Weird motor locking up issue - KA vs RB flywheel

[ch1873857]

OK. So most of you know Im not a rookie but Im a little stumped on this one. Searched a bit. I google probably 50-100 things a day. Havent found anything useful for RB motors (if it matters).

Ive done probably 4 swaps with this same setup and no similar issues. Ill make this short and to the point.

Problem: rb25 swap. go to first crank. motor locked up. known good motor

Setup:

Stock rb25 s2
RB20 trans
KA white bunny clutch setup
stock driveshaft/diff

Situation:

Motor spun freely before install weeks ago when i replaced the front end (t belt water pump, oil pump). very clean inside.

installed clutch. had a KA flywheel around which is the same flywheel essentially. removed pin on the crank to fit. *didnt spin the motor since front end install*

Rb20 trans spun fine tail and input. lubed up good, went on like butter.


Once I finished the wiring, i roughed everything in. wired the power plugs, start sig, and ground, just to test power and wiring splice. Went to crank and the sound it made was exactly that of a locked up motor. I knew the starter was good because it was the one on my drift car.

Tried.
changing batteries, charging batteries, and jumping batteries. Power is GOOD
changed starter
checked wiring, fuses, battery cables
starting with clutch disengaged (was 5spd swapped prev.- neutral safety jumped)
putting a breaker bar and a 27mm on the crank. no spin

SOMETHING is keeping it from spinning and I THINK its the flywheel. Ive used the white bunny clutch on the 25 multiple times but always used the 25 flywheel because of the pin. This was a last resort thing. I am worried the backspacing it wrong and the flywheel is ON the block keeping it from spinning.

If the motor is know its good and the trans too. clutch seems to be working fine, cant think of anything else. I have read conflicting things about using KA and RB flywheels interchangably and havent found an solid evidence that is does or does not work.

Anyone?
Ray?

[zerodameaon]

You answered your own question on what you have to do, take the transmission off and see if the flywheel is hitting the block. Seriously just use a RB25 flywheel from now on.

[ch1873857]

Originally Posted by zerodameaon

You answered your own question on what you have to do, take the transmission off and see if the flywheel is hitting the block. Seriously just use a RB25 flywheel from now on.

I didnt answer my own question. I dont have the ability to pull the motor back out right now. Not until the weekend. BUT if i had some proof that thats indeed the problem i can have him order a flywheel and he would essentially have it quicker. Not going to have him spend 200 bucks if he doesnt have to. Your smart.. I dont make thread for the fucking hell of it. If you actually had any experience with the issue youd know the d21 flywheel is identical to the eye. Never thought of backspacing being an issue. So if i have it and it works im going to use it or try it. You must love wasting moneym

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[xoxide]

Out of curiosity, why are you so hostile towards everybody on this forum? I dont think ive seen a post from you where you arent telling someone where they can stick their opinion/advice.

Does not seem like a productive way to get help.

[zerodameaon]

LOL mad much? You asked for advice, I gave you some advice based on my experiences, which I do have plenty of it with RB25s, and you didn't like it/not the answer you want, so fuck you sir.

Originally Posted by ch1873857

SOMETHING is keeping it from spinning and I THINK its the flywheel. Ive used the white bunny clutch on the 25 multiple times but always used the 25 flywheel because of the pin. This was a last resort thing. I am worried the backspacing it wrong and the flywheel is ON the block keeping it from spinning.

If the motor is know its good and the trans too. clutch seems to be working fine, cant think of anything else. I have read conflicting things about using KA and RB flywheels interchangably and havent found an solid evidence that is does or does not work.

Anyone?
Ray?

Looks to me like you answered your own question right there on things to do next. The reason I say stick to the RB25 flywheel is because I have looked into the D21 flywheel for my RB25DET but decided not to try it because it looked a bit different then the RB25 flywheel I had. It is always possible I got sent the wrong part, but doubtful. Also when did I say waste money? Don't order parts until you know whats wrong, and how is it a bigger waste of money if you pull the transmission and the fucking flywheel is wrong?

[ch1873857]

Im hostile because a lot of people on here are worthless. "just use an rb flywheel" isnt going to help in this situation.

Im a simple person. If i say im looking for someone who has run into a similar issue and/or can confirm my theory. A response of yeah dude thats your problem etc etc or i have a ka flwheel on my rb would suffice and is the only thing i will likely respond pleasantly to.

Why is that concept hard to get. I dont give a crap about your 2 sense or your advice. I dont need advice or help. Im looking for a solid answer to save me a day or two because i need the shop back..

Hope i answered your question

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[zerodameaon]

Originally Posted by ch1873857

Im hostile because a lot of people on here are worthless. "just use an rb flywheel" isnt going to help in this situation.

Im a simple person. If i say im looking for someone who has run into a similar issue and/or can confirm my theory. A response of yeah dude thats your problem etc etc or i have a ka flwheel on my rb would suffice and is the only thing i will likely respond pleasantly to.

Why is that concept hard to get. I dont give a crap about your 2 sense or your advice. I dont need advice or help. Im looking for a solid answer to save me a day or two because i need the shop back..

Hope i answered your question

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Ok I will make this simple, since you need it that way, that is your issue based on my experiences. I saw the issue before I even tried it, returned the parts(which you get your money back for doing if you have not damaged them FYI) and bought the correct RB setup. I mean if you don't want help, which a answer would be btw, then why the fuck did you ask the question? If you want place to bounce your theories off of that won't talk back use notepad, word, etc. Maybe you are a little too simple to be using a computer and an online forum if you can't figure that out.

[ch1873857]

Originally Posted by zerodameaon

Ok I will make this simple, since you need it that way, that is your issue based on my experiences. I saw the issue before I even tried it, returned the parts(which you get your money back for doing if you have not damaged them FYI) and bought the correct RB setup. I mean if you don't want help, which a answer would be btw, then why the fuck did you ask the question? If you want place to bounce your theories off of that won't talk back use notepad, word, etc. Maybe you are a little too simple to be using a computer and an online forum if you can't figure that out.

You never said they tou had this same problem... Am i blind? Because i know im not stupid. You came off like a know it all with a condescending tone. So immediately disregarded anything you said as valid. You dont know me. Youd honestly understand. So why not actually explain yourself to begin with?

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[zerodameaon]

Sorry I cut to the chase on that first post as I was posting from a phone that I have yet to get used to, and I may have missed that first line about you being around the block on this your fair share. I apologize for being a dick the rest of the time, now that I am home I realize this was a place to funnel my anger at work.

[mantas]

I can tell you right now. You cant use a ka clutch or flywheel on an rb even if it has a rb20 trans. You need to use rb25 or z32 clutch and flywheel.

[fliprayzin240sx]

Originally Posted by mantas

I can tell you right now. You cant use a ka clutch or flywheel on an rb even if it has a rb20 trans. You need to use rb25 or z32 clutch and flywheel.

How can you say you can't when he already said he's done atleast 4 other swaps using the white bunny setup?

[ch1873857]

Originally Posted by fliprayzin240sx

How can you say you can't when he already said he's done atleast 4 other swaps using the white bunny setup?

Exactly why i toyed around with this idea to begin with. Ka flywheel anyway.

Mind you this is a D21 KA flyhweel. The D21 clutch kit found at any nissan dealer fits exactly perfect on an rb flywheel using an rb20 trans. Ive done it! And is a fantastic budget clutch for a mild rb25 swap.. Those clutches hold awesome on stockish setups. The rb uses a 240mm disk as does the d21.. Ka is 225mm iirc




Whitebunny on rb25


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[godsmack]

So gathering on this info. I take it that you have done the whitebunny but it was with an rb flywheel and not the ka. Now you are trying it with a ka flywheel and running into a problem? I have no actual info to be helpful on your problem, but trying to clarify things to become more knowledgeable on this for future installs.

[mantas]

Idk. I have compared the two flywheels and they were different sizes. May be the one op used fits, but from what i recall the ka clutch is also smaller or the holes didnt align. This was a while back and i did research which affirmed my findings.