Jump to content
SAU Community

Spun Bearings?


Recommended Posts

Hello SAU

Need a bit of guidance as to what needs to be done. Haven't checked any of this stuff before so it's a learning experience.

Long story short - Drifting 3rd gear full boost and I saw oil pressure drop, turned off car immediately and rolled back into pits. Did a quick start, Oil pressure was back up put it on the trailer and that was it. Pulled motor today to check the damage.

These are pictures of the bearing cap and bottom half of bearing. In my opinion it's the worse of the lot. Do I replace it or it it ok to go back in?

Bearing Cap

20go22p.jpg

Bearing

iyg1mw.jpg

What do you guys think?

Also if it's bad, Can I just pull the crank and pistons out, replace/machine crank if need be and new bearings. Do I need to do anything with the pistons and rods? Like adjust or replace rings? Get anything checked? Or can I just bolt the rods back to the crank and put it back in no worries?

Thanks all.

Link to comment
Share on other sites

How are the crank journals, scored?

Was a bearing spun?

If so dont muck around, in fact id look at getting some beefier rods in there to avoid this happening again.

Hows the oil pump, is it cracked?

What happened, were you holding the revs up high for a while, while redlining it? If so could be oil surge that built up in the head and dried out your sump that caused this.....good oil drain back to the sump is a known RB issue.

Link to comment
Share on other sites

How are the crank journals, scored?

Was a bearing spun?

If so dont muck around, in fact id look at getting some beefier rods in there to avoid this happening again.

Hows the oil pump, is it cracked?

What happened, were you holding the revs up high for a while, while redlining it? If so could be oil surge that built up in the head and dried out your sump that caused this.....good oil drain back to the sump is a known RB issue.

Crank looked alright to me and bearings had not moved. There was no rod knock that i could hear after it happened. I just assumed the worst.

Have not looked at the oil pump yet. Was likely going to opt for a new one anyway.

Was holding about 5500-6000 rpm i dont like getting near limiter if possible.

Motor has done 2 sprint days and about 11 drift days now and this is my first engine issue.

Link to comment
Share on other sites

Does it make any noise when running, like a nock nock nock sound?

To me It looks fine in those pics.

My old RB20 did this, drop oil pressure to zero under sudden heavy breaking, then come back up straight away. Although it eventually developed a nock.

Link to comment
Share on other sites

Yeah thats why my questions were worded as they were.

It does not look like a spun bearing, cap does not look like its cooked, id be looking elsewhere for the oil pressure drop.

I would however inspect all bearings for metal to metal contact before reassembly in case one or more is damaged due to the momentary pressure drop.

One thing about track days and drift sessions is the high g loadings can move the oil away from the pickup, add to that higher RPMS which pools the oil in the head and its a recipy for oil starvation and spun bearings.

If all checks out OK drop a oil restrictor in under the head, and a larger oil sump with trap doors and longer pickup to make sure you dont starve it of oil at minimum.

Link to comment
Share on other sites

There was no knocking sound that I could hear afterwards. Didn't want to run the engine for more than a couple seconds incase somthing was up.

Will check everything out today and see if there is any damage.

Ordered an oil restrictor and some fittings for a head drain last night so it will be done before motor goes back in. Going to check out sump options now.

Cheers

Link to comment
Share on other sites

There was no knocking sound that I could hear afterwards. Didn't want to run the engine for more than a couple seconds incase somthing was up.

Will check everything out today and see if there is any damage.

Ordered an oil restrictor and some fittings for a head drain last night so it will be done before motor goes back in. Going to check out sump options now.

Cheers

Forget the "head drain" - read the last 10 or so pages (or the whole thread if you have time to kill) of the oil control thread: http://www.skylinesaustralia.com/forums/topic/110680-oil-control-in-rbs-for-circuit-drag-or-drift/?&hl=sk+oil+control

Link to comment
Share on other sites

I don't see a problem with the bearings or the cap. Looks fine with no actual significant wear.

I would check the pump for issues but if its fine I would put the car back together with a good aftermarket oil pressure gauge (assuming you were basing the reading off the OEM gauge).

Link to comment
Share on other sites

Just replace it. Bearings are worth stuff all and well worth being changed given the motor is out.

With regard to the rest of the motor, if you can afford it rebuild it if you plan to continue drifting it as its a pretty destructive sport. The engine will need to be rebuilt sooner or later so why not do it now ;)

Link to comment
Share on other sites

how do you know the oil pressure was down? what if the gauge was having a hissy fit ?

Honestly I don't, I bought a new gauge anyway and will most likely run them both.

Forget the "head drain" - read the last 10 or so pages (or the whole thread if you have time to kill) of the oil control thread: http://www.skylinesaustralia.com/forums/topic/110680-oil-control-in-rbs-for-circuit-drag-or-drift/?&hl=sk+oil+control

Had a good read of all of it.

I've already got the fittings to do it, even if it just acts as a sump breather then it's better than nothing.

I don't see a problem with the bearings or the cap. Looks fine with no actual significant wear.

I would check the pump for issues but if its fine I would put the car back together with a good aftermarket oil pressure gauge (assuming you were basing the reading off the OEM gauge).

Thanks man, new bearings are sitting here ready to go on tomorrow anyway. Pump is off tomorrow too. Would like to replace it but will see what it's like.

Just replace it. Bearings are worth stuff all and well worth being changed given the motor is out.

With regard to the rest of the motor, if you can afford it rebuild it if you plan to continue drifting it as its a pretty destructive sport. The engine will need to be rebuilt sooner or later so why not do it now ;)

Bearings are getting done tomorrow.

I'd love to do a rebuild but it's a large expense I can't afford at the moment. I will of course one day, just hoping to get what I can out of it now before I take that path.

Destructive is an understatement.

Thanks For the input!

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share



  • Similar Content

  • Latest Posts

    • TBH it's almost always due to inaccurate/misinterpreted use case, but this is not just brakes, it's everything. Dose's above post would be unacceptably shit, in my experience. When I say "track day performance" I mean 30 minutes of continuous hot lap braking with no cooldowns, no fade, no letting up. Your use case is paramount when selecting... well... anything.
    • Really comes down to user requirements, I have found my 324mm 350Z Brembo front set up more than sufficient for track use, especially for Wakefield Park with good brake pads. At Sydney Motorsport Park the GP Circuit can be a bit taxing on the braking system, I find by the 3rd hot lap there's rapid degradation in braking performance but at that point non semi slick tyres are about to give up anyway. And yes, the brakes are effective, slowing me down from 230km/h+ each time going into turn 1. Street use, it's more than enough for street activities. Most of the time people complain their brakes aren't sufficient, it's due to incorrect bleeding, poor choice of friction material, or faulty master cylinders.
    • I'm about to sell my Attakd kit actually, so if you want a budget 2nd hand kit they definitely do work, though make sure you update your BMC when/if you do. Just keep in mind that buying pads (for any aftermarket kit) can be a bit more complicated when you have an aftermarket caliper. Not all brands make pads in the shapes and sizes you may want, no matter what you end up with.
    • Hey guys, I had an R32 M/T RB20DET in my S13 quite a while ago, however I have replaced the chassis harness on the S13 and picked up a new motor (A31 A/T RB20DET according to the ECU) and I am having a hell of a time trying to figure out the dash wiring (specifically the black/pink wire for the fuel pump).  It seems this A31 loom is quite different at the dash connector and there is not even a black/pink wire anywhere on the engine loom (on one of the 5 dash plugs that are there), or on the ECU for that matter.  Every pinout I have seen is totally different from the actual wires on my ECU and i'm at a loss on how to wire this thing into my S13....     Any ideas?   In summary : A31 A/T engine loom/ecu pinouts are different than any pinouts i have seen online (specifically around pin 18 Fuel Pump Relay) 
    • What are you doing with the car? Drags, sprints, racing? A decent upgrade of dba 4000 rotors, good quality pads (endless, project mu, intima are all I have used), quality fluid and braided lines. All have held up to multiple big track days and street duties. No need for big fancy kits as some also require significant energy to come upto operating temp. Look at 350z caliper and rotor upgrade too.  @Dose Pipe Sutututu comment on them and did a good write up.
×
×
  • Create New...