F/I Blowing motors facts

[SPCorBUST]

Not sure about anybody else, but I'm on to a new build. My first built motor didn't go kaboom but it was on its way out due to a suspected fueling issue. I was using a slightly modified OTS tune. (won't be doing that again)

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Paraphrasing from my builder:

The bore in cyl #1 was .005 out of round. The bore in cyl #2 was .001 out of round. There were "eye brows" at the tops of the cylinder where the most heat and pressure are applied. (It takes an enormous amount of pressure (and heat) to out of round the cylinder)

The rod bushings in cyl #1 and #2 were also pounded flat, most likely from detonation, hence the suspected fueling issue, which could either be a failing or failed direct injector seal contributing to the fueling issue (lean and detonation).

The piston skirts were collapsed and a couple thousandths out of round.

The piston rings were loose in the pistons. There was up and down play. Also there was no spring tension in the rings anymore, the cause of low compression and increased oil consumption.

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Anyhoo, new built motor will be similar, but using Outfront's closed deck, different head gaskets, 1/2" ARP studs, and back to a custom dyno tune, will do several sessions so its safe. Should be ready in a few weeks.

[CSG Mike]

Originally Posted by DarkPira7e

INSANE necro thread revival. I wonder how much our understanding of this has improved? My ostentatious logic says that a large contributor to this is from load on the rods. Turbo tends to pile on low end load quickly, as torque comes in much harder and faster than on most supercharger types people are running on this platform. Also, people who put load on at low RPM (lugging the engine WOT at 2,000RPM) are going to stress the rods a lot more than those who are softer with their input.

Just wanted to open this up for discussion again, as after reading this thread, I feel more success and more failure has been had. Any good experiment's data has a large test pool, right? Too bad we have no control..

I've been daily driving this the past month, and have put 18 track days on it since it's been turboed last November.

Still on the stock engine.

[DarkPira7e]

Originally Posted by CSG Mike

I've been daily driving this the past month, and have put 18 track days on it since it's been turboed last November.

Still on the stock engine.

My point exactly; I think it's something that is more reliant on an understanding of the dynamics of the power delivery. Certainly you're not doing uphill pulls in 5th at 2100 RPM. It's under those conditions I think that people are most likely to see the rods' weakness and not realize what they're doing is very harmful.

SPCorBUST, thank you for the information! it's information like this that I thought would be a good reason to bring this back from the dead and see how much more we know / can theorize.

[SPCorBUST]

Originally Posted by DarkPira7e

My point exactly; I think it's something that is more reliant on an understanding of the dynamics of the power delivery. Certainly you're not doing uphill pulls in 5th at 2100 RPM. It's under those conditions I think that people are most likely to see the rods' weakness and not realize what they're doing is very harmful.

SPCorBUST, thank you for the information! it's information like this that I thought would be a good reason to bring this back from the dead and see how much more we know / can theorize.

No worries. Certainly there are people like Mike beating the piss out of this motor and it doesn't blow. You've got to account for that experience, but on the other hand, the first motor blew from a stop at <5 mph (and no, it wasn't lugged) and this last time, I drove it gently save <10 canyon days, and still blew a motor. This is including the other early 2013 motor fixes and some other precautionary measures I took. So, two different parts of the spectrum there. From my experience, user error (e.g. lugging) or something like lack of care is plausible, but not always the case. There are mechanical reasons why these motors can fail that are outside of user involvement and even tuning. (other builders have detailed some of these reasons) In my case, user error/care would be a laughable explanation.

Some details: motor lasted 7.2k miles, 3k of which were in a no-WOT break-in period, 5W-40 Motul 300V every 1500 miles, E85 only during this period but SeaFoam every oil change, ran an OTS tune with slight mods. JR oil cooler. No launches. Zero track days.

[gtengr]

Originally Posted by DarkPira7e

My point exactly; I think it's something that is more reliant on an understanding of the dynamics of the power delivery. Certainly you're not doing uphill pulls in 5th at 2100 RPM. It's under those conditions I think that people are most likely to see the rods' weakness and not realize what they're doing is very harmful.

Yep, oil pressure is rpm dependent, yet the engine can produce close to peak cylinder pressure at low/mid rpm's. The oil film provides a small cushion between the rod and rod bearing, and if there's enough cylinder pressure to compromise the oil film then the result is the metal-on-metal contact, and a sharp increase of compression force in the rod. I would like to know what the rod bearings look like in the blown engines, especially those that were run hard without an oil cooler and/or 0-w20.

[SPCorBUST]

Originally Posted by gtengr

Yep, oil pressure is rpm dependent, yet the engine can produce close to peak cylinder pressure at low/mid rpm's. The oil film provides a small cushion between the rod and rod bearing, and if there's enough cylinder pressure to compromise the oil film then the result is the metal-on-metal contact, and a sharp increase of compression force in the rod. I would like to know what the rod bearings look like in the blown engines, especially those that were run hard without an oil cooler and/or 0-w20.

Scary. Hopefully that is... Noone.

[CSG Mike]

Originally Posted by gtengr

Yep, oil pressure is rpm dependent, yet the engine can produce close to peak cylinder pressure at low/mid rpm's. The oil film provides a small cushion between the rod and rod bearing, and if there's enough cylinder pressure to compromise the oil film then the result is the metal-on-metal contact, and a sharp increase of compression force in the rod. I would like to know what the rod bearings look like in the blown engines, especially those that were run hard without an oil cooler and/or 0-w20.

The CSG BRZ (2014) ran almost exclusively 0W20 (with an oil cooler), and saw nearly 700 track sessions.

[CSG Mike]

Originally Posted by DarkPira7e

My point exactly; I think it's something that is more reliant on an understanding of the dynamics of the power delivery. Certainly you're not doing uphill pulls in 5th at 2100 RPM. It's under those conditions I think that people are most likely to see the rods' weakness and not realize what they're doing is very harmful.

SPCorBUST, thank you for the information! it's information like this that I thought would be a good reason to bring this back from the dead and see how much more we know / can theorize.

Even, NA, you shouldn't be flooring it at those RPMs to be nice to the engine!

That being said, I have a pretty good feel for how my engine likes things, and once its warmed up, going WOT at 2500rpm is okay, at 2000 its not happy.

[SPCorBUST]

Originally Posted by CSG Mike

The CSG BRZ (2014) ran almost exclusively 0W20 (with an oil cooler), and saw nearly 700 track sessions.

Was it a built motor? I think he was curious about those specifically, but it was not mentioned. Could be wrong though.

[CSG Mike]

Originally Posted by SPCorBUST

Was it a built motor? I think he was curious about those specifically, but it was not mentioned.

100% oem parts, but re-assembled to CSG tolerances.

[gtengr]

Originally Posted by CSG Mike

The CSG BRZ (2014) ran almost exclusively 0W20 (with an oil cooler), and saw nearly 700 track sessions.

Point taken. I would never do that myself though (on 0w20), and it may speak more to your sense of when things are getting too hot than it does about whether or not running 0-w20 for extended sessions on boost is ideal. Either way, you had an oil cooler, and the number of trashed engines with much less than 700 sessions leaves a lot of questions.

[CSG Mike]

Originally Posted by gtengr

Point taken. I would never do that myself though (on 0w20), and it may speak more to your sense of when things are getting too hot than it does about whether or not running 0-w20 for extended sessions on boost is ideal. Either way, you had an oil cooler, and the number of trashed engines with much less than 700 sessions leaves a lot of questions.

Most recently, I saw a rant about a guy who autox'd his car for 5 years, and eventually spun a bearing. Subaru told him to pound sand.

Even if AutoX classing doesnt' allow for it, any car driven hard should have an oil cooler to extend the life of the engine.

The CSG BRZ was tracked in temps north of 120F at times (CA tracks are in the desert), without issue. Preventative maintenance and modification is key.

[Deep Six]

Amazing how some motors just keep on chugging under very harsh conditions. I now have blown motor #2 thanks to a rocker arm failure. This was a fresh block, forged rods and pistons, 11.5 :1 , JRSC 90mm pulley with the rev limiter set at 7K, all the fuel upgrades, fresh 5w30 Castrol Syntech and JR oil cooler. Motor was built local in Orlando by well respected shop and I watched the assembly so I know what went in. Tuning was specifically modified for the 90mm pulley by again a very well respected local tuner. The passenger side head is total carnage with a hole in the cover and the rod from cylinder #1 busted through the top of the block. This happened at Sebring approaching the hairpin.
Pretty much made up my mind that I will be going with an LS swap next as I can't see rolling the dice with another FA20.

[amcp1]

Thats slightly aggravating. What yr was the motor? The 2015+ motors have changes made that may or may not have helped.