Rebuilding motor, spun a bearing
 

Ahh yes, struck down by the ol zoom zoom boom. Last night the car spun a bearing, after installing an EBC and raising the boost from 7-8 psi to around 11. Well it definitely put out a good bit more power (unsure of HP) and felt strong throughout the day including an autocross early on, until a catastrophic failure during a freeway pull in the evening. Car still starts up, but is blowing tons of smoke and making a pretty loud banging around. Im excited to dive in and investigate thoroughly.

l am spoiled enough to have a turbo DD, so I am not left entirely without fun.

nonetheless, i know how much yall like to read of noobs blowing up their $#!7 so here it is haha

I did get 5 years of rough use with the motor, 140k miles about a third are mine, and more track days that I can count on hands and feet. One year of that being boosted. While I couldve stayed at 7-8 psi for a bit longer and not grenaded, the engine was already consuming a good bit of oil and didnt have the best leakdown/compression numbers.

All of that said, and I appreciate your patience, I am now going to build the engine for a predetermined goal. I really want track reliability, not internet points awarding HP. Is a 220-230HP goal pretty reasonable? At that power point, am I better off going higher compression? (Currently 8.8:1)

Heres my current parts list:
Rods
Pistons
Gaskets and Seals etc
BE Oil pump
Headwork (94 head currently, might replace with 99-00)
silicone hoses
flattop or skunk2 mani if head upgrade

still have 3.63 waiting to go in, was pretty damn torquey with the 4.1 and 6spd
Cooling is pretty well sorted, might include an oil cooler and put on more shrouding


any suggestions? I have no engine building experience but I do have a cherry picker. I was gonna pull out the engine and take it to a build shop in the SA area.

You dont need pistons for that power. I would only go for rods and maybe some kind of damper.

+1.

Smoking isn't a rod problem. There may be bore damage.

I was also going to ask- how do you know that it’s a spun bearing? Glittery oil is the usual sign. If run long enough, the motor will seize completely. A lot of people run 11 psi without issues, your symptoms don’t sound like a spun bearing.

Seems like there’s a lot of guys here running stock motors at 220-230hp with no issues.

Wont be 100% sure until I dig into it but yes, i think cylinder damage may have occurred. The smoking occurred before the loud failure of the crank bearing. I was in the far left lane of a busy freeway, so I couldnt just shut the car off. The loud clatter began on the exit ramp and and billows of smoke began coming out.

whatever the likely culprit is probably wont change the fact that the block will either need machine work or replacement

the reason i asked about pistons isnt because of the max power goal but because of the power curve goal, would a higher comp (9.5:1) low boost turbo get me what I want?

cant say how much power i was making.. car never saw a dyno which may contributed to the boom. But i have a full 3" exhaust running a 2560 FM2 diy kit. I wanna say that it wasnt from just having an 11 psi stock motor, but more from it being a tired motor and the ebc possibly causing a spike in boost.. i did set a limit in tunerstudio but i think it may have spiked past it

edit: just double checked, had boost limit set to 200kpa or 14.3 psi and it may have gone past that.. i think i may have been tip toeing towards that 250 mark and the tired motor gave up short of it

Rod bearing failure doesn't produce smoke. I would take a hard, uncomfortable look at your tune in the 11psi cells

I'm running a 2560 at 13psi and survived 4 days on track, multiple auto x events, and countless pulls on the interstate...... What timing and AFR's are you shooting for, and what's your redline?

Had afr target of 11.8, redline at 7000, but never made it there. What does it sound more like to you sav? That i ran super lean and snapped a rod and scored the cylinder? Ive never built an engine and luckily this is the first time ive really broken one.

Maybe i burned an exhaust valve, lost my oil that way and ran low on oil until the bearing slipped?

Not Sav, but a burnt valve won't cause oil loss, that's rings.

You left out the most important part, what kind of timing are you running under boost?

Just the base timing map.. didnt wanna touch it until I got to a dyno..

could have maybe been a HG leak that turned into a hydrolocked cylinder than broke a rod?

You said it was already burning oil. Oil causes detonation so safe timing or not is irrelevant in boost, things will break eventually.

Lol, you're dancing around the problem. There isn't just one base map, could be anything in there. Your base timing (assuming this is an NA with a CAS) could be off.

Most likely your timing is aggressive and the burning oil from around the rings made it detonate beating the bearings out of it.

Bronson I think you got it. I used the most logical base map for my vehicle, the turbo tuner base map MM9495, so it wasn't just a random ignition table haha.

At 184 kPA for instance, from 4000-7000 RPM, the igntion timing goes from 14.1 to 16.9 gradually.
Whereas at 100 kPa I am at 28.1-28.8

and sixshooter is right, the car was burning oil and was going to break EVENTUALLY. motors dont last forever, shoot even the highest HP motors sometimes last less than 5 years because of the type of use they see.

Make all the excuses you want, but your failure mode indicates a tuning error. A well-tuned turbo BP will run until it burns so much oil it no longer needs gas, or until it bends all the rods just a little bit. No HG leaks, no spun bearings, no other problems.

Sav, im not making excuses i am analytically speculating as to what could have been the cause. I suggested tuning errors in the form of ebc spikes, likely from using a ebc duty table that was too aggr. I suggested oil burning.. it has definitely been getting worse.

i was also on your website speculating a motor build but i wont if your customer service is reflected here in your last comment. I am really trying hard here without the expertise of some of you guys

edit: i will say that i am trying to do things more correct this next time around, learning from some of my mistakes. I think some of the expressed ideas here were spot on. Still figuring out next steps, whether or not to pull the motor or tow to a shop. Whether to build using current compression or higher? And ultimately whether i am better off getting a new long block?

It's tough love, that's how we operate. Disabuse yourself of the idea that a worn-out motor may have contributed to the cause of your failure. The symptoms of your failure indicate a major internal component failure, and worn-out motors aren't more prone to failures like that. It's important for you to understand that little EBC mistakes and boost spikes can cause serious motor damage irregardless of the condition of your engine. If you can fully grasp that, it will prevent you from making the same expensive mistake again.

I'd hate to see you blow up a second, expensive, built motor because you didn't get your money's worth out of the post-mortem on the first one.

I have to agree with a tuning problem likely taking out the stock engine.

I have a log from the day before that I will upload. It was right after a firmware update so you'll have to excuse some of the corrections to idle etc.

also, could it just be that I was over the 250HP limit? What mods bring you to that point? I do have a complete 3'' exhaust and dp... any ideas of what kind of power range I may have been operating in?

I had to get the car off the street and up my steep driveway.. I was actually able to get it started this morning and get it up into the garage. Now that it is daylight I can see that the smoke is actually a lot whiter than it is grey, and there is definitely coolant coming out of the exhaust tip. Could this just be a simple HG blowout?

EBC can bite you really fast and easily. Especially if you are using open loop boost, then just temp change can cause you to over boost. I dont think you were over the power limit. If i had to guess i would say a tuning error in the upper boost cells caused a single catastrophic event leading to this

No.

No.

Here is the datalog I took the day before, just after updating the firmware, the idle was really high because the idle setting had reversed, but I got that corrected. I increased the boost limit further after this, before reviewing this datalog completely, so while this peaks at 194.3 kpa, it is very likely that when i had it set to a 200 kpa limit it was peaking above that. I thought I had recorded a datalog from that morning but I guess not.. :/

On another note, what makes a 250 HP BP? What is the max boost a stock motor could take given the "perfect" tune?

ALLOFIT

Well, there you go, you were definitely overboosting. Not sure if you ran out of fuel or luck as you haven't posted any other details about your car.

Asking "what is the max boost" any motor can take is a bad question and nobody is going to bother answering that.

This is a big question that will vary HIGHLY depending on who you ask. It depends a lot on the setup itself. A small turbo making 250whp will be more likely to bend rods than a bigger turbo making 250whp, for several reasons. The definition of perfect tune is also debatable. Perfect as in, optimized for power? Optimized for 93 octane? Optimized to not break when you get a bad tank of gas? Optimized for track duty? My idea for a "perfect tune" for a stock motor is a tune that errors on the side of safety above all else. But that means it's not gonna make the power a more aggressive tune would make.

FWIW, I ran 17 PSI on my stock 99 motor for about a year before I killed it. Overboosted to 22 PSI a few times. I bent the rods with a 100 shot of nitrous before I ever turbo'd it, then boosted it with two bent rods. After a year of abuse the thing shook the front crank bolt out that holds the balancer on and destroyed the keyway in the crank killing it.

I didn't have any engine building experience before I built mine. That being said, 220whp doesn't require a build at all. Just swap in another 1.8 and put a turbo on it with 12 lbs of boost. With a decent tune that will easily hit your power goals and still be reliable. Countless people were hitting 220+ with boring builds on stock motors like 20 years ago.

From the description of your problem, I bet that you killed your engine with shitty tuning. You are running way too low a power level to kill a stock BP. Also, the fact that your engine died from highway pulls right after you raised the boost (especially since you raised it from really low to sorta low) tells me that you probably ran lean and damaged something because you tuned your car poorly. Or there's something else grossly wrong with your setup that isn't obvious from your posts.

You need to remedy your ignorance before you put any more money into this. Don't spend any money on this until you run compression/leakdown and then take the whole thing apart to figure out what went wrong.

Some other things you brought up:

• Don't waste money on head work for any sort of modest power build. Good headwork is expensive and raising boost is cheap.
• Don't get headwork done on a pre 99 head. They flow for shit and you're just polishing a turd.
• Don't go for higher compression to make more power unless you're running ethanol. You get a much bigger margin of error for timing running 8.5 vs 9.5 compression and the power difference is modest at a given boost level. And since the lower compression motor can run more boost safely...
• Honestly, every penny you sink into the above unnecessary power mods is money you aren't spending on reliability mods. Instead of getting a junk 2 intake, get a coolant reroute. And so on.

Just get an unopened BP4W with VICS intake and learn how to tune.
Unless decent BP4W are getting rare as unicorns and expensive that's a route that's much faster and fit for purpose (the lack of engine building knowledge is not your issue, so why start there?).

Thank you very much for the lengthy reply and suggestions! I do have a coolant reroute and have upgraded the cooling system quite effectively. No issues there.

tuning error. Everyone keeps pointing to that while only one person has really been specific.. boost spike. Could a spike up to 20 psi bring the car to 250 hp?

Cure my ignorance? Tune better? I had been running MS n/a for a few years as suggested here so i thought I was doing things correctly. I posted a log that nobody has commented on. Im not giving up but I dont wanna just waste money. I answered the questions about afr, is 11.8 too lean? I dont think so. I had just recalibrated my o2 sensor. Are the ign timing values i listed off? By how much?

of course theres a lot to learn from tearing it apart, but if it IS a tuning error mainly at fault here, i think it should be evident from either the tune or the log

so i might just drop in a 99/00 long block and call it good for my power level goals? I wouldnt try porting the na head.. haha. Im not as new to miatas as you might think. But it does take some humility to open up to yall here on MT

i might add that on the stock wastegate pressure ~8psi the car ran great, idled great, hit afrs smoothly, and didnt grenade lol. The ebc, a boost gauge, and a firmware update were all that I changed.

Even if you went over 250 hp that is not what killed your engine.

You say this like its trivial. FW updates can wreak havoc if the tune isn't combed through after the update. The EBC was already described to you. If I remember, ill look at your tune and logs when I get home, but there are other who are much better at that, than I am.

gotcha. Probably ran lean in the overboost cells, as I hadnt planned on hitting those cells. And because of negligence i hit those boost cells a lot. Was having a blast with the new found power until boom

You can break your rings at 180 horsepower with detonation by running too lean or too much timing or too much oil in your combustion chamber. Stop focusing on stupid shit like 250 horsepower. It's just a number and lots of people have destroyed their engines at far less than that. 250 horsepower is around the limit if everything is perfect. Nothing about what you've described would cause me to use the word perfect.

You've made lots of assertions about things you don't know. You have not yet taken apart the bottom end to see if you have a spun bearing. You may have a bent rod or broken piston(s) or water in your oil from a blown head gasket wiped out all the bearings and galled the cam bearing surfaces.

All we do know is that you had a shit tune on a motor that was already hurt. The result is no surprise. Take some pictures when you get it apart and then we'll know what happened but I'm pretty confident with the "why" already.

At your boost level, it's a crap tune. My original build like 15 years ago inherited a lot of parts from some guy who blew up his motor at 6psi. I drove on the stock motor with those same parts and a safe tune at 15 psi on a larger turbo for a year with no problems before I built the motor.

One thing I don't get is why you would not program in your high boost rows to be pig rich with retarded timing, especially if you never plan to hit them. Leaving them lean seems like a blatantly retarded thing to do.

What size injectors are you running? Original fuel pump? What year?

Or runs out of oil.

(ask me how i know)

How do you know?

I ran a motor out of oil

My .02
Listen to the others, they have some (lots) good advice.
Based on the bad noises you described on the first page and the (smarter than me) others conjecture, my WAG as to what happened is the extra boost put you into an untuned area of the map, possibly causing some light detonation, then a boost spike for whatever reason plus the detonation = piston failure, probably around the ring lands by the exhaust valves, as that is the hottest and therefore becomes the weakest area of the piston. Take it apart if you want and see the damages.