Spun Bearing Questions

Basic tech questions such as future setups, different turbo kits, car diagnosis, etc
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DRFTPUNK
Knows Some Stuff About 240's!
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Location: Port St Lucie FL

Spun Bearing Questions

Post by DRFTPUNK »

So I'm going to abbreviate a long story.

4yr ago mostly finish with build
CP piston,Eagle, ARP, Clevite, bored 20, decked, MRP sealed mafs housing , 80lb injectors, walbro 255.
Join Air Force.
Stationed in Italy.(yay travel, f!.. My car 😞)
Car Sits at home (FL) in a trailer mostly protected from elements.
New orders to California (Vandenberg)
Leave in route for a month to get car good.
Finish odds and ends boost leaks etc, car running lean (15-17) on Enthalpy ecu on idle, (drops to 10-12 on cruise/wot but slowly climbs back up)
Ask him for help. He says fuel pump rewire. I do.
AFRs great.
I drive around town for a bit everything seems good mostly nice and easy.
Hit maybe 2 nice 3rd gear pulls. Pulls hard. (10psi gt35 cxracing 0 shaft play)
Barely touch boost maybe 10 times all together just to hear BOV

Bearing spun at some point maybe with 10 miles all together. Also AFRs are climbing back up for what seems like no reason. Fuel pump still rewired (brand new W255) why would it hold good AFRs for 2 days and then when on startup slowly lean out? Knock sensor and harness also new.

I have yet to pull it apart as I am currently in California and need to now ship it out here (not happy)

What would have caused such a failure on a basically brand new motor? I know it sat for a while but it seems crazy that on a fully built motor it would handle basically zero abuse.

Are these oiling issues? The oil pump is brand new Nissan OEM. pan is not dented.

Current plan is to ship it here to the base, pull motor, drop bottom out inspect crank and rods. Maybe reassemble with KING bearings people seem to like. If it's damaged maybe I can find a machine shop to repolish and fully balance the rotating assembly.

But I'm worried there is some other issue at hand that I over looked. Cranks are hard to find these days.
supakat wrote:I will tell you one thing, if I had to choose between stretched tires and stretched pu$$y, I would go with tires.

S14 Zenki, GT35, 80lb injectors, RS Enthalpy tune, Eagle/ Wiseco 8.8/1.
Formerly Known as ISpentAllMyMoneyOnTires

RIP 480sx
tuzzio
240sx Wannabe
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Re: Spun Bearing Questions

Post by tuzzio »

Unfortunately too many variables. Did you change your oil before first start after it sat for years? Do you monitor oil pressure at all?
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DRFTPUNK
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Posts: 315
Joined: Sun Feb 07, 2010 10:03 pm
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Re: Spun Bearing Questions

Post by DRFTPUNK »

Yes fresh oil 10w30 full synthetic. Unfortunately no oil pressure monitoring. There were a few dead cranks before I changed the oil but even on swapping the oil the old stuff looked brand new so I don't think it was that.

I was a bit concerned the turbo was robbing it somehow since Chinese? But I wasn't getting any smoke or major leakage. A small amount was dripping from the multi port I had T'ed into the oil filter bracket (at the stock oil gauge port). But after tightening it stopped.
supakat wrote:I will tell you one thing, if I had to choose between stretched tires and stretched pu$$y, I would go with tires.

S14 Zenki, GT35, 80lb injectors, RS Enthalpy tune, Eagle/ Wiseco 8.8/1.
Formerly Known as ISpentAllMyMoneyOnTires

RIP 480sx
User avatar
DRFTPUNK
Knows Some Stuff About 240's!
Posts: 315
Joined: Sun Feb 07, 2010 10:03 pm
Location: Port St Lucie FL

Re: Spun Bearing Questions

Post by DRFTPUNK »

I really want this motor situation settled so I can put a z32 Trans in it 🤣🙃🤷‍♂️
supakat wrote:I will tell you one thing, if I had to choose between stretched tires and stretched pu$$y, I would go with tires.

S14 Zenki, GT35, 80lb injectors, RS Enthalpy tune, Eagle/ Wiseco 8.8/1.
Formerly Known as ISpentAllMyMoneyOnTires

RIP 480sx
Boosted90Hardbody
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Location: St. George, UT

Re: Spun Bearing Questions

Post by Boosted90Hardbody »

Unfortunately, it's hard to pin down a definite cause until you pull the motor apart. My guess would be inadequate oil pressure, severe oil contamination(metal, dirt or fuel) or error in assembly. From personal experience, I can tell you it takes quite a bit to spin a bearing in these motors. When I first boosted mine on stock internals, I put the #4 rod cap on backwards, rookie mistake. I drove that sucker for a month on 10 lbs, well over 2000 miles, blew a hg and replaced it, racing anybody and everybody, and that bearing held until about 10 minutes after setting up the 2 step. One thing I can tell you for sure is that you're gonna need to get the crank ground for undersized bearings and you'll need a new rod to replace the one that spun the bearing. I'd also look into getting the ball plugs removed from your crank and the holes tapped for socket head plugs so you can clean out the oil galley. You'd be surprised how much crud is hiding in there, could be a factor in what caused the bearing to spin.
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DRFTPUNK
Knows Some Stuff About 240's!
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Joined: Sun Feb 07, 2010 10:03 pm
Location: Port St Lucie FL

Re: Spun Bearing Questions

Post by DRFTPUNK »

To resolve this thread, I had to pull everything apart to check the bearings... when I finally get to the machine shop to get their opinion, it turned out the flywheel was loosening O_0 ... on my initial inspection it wasn't apparent because it was galled onto the center ring and felt sturdy. I had used ARP FW bolts for the initial install but didn't use threadlocker (as per their recommended instruction) and just used their proprietary grease... well I re installed with new ARP bolts but this time used threadlocker and torqued to 100+ ft lbs.
supakat wrote:I will tell you one thing, if I had to choose between stretched tires and stretched pu$$y, I would go with tires.

S14 Zenki, GT35, 80lb injectors, RS Enthalpy tune, Eagle/ Wiseco 8.8/1.
Formerly Known as ISpentAllMyMoneyOnTires

RIP 480sx
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