Why #7?
04-06-2012, 03:22 PM
#101
That leads to the next issue of cooling.
A wise man once told me, keep the cylinders cool, and you'll keep the motor happy.
04-06-2012, 06:30 PM
#102
04-06-2012, 08:56 PM
#103
I was playing devil's advocate to him about the accesories and where he said #7 was. Is it a combination maybe so. I still don't think if you're running your rears blocked you're automatically going to blow your engine. If you have a competent tuner, the right heat range plug and the right octane fuel for the boost and compression you're running there should be no problem. I know this because I know of several boosted cars and nitrous cars without the rear steam ports vented that have been running fine for years now.
04-06-2012, 09:00 PM
#104
I know of plenty of cars that run with stock tunes on huge cams. Just because you do it and dodge the bullet does not mean its just never going to happen.
FYI on a dyno it has nothing to do with a tuner, as they are normally taken out of the equation.
You were wrong though, in your many tirades about it being just an f body motor turned on its axis. Its ok, it takes a bigger man to say he was wrong without giving excuses.
FYI on a dyno it has nothing to do with a tuner, as they are normally taken out of the equation.
You were wrong though, in your many tirades about it being just an f body motor turned on its axis. Its ok, it takes a bigger man to say he was wrong without giving excuses.
04-06-2012, 09:02 PM
#105
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So if the intake isn't the issue and fueling isn't the issue since it sounds like #7 can still go to hell even if the fuel enters the rails at the rear of the head. It sounds like cooling could be the culprit and venting the rear of the head could help. Is there any flaws in that observation? I'm all for doing what is necessary to make for a happy and longer lasting motor.
04-06-2012, 09:07 PM
#106
I believe that the best combo is a decent intake, a better set of rails than stock, fuel as cool as you can keep it, the water/vapor vent combo, good tune, good engine coolant temp, high quality oil, and maintenance of all the above.
PS even a small amount of scale buildup will dramatically decrease the cyls ability to shed heat. Not only does heat from the combustion event pass through the cyl walls to the coolant, but also to the oil as well and to the piston, cyl head, valves and the exhaust. So the better you can take that heat out, the better you are. Through the coolant or the oil. I like oil coolers on almost everything. There is a reason Gm puts them on the new camaro, and the vettes, but also a reason they put it on most every 3/4 ton and 1 ton vehicle regardless of what engine it has.
If coolant flow were not an issue, then GM never would have put a crossover tube on the LT1s either.
PS even a small amount of scale buildup will dramatically decrease the cyls ability to shed heat. Not only does heat from the combustion event pass through the cyl walls to the coolant, but also to the oil as well and to the piston, cyl head, valves and the exhaust. So the better you can take that heat out, the better you are. Through the coolant or the oil. I like oil coolers on almost everything. There is a reason Gm puts them on the new camaro, and the vettes, but also a reason they put it on most every 3/4 ton and 1 ton vehicle regardless of what engine it has.
If coolant flow were not an issue, then GM never would have put a crossover tube on the LT1s either.
04-07-2012, 04:09 AM
#110
I seen it several times a 20 to 30 degree drop from venting the rear cylinders. IMO thats enough to not even question to do it or not. I seen PPl run fast and there not vented. But if there is a drop in temp why not do it and save a little abuse on those cylinders.
04-07-2012, 05:47 PM
#111
I really said that an engine dyno rules the tuner out. Because they use a program that works on its own. I did not say engine, but honestly you should know the difference being that you are never wrong.
04-09-2012, 01:02 AM
#114
Most likely the Best we can do is prolong the cylinder/piston life. It will most likely be an unforeseeable flaw.
Mustangs, and other cars also have infamous cylinder/ringland failures from what I have read. I wondered for a lil while if it had anything to do with the single exhaust systems back-pressure causing temps on that side to sky rocket due to an uneven flow from both sides... I mean surely both sides cannot flow the same rate out when one is obviously always closer to the least path of resistance due to the stock single exhausts restrictive design. Makes me want to log those temps with guys running cutouts and TD's or dumped exhaust. I highly doubt that is the cause.
Plus the 05-06 goats and vettes are true dual so I dont see that really being a culprit. But to put the thought into perspective, This is Much like clogging up the vent on a clothes dryer only to have the element glow bright yellow instead of dull red, and short out due to extreme heat defecting the material. Maybe we are just putting in more heat than we can get out. Just my $0.02
So far though:
Run Cold Plugs
Equalizing air distribution would be technically impossible since it will still follow the path of least resistance despite what intake you choose.
Run E85/Meth Combo
Run Steam Vents
Distribute Even Fuel Pressure
and just hope for the best.
Mustangs, and other cars also have infamous cylinder/ringland failures from what I have read. I wondered for a lil while if it had anything to do with the single exhaust systems back-pressure causing temps on that side to sky rocket due to an uneven flow from both sides... I mean surely both sides cannot flow the same rate out when one is obviously always closer to the least path of resistance due to the stock single exhausts restrictive design. Makes me want to log those temps with guys running cutouts and TD's or dumped exhaust. I highly doubt that is the cause.
Plus the 05-06 goats and vettes are true dual so I dont see that really being a culprit. But to put the thought into perspective, This is Much like clogging up the vent on a clothes dryer only to have the element glow bright yellow instead of dull red, and short out due to extreme heat defecting the material. Maybe we are just putting in more heat than we can get out. Just my $0.02
So far though:
Run Cold Plugs
Equalizing air distribution would be technically impossible since it will still follow the path of least resistance despite what intake you choose.
Run E85/Meth Combo
Run Steam Vents
Distribute Even Fuel Pressure
and just hope for the best.
Last edited by I8UR4RD; 04-09-2012 at 01:12 AM.
04-09-2012, 01:32 AM
#115
At 9 lbs you doubtfully need the meth or e 85 honestly unless you run over 10.5 compression and a helluva lot of timing.
Exhaust happens in pulses, a clothes dryer does not pulse the air....unless you drive a Cube, in which case it looks like a Maytag anyway.
Exhaust happens in pulses, a clothes dryer does not pulse the air....unless you drive a Cube, in which case it looks like a Maytag anyway.
04-09-2012, 02:29 AM
#116
Oh boy here we go again.
Here is a picture of a LS4.
Looks to me like the #7 cyl is farthest from the person taking the picture on the far left.
Now you turn that motor 90* clockwise and tell me it isn't facing the same way a F-body or corvette does with the tb facing the radiator and not parallel to the radiator. It faces the same way.
Here is a picture of a LS4.
Looks to me like the #7 cyl is farthest from the person taking the picture on the far left.
Now you turn that motor 90* clockwise and tell me it isn't facing the same way a F-body or corvette does with the tb facing the radiator and not parallel to the radiator. It faces the same way.
here is the order:
Flywheel side
8 7
6 5
4 3
2 1
Crank pulley side
#7 is the bottom right on an LS4
Take this from an ASE Master Certified GM Technician.
Most people arent going to push an LS4 hard enough to every notice anything, so even talking about that motor doesnt get you anywhere.
and about the oil fill, the valve covers are switched. our passenger cover would be on the Front cyl head of the LS4.
Also notice the coolant temp sensor in the head. its in the same spot as an LS1. In the FRONT of the "Left" (drivers side) cylinder head.
04-09-2012, 02:46 AM
#117
Maybe you should read the thread again and once more before you go correcting this person as he has already been shown this multiple times. Does your ASE cert mean that you are able to not read the entire thread, skip to the end, and post the obvious and already rehashed problem?
04-09-2012, 04:53 PM
#118
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I like how it is mostly just accepted on here that the #7 issues is a coolant flow problem. A few people have real results that came to this conclusion. Then you have people reciting what that person posted like they've been there and done that.
I bet none of you would toast #7, spent a few grand rebuilding it exactly as it was, not touch or look at the tune, put it together, and go beat on the car.
Detonation is by FAR the contributing factor. Air/fuel distribution is not going to be perfect on these intakes. Tune it a little fat and not on the ragged edge of timing and octane requirements.
I went 2 years racing the hell out of my stock ls6 making 700+rwhp. Power never dropped off. Just a small puff of smoke indicating a little blowbye. Pistons looked great.
Now I have a budget 347 making 950rwhp/900rwtq on pump/meth. I don't have rear coolant passages.
I bet none of you would toast #7, spent a few grand rebuilding it exactly as it was, not touch or look at the tune, put it together, and go beat on the car.
Detonation is by FAR the contributing factor. Air/fuel distribution is not going to be perfect on these intakes. Tune it a little fat and not on the ragged edge of timing and octane requirements.
I went 2 years racing the hell out of my stock ls6 making 700+rwhp. Power never dropped off. Just a small puff of smoke indicating a little blowbye. Pistons looked great.
Now I have a budget 347 making 950rwhp/900rwtq on pump/meth. I don't have rear coolant passages.
04-09-2012, 06:16 PM
#119
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I bought the Kurt Urban coolant kit, I don't know if it's the fix but I do know purging the air and moving coolant in the back of the heads is a good thing.
04-09-2012, 06:21 PM
#120
No doubt detonation plays a role, but a major cause of detonation is excessive heat.
I really wish I still had my research journal from when I worked as a chemist at Sunoco. We had simulated combustion chambers that we could control the temperature very precisely as well as timing and AFR.
Ultimately, temperature had the largest impact on resistance to detonation, not timing and not AFR.
But I'm not an engine builder or tuner, nor do I have 1000 of passes at sub 7 seconds, but I do know how to make gasoline from crude and how they formulate everything from 87 to 116 octane gas.... at least I used to get paid to do that.
I really wish I still had my research journal from when I worked as a chemist at Sunoco. We had simulated combustion chambers that we could control the temperature very precisely as well as timing and AFR.
Ultimately, temperature had the largest impact on resistance to detonation, not timing and not AFR.
But I'm not an engine builder or tuner, nor do I have 1000 of passes at sub 7 seconds, but I do know how to make gasoline from crude and how they formulate everything from 87 to 116 octane gas.... at least I used to get paid to do that.