cmcnitt
Parking Attendant
Posts: 15
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posted August 25, 2003 06:50 PM
zx12 bearing questions
Help! While I have my 2000 zx12 apart, I'd like to replace the rod and crank bearings. I am planning on having the main and rod journals checked and polished. Can someone tell me what the main and rod journals should measure? Also, what's the difference between the blue, black, and brown bearings? As you can guess, I've never had a zx apart before and I don't have a manual (that would be too easy!).
  
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ninja12
Needs a job
Posts: 3310
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posted August 25, 2003 09:01 PM
If you just check them you can use the same color that comes out.
If you polish them you better plastigage to be sure your clearances are still good . blue black brown are different thickness of the bearings. Use the
colors/ thickness that gives the correct clearance. better get a manual!
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MadMike
Moderator
FEAR THE BLACK FLAG!!!!!!!!
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posted August 26, 2003 04:11 AM
Dude, get a manual, if your going that deep, and i would reccomend NOT changing your bearings or polishing your journals, unless you have to. you are not going to see any gains from that. and then if you dont get your clearance correct you will be in a world of hurt!
Mad Mike
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cmcnitt
Parking Attendant
Posts: 15
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posted August 26, 2003 05:41 AM
manual
I guess I'll get a manual... I was just trying to save a buck but I guess I'll cut back on the potato chips instead!
Thanks
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ra12r
Zone Head
Posts: 919
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posted August 26, 2003 05:56 AM
Standard main clearance has a max spec of .0031 approx. Rod journal clearance max is .0033. Blue is OEM and will keep you tight......not neccessarily good. I went Blue for rod journals and black for main(the first time). Second time, went with blue for rod journals and Brown for main. Plastigage everything so you will know what the clearances are and mainly so you are not too tight. The aluminum cases have some mild flex and clearances can change,,,,,
Blue = oem
black= more clearance
brown = most clearance
Remember these are all factory bearings that WILL work if they are NOT too tight to prevent proper oiling........(This is the failure problem i believe with the early muzzy cranks, the journals were too tight with blue bearings)
There is an online service manual on Easy's site, you need to go there!
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cmcnitt
Parking Attendant
Posts: 15
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posted August 26, 2003 06:38 AM
cool
Thanks ra, that's the info I was looking for
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ninja12
Needs a job
Posts: 3310
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posted August 26, 2003 06:38 AM
You can't just say blue is OEM.
Look at the manual.
simple explanation. The case and rod have two sizes big or small.
The crank journal has two sizes big and small. (difference is very small)
big crank small rod = thin bearing
small crank and big rod = thick bearning
big crank + big rod = med
small crank + small rod = med.
The same goes for the crank and main case journal.
don't remember the exact order but i THINK its blue thin , black med, brown think like ra12 says.
If it ain't broke DON'T FIX IT.
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cmcnitt
Parking Attendant
Posts: 15
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posted August 26, 2003 08:41 AM
wear
ninja,
The rod bearings are worn pretty bad. This motor is in a dwarf car and I've seen the oil light come on several times while racing it. The crank main journals look fine so I'll probably re-use the main bearings but I want to replace the rod bearings and rod bolts. I will probably buy a set of BLUE bearings and check them. I was also planning on having a machine shop polish the rod journals and measure them just to be sure they're ok. I also installed an oil accumulator so hopefully that big red light will stay out!
Is it a bad idea to have the journals polished?
Thanks for the input
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MadMike
Moderator
FEAR THE BLACK FLAG!!!!!!!!
Posts: 6579
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posted August 26, 2003 09:07 AM
No it is not a bad idea, but why are you doing it, just to do it, Dont. but ifyou feel you need to do to some wear showing then yes do it! another note do Not Touch the bearings that you are going to keep in there with your bare hands, there are oils that are in your hands that could prevent even oil flow for just a few seconds, wear gloves, it is easy. and another note when you are plasti gauging the rods, make sure that you use the Old bolts to check the clearance, or buy two new sets, once you tighten the rod bolts including the streach or degree turn, you do not want to reuse them.
Good luck!! hope the accumulator helps.
Mad Mike
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kawachan
Pro
Posts: 1031
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posted August 26, 2003 02:10 PM
Peter D MotorSports has a bypass oil mod for the 12 motor that will help the oil return problem on a dwarf. It involves drilling a hole in the side of the 12's head (back side of motor) to help drain the accumulated oil in the head back down to the oil pan. They also have a larger oil pan (5 quart) for it.
Matter of fact, I might race a dwarf this weekend!! My mech and one of my friends both have one, and one of them is out of town......so I get to try it out this weekend. Both have 00 12 motors in them. Going to be fun, fun fun!!
Do you ever visit http://www.dwarfcarracing.com/ ??
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RED NINJAS RULE!!
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cmcnitt
Parking Attendant
Posts: 15
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posted August 26, 2003 03:49 PM
crank
I didn't want to bore ya'll with the details, but here it is! I've been tuning this thing on the dyno for a while now, I have carbs on it and am running alcohol. This thing LOVES the alcohol! I got a little crazy with the size of the mains and was getting alcohol into the oil. Well, about 30 pulls later and the oil was way too thin. On the last pull, the power went down suddenly. I shut it off and pulled it apart to find the rods tightened up. I had the crank checked today at a shop and found out that it's ok. I wanted to put pistons in anyway so now I'm going to do the whole thing. I'm debating whether I want to send it to APE to have it lightened and balanced. Either way, the balancer is coming out and I ordered a manual today.
Yes, I go to dwarfcarracing all the time and Peter D. has plenty of my money! I've already made my own pan and I think I'm going to plumb up a drain like you're talking about. This is a great motor but the oil system sucks!
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krexken
Zone Head
Posts: 732
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posted August 26, 2003 05:33 PM
I'd love to hear your dyno numbers on the brew. Not too sure if lightening the crank is the greatest idea. Could be, just my opinion though. Balancing sure never hurt anything. I didn't balance my 1361(although the crank should've been) and I chunked the balancer on it. Ran as smooth as ever. On my ZRX, I went back blue on my new crank and just happen to have the engine back apart and all the rods are showing some wear. Clearance was .0015 when assembled and I'm thinking I'm gonna loosen it up a tad when it goes back together.
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kawachan
Pro
Posts: 1031
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posted August 26, 2003 06:39 PM
Alcohol!! Yes, I'd love to hear more about that!! Been thinking about that too. Worked on one of the old GS alkys the other night and it got me thinking again. Sure would run cooler....and faster. Having problems getting the old-style dwarf to hook up as it is, but we're working on that.......... Those newer lighter cars are hard to beat.......
Balancer is out of my 1270 too. If you had to split the cases, you're there. Muzzy sells a balancer insert replacement, but I just welded up my balancer shaft and chunked the other two pounds in a box. Muzzy AL piece might be a lil lighter though .....
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RED NINJAS RULE!!
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cmcnitt
Parking Attendant
Posts: 15
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posted August 26, 2003 07:58 PM
alky
The alcohol gave it about 12 hp over stock at about 10k rpm. I had to make some angled manifolds to make the carbs fit so I think I'm loosing some top end there. With the carbs on gas it has about equal to the injection until about 10k then it dropped off. I pulled the base gasket out and degreed the cams to 109/105 and got about 4 more hp. The best I have gotten so far in the car is 174hp and 104tq with 4.10 gears in the rear and 215 hoosiers at 10psi. The best I got with gas/injection was 152hp. I was playing with timing when it went bad on me. I've raced it about 6 times on alky and it made a world of difference! Stays cool the whole race and I've yet to have a car out pull me on the straights. If I could only get it to turn left! With the zx11 I could go wide open all the way around but with this thing it's more like drag racing on the straights and tip toeing through the corners. What started all this is FI isn't allowed at one of the tracks I race at.
I was thinking about just grinding the teeth off the balancer but if I have any money left I'd like to buy the Muzzy plug instead.
Thanks for the input, I think I'm just going to put it together with new rod bearings / bolts and forget about lightening the crank for now.
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MadMike
Moderator
FEAR THE BLACK FLAG!!!!!!!!
Posts: 6579
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posted August 26, 2003 09:13 PM
the muzzy plug is only 20 bucks dude and it works slick!!! you have to split the cases to remove though...
Mad Mike
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kawachan
Pro
Posts: 1031
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posted August 27, 2003 06:41 AM
Not much grinding either. All you need to do is weld up the oil relief holes in the shaft and re-install it. 20 bucks to Muzzy and save a whole lot of time!!
No FI huh. They have that "no PC " rule here. What a joke.....
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RED NINJAS RULE!!
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cmcnitt
Parking Attendant
Posts: 15
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posted August 27, 2003 09:39 AM
no pc!
I hear ya, although the rule made my car faster! I never looked at the price of the block-off, I guess because it was from muzzy's I assumed it was high $$. I'll definitely get one for $20.
Thanks again, I learn from this forum every day!
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