LML with a blown motor

minerigger

Active member
Dec 24, 2013
2,660
1
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Casper, WY
50,000 miles on my built motor. Lived its entire life at 700rwhp and I'm not nice to it. Keep the torque out of it down low and it'll live.



They crack them more often than you'd think.
I Like your truck Chris. Does that as you call it "375" have just as many miles as the motor?
 

MAXX IT OUT

<<<IT WORKS
Mar 1, 2013
1,780
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48
Des Moines, Iowa
LmL' s are a lot less likely to crack pistons than previous models.......but just speculation at this point

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They don't crack as often as LBZ's, just because there are less of them on the road with higher miles and abuse compared to a truck that 4 years older. Most of them crack around 200K on a mostly stock tow rig.
 

Digmax

Member
Jan 23, 2016
289
2
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Didn't know that..... wonder y gm would have changed them up?

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DMAXchris

It’s only temporary!
Apr 28, 2009
2,273
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38
44
Natrona Heights PA
I Like your truck Chris. Does that as you call it "375" have just as many miles as the motor?

Technically It has more. Lol. It lived life for an entire pulling season on Girls Night Out @ high 900s in 2011. Its six years old and has very little shaft play. Super impressed with this turbo.

Its a 475, but Bullseye called their t4 475 a 375 for some odd reason for a few years.
 

Digmax

Member
Jan 23, 2016
289
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I was told an lml had better piston cooling than earlier models due to larger oil pump......not sure if that's true?

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Brshan01

New member
Aug 19, 2013
55
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Zimmerman, MN
Cracked piston sounds about right but I'm no engine builder. I know it had enough pressure to blow the cap off the oil fill tube and shit all over the turbo.

Truck just turned 100k miles, I think it was around 103,000.
 

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Digmax

Member
Jan 23, 2016
289
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Yea prob cracked...... ever tow heavy on a big tune with that 475?

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Hoffie

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Mar 10, 2015
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Far East LA - aka Phoenix
Eek! Here, I was upset that my radiator blew out on me last night 2000 miles away from home. My repair only cost me $1000 for a new radiator and t-stats installed. I am definitely keeping my motor stock. Just turned 464,115 miles on it.
 

Digmax

Member
Jan 23, 2016
289
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Eek! Here, I was upset that my radiator blew out on me last night 2000 miles away from home. My repair only cost me $1000 for a new radiator and t-stats installed. I am definitely keeping my motor stock. Just turned 464,115 miles on it.


All original?

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MAXX IT OUT

<<<IT WORKS
Mar 1, 2013
1,780
37
48
Des Moines, Iowa
I was told an lml had better piston cooling than earlier models due to larger oil pump......not sure if that's true?

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They do have a bigger oil pump, I am not sure how much and I don't if they have larger oil squirters to flow more oil or if they are the same ones as the earlier engines.
 

Brshan01

New member
Aug 19, 2013
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Zimmerman, MN
Not on a big tune, I always set it on a tow tune whenever I hooked up a trailer unless it was just getting moved in the yard. I dumped the compound kit because I kept blowing Intercooler boots while towing, cracked the stock Intercooler, and popped the HG's. Drive pressure was maxing out my pressure sensor at 100psi on the compounds also.

I have a 10k lb max weight bumper pull toy hauler 29' and took it from MN to CO for a track day and concert on the compounds, I lost about 5 silicone boots on that trip all on the driver side of the charge system. I was tired of workin on the truck so Jags recommended I swap to the 369 to simplify it and drop the drive pressure while still keeping the power and reliability.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
They do have a bigger oil pump, I am not sure how much and I don't if they have larger oil squirters to flow more oil or if they are the same ones as the earlier engines.

more oil wont do much if the temp doesnt stay under control. im curious what oil temps LMLs see towing heavy in heat

Not on a big tune, I always set it on a tow tune whenever I hooked up a trailer unless it was just getting moved in the yard. I dumped the compound kit because I kept blowing Intercooler boots while towing, cracked the stock Intercooler, and popped the HG's. Drive pressure was maxing out my pressure sensor at 100psi on the compounds also.

I have a 10k lb max weight bumper pull toy hauler 29' and took it from MN to CO for a track day and concert on the compounds, I lost about 5 silicone boots on that trip all on the driver side of the charge system. I was tired of workin on the truck so Jags recommended I swap to the 369 to simplify it and drop the drive pressure while still keeping the power and reliability.

drive pressure should have never been that high on a compound setup unless you were pushing 90-100psi of boost. i sounds like you had some tuning or hard part issues playing a roll in this engine going up in smoke
 

Digmax

Member
Jan 23, 2016
289
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Wow 100 psi...... ive never blown a boot off got 25000 on mine since install honestly haven't touched it..... but still stock injectors. Was your vain position at 0 percent at wot? With 475?

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Digmax

Member
Jan 23, 2016
289
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Chevy 1925 Not sure on oil temp on lml but I'm about to find out. I do know that the water temp stays down a lot better. So oil should be some better anyway

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Brshan01

New member
Aug 19, 2013
55
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Zimmerman, MN
James - drive pressure went down to 60psi max after the 369 went in, not sure if that tells you anything else... I suppose the stock turbo may have been gummed up? It's still sitting on the floor in my shop.

The injectors were stock but I had a 10mm cp3 and transmission before I installed the s475/stock kit. Also had a billet wheel from SDP on the 475.

Rough history of the truck and tuning purchased May of 2012 400 miles on the clock.
700miles DPF delete and HS tuning and lift pump/sump
60k miles PPEI tuning
65k miles EGR delete 10mm CP3 install
69k transmission
Not sure when I put in the s475 but I'd say roughly 78k
98k s369, 40% over injector, manifolds/ups, head studs and new gaskets

Just got a call from Josh at Jags and he said it looks like a cracked piston, it's on the schedule for start of next week. He's pretty proud of these LML blocks from past experiences and doesn't seem to have a problem standing behind a 2yr warranty with its current setup so I guess I'm going to have them rebuild "mild build" then run it for 2 more years before I look at selling it.
 

S Phinney

Active member
Aug 15, 2008
4,008
18
28
Quncy, Fl
You can build it to be reliable without a doubt. It us a matter of money and the right man doing the work. The cheapest way will be going back stock. To be reliable you would spend around 15k on the build without any fueling,turbo or head (port work) changes. Did you change up pipes when you did the turbo?

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Brshan01

New member
Aug 19, 2013
55
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Zimmerman, MN
Up pipes and manifolds were done 4K miles ago with the s369 install. At this point I'm waiting for the shop to pull the motor and take it apart. Based on their findings we will determine where to go with the build. I'm going to keep it as cheap as possible without cutting any corners and still maintaining their 2yr warranty. After the 2yrs are up I'll probably dump the truck for something new and stock.