Why did my sr20 blow?? Need your opinions. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

civicej8 · 10-14-2015, 04:41 PM

Hey guys. Here's my setup:

S13 sr20det.45k miles,
Gt30r twin scroll at 19psi
Arp studs
Tomei gasket

Setup was professionally tuned. Tune was verified to be running safely. I've had the setup running absolutely great for 3 weeks. Went to the track. Did one run, and there goes my rod bearings. Drained the oil, and found gold tint. So I know that it's the rod bearings.

What I don't get is why did it ruin my bearings? Can knock kill a motor that fast. I was running about 19 on the fc when doing a wot pull. Oil pressure was great.

It's now making me think that the sr20s physics just can't handle the pressure. Car ran perfect before.

Kingtal0n · 10-14-2015, 10:24 PM

Did you run a heavy weight oil and repeatedly bang 7200rpm?

Or you had 15* btdc of timing at 18psi of boost, and it ate the rod bearings.

Or it starved for oil, check if the oil pan is dented up into the pickup. In fact sometimes it completely falls off on redtops. You have to tear down and inspect for clues. Everybody knows you need an S14 bolt on pickup for the redtop- wheres yours?

civicej8 · 10-14-2015, 11:05 PM

Quote:

Originally Posted by Kingtal0n

Did you run a heavy weight oil and repeatedly bang 7200rpm?

Or you had 15* btdc of timing at 18psi of boost, and it ate the rod bearings.

Or it starved for oil, check if the oil pan is dented up into the pickup. In fact sometimes it completely falls off on redtops. You have to tear down and inspect for clues. Everybody knows you need an S14 bolt on pickup for the redtop- wheres yours?

I have a greddy oil pan and s14 pickup tube.

I think only my idle is 15 btdc at idle.

I ran synthetic 5w30 and I wouldn't hit the rev limiter. But my tuner said 8k redline would be okay since I have upgraded springs and cams.

civicej8 · 10-14-2015, 11:07 PM

And to add this was a strict street car. Didn't do any tracking with it. The metal in the oil was so small we needed a light to see the gold tint. Which to me means that maybe it was slowly degrading.

Sent from my SM-G925T using Tapatalk

zombiewolf513 · 10-14-2015, 11:20 PM

Quote:

Originally Posted by civicej8

Went to the track. Did one run, and there goes my rod bearings.

Quote:

Originally Posted by civicej8

And to add this was a strict street car. Didn't do any tracking with it.

So what really happened

civicej8 · 10-14-2015, 11:22 PM

Ha-ha. Well. I meant before I went there lol. It was one 1/4 mile run. Just a plain run. And started hearing some ticking. That's it.

Sent from my SM-G925T using Tapatalk

Kingtal0n · 10-14-2015, 11:35 PM

last piece of the puzzle. check your timing map for 14-15* btdc during boost.

civicej8 · 10-15-2015, 12:43 AM

Quote:

Originally Posted by Kingtal0n

last piece of the puzzle. check your timing map for 14-15* btdc during boost.

So basically your saying that knock killed the motor? Can knock kill your rod bearings to wear out faster ?

Croustibat · 10-15-2015, 04:25 AM

Are you seriously asking why your engine blew ? On a forum ?

Reminders :
-we know absolutely nothing about your engine. Who built it, what machining was done, what parts are in.
-what did you got "3 weeks ago" ?
-stock SR20DET, 45k miles ? Sorry, i don't believe it.
-gt30, 19psi, stock pistons ? Yup, PEBKAC.
-we know absolutely nothing about how it was used, except it "was a strict street car until you decided to track it" which tells us... well, nothing.
-do you have anything at all to monitor your engine ? like AFR gauge, EGT, fuel pressure ?

So far it can range from clearance / machining error to PEBKAC.

civicej8 · 10-15-2015, 04:33 AM

Quote:

Originally Posted by Croustibat

Are you seriously asking why your engine blew ? On a forum ?

Reminders :
-we know absolutely nothing about your engine. Who built it, what machining was done, what parts are in.
-what did you got "3 weeks ago" ?
-stock SR20DET, 45k miles ? Sorry, i don't believe it.
-gt30, 19psi, stock pistons ? Yup, PEBKAC.
-we know absolutely nothing about how it was used, except it "was a strict street car until you decided to track it" which tells us... well, nothing.
-do you have anything at all to monitor your engine ? like AFR gauge, EGT, fuel pressure ?

So far it can range from clearance / machining error to PEBKAC.

The bottom of the engine is stock. Drove in the engine before buying it.

I have aem wideband and verify my air/fuels constantly.

Car is tuned on a apexi fc d detro.

Made 380whp on a mustang dyno.

I think all the hype about having a sr at that power level last is bullshit. I would hope the experts would say something. Thanks

jorge1190 · 10-15-2015, 05:14 AM

My stock rebuild SR made those power levels for like 2 years before blowing due to a boost controller malfunction.

Why are you running 5w-30?

Croustibat · 10-15-2015, 07:14 AM

19psi from a gt30 on stock bottom end is a bit asking for trouble. Stock pistons are weak on ringlands, they usually break there from very few det. If the bearings are gone and they have been done recently, then it is related to bad clearances.

You won't know what has gone until you tear that engine down, so i suggest you start there. Maybe the oil pump got problems and the bottom end was starved, too.

*TheRealSy90* · 10-15-2015, 08:23 AM

15w-50 or bust

that's what the FSM calls for.

Kingtal0n · 10-15-2015, 09:10 AM

Quote:

Originally Posted by civicej8

So basically your saying that knock killed the motor? Can knock kill your rod bearings to wear out faster ?

I have seen lots of rod bearing failure in sr20det engines. The most common causes I have already had the honor of outlining for you.

As to this new question, yes, it is common for "tuners" to set the ignition timing too far advanced, as much as 15* btdc for boost situations in the 9-19psi range. The knock sensor will typically report nothing is wrong. Meanwhile, this timing setting will eat up the rod bearings over time, gradually wearing them out and causing failure. You will find the bottom halves of the bearings scored as if you need more proof that the piston were prematurely being forced down.

*TheRealSy90* · 10-15-2015, 09:17 AM

I'm curious, what about the guys that run e85? I've always heard one benefit is being able to run more ignition timing, but in reality you couldn't run much more timing regardless of the fuel because of the wear on the rod bearings right?

Croustibat · 10-15-2015, 09:23 AM

Quote:

Originally Posted by TheRealSy90

15w-50 or bust

that's what the FSM calls for.

Absolutely not. The FSM gives you pressure targets when cold and hot, at idle and 3000 (or 3500)rpm.

Hot, 3000rpm pressure is a WINDOW, too much pressure is bad too. Our oil pump regulation is pressure based, more pressure = less flow, so you really want the thinnest oil that gets you in that pressure window while maintaining idle pressure above threshold (as long as your engine does not eat it) at oil operating temp.

Basically, unless you live in dubai, if you need 15w50 to get that pressure range, your oil pump is worn. Change your oil pump before the lack of flow makes further damage.

I went that way too, ended up using 10w50 then 10w60 to get the correct pressure, but oil was heating more, thinning and wearing even faster. And then i replaced the pump. Now i can use 5w40, heat problems are gone (oil hardly reach 110° on track when i used to stop at 130° before, after 10mins), the oil is still good after 2000 miles, and the cost per littre is halved ...

Croustibat · 10-15-2015, 09:29 AM

Quote:

Originally Posted by TheRealSy90

I'm curious, what about the guys that run e85? I've always heard one benefit is being able to run more ignition timing, but in reality you couldn't run much more timing regardless of the fuel because of the wear on the rod bearings right?

You are right, we can run (much) more timing.

When there is too much gnition advance like kingtal0n says, the engine kind of "knocks", it vibrates badly and has less power (this is not det). You can't miss it.

E85 guys stop under that "lower power" threshold, and it is way higher than what you get with 93 octane. My CA has more than 20° @ WOT with 18psi of boost for example. I start feeling that "knocking" around 30°.

*TheRealSy90* · 10-15-2015, 09:40 AM

So what's the timing threshold in boost on e85, if 91 is around 8-9 degrees?

Also this is incorrect? From the fsm. Where I live it's between 60-120 year round.
http://i118.photobucket.com/albums/o...rtible/Oil.jpg

Javi802 · 10-15-2015, 09:46 AM

Quote:

Originally Posted by TheRealSy90

15w-50 or bust

that's what the FSM calls for.

I thought it called for 10w30? Or are you being sarcastic??

*TheRealSy90* · 10-15-2015, 09:48 AM

Quote:

Originally Posted by Javi802

I thought it called for 10w30? Or are you being sarcastic??

I really wasn't, refer to my previous post. I've been running 15w50 in my sr for 6 years and it still runs as good as it did when I first swapped it in '09.

civicej8 · 10-15-2015, 03:19 PM

Quote:

Originally Posted by TheRealSy90

I really wasn't, refer to my previous post. I've been running 15w50 in my sr for 6 years and it still runs as good as it did when I first swapped it in '09.

So just the mere fact I was running 5w30 in 90 degree weather resulted in worn bearings? I mean I understand that can happen. But in my opinion unless your really pushing the motor hard then I can see engine wear. A few wot pulls a day I couldnt see.

I guess the conclusion I'm going with is maybe my oil pressure was low causing bearing failure.

Im proly going to build the block and see how long the motor will last at 500whp. Then I'll go back to a ls1 if it doesn't stand up to it.

Sent from my SM-G925T using Tapatalk

*TheRealSy90* · 10-15-2015, 04:09 PM

I don't see it lasting long at all unless you have it built by someone knowledgeable in bearing clearances etc.

jr_ss · 10-15-2015, 09:06 PM

I run 15w-40 in my VET. I also live in a hot humid climate where those viscosities are acceptable.

There's a multitude of reasons your motor could've popped. More than likely though, your motor was about to shit the bed anyway, the drag strip was just the final nail in the coffin. A tear down is in order to inspect everything.

cotbu · 10-15-2015, 09:27 PM

I change oil viscosity and tunes, according to the weather!

It's tear down season!!!

Sent from a Highly Tuned Note 4.5!!!

civicej8 · 10-16-2015, 01:55 AM

Quote:

Originally Posted by cotbu

I change oil viscosity and tunes, according to the weather!

It's tear down season!!!

Sent from a Highly Tuned Note 4.5!!!

It might have been the 5w30. I mean I was running it through 90-100 degree weather. Maybe the oil was too thin causing it to wear fast. Yes. It's true that I could of been running on a hurt motor. I'm gonna look into building the block and seeing how that goes. I just wanted some clarification of things that can kill any motor. I'm aware that knock. Running lean. All of that can kill a motor fast. But rod bearings for me have always been running low on oil. Which I made sure not to do. You gotta pay to play.

Croustibat · 10-16-2015, 07:20 AM

Quote:

Originally Posted by TheRealSy90

So what's the timing threshold in boost on e85, if 91 is around 8-9 degrees?

Also this is incorrect? From the fsm. Where I live it's between 60-120 year round.
http://i118.photobucket.com/albums/o...rtible/Oil.jpg

timing : i can't tell, it depends on many things.

As far as the oil go, i don't know what FSM you are talking about, but here is the S14 SR20DET one.
http://www.240edge.com/manuals/s14_sr20det.pdf

Look at page LC5 (numbered 122 in the pdf file)
oil pressure when hot at 3200 = 3.14 to 3.92bar, period. Chose you oil accordingly, if you need 10w50 to be in that window and don't live in a very hot country, you need a new oil pump.

Quote:

Originally Posted by civicej8

So just the mere fact I was running 5w30 in 90 degree weather resulted in worn bearings? I mean I understand that can happen. But in my opinion unless your really pushing the motor hard then I can see engine wear. A few wot pulls a day I couldnt see.

I guess the conclusion I'm going with is maybe my oil pressure was low causing bearing failure.

Im proly going to build the block and see how long the motor will last at 500whp. Then I'll go back to a ls1 if it doesn't stand up to it.

Sent from my SM-G925T using Tapatalk

If you didn't have the right oil pressure, then yes, it could, but it could be million of things as said before. Bad clearances, out of round crank and so on.

You won't see how long the motor will last because the transmission will be long gone at that power level. You will start breaking gearboxes from 350hp with sticky tyres, or even lower depending on how you drive the car.

You need a stronger gearbox. Easiest route is the Z32 gearbox conversion, but they are kind of old, crappy and have loooooooooooooooooong gearing ... Z33 conversion is much better in every aspect. But it is more expensive, and you will need some massaging work (with a bigass hammer) on the firewall and tunnel.
But it really is worth it. GB is very smooth, precise, supports high revs shifting, and has an interesting gearing.

civicej8 · 10-17-2015, 02:35 AM

Quote:

Originally Posted by Croustibat

timing : i can't tell, it depends on many things.

As far as the oil go, i don't know what FSM you are talking about, but here is the S14 SR20DET one.
http://www.240edge.com/manuals/s14_sr20det.pdf

Look at page LC5 (numbered 122 in the pdf file)
oil pressure when hot at 3200 = 3.14 to 3.92bar, period. Chose you oil accordingly, if you need 10w50 to be in that window and don't live in a very hot country, you need a new oil pump.

If you didn't have the right oil pressure, then yes, it could, but it could be million of things as said before. Bad clearances, out of round crank and so on.

You won't see how long the motor will last because the transmission will be long gone at that power level. You will start breaking gearboxes from 350hp with sticky tyres, or even lower depending on how you drive the car.

You need a stronger gearbox. Easiest route is the Z32 gearbox conversion, but they are kind of old, crappy and have loooooooooooooooooong gearing ... Z33 conversion is much better in every aspect. But it is more expensive, and you will need some massaging work (with a bigass hammer) on the firewall and tunnel.
But it really is worth it. GB is very smooth, precise, supports high revs shifting, and has an interesting gearing.

Thanks for your input bro. I think I've seen the z33/conv for 1300. Not sure how much it is. I know alot of people say this but I baby the car. That's why I was so surprised it failed lol.

I wish there were more people pushing good power with sr20s that lasted a while for them. For competition I mean go for the most reliable setup. But time attack cars like scorch s15 and motive s14 have been having good luck with them so hopefully they can stand up to the abuse.

2muchboost · 10-17-2015, 10:16 AM

Let me guess spun bearing on #3? If so there is a solid explanation for it as I have seen almost every SR with a spun bearing be piston 3 while drag racing.

civicej8 · 10-18-2015, 03:14 AM

Quote:

Originally Posted by 2muchboost

Let me guess spun bearing on #3? If so there is a solid explanation for it as I have seen almost every SR with a spun bearing be piston 3 while drag racing.

Not sure I haven't tore it down yet. I'll definitely update.

Sent from my SM-G925T using Tapatalk

codyace · 10-18-2015, 08:20 AM

Engine oil didn't hurt the engine

20 psi on a 30r did

It's stock junk, regardless of 'how it is tuned'. One little ping can ruin the day, or constant knock that you didn't (really, you can't hear in the car at speed if you're not trained) recognize smashed the rod bearings to smithereens (an already week item on these cars)

Nothing more, nothing else.

10-14-2015, 04:41 PM	#1
civicej8 Zilvia Junkie Join Date: Apr 2007 Location: las vegas Age: 35 Posts: 525 Trader Rating: (8) Feedback Score: 8 reviews	Why did my sr20 blow?? Need your opinions. Hey guys. Here's my setup: S13 sr20det.45k miles, Gt30r twin scroll at 19psi Arp studs Tomei gasket Setup was professionally tuned. Tune was verified to be running safely. I've had the setup running absolutely great for 3 weeks. Went to the track. Did one run, and there goes my rod bearings. Drained the oil, and found gold tint. So I know that it's the rod bearings. What I don't get is why did it ruin my bearings? Can knock kill a motor that fast. I was running about 19 on the fc when doing a wot pull. Oil pressure was great. It's now making me think that the sr20s physics just can't handle the pressure. Car ran perfect before.

10-14-2015, 10:24 PM	#2
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	Did you run a heavy weight oil and repeatedly bang 7200rpm? Or you had 15* btdc of timing at 18psi of boost, and it ate the rod bearings. Or it starved for oil, check if the oil pan is dented up into the pickup. In fact sometimes it completely falls off on redtops. You have to tear down and inspect for clues. Everybody knows you need an S14 bolt on pickup for the redtop- wheres yours? __________________ 5.3/4l80e/turbo 240sx playthrough: https://tinyurl.com/turbo240

10-15-2015, 05:14 AM	#11
jorge1190 Zilvia Junkie Join Date: Mar 2008 Location: Culpeper, Va Age: 30 Posts: 593 Trader Rating: (12) Feedback Score: 12 reviews	My stock rebuild SR made those power levels for like 2 years before blowing due to a boost controller malfunction. Why are you running 5w-30? __________________ 96 240sx S13 SR20 521 WHP 405 TQ

10-15-2015, 09:06 PM	#23
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,056 Trader Rating: (34) Feedback Score: 34 reviews	I run 15w-40 in my VET. I also live in a hot humid climate where those viscosities are acceptable. There's a multitude of reasons your motor could've popped. More than likely though, your motor was about to shit the bed anyway, the drag strip was just the final nail in the coffin. A tear down is in order to inspect everything. __________________ My SR20VET

10-15-2015, 09:27 PM	#24
cotbu Post Whore! Join Date: Sep 2005 Location: SWFL Age: 47 Posts: 3,318 Trader Rating: (3) Feedback Score: 3 reviews	I change oil viscosity and tunes, according to the weather! It's tear down season!!! Sent from a Highly Tuned Note 4.5!!! __________________ LoverTechnologies "Half Broken Things!"

10-14-2015, 11:07 PM	#4
civicej8 Zilvia Junkie Join Date: Apr 2007 Location: las vegas Age: 35 Posts: 525 Trader Rating: (8) Feedback Score: 8 reviews	And to add this was a strict street car. Didn't do any tracking with it. The metal in the oil was so small we needed a light to see the gold tint. Which to me means that maybe it was slowly degrading. Sent from my SM-G925T using Tapatalk

10-14-2015, 11:22 PM	#6
civicej8 Zilvia Junkie Join Date: Apr 2007 Location: las vegas Age: 35 Posts: 525 Trader Rating: (8) Feedback Score: 8 reviews	Ha-ha. Well. I meant before I went there lol. It was one 1/4 mile run. Just a plain run. And started hearing some ticking. That's it. Sent from my SM-G925T using Tapatalk

10-14-2015, 11:35 PM	#7
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	last piece of the puzzle. check your timing map for 14-15* btdc during boost.

10-15-2015, 04:25 AM	#9
Croustibat Nissanaholic! Join Date: Aug 2011 Location: France - Toulouse Age: 41 Posts: 1,851 Trader Rating: (0) Feedback Score: 0 reviews	Are you seriously asking why your engine blew ? On a forum ? Reminders : -we know absolutely nothing about your engine. Who built it, what machining was done, what parts are in. -what did you got "3 weeks ago" ? -stock SR20DET, 45k miles ? Sorry, i don't believe it. -gt30, 19psi, stock pistons ? Yup, PEBKAC. -we know absolutely nothing about how it was used, except it "was a strict street car until you decided to track it" which tells us... well, nothing. -do you have anything at all to monitor your engine ? like AFR gauge, EGT, fuel pressure ? So far it can range from clearance / machining error to PEBKAC.

10-15-2015, 07:14 AM	#12
Croustibat Nissanaholic! Join Date: Aug 2011 Location: France - Toulouse Age: 41 Posts: 1,851 Trader Rating: (0) Feedback Score: 0 reviews	19psi from a gt30 on stock bottom end is a bit asking for trouble. Stock pistons are weak on ringlands, they usually break there from very few det. If the bearings are gone and they have been done recently, then it is related to bad clearances. You won't know what has gone until you tear that engine down, so i suggest you start there. Maybe the oil pump got problems and the bottom end was starved, too.

10-17-2015, 10:16 AM	#28
2muchboost Nissanaholic! Join Date: Apr 2003 Location: Austin, TX Age: 37 Posts: 2,183 Trader Rating: (33) Feedback Score: 33 reviews	Let me guess spun bearing on #3? If so there is a solid explanation for it as I have seen almost every SR with a spun bearing be piston 3 while drag racing.

10-18-2015, 08:20 AM	#30
codyace Post Whore! Join Date: Dec 2004 Location: Poconos, PA Age: 36 Posts: 8,030 Trader Rating: (58) Feedback Score: 58 reviews	Engine oil didn't hurt the engine 20 psi on a 30r did It's stock junk, regardless of 'how it is tuned'. One little ping can ruin the day, or constant knock that you didn't (really, you can't hear in the car at speed if you're not trained) recognize smashed the rod bearings to smithereens (an already week item on these cars) Nothing more, nothing else. __________________ *Want Air Conditioning in your SR20 Swapped car? Check out www.sr20acbrackets.com for more information! Quest Alternator Conversions for SR20!* Check my Group Buy! Tired of lousy internal gates? Go external wastegate with one of my manifolds, Check out my group buy

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode