blow by
TECH Enthusiast
Joined: Feb 2020
Posts: 734
Likes: 209
Ok , that was a good test. Of course you know it's going to have to come apart , as to the cause should maybe label and send out the injectors to be flowed - that may or may not be the problem but I wouldn't risk another engine on that
I would redo cylinder 7 and any of the other ones that read good to confirm 7 is really that far off. Throw a teaspoon of oil in the cylinder and see if it gets better. Also buy a cheap borescope off Amazon that hooks to your phone and put it in the spark plug hole and see if you see damage.
My 434 does this just about as bad, as does my brothers 6liter I built for him, both have breathers setup on vented catch cans. All the research I’ve done on this indicates that it’s the ethanol in the fuel (both pump 93 here) causing this steam. I’ve found a good bit of info on this subject.
Definitely get those injectors checked, might want to re-evaluate your engine builder too.
Thread Starter
Teching In
Joined: Nov 2012
Posts: 21
Likes: 1
I had pat g hook me up with a driveability tune when the ls3 had a stock bottom end, I didnt change anything else as far as mods, so I kinda assumed it would be fine. It ran pretty good with the tune it had, soo I never really thought about data logging. Would have been a good idea too.
I had pat g hook me up with a driveability tune when the ls3 had a stock bottom end, I didnt change anything else as far as mods, so I kinda assumed it would be fine. It ran pretty good with the tune it had, soo I never really thought about data logging. Would have been a good idea too.
I run ethanol and have both valve covers and valley cover vented to atmosphere I get a lot of steam and have water dripping out the exhaust until I'm warmed up every time I start the car. It was kind of freaky at first.
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Verdad Gallardo I had pat g hook me up with a driveability tune when the ls3 had a stock bottom end, I didnt change anything else as far as mods, so I kinda assumed it would be fine. It ran pretty good with the tune it had, soo I never really thought about data logging. Would have been a good idea too.
A bad flowing set of injectors will absolutely cause a lean condition but my gut says you have an engine builder problem since it happened on #7.
I'd get a second opinion, have your mechanic pull the long block and take it unopened to a builder you trust or that is highly recommended by performance guys.
Seen plenty of "pro builders" fully **** up a forged engine with incorrect tolerances.
Thread Starter
Teching In
Joined: Nov 2012
Posts: 21
Likes: 1
Yeah it’s looking like it’s gonna be awhile before we get there. I think my mechanic is real busy I haven’t gotten a good answer on when to drop off the ride yet. Idk when it will happen, it’s hard to find good builders to trust here in San Antonio. I’m tempted just taking the car to whoever pat g recommends and let them handle it. From there it can go straight to pats dyno to get a full tune session.
I’m not saying it’s a tuner issue. I’m saying no matter how good the tuner is I wouldn’t drive a new motor 3 months with a base tune without ever logging to verify everything looks good.
I don’t care how good the tuner is putting a base tune on a new boosted motor is never as good as logging to verify and tweaking everything to make sure it’s dead on fueling with no knock. This includes reading plugs to verify.
If only number 7 lifted the ring lands how do we know it was the builder and not lean on that cylinder? We never checked plugs to see if they all looked the same and safe?
Im having a hard time blaming the builder when it was driven 3 months without being tuned on pump gas. Unless there is more found then just lifted ringlands on 7.
too many unknowns after building a new motor with the base tune from a previous motor to not log and verify. We don’t know if compression ratio was changed which would be huge on a boosted pump gas motor. We don’t know if an injector was clogged because we never checked plugs and even a wide band on a bank may not show that. Too many variables and I don’t care how good the tuner was that put the base tune on the PREVIOUS motor.
I don’t care how good the tuner is putting a base tune on a new boosted motor is never as good as logging to verify and tweaking everything to make sure it’s dead on fueling with no knock. This includes reading plugs to verify.
If only number 7 lifted the ring lands how do we know it was the builder and not lean on that cylinder? We never checked plugs to see if they all looked the same and safe?
Im having a hard time blaming the builder when it was driven 3 months without being tuned on pump gas. Unless there is more found then just lifted ringlands on 7.
too many unknowns after building a new motor with the base tune from a previous motor to not log and verify. We don’t know if compression ratio was changed which would be huge on a boosted pump gas motor. We don’t know if an injector was clogged because we never checked plugs and even a wide band on a bank may not show that. Too many variables and I don’t care how good the tuner was that put the base tune on the PREVIOUS motor.
Last edited by BCNUL8R; Apr 13, 2021 at 10:53 AM.
I’m not saying it’s a tuner issue. I’m saying no matter how good the tuner is I wouldn’t drive a new motor 3 months with a base tune without ever logging to verify everything looks good.
I don’t care how good the tuner is putting a base tune on a new boosted motor is never as good as logging to verify and tweaking everything to make sure it’s dead on fueling with no knock. This includes reading plugs to verify.
If only number 7 lifted the ring lands how do we know it was the builder and not lean on that cylinder? We never checked plugs to see if they all looked the same and safe?
Im having a hard time blaming the builder when it was driven 3 months without being tuned on pump gas. Unless there is more found then just lifted ringlands on 7.
too many unknowns after building a new motor with the base tune from a previous motor to not log and verify. We don’t know if compression ratio was changed which would be huge on a boosted pump gas motor. We don’t know if an injector was clogged because we never checked plugs and even a wide band on a bank may not show that. Too many variables and I don’t care how good the tuner was that put the base tune on the PREVIOUS motor.
I don’t care how good the tuner is putting a base tune on a new boosted motor is never as good as logging to verify and tweaking everything to make sure it’s dead on fueling with no knock. This includes reading plugs to verify.
If only number 7 lifted the ring lands how do we know it was the builder and not lean on that cylinder? We never checked plugs to see if they all looked the same and safe?
Im having a hard time blaming the builder when it was driven 3 months without being tuned on pump gas. Unless there is more found then just lifted ringlands on 7.
too many unknowns after building a new motor with the base tune from a previous motor to not log and verify. We don’t know if compression ratio was changed which would be huge on a boosted pump gas motor. We don’t know if an injector was clogged because we never checked plugs and even a wide band on a bank may not show that. Too many variables and I don’t care how good the tuner was that put the base tune on the PREVIOUS motor.
Thread Starter
Teching In
Joined: Nov 2012
Posts: 21
Likes: 1
Ok fellas quick update, had the car taken to the shop. They confirmed by compression test cylinders 3,5,7 were low and 7 being the lowest. They used a borescope and said their is some glazing on the cylinder walls. They were also concerned with the ring gap, soo they verified with wiseco and they said my ring gap is way too wide. Soo now we are going to pull the motor, and send back to the machine shop and re ring the pistons. Hopefully no damage done to pistons or cylinders will keep yall posted.