Blowed up the boosted 370ci!!!
Thread Starter
Joined: Dec 2009
Posts: 2,331
Likes: 29
From: Glennville, GA.
Blowed up the boosted 370ci!!! Hey guys i took a friend for a quick hit up the road last week, trip didnt end so well! On a 3rd gear pull heard motor let loose and blowed oil everywhere. Pulled over to see a dam fire burning under the hood. (oil and hot turbo piping dont mix) throwed dirt on the fire and managed to put it out. Only damage was my new painted hood! Sucks but it could have been worse! Thank god!
Anyways yesterday i finally got around to pulling engine. During inspection i noticed it busted the the #6 cylinder wall all to hell. Busted tht piston and broke tht rod. Damaged a couple other rods and pistons from all the crap bouncing around.
The #6 & #5 rod bearings had spun and looked the worse. #8 rod bearing looked bad as well. #3 main thrust looked pretty bad as well. Broke cam!
I built this engine and it seemed to be doing really well. Tune was a lil fat but safe. 16 psi boost.
Had 40psi hot idle oil psi and over 60psi wot.
Diamond pistons, lunati boosted i beam rods, stock crank, king hp main and rod bearings. All machine work done at local machine shop. I was spinning it to 7600rpm. Maybe tht could have been an issue?
Bearing clearance were .025 rods and .030 mains.
Whats your thoughts on what happined??? Motor made no indication of a problem. No knocks and good oil psi??? This has me a lil pissed with the money and time invested. Not to mention burning my truck!
Ill try and get some pics later of the damage.
Anyways yesterday i finally got around to pulling engine. During inspection i noticed it busted the the #6 cylinder wall all to hell. Busted tht piston and broke tht rod. Damaged a couple other rods and pistons from all the crap bouncing around.
The #6 & #5 rod bearings had spun and looked the worse. #8 rod bearing looked bad as well. #3 main thrust looked pretty bad as well. Broke cam!
I built this engine and it seemed to be doing really well. Tune was a lil fat but safe. 16 psi boost.
Had 40psi hot idle oil psi and over 60psi wot.
Diamond pistons, lunati boosted i beam rods, stock crank, king hp main and rod bearings. All machine work done at local machine shop. I was spinning it to 7600rpm. Maybe tht could have been an issue?
Bearing clearance were .025 rods and .030 mains.
Whats your thoughts on what happined??? Motor made no indication of a problem. No knocks and good oil psi??? This has me a lil pissed with the money and time invested. Not to mention burning my truck!
Ill try and get some pics later of the damage.
TECH Senior Member
Joined: Jun 2016
Posts: 22,295
Likes: 3,617
From: Central Cal.
Get the pics up and the internet experts will get right on it.
Seriously man, that's a bummer! Sounds like it was assembled right, so maybe a defective part (poor metallurgy, etc.).
Seriously man, that's a bummer! Sounds like it was assembled right, so maybe a defective part (poor metallurgy, etc.).
Thread Starter
Joined: Dec 2009
Posts: 2,331
Likes: 29
From: Glennville, GA.
Rings were gapped .28 top and .30 second
93 pump gas
AFR was around 10-10.5 at 16psi
12* timing
Br7ef plugs. Gapped around .28
I was still working on the tune up and was tryin to play it safe. I know the timing was safe, and the afr was a lil fat. I was workin on leaning it out etc.
Ive built alot of ls based setups over the years. Alot of them are sbe nitrous setups. This was my first time actually tryin to use good parts since im boosted. Ive bent rods with the sbe setups before under boost. So i wanted this motor right! Guess tht didnt happin! Motor had 3-400 miles on it. With the second oil change using rotella 10-40
Thread Starter
Joined: Dec 2009
Posts: 2,331
Likes: 29
From: Glennville, GA.
Its very possible. The broken rod looks like a limp noodle twisted all to hell. Rod cap come off and both rod bolts were in bottom of pan. The rod showed alot of heat on the big end! It definately spun looking at the bearings etc.
Block was hot tanked, honed, new cam bearings, line honed for arp main studs etc. I didnt cut no corners! Shitty luck!
Rings were gapped .28 top and .30 second
93 pump gas
AFR was around 10-10.5 at 16psi
12* timing
Br7ef plugs. Gapped around .28
I was still working on the tune up and was tryin to play it safe. I know the timing was safe, and the afr was a lil fat. I was workin on leaning it out etc.
Ive built alot of ls based setups over the years. Alot of them are sbe nitrous setups. This was my first time actually tryin to use good parts since im boosted. Ive bent rods with the sbe setups before under boost. So i wanted this motor right! Guess tht didnt happin! Motor had 3-400 miles on it. With the second oil change using rotella 10-40
93 pump gas
AFR was around 10-10.5 at 16psi
12* timing
Br7ef plugs. Gapped around .28
I was still working on the tune up and was tryin to play it safe. I know the timing was safe, and the afr was a lil fat. I was workin on leaning it out etc.
Ive built alot of ls based setups over the years. Alot of them are sbe nitrous setups. This was my first time actually tryin to use good parts since im boosted. Ive bent rods with the sbe setups before under boost. So i wanted this motor right! Guess tht didnt happin! Motor had 3-400 miles on it. With the second oil change using rotella 10-40
Thread Starter
Joined: Dec 2009
Posts: 2,331
Likes: 29
From: Glennville, GA.
Hmmm i was always under the assumption tht u wanted it a lil fat till u could get ahold of the tune up. A popped ring land is possible. Ill have to look the piston over. Would tht still eat the rod bearing up?? The bad cylinder was busted all to ****. Piston spun sideways with rod hung into the crank. Pretty bad carnage!
I have a ls1 bare block tht i could rebuild into something, but having the money i already spent down the drain has me worried! Wonder if i should just throw a sbe gen4 6.0 back in it. Turbo stuff is just hard on parts etc.
I have a ls1 bare block tht i could rebuild into something, but having the money i already spent down the drain has me worried! Wonder if i should just throw a sbe gen4 6.0 back in it. Turbo stuff is just hard on parts etc.
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Hmmm i was always under the assumption tht u wanted it a lil fat till u could get ahold of the tune up. A popped ring land is possible. Ill have to look the piston over. Would tht still eat the rod bearing up?? The bad cylinder was busted all to ****. Piston spun sideways with rod hung into the crank. Pretty bad carnage!
I have a ls1 bare block tht i could rebuild into something, but having the money i already spent down the drain has me worried! Wonder if i should just throw a sbe gen4 6.0 back in it. Turbo stuff is just hard on parts etc.
I have a ls1 bare block tht i could rebuild into something, but having the money i already spent down the drain has me worried! Wonder if i should just throw a sbe gen4 6.0 back in it. Turbo stuff is just hard on parts etc.
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Verdad Gallardo If I hit boost and see it dip into the tens I lift and get it right before I push it any further.
"Rod cap come off and both rod bolts were in bottom of pan"
What condition are the bolts in?
Broken? Bent?
What condition are the threads in?
What do the rod side threads look like?
What condition are the bolts in?
Broken? Bent?
What condition are the threads in?
What do the rod side threads look like?
Rich is not safe.
10.0 isn't just a lil rich.
I will be happy when the internet tuners will finally realize that. Nitrous guys say the same thing.
OP i'm not bashing you at all, please don't take it that way. What aggravates me is people unknowingly following bad advice by "run it rich, its safe" thinking they are doing the right thing, then blowing their **** up loosing thousands of dollars.
I hate to hear this happened. I'm glad you were able to put the fire out.
10.0 isn't just a lil rich.
I will be happy when the internet tuners will finally realize that. Nitrous guys say the same thing.
OP i'm not bashing you at all, please don't take it that way. What aggravates me is people unknowingly following bad advice by "run it rich, its safe" thinking they are doing the right thing, then blowing their **** up loosing thousands of dollars.
I hate to hear this happened. I'm glad you were able to put the fire out.
I went back and looked at some other posts after I posted. I didn't mean to repeat what already has been said but I am glad to see others have the same line of thinking.
OP,
Running it rich do get the tune dialed in is not the way to do it. Pull a **** ton of timing out(withing reason, you can go to low)and work on your fueling slowly. Don't start out going WOT to redline. With a turbo it's actually a little easier because you can either change springs or if you are using a boost controller it's even easier.
You will start to see a trend in fueling. What I mean is for every lb of boost your fueling is going to increase a certain percentage. After you figure that out you can safely build a fuel map into boost levels you haven't reached yet. So when you do get to that boost level your fueling is going to be close, yes you will have to fine tune it but it should be in the ball park.
After you map out all the fueling for your max boost level, THEN start adding timing.
Just my .02
OP,
Running it rich do get the tune dialed in is not the way to do it. Pull a **** ton of timing out(withing reason, you can go to low)and work on your fueling slowly. Don't start out going WOT to redline. With a turbo it's actually a little easier because you can either change springs or if you are using a boost controller it's even easier.
You will start to see a trend in fueling. What I mean is for every lb of boost your fueling is going to increase a certain percentage. After you figure that out you can safely build a fuel map into boost levels you haven't reached yet. So when you do get to that boost level your fueling is going to be close, yes you will have to fine tune it but it should be in the ball park.
After you map out all the fueling for your max boost level, THEN start adding timing.
Just my .02
We need to end this mind set of rich being ok. We need to always run the correct afr within a few tenths instead of shooting for a way rich afr thinking we are being safe. I’ve seen more people wash out rings on a brand new engine or lift rings from being way rich than people hurting engines from being lean because everyone thinks rich is safe.
If I hit boost and see it dip into the tens I lift and get it right before I push it any further.
If I hit boost and see it dip into the tens I lift and get it right before I push it any further.
I don't know what size turbo the OP has so 16 psi could be all over the map power wise but I bet the pistons/ringlands are fine. Rod bearing sounds like the culprit, which sucks but have seen it when they are put together a little too tight. What were tolerances on the bearings?
When you are running NA or low boost sure 10.x is fat but when you start pushing 20,25,30+ PSI on SBE stuff you are using the extra fuel to cool the cylinder a bit as well even if it sacrifices a little power. Even at higher power levels the extra fuel doesn't hurt anything so if you hurt something by brushing into the 10's AF then it was junk anyway. The extra fuel alone doesn't break it especially if you don't leave it there and its just a pass or two in tuning.
I don't know what size turbo the OP has so 16 psi could be all over the map power wise but I bet the pistons/ringlands are fine. Rod bearing sounds like the culprit, which sucks but have seen it when they are put together a little too tight. What were tolerances on the bearings?
I don't know what size turbo the OP has so 16 psi could be all over the map power wise but I bet the pistons/ringlands are fine. Rod bearing sounds like the culprit, which sucks but have seen it when they are put together a little too tight. What were tolerances on the bearings?
True I try to limit straight pump to 15 or so depending what it is. Haven't done 30 on 93 yet and don't plan to, but seen 20+ on pump with meth. Usually so timing limited on straight pump with higher boost that its not even worth it so throwing meth on is a quick and easy power bump. I still don't think meth would have saved this one, seems something else went awry.
I have as well. I pulled timing and still got it. Took fuel out then I was able to put the timing back and got no Kr. I haven’t tuned a bunch of different setups and each setup is different, but I’ve seen it more if too rich at lower rpms where above 6000 rpm doesn’t seem to mind as much.
Thread Starter
Joined: Dec 2009
Posts: 2,331
Likes: 29
From: Glennville, GA.
Ok guys thanks for all the advice. Really kinda glad we discussed alot of this stuff. Next time around ill be a lil more cautious with the tune up. Im still leaning toward the rod bearing being the issue tho.
Like i said all other bearings lookes ok. Im guessing bearings picked up some trash some where etc.
Clearancea were .025 rods. .030 mains. Turbo is a t6 billet s480 96 1.32ar. Power does some in hard!!!
Like i said all other bearings lookes ok. Im guessing bearings picked up some trash some where etc.
Clearancea were .025 rods. .030 mains. Turbo is a t6 billet s480 96 1.32ar. Power does some in hard!!!
You were certainly revving it pretty good so could have been a couple things at once or enough boost and rpm and fuel to just put it over the edge. I'm guessing no log when it happened?