Headlift -- sleeved and non-sleeved engines
04-11-2006, 05:17 PM
#41
yes already figured out a way to stiffen the cylinders without needing sleeves, and how to do the larger headstuds. got a blown block we have been messing with. i hate to pull mine apart seeing nice weather start to come around, but i know it is inevitable. will be doing these mods to my motor.
04-11-2006, 05:41 PM
#42
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Originally Posted by chimmike
what fans are you running? Believe it or not, these can play a big part as well. a pair of high cfm fans can make a big difference.
04-11-2006, 05:43 PM
#43
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Originally Posted by Yancy
I believe Gman and overZealous are non-sleeved, correct?
Originally Posted by Yancy
If the motor is sleeved, would the same issue arise (if that is what the issue is)?
04-11-2006, 05:44 PM
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I have also speculated on the cooling system, but even with the upgraded radiator everyone is having problems. The coolant channels being too close to the cylinder wall is an interesting theory.
Phunk - your AEBS sleeved motor eliminates the cooling channels all together, right? Do you think you were seeing headlift, a blown headgasket or cooling issues?
Phunk - your AEBS sleeved motor eliminates the cooling channels all together, right? Do you think you were seeing headlift, a blown headgasket or cooling issues?
04-11-2006, 05:49 PM
#45
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Originally Posted by t32gzz
I have also speculated on the cooling system, but even with the upgraded radiator everyone is having problems.
Maybe the upgraded radiators that everyone is using aren't effective enough for our needs?
04-11-2006, 07:19 PM
#47
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I think there is some confusion here...
Let's define a few things:
HEADLIFT: the cylinder heads are seperating, ever so slightly from the block, the pressure from inside the cylinders slips past the cylindersurface and gets into the neighboring coolant channels, this pressurizes the cooling system..this is not a cooling system problem, this is a problem where two closed environments interfere...
the culprits:
head gasket failure; the gasket material weakens allowing combustion chamber gasses to overflow into the coolant channels, thus pressurizing the cooling system
head stud stretching; the studs elongate and allow the cylinder heads to lift, now the seal between the heads and the block are compromised- leading the abovementioned scenario
cylinder failure; the cylinders drop/distort and now again, the mating surface between the heads and the block is compromised
DETONATION: this will increase the likelihood of all of the abovementioned scenarios
So, a larger radiator/upgraded cooling system will help lower temps, helping to raise the threshold for detonation, but in the case of cylinder headlift, the cooling system is not the problem, the clamping load applied to the heads is issue.
Let's define a few things:
HEADLIFT: the cylinder heads are seperating, ever so slightly from the block, the pressure from inside the cylinders slips past the cylindersurface and gets into the neighboring coolant channels, this pressurizes the cooling system..this is not a cooling system problem, this is a problem where two closed environments interfere...
the culprits:
head gasket failure; the gasket material weakens allowing combustion chamber gasses to overflow into the coolant channels, thus pressurizing the cooling system
head stud stretching; the studs elongate and allow the cylinder heads to lift, now the seal between the heads and the block are compromised- leading the abovementioned scenario
cylinder failure; the cylinders drop/distort and now again, the mating surface between the heads and the block is compromised
DETONATION: this will increase the likelihood of all of the abovementioned scenarios
So, a larger radiator/upgraded cooling system will help lower temps, helping to raise the threshold for detonation, but in the case of cylinder headlift, the cooling system is not the problem, the clamping load applied to the heads is issue.
04-11-2006, 07:49 PM
#49
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Originally Posted by 350zDCalb
I think there is some confusion here...
Let's define a few things:
HEADLIFT: the cylinder heads are seperating, ever so slightly from the block, the pressure from inside the cylinders slips past the cylindersurface and gets into the neighboring coolant channels, this pressurizes the cooling system..this is not a cooling system problem, this is a problem where two closed environments interfere...
the culprits:
head gasket failure; the gasket material weakens allowing combustion chamber gasses to overflow into the coolant channels, thus pressurizing the cooling system
head stud stretching; the studs elongate and allow the cylinder heads to lift, now the seal between the heads and the block are compromised- leading the abovementioned scenario
cylinder failure; the cylinders drop/distort and now again, the mating surface between the heads and the block is compromised
DETONATION: this will increase the likelihood of all of the abovementioned scenarios
So, a larger radiator/upgraded cooling system will help lower temps, helping to raise the threshold for detonation, but in the case of cylinder headlift, the cooling system is not the problem, the clamping load applied to the heads is issue.
Let's define a few things:
HEADLIFT: the cylinder heads are seperating, ever so slightly from the block, the pressure from inside the cylinders slips past the cylindersurface and gets into the neighboring coolant channels, this pressurizes the cooling system..this is not a cooling system problem, this is a problem where two closed environments interfere...
the culprits:
head gasket failure; the gasket material weakens allowing combustion chamber gasses to overflow into the coolant channels, thus pressurizing the cooling system
head stud stretching; the studs elongate and allow the cylinder heads to lift, now the seal between the heads and the block are compromised- leading the abovementioned scenario
cylinder failure; the cylinders drop/distort and now again, the mating surface between the heads and the block is compromised
DETONATION: this will increase the likelihood of all of the abovementioned scenarios
So, a larger radiator/upgraded cooling system will help lower temps, helping to raise the threshold for detonation, but in the case of cylinder headlift, the cooling system is not the problem, the clamping load applied to the heads is issue.
If the symptoms are similar to common coolant issues where bubbles or air can get trapped into the system, people will automatcially assume that thier coolant issues are related to head lift instead of thinking to replace a faulty radiator cap or bleed the system.
The only way to actually know that headlift is occuring is if you have noticable amounts of coolant spewing out of any possible place due to the pressure from the combustion chambers entering the coolant path as 350zDCalb has previously mentioned.
Anyway, it seems that the only real solution to this using the stock block would be to utilize larger head steads like previously mentioned. An upgraded radiator or any other sort of upgraded cooling system wouldn't neccessarily do a better job at keeping the head mated to the block.
Nissan obviously didn't have any plans to FI this motor, otherwise you'd see a closed deck design similar to the RB26 so my guess is if larger head studs don't work, sleeving along with those larger headstuds would be my option.
Stretching an ARP headstud sure isn't an easy thing to accomplish.
Sharif: Are you experiencing head lift? If so have you checked your ARP head studs to see whether or not they have shown any signs of stretching? If they haven't stretched, the only sensible possibility would be that the open deck design of the VQ35 just can't handle detonation at higher levels of power without sleeves. It seems like it's not the acutal cylinder integrity, but the upper part of the sleeves that would benefit have a larger surface area to mate with the head opposed to the stock thinner walled cylinder design.
04-12-2006, 02:20 AM
#50
Originally Posted by tvieira24
What I meant is the fact that some of the symptoms you mentioned were fairly similar to air getting sucked into the coolant system and causeing dead spots/bubbles in the coolant system, thus affecting the heat inside the cabin as well as the engine overheating.
If the symptoms are similar to common coolant issues where bubbles or air can get trapped into the system, people will automatcially assume that thier coolant issues are related to head lift instead of thinking to replace a faulty radiator cap or bleed the system.
The only way to actually know that headlift is occuring is if you have noticable amounts of coolant spewing out of any possible place due to the pressure from the combustion chambers entering the coolant path as 350zDCalb has previously mentioned.
Anyway, it seems that the only real solution to this using the stock block would be to utilize larger head steads like previously mentioned. An upgraded radiator or any other sort of upgraded cooling system wouldn't neccessarily do a better job at keeping the head mated to the block.
Nissan obviously didn't have any plans to FI this motor, otherwise you'd see a closed deck design similar to the RB26 so my guess is if larger head studs don't work, sleeving along with those larger headstuds would be my option.
Stretching an ARP headstud sure isn't an easy thing to accomplish.
Sharif: Are you experiencing head lift? If so have you checked your ARP head studs to see whether or not they have shown any signs of stretching? If they haven't stretched, the only sensible possibility would be that the open deck design of the VQ35 just can't handle detonation at higher levels of power without sleeves. It seems like it's not the acutal cylinder integrity, but the upper part of the sleeves that would benefit have a larger surface area to mate with the head opposed to the stock thinner walled cylinder design.
If the symptoms are similar to common coolant issues where bubbles or air can get trapped into the system, people will automatcially assume that thier coolant issues are related to head lift instead of thinking to replace a faulty radiator cap or bleed the system.
The only way to actually know that headlift is occuring is if you have noticable amounts of coolant spewing out of any possible place due to the pressure from the combustion chambers entering the coolant path as 350zDCalb has previously mentioned.
Anyway, it seems that the only real solution to this using the stock block would be to utilize larger head steads like previously mentioned. An upgraded radiator or any other sort of upgraded cooling system wouldn't neccessarily do a better job at keeping the head mated to the block.
Nissan obviously didn't have any plans to FI this motor, otherwise you'd see a closed deck design similar to the RB26 so my guess is if larger head studs don't work, sleeving along with those larger headstuds would be my option.
Stretching an ARP headstud sure isn't an easy thing to accomplish.
Sharif: Are you experiencing head lift? If so have you checked your ARP head studs to see whether or not they have shown any signs of stretching? If they haven't stretched, the only sensible possibility would be that the open deck design of the VQ35 just can't handle detonation at higher levels of power without sleeves. It seems like it's not the acutal cylinder integrity, but the upper part of the sleeves that would benefit have a larger surface area to mate with the head opposed to the stock thinner walled cylinder design.
the stock cylinder walls still create a decent coolant surface. the stock casting creates a solid brace across the block at roughly 1.5"-2" down. that is still a touch below where most of your cylider pressure will happen. the stock cooling passages are designed to only put water above this 1.5-2" point.
i have found a very good and easy way to simulate more head bolts, but i really hope the point is not mute.
my own car is sitting in the garage with the overflow tank bubbling!!! i know it is because of lack of water in the coolant passages. i have some very good ideas to help fix this, but i think i am going to take a different angle of attack than just the heads lifting.
04-12-2006, 03:47 AM
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Originally Posted by Gman2004
stock fans
I hope you're joking man! You spend all that money on a rad, breather tank, and cap, and you're using low-flow stock fans?
Seriously, and I mean ASAP, buy a pair of high flow slim fans. You'll end up thanking me, I think.
04-12-2006, 04:32 AM
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Originally Posted by chimmike
I hope you're joking man! You spend all that money on a rad, breather tank, and cap, and you're using low-flow stock fans?
Seriously, and I mean ASAP, buy a pair of high flow slim fans. You'll end up thanking me, I think.
Seriously, and I mean ASAP, buy a pair of high flow slim fans. You'll end up thanking me, I think.
04-12-2006, 04:36 AM
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the point I am making is once the coolant and water cannot dissipate the heat anymore it can not cool down and then starts to boils over into the overflow tank. If this is the case sleeves or longer bolts is not going to help.
beastie most people are using the stock headgasket, but I think with all future builds most people are going with the cometic.
beastie most people are using the stock headgasket, but I think with all future builds most people are going with the cometic.
04-12-2006, 05:21 AM
#54
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Originally Posted by Gman2004
I didn't know there were made for our cars yet. The last time I saw a post about flex lite fans was when MIA was telling everyone to call them so they would see people were interested and make them.
Universals work just fine man. www.summitracing.comI'd get a pair ASAP if I were you. I'd be willing to bet you'll see a difference.
04-12-2006, 05:42 AM
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According to SGP when the system is bled correctly the headlift issues go away. If this is true there may not be head lift at all.
At this point we are all speculating what the cause of the overflowing coolant is. We have seen it on sleeved motors, non-sleeved motors, those with Cometic HG's and those with Cometic HG's. No one has actually seen signs that the studs have stretched at all.
My point is just to let the opinions flow freely and don't shoot them down. One person may solve this with larger head studs, copper o-ringed HG's, a new cooling system or some other resolution, but until someone can prove that one or all of these methods will solve the problem, we are all in the same place.
I am listening to all schools of thought and waiting for the outcome.
At this point we are all speculating what the cause of the overflowing coolant is. We have seen it on sleeved motors, non-sleeved motors, those with Cometic HG's and those with Cometic HG's. No one has actually seen signs that the studs have stretched at all.
My point is just to let the opinions flow freely and don't shoot them down. One person may solve this with larger head studs, copper o-ringed HG's, a new cooling system or some other resolution, but until someone can prove that one or all of these methods will solve the problem, we are all in the same place.
I am listening to all schools of thought and waiting for the outcome.
04-12-2006, 06:06 AM
#56
Todd is on the right track here. If your car overheats, but nothing else occurs..no air in the cooling system...etc...then you are simply overtaxing your current cooling system. From experience, when engines overheat to 230F+, its usually a result of blowing combustion gases through the head gasket, and into the cooling system under heavy boost or load. The cooling system is a close system, so barring any obvious leaks in the system, if air is introduced into the cooling system, it can only be coming from one place. Bingo: The combustion chamber gases. This is confirmed by the immediate overheating of the engine, and a loss of in cabin heat through the vents. An upgraded radiator cap, radiator, high flow fan, etc..will NOT improve this situation. Of course, if you overheat your coolant, and it simply burps out through the radiator cap, then you will need to replace the coolant that left the system.
Darton sleeved blocks have been showed to reduce the chances of headlift, but not completely eliminate it past 750whp. Upgrading studs, and upgraded gaskets should completely solve this problem to 800whp. Beyond that, nobody has tested this on a street car...so I am sure we'll find some other hurdle at some point.
One last morsel of food for thought. All engine produces two things: Heat, and torque. Depending on how the engine is tuned, it could very well produce a lot of HEAT, but not a lot of power. Or, it can produce a LOT of power, and far less heat. All depends on how the car is setup and tuned.
Darton sleeved blocks have been showed to reduce the chances of headlift, but not completely eliminate it past 750whp. Upgrading studs, and upgraded gaskets should completely solve this problem to 800whp. Beyond that, nobody has tested this on a street car...so I am sure we'll find some other hurdle at some point.
One last morsel of food for thought. All engine produces two things: Heat, and torque. Depending on how the engine is tuned, it could very well produce a lot of HEAT, but not a lot of power. Or, it can produce a LOT of power, and far less heat. All depends on how the car is setup and tuned.
04-12-2006, 06:37 PM
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Originally Posted by failsafe306
Just as you posted earlier, once the coolant soaks up all the heat it can, it'll just start to overheat. I can't imagine your heads lifting at that level. Or even at your high hp level, provided you give it time to cool down between runs.
It happened to me today. I was racing someone at 16psi. The water temps started getting hot so I lowered it to 10psi and let it cool down. I continued at 10psi but the water temps started rising again. I then set it 5.5psi, but the water temps kept raising if I beat on it.
It's a good thing I have the defi meter gauges with alarms cause it's hard to keep your eyes on the gauges when you are doing 130mph.
The alarms arleted me at 230 degees and I let off. After that the temp went down to 190.
Last edited by Gman2004; 04-12-2006 at 06:40 PM.
04-12-2006, 06:44 PM
#60
Originally Posted by Gman2004
What does it mean when your water temp starts to rise on repeated abuse at only 5.5psi? Are my heads lifting?