold one day from sitting inside house with AC on, Engine Case settling/burrs, ......ETC ( I'm rambling and guessing!!!)


Talking with a rebuilder he advised on using ALL BLUE for the conn rods..!!

..and it seems I need ALL BLUE for the MAINS = ??? Even using the Blue bearings would probably only change it .0005 - .001" if I am lucky...


...any input would be Appreciated...

I already spent 50.00+ on main bearings...Looks like I will have to buy at least 3 more sets of Blue to try and get it close to specs.. (keeping black on Journal 4

>> :bang head:

 

[namyzzo]

...forgot the balancer specs

86 case with NEW green bearings = 1.1861"


86 Balancer with #'s 22, unpolished, high spot/less wear = 1.1799 - 1.1801"

96 Balancer with #'s 33, unpolished,high spot/less wear = 1.1795 - 1.1798"


I plan on using the 96 Balancer even though it mic's smaller because the 86 has gouges/rash..etc...


So again it is far from being in specs..Yamah Specs for Balancer.. =
> .0008 - .002" .... Alot more generous huh LOL

96 Balancer,86 case with Green Bearings gives me this .... 1.1861" - 1.1798" = a difference of .0066" ....

so looks like I need Blue's here to..????

what gives?
:bang head:

 

[one2dmax]

Make sure you are using the guide in the front supplement area of the book to use to set the codes with.

Sean

 

[namyzzo]

Sean are you seeing some discrepency's in my above ramblings or??

 

[one2dmax]

You're going far deeper into the setup then I ever do. There is nowhere near the loads on the mains and balancer as there is on the rod journals so not quite as critical. We do check the rods with the plastigauge which is usually accurate enough for us. I can send a few different sets for you to use if desired. Save you buying all kinds of sizes you can't use.

Sean

 

[namyzzo]

:eusa_dance:..Well

Basically what I found with a little help was I had missed a few burrs/high spots on the case half mating surfaces..!!
( when I removed all the gasket materials I removed all suspected high spots slightly...was scared to do too much.. I should have rechecked them after the cylinder machine work was done and before doing the bearing clearance inspection)

When I originally tore down the motor I found that who ever had the case open before me, had at least created 2 issues and maybe the cause of the engine failure..

When they reassembled the case, they installed the Clutch Push Rod seal assembly backwards.Also - one of the bearings on the trans assembly has a "stake Pin" that drops into a groove in the case...Well - they had that pin in the wrong spot at it got crushed in between the engine case halves!...
....So those things alone caused some burring of the surrounding metal...


So after prepping these areas, switching the bearings back to factory advised positions and reassembling with a few more hold down bolts = everything mic's out aLOT lot better... Bearings that used to mic' out close to 5thou are now closer to 2thou...

Mystery Solved :eusa_dance:

 

[satariel666]

Nasty indeed.
Maybe not the whole engine failure but for sure thansmission failure.
Hopefuly the trans is not that fragile with lubrication problems.

By this way the cases may be bend some, hope not tho.
Good luck.

 

[one2dmax]

Nice find. I would not have even thought about that as it's a normal assembly procedure to orientate the pins correctly.

Sean

 

[namyzzo]

..Yah, probably your basic dealer mechanic worked on it.. If they dont do these often - I'm sure they would be worried about just remembering where the right bolts go - let alone the minor yet important things Like those Stake Pins..etc.. ...easy to forget about it I suppose...?