Forced Induction and #7 Faliure...
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Forced Induction and #7 Faliure... I know this has been discussed time and time again but I couldn't find any of the threads addressing the common #7 piston failure with forced induction LS motors.
A few reasons for the failure that I have heard are:
-Intake manifold design hitting the rear cylinders with more air
-Stock fuel rails starving the rear cylinders
-Using the steam vent block offs on the rear of the cylinder heads instead of the crossover setup
I think I remembered reading that a company with a engine dyno tested the intake manifold theory by turning it around to see if the EGT's on cylinders #7 & #8 changed. I can't remember what the outcome was though....
I would like to hear what you guys think is causing the problem is and what the best remedies are.
A few reasons for the failure that I have heard are:
-Intake manifold design hitting the rear cylinders with more air
-Stock fuel rails starving the rear cylinders
-Using the steam vent block offs on the rear of the cylinder heads instead of the crossover setup
I think I remembered reading that a company with a engine dyno tested the intake manifold theory by turning it around to see if the EGT's on cylinders #7 & #8 changed. I can't remember what the outcome was though....
I would like to hear what you guys think is causing the problem is and what the best remedies are.
Last edited by Turbo 6.0; Dec 19, 2010 at 09:38 PM.
Nope, I have broken #7s on just high CR H/C cars.... Pretty sure its the steam vents, I am going to make a cool cross over, and run it under the Vic Jr up to the front, then out to the rad or pump not too sure yet..
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So how does one remedy the steam tube block offs while running an ls6 intake?
I heard that you can just run line to the top of the radiator at the overflow tube but I am not sure on that...
I heard that you can just run line to the top of the radiator at the overflow tube but I am not sure on that...
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this is what i was thinking too. i am trying to find pic of it already done.
I know this has been a concern on first generation small block motors as well. I run a high performance 400 small block in my 1955 Chevy. I tied the front head water inlets to the rear with hoses that run parallel to the valve covers. This is supposed to get more of the cooler water back to the rear of the block.
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With a Magnacharger they don't give you much room in the back to deal with anything like that. I'm building a 415 with a Maggie pushing 10Lbs and 10:5:1 compression. kinda concerned about this happening with L92 heads. Do any of you guys have a custom design to get around the back of the Maggie and tie it back into the front vents or something like that?
Evans has helped big time with redesign on there water pump as well. It redirects more flow to that side and has a 40% volume increase. Any High HP motor I have used one on has never had an issue. Even in road race cars.
) Kurt sells a nice kit that allows you to go around the intake for those running the LS6, LS2, LS7, FAST, etc with no room underneath. If you are running a sheetmetal or cast carb intake, you should just run the 98-00 crossover tube that ties the corners together as there is plenty of room underneath. The LS1 intake is not the answer.
That Evans **** is down right nasty. I mean that in the worst possible way. The cooling system must be completely void of all water/coolant before you put it in. It is EXTREMELY expensive, so be sure that you don't have to drain it for any reason because if you do, you will likely want to catch it. That's when you'll discover how it is impossible to get off anything that it touches. And last but not least, the track guys LOVE cleaning that **** up off the track and I mean that in the most sarcastic way possible. Oh and then there is the psychological impact that it actually raises your coolant temps so you just have to come to terms with the fact that it's better for the engine despite the fact that it reads hotter on the gauge.
That Evans **** is down right nasty. I mean that in the worst possible way. The cooling system must be completely void of all water/coolant before you put it in. It is EXTREMELY expensive, so be sure that you don't have to drain it for any reason because if you do, you will likely want to catch it. That's when you'll discover how it is impossible to get off anything that it touches. And last but not least, the track guys LOVE cleaning that **** up off the track and I mean that in the most sarcastic way possible. Oh and then there is the psychological impact that it actually raises your coolant temps so you just have to come to terms with the fact that it's better for the engine despite the fact that it reads hotter on the gauge.
I wonder if there could be two approaches to this problem? The Urban steam setup and modifications to get more cool coolant to the back of the motor? Do iron block LS motors also have problems with the back cylinders?
^^^^Evans dont make a electric. besides that it is proven most electric pumps from less then stock.
i have built a lot of rear coolant cross over tubes. and never had an insue with 7 or 8. i will post some pictures later.
thanks
i have built a lot of rear coolant cross over tubes. and never had an insue with 7 or 8. i will post some pictures later.
thanks
only thing i didnt like about Kurts that it isnt the best for stock style intakes. it problay works,but ... Now if i had a single plan it would be great. but i dont.
Besides buying a 01-02 front cross over and putting it in the rear. then y-ing the two together. cost less then 200. and works great on stock stlye intakes.
Besides buying a 01-02 front cross over and putting it in the rear. then y-ing the two together. cost less then 200. and works great on stock stlye intakes.
Kurt sells a nice kit that allows you to go around the intake for those running the LS6, LS2, LS7, FAST, etc with no room underneath. If you are running a sheetmetal or cast carb intake, you should just run the 98-00 crossover tube that ties the corners together as there is plenty of room underneath. The LS1 intake is not the answer.
That Evans **** is down right nasty. I mean that in the worst possible way. The cooling system must be completely void of all water/coolant before you put it in. It is EXTREMELY expensive, so be sure that you don't have to drain it for any reason because if you do, you will likely want to catch it. That's when you'll discover how it is impossible to get off anything that it touches. And last but not least, the track guys LOVE cleaning that **** up off the track and I mean that in the most sarcastic way possible. Oh and then there is the psychological impact that it actually raises your coolant temps so you just have to come to terms with the fact that it's better for the engine despite the fact that it reads hotter on the gauge.
That Evans **** is down right nasty. I mean that in the worst possible way. The cooling system must be completely void of all water/coolant before you put it in. It is EXTREMELY expensive, so be sure that you don't have to drain it for any reason because if you do, you will likely want to catch it. That's when you'll discover how it is impossible to get off anything that it touches. And last but not least, the track guys LOVE cleaning that **** up off the track and I mean that in the most sarcastic way possible. Oh and then there is the psychological impact that it actually raises your coolant temps so you just have to come to terms with the fact that it's better for the engine despite the fact that it reads hotter on the gauge.
I was mistaken they dont make an electric but they do make a conventional pump.