dubious
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posted April 28, 2009 10:57 PM
 Edited By: dubious on 29 Apr 2009 07:00
Rod bearing clearances?
Some fantastic guys with tons of knowledge here, so i thought I would hit ya ll up !
I am building up my zx14 engine for boost... up to 25 PSI eventually.
Its got falicon -2mm rods, and MTC pistons with +2mm compression height above the top ring, the entire ring assembly and the pins are dropped 2mm, to allow for more meat above the top ring.
What rod clearances do you recommend?
If i mix black and blue shells I get 0.0030 to .0035 across all 4 rod journals,
If I go symetricl colors it ends up with .0025-.0035 or .0035 to .0042.
I am scared to go to loose or too tight, and figured mixing the shells would give me best clearance.
My car engine builder agreed, but he is not used to the tight tolerances we can get by with on the smaller engines.
he is used to 4- 6" bores, and some heavy iron compared to the bikes.
He lives by the run it loose mantra, rather than squeeking anything.
I am also running the balance shafts welded up, the crank should see more flow and more pressure, wheras the upgraded regulator doesn't increase flow I don't think.
Any idea's or input is very much appreciated.
Also my assistant mechanic who should know better than I scored the deck from a cylinder straight across to the water jacket... almost looked intentional.
I had to have the deck machined ,005" to clean it up, but the mill grabbed the nickasil and caused it to bounch a few times, goughes look to be about .0003" deep, what is the best way to dress this.
I am in Canada and trusting a performance car shop to machine it.
I wanted him to beburr the plating down 1-2mm from the deck so this wouldn't happen , but i honestly think he's afraid the plating will flake off once he starts to cut into it.
He bought a diamond stone last month to hone my cylinders, since nothing he had for the car engines would touch it...LOL
Again.
Thanks
Lyle
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whitehendrix
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posted April 28, 2009 11:21 PM
Edited By: whitehendrix on 29 Apr 2009 07:25
about the only useful info i think i can say is lap the deck on the gouges. or re-run it and run the shellmill at a higher rpm and lower feedrate.. i'd err towards lapping tho.. slowing the feedrate makes it rewmove more material, as does a higher rotational speed on the mill, but it's a little less prone to "skipping". i use a piece of paper to set a mill.. gives me .003 to play with as well. not sure how your shop does it..lol
other than that, i'm about worthless..lol
i'm building a turbo motor as well, but kinda doin the learn-as-i-go deal, so i'll be awaiting our pro's inputs here on clearances. just my random crap 2 cents, i'd say run a tiny bit loose because of the heat that'll be generated. 25psi is a shitload of boost and if you're not running W/M injection or intercooling, you're looking and air intake temps of around 336*F on a 70% efficient turbo and some VERY rough base numbers without an IC.
i won't be seeing 25psi i don't think, and i am going to run a small IC, but nonetheless, i think i'll stay a teeny tiny bit on the sloppy side.. with my limited knowledge, it just makes sence. lol
i do think .0042 is a bit too much tho.. i'm feelin the .003-ish gap.
again, i build friggin low-perf motors and whatnot. i know just enough to be dangerous! most of the engine building i've done (and still do so far) is stock-spec rebuilds and "light" race stuff for off-road toys.. so, take anything i say with a grain of salt until it clears with someone who KNOWS.. lol
that way, i'll know i'm right or wrong as well and learn somethin!! 
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ill never own a busa unless
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Y2KZX12R
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posted April 29, 2009 04:22 AM
WH, give yourself more credit than that. Your right on the money.
DUB,
I'd recommend .0026"-.003" for the rods.
The nicasil will keep dragging so don't use a resurfacer, lap the block. If you have deck scratches or warpage of more than about .003" then you will be there forever lapping, so in that case resurface and then lap the deck smooth the last thou or two.
Next time, you can use a sand paper roll on a 45deg angle and lower the nicasil down from the top of the bore before resurfacing but be careful not to open the bore into the head gasket. You only want to get the nicasil down just enough so the cutter insert doesn't catch the nicasil.
Be very careful and take your time.
You need to use a ground surface (granite table) for lapping or a ground lapping plate. We made up several lapping plates that we have sold to other shops. If you need one I'll see if we have enough material to put one together for you.
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TRNorBRN6001
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posted April 29, 2009 05:52 AM
Kind of on topic and relevant, I have heard people say to only use a surface grinder for cylinders that are nikasil coated otherwise using a mill may chip the coating. With that said I have known people that have had their cylinders milled without any chipping. Any comments would be great.
Gary
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dubious
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posted April 29, 2009 07:38 AM
quote:
WH, give yourself more credit than that. Your right on the money.
DUB,
I'd recommend .0026"-.003" for the rods.
The nicasil will keep dragging so don't use a resurfacer, lap the block. If you have deck scratches or warpage of more than about .003" then you will be there forever lapping, so in that case resurface and then lap the deck smooth the last thou or two.
Next time, you can use a sand paper roll on a 45deg angle and lower the nicasil down from the top of the bore before resurfacing but be careful not to open the bore into the head gasket. You only want to get the nicasil down just enough so the cutter insert doesn't catch the nicasil.
Be very careful and take your time.
You need to use a ground surface (granite table) for lapping or a ground lapping plate. We made up several lapping plates that we have sold to other shops. If you need one I'll see if we have enough material to put one together for you.
Cool,
How much would it cost and what time frame would you be able to send it out?
The local machine shop, or car builder shop should have one no?
Can I buy a scrap piece of granite from the local kitchen supplier?
I have seen ppl use glass plate but that would flex enough I think
I have granite in the kitchen... LOL
Do you lap the rings when building a motor too?
Light polish on the bearings surfaces with white scotchbrite and wd 40?
Thanks, for the input on the rod bearings!
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KZScott
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posted April 29, 2009 04:03 PM
dont mix bearing colours to get the proper clearance. try to match up bearings by size (mic them) and use the correct sizes, or resize the rods slightly to get the desired clearance with the bearings you have as long as that resized size is withing the factory service limit.
____________
01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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dubious
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posted April 29, 2009 04:13 PM
Why not mix bearing colors?
Car guys do it all the time?
we are talking less than 1 / 10 the thickness of a hair
Do you think it will grab and spin the bearing?
The rods are all brand new, identical ID, and the crank journal OD are all stock and identical.
I am thinking the more I play with this stuff, especially with the level of competency or knowledge available locally, that the better the chances of making something 95%, turn out bad...
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dubious
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posted April 29, 2009 04:35 PM
Edited By: dubious on 30 Apr 2009 00:36
Mixing blue and black shells on each Journal gets me .0027-.0029 on each Journal.
Seems real close for me.
I have bad luck with anyone touching my stuff, my parts always seem to be worse off after they are handled, and were pretty close to ideal before they got them.
I just measured everything again, and the variance is the bearings, these are the best 4 picked out of 8 shells for each color,
I would be in factory specs if I stayed tighter as they recommend, but looser definately is the key with a turbo. My stock bearings looked like they were a little tight from the factory already when i took them out...
Doug Meyer?
please post your opinion.
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whitehendrix
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posted April 29, 2009 07:19 PM
thanks for the confirmation Jim!! haha.. appreciate it.. wasn't sure on the nikasil stuff. i've only done two builds with plated bores...not really that knowledgeable on the plated stuff yet.
oh.. you bring an awesome point up on the kitchen granite.. the surfaces are rated in smoothness and flatness, but most times you can get a chunk big enough to do lapping and other misc precision measurements for free.. just go in, be nice and ask em what extras and scraps they might have.
won't be toolroom grade stuff, but it will certainly get the job done! a local suuplier lost a 4x8 sheet in a wind storm off their outside rack.. insurance covered it.. for a few bucks they were more than willing to cut it square for me as well.
after all, free is the best F word ever.. a good starrett slab starts at $600 and i think thats the tiny one.. you can get cheapy MSC slabs for a couple hundred, but i'll almost bet their finish is about the same grade as a good countertop piece.
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Duct tape is the handyman's secret
weapon. The black is for formal
occasions. - ZRXDean
ill never own a busa unless
someone gives me one.... and then
ill sell it -KZScott
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dougmeyer
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posted April 29, 2009 07:23 PM
What's the clearance with the "tight" (same color) setup?
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dubious
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posted April 29, 2009 10:36 PM
.0017 to .0020 across the board... on the rods with original brgs, they didn't look as good as I would have liked when i took them out, that was just a pipe, and a 50HP nitrous shot.
I am getting .0027 to .0029 with the mixed brgs.
Checked them again... LOL
I intend to push 20+ PSI through my zx14 engine.
MTC 9.5:1 dished pistons with +2 mm compression height above the top ring from stock, pin and all rings are moved down 2mm
Falicon -2mm rods to allow for extra piston height, and pin relocation
Another question, do you lap your rings after filing them, just to make sure they are flat and smooth?
Is it worth my time to polish the brags very lightly with white scotch brite pad and wd 40 or similar, checking for impewrfections and removing the ridges or imperfections ?
I was told I could polish the bearings lighlty by hand , put a light crosshatch in them, he said its just for looks, and the last grey coat is really just for looks?
I used a piece of flat plate glass with 600 grit , lapped the imperfections from milling the gouge my mechanic did to the deck. It turned out like a new piece
He won't be coming back.
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whitehendrix
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posted April 29, 2009 11:39 PM
i'd definitely dress the rings without a doubt and deburr the bearings.. personally, i don't know about the polishing on the bearings.. polishing removes material, so.. not sure what to tell ya on that.
i'd say "no" if i was doing it without the aid of bikeland.. unless i see otherwise from Doug, Karl, Jim and company, i'll always stick with a close inspection and slight deburring if need be.
____________
Duct tape is the handyman's secret
weapon. The black is for formal
occasions. - ZRXDean
ill never own a busa unless
someone gives me one.... and then
ill sell it -KZScott
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dubious
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Needs more time to ride!
Posts: 8442
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posted April 30, 2009 06:38 AM
Thats why I am here,
some really good knowledge on here,
Most appreciated BTW, and thanks to everyone who contributes.
The car builder wh has been doing my machining was the one who mentioned light buff with scotch brite on the brgs, and told me the last grey coat on them is just for ashetics , to please the customer...
Any input from Doug , Karl, Jim, or Tim is most appreciated.
This is my first detailed engine build, done a couple hundred dirt bikes over the last 30 years, but this is my first big performance project.
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natural selection.....
destiny will overcome intervention.
Some are not worthy of the effort.
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KZScott
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posted April 30, 2009 07:06 AM
this is an exaggeration, and doent take into account the slight taper of the bearing shells(i may have mixed up the colours too). clearance is good top and bottom, but notice the tight and loose spots:
____________
01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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