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Dori240sx
01-25-2013, 08:12 PM
Hey guys I just picked up a 1992 convertible and I was wondering you guys could help me shed some light on the subject

When I bought it the previous owner told me that he didn't know much about mechanics. The bottom and was rebuilt with a eBay rebuild kit
new pistons
1 rod replaced btw how is it possible to bend a rod?


New rings
New bearings
new water pump
new timing cover
block was decked and dipped.
Ect


The crankshaft was replaced and bought brand new from autozone. Does it need to be balanced after being installed? Or just dropped in.

My question is the eBay rebuild kit comes with rod bearings and as far as I know so does the crankshaft kit from autozone are there sizes differ between the 2? My friend was given a set of unpackaged rod bearings and I'm not sure which kit they go to the crankshaft kit or the ebay rebuild kit? how do I find out?

It makes me nervous because I don't know the mechanic and I don't know if the correct rod bearings were used during the rebuild I want to be extra safe and check clearances with a micrometer as well as plastic gauge in the end if it's done correctly great if not I want to fix it now before I lock the motor up on accident.


Fuuuuuu!!!! Ask away if you have any questions...

s13livin
01-25-2013, 08:49 PM
most of the times bent rods is due to detonation, also did you check the hg? if thats blown it could suck coolant into the combustion chamber and obviously liquid wont compress bending the rod when it comes back up to tdc.

Dori240sx
01-25-2013, 09:02 PM
Ya the hg was replaced as well when rebuild was done. Thanks for shedding the light on the bent rod subject I was pretty much stumped. Any ideas on the rod bearings?

s13livin
01-25-2013, 09:36 PM
well is the motor already apart? they should be the same. and it is recommended to balance a new crankshaft

Dori240sx
01-25-2013, 09:48 PM
Okay I'm not sure if it's been balanced or not I'll have to ask the previous owner and as far as the motor goes no it's not a part I still need to pull it out of the car

Dori240sx
01-25-2013, 09:51 PM
I just called autozone and they said that the crankshaft that the previous owner purchased that model slash part from autozone comes pre balanced. What are your thoughts on that

s13livin
01-25-2013, 10:55 PM
Yeah they come pre-balanced, but you would want to balance the engine (crank, rods, pistons etc) but most people say if you stay stock it's not necessary, but that's opinion so well leave that up to you. if you have extra money to waiste it could help with smoothness

Dori240sx
01-26-2013, 07:12 AM
Ok ill look into how much it would cost to balance it. So you think im ok with the rod bearings? Is there such thing as undersize bearings or oversize bearings that might have came with the rebuild kit?

s13livin
01-26-2013, 11:58 AM
depends on the shop, anywhere from $100-$300. there is undersize, if your crankshaft journals have been ground which they havent because previous guy bought it new, you would run undersize bearings but i doubt the ebay kit considers that, most likely they're to the spec of a new crankshaft just my thought, if anyone else wants to chime in lol

Dori240sx
01-26-2013, 02:09 PM
So if I just checked the clearances and everything checks out to spec do you think it should be okay as long as the torque specs are also good

s13livin
01-26-2013, 03:18 PM
is there a reason or problem causing you to want to do all this? its a lot more complicated than may you think

Dori240sx
01-26-2013, 03:25 PM
No im just trying to find out if the new crankshaft bearings and the ebay rebuild kit bearings are basically the same. I didnt know if ons set was bigger than the other.

s13livin
01-26-2013, 03:32 PM
i see. do you have an understanding of engine rebuilding, or have you ever before. ripping it apart if not may cause more problems in the future, not talking shit just saving you from future problems

Dori240sx
01-26-2013, 03:45 PM
Ya this will be my 6th 240. And as far as rebuilding a motor. Only 1. I did help my friend rebuild mine but he did most of the work. When i get the chance im going to pull the motor and check EVERYTHING. That right there should save me alot of trouble in the future. Im terrified to just take the guys word for it and finish putting the rad and fan in and someother small stuff and start it up and the rod starts to knock after 8 fucking minutes of idle.

Dori240sx
01-26-2013, 03:47 PM
Anything you recommend that i should focus on more than the next? Bearing clearance, torque specs, rtv jobs, blah...? It was a EBAY rebuild kit so im really nervous bevy ive seen the quality of there parts.

S14DB
01-26-2013, 04:31 PM
For one rod and the crank to be replaced it sounds like he spun the rod bearing destroying the crank and rod.

-If one rod was replaced. Make sure they were all weighed and matched to each other.
-Make sure the mains are straight and round.
-Bearing sizes should be based on the crank and main sizing.

As far as ebay vs autozone. You can get nice stuff and crap from both. Hard to tell without knowing actual brands.

Did you flip the motor with the head still on?

Dori240sx
01-26-2013, 04:50 PM
No sir not yet. But that is the first thing im going to do. Since the crankshaft was replaced the bearings that came with that should have been put into the motor not the ones from the rebuild kit? Right? Im tryimg to get in contact with the mechanic but not having any luck.

How do i check to see if the mains are straight? And what are the mains?

S14DB
01-26-2013, 05:54 PM
No sir not yet. But that is the first thing im going to do. Since the crankshaft was replaced the bearings that came with that should have been put into the motor not the ones from the rebuild kit? Right? Im tryimg to get in contact with the mechanic but not having any luck.

How do i check to see if the mains are straight? And what are the mains?

Mains are the bearings in the block that hold the crank in. Pull the crank out put the main caps back in and TQ to spec. Measure them for round and width(diameter). Check that they are straight then compare to the diameter of the crank for bearing size.

s13livin
01-26-2013, 07:09 PM
use a straightedge and and feeler gauge to check for main bearing alignment. if there's more than i think .0015in deviation (correct me if I'm wrong) s14db, they should be align bored or honed, and youre going to need a bore gauge to check diameter

BiGMerK215
01-26-2013, 08:08 PM
Does the 240 you bought with supposedly rebuilt motor not run? or does it just come with the ebay kit?

As far as the rebuild goes, everyones gotta start somewhere. Just try to keep it organized.

cyl head gotta come off and your going to want to invest in an engine stand. Plastigauge is probably your best bet for measuring bearing clearances otherwise your going to end up investing in measurement tools which arent cheap by any means.

Are you looking to do a full rebuild or just check for internal damage?

S14DB
01-26-2013, 10:12 PM
use a straightedge and and feeler gauge to check for main bearing alignment. if there's more than i think .0015in deviation (correct me if I'm wrong) s14db, they should be align bored or honed, and youre going to need a bore gauge to check diameter
Yeah, I just don't know may mechanics that have one. Machinist do.
Machinist Straight Edges - SummitRacing.com (http://www.summitracing.com/search/part-type/machinist-straight-edges)

The acceptable deviation depends on the engine and how tight the clearances are.

More important is to check the bores for round using a caliper.

KiLLeR2001
01-26-2013, 10:18 PM
I'd look into sourcing another KA motor to swap into the car while you dilly dally around with this motor. No way in hell would I even think about putting ebay parts into my engine. The sheer thought gives me goosebumps.

mxexux
01-26-2013, 10:36 PM
OP, either trust what the previous owner did and run it or don't trust what he did and tear the whole thing apart and redo it your self. Seems like this decision should have been made before you bought the car.

Nonetheless, by your comments, I would guess that you don't trust the previous work done at all. At the very least, pull the motor apart and check all the clearances.

For the rod bearings, you could try and find a part# and cross reference with standard bearings part#. I'm pretty sure that when you order bearings, they automatically give you standard ones unless you ask for under or over sized ones.

s13livin
01-26-2013, 10:46 PM
I'd look into sourcing another KA motor to swap into the car while you dilly dally around with this motor. No way in hell would I even think about putting ebay parts into my engine. The sheer thought gives me goosebumps.

i agree with sourcing another one. and not talking shit but never got that, ebay doesn't make any parts just a place for people/companies to sell stuff.

s13livin
01-26-2013, 10:48 PM
thought this might help you, if you don't already have it.

Index of /FSM/240sx/91-94 (http://www.nicoclub.com/FSM/240sx/91-94/)

KiLLeR2001
01-26-2013, 10:57 PM
By ebay parts I mean, random no name brand from china with who knows what kind of quality control.

Dori240sx
01-27-2013, 09:16 AM
The motors rebuilt. Im concerned about how it was rebuilt. I need to pull the motor and check to make sure it was done correctly. The ebay kit has already been installed. New rod as well. And new crankshaft.

Dori240sx
01-27-2013, 09:18 AM
Yes exactly... i plan on redoing everything jusy to be safe