Drilling holes in head gaskets = more flow = lower temps: Change My Mind!

[Walter R. Malik]

Adam, BillK stated the Facts very well and RCJ brings up a good point, the Hottest area is between the two center Exhaust ports, and plumbing water from the water pump to each Head or engine Block directly below the two ports is a good move . Mark H.

That gasket in the photo is already different than the GM gasket and has been manufactured to even out the water temperatures in the cylinder head. Only SOME gaskets have that center hole and only SOME blocks and heads have it also. Be certain that all 3 have that water hole ... and actually block the front most little hole.

[Robban 54]

There must be a difference if you have an original water pump or for example an edelbrock with a 3.5 inch impeller then there must be flow to supply larger holes in the cylinder head gasket.

20150924_193737_resized.jpg

[swampbuggy]

Yes ^^^^^^^^^^^^^^^^^^^^^^^^ .

[swampbuggy]

The yes above was meant for Joes remarks at the bottom of page 1, sorry about that Chief . Mark H.

[swampbuggy]

Robban54 you are probably correct in your thinking, and a water flow restrictor in place of the T-Stat might well become more effective or needed with a large increase in volume . Mark H.

[PackardV8]

Yer, Chevrolet worked it out after several decades, that's how we got the reverse cooling system LT1.

Get enough capacity and air to keep the old girls around 180 degrees and you may not pass an emissions test but it'll go forever without needing crazy 24psi caps or anything stupid to stop steam pockets.

Pick your hole size and quantity.

FWIW, reverse-flow cooling was about the last hurrah for iron heads on GM V8s. To combine high compression, cheap iron, pass emissions, the engineers spent thousands of hours of design and dyno time and there was even a lawsuit from John Evans, who claimed his idea was stolen by GM.

Evans had figured out that the solution involved placing a small-diameter venting hole in the cylinder head, instead of the thumb-sized vents suggested by conventional wisdom. “It was counterintuitive,” he told Fortune. “Everyone else was using a big hole, figuring it would allow more vapor to escape faster. I made it smaller, and it worked.”

The issue in that case stems from charges that General Motors is guilty of stealing a trade secret from John Evans, of Evans Cooling Systems. In the long and complex dispute, GM recently admitted that a key document was falsified and the case has turned toward whether the company owes Mr. Evans $612 million in damages, or much less.

According to a written account supplied by Mr. Evans that details his claims, sometime in the 1980s GM learned about a non-aqueous (water free) reverse-flow, liquid cooling system he invented, and invited him to Detroit in1989. They were considering using the system in their 1992 model Corvette.

Before he went out, GM also asked him to bring a non-patented reverse-flow, water-based system he had devised. Reverse-flow cooling isn't new, and, in fact, it was pointed out in court that GM filed a patent for such a system in 1928.

The problem was that no one had figured out how to make it work as well as theoretically possible. Mr. Evans' secret, a venting system, enabled the aqueous cooling system to work, thereby allowing more horsepower, lower emissions, fewer engine problems and higher fuel economy. It also allowed for a reduced engine height for a sleeker hood line.

Understanding the value of his invention, Mr. Evans agreed to allow GM to test it if he could have an assurance that the corporation wouldn't look at how it worked. In the automotive industry, that's called a "black box" consideration, which means the car is locked and the hood is down during testing.

GM engineers were under tremendous pressure to make their own aqueous water-cooling system work by May of 1989, according to Mr. Evans's attorney, Frank Porcelli of Fish & Richardson in Boston, who said the company had plans to use it in an engine they dubbed the Gen II, which would be installed in their next generation of Camaro and Corvette models. Some $58 million had been slated for the cars' development, Mr. Porcelli claimed.

On March 16, 1989 GM ran a test on its version of the reverse-flow engine, according to court documents. The test simulated driving up a hill at 50 miles per hour in second gear. It took one minute for GM's engine to fail.

The same test was conducted on Mr. Evans' engine two weeks later. This time, the car stopped after 20 minutes, "not because there was anything wrong intrinsically with the cooling system, but because of the hook-up General Motors had required Evans to make," Mr. Porcelli noted in a Jan. 23 court hearing.

It was supposed to be a one-day test, but GM asked him to leave the car overnight, saying there was a problem with the results, Mr. Porcelli said.

"When they put their … [car] in a hot tunnel and … after one minute it overheated and failed, and it was two weeks later that they asked Mr. Evans, you know, 'Leave your-leave your car [with the un-patented vent system in it] overnight. Don't worry. It will be locked.' and they broke in," Mr. Porcelli said at the hearing.

In the morning, Mr. Evans learned that someone had been in the test area overnight, but he was told it was just for routine maintenance. "He believed them because he trusted them," commented Mr. Porcelli in a recent interview.

Mr. Evans was unaware until 1991 that GM engineers had investigated his technology. That fall, a magazine, announced GM's new Gen II engine. "Its most noteworthy feature was its reverse-flow aqueous cooling system," according to the account Mr. Evans provided. "Evans immediately knew from reading the article that he had been tricked."

He applied for a patent, which was granted in 1993, and then filed two lawsuits against GM in 1994.The second su it, for theft of trade secrets, has been ongoing for nine years, and is only now heading toward its conclusion.

FWIW, they still ran them as hot as Mobil 1 would tolerate; the fan switch didn't trigger until the coolant hit 230 degrees.

[Robban 54]

In a sbc I think it is almost impossible to get too much flow.
The more flow, the more even the temperature.
If it gets too cold, put in a thermostat.
I have thought about having the water flow at maximum without regulation and controlling the temperature by regulating the air flow through the cooler, but have not thought of a good method to do that.

[Robban 54]

When driving slowly, just start and stop the electric fan. But at 60 mph you have to throttle the air flow. With some kind of damper.

[RCJ]

Do away with the tstat housing and run 2 lines off the heads to the radiator. Flow is good ,high boiling point too but you have to get a tempature drop a cross the radiator. Air flow is key to getting the Temps down but bad for downforce

[NewbVetteGuy]

When driving slowly, just start and stop the electric fan. But at 60 mph you have to throttle the air flow. With some kind of damper.

Modern OEM-style electrically operated grills that can be opened / closed dynamically and controlled by the ECU?


Adam

[NewbVetteGuy]

Thanks folks!

This was honestly a rhetorical question and one that I run into every once-in-a-while and I didn't see a good discussion thread here on ST addressing the "just drill all the head gasket holes as big as possible" idea directly.

Good to just see everyone's thinking and honestly, fun to play devi's advocate sometimes.

Adam

[RCJ]

In reference to controlling air flow thru the radiator. Put the fans at the front of a duct . When you don't want air flow run the fans in reverse. Don't know if it would work but I was watching in car video of Jimmy Johnson flipping switches on the straightaway and this ideal came to me.

[NewbVetteGuy]

In reference to controlling air flow thru the radiator. Put the fans at the front of a duct . When you don't want air flow run the fans in reverse. Don't know if it would work but I was watching in car video of Jimmy Johnson flipping switches on the straightaway and this ideal came to me.

But grill shutters not only control air-flow through the radiator / could be a control point for engine heat, but also improve aerodynamics. Both seem useful at highway cruise for MPG gains, anyway which is where my thinking goes.


Adam

[NewbVetteGuy]

Yer, Chevrolet worked it out after several decades, that's how we got the reverse cooling system LT1.

Get enough capacity and air to keep the old girls around 180 degrees and you may not pass an emissions test but it'll go forever without needing crazy 24psi caps or anything stupid to stop steam pockets.

Pick your hole size and quantity.

FWIW, reverse-flow cooling was about the last hurrah for iron heads on GM V8s. To combine high compression, cheap iron, pass emissions, the engineers spent thousands of hours of design and dyno time and there was even a lawsuit from John Evans, who claimed his idea was stolen by GM.

Evans had figured out that the solution involved placing a small-diameter venting hole in the cylinder head, instead of the thumb-sized vents suggested by conventional wisdom. “It was counterintuitive,” he told Fortune. “Everyone else was using a big hole, figuring it would allow more vapor to escape faster. I made it smaller, and it worked.”

The issue in that case stems from charges that General Motors is guilty of stealing a trade secret from John Evans, of Evans Cooling Systems. In the long and complex dispute, GM recently admitted that a key document was falsified and the case has turned toward whether the company owes Mr. Evans $612 million in damages, or much less.

According to a written account supplied by Mr. Evans that details his claims, sometime in the 1980s GM learned about a non-aqueous (water free) reverse-flow, liquid cooling system he invented, and invited him to Detroit in1989. They were considering using the system in their 1992 model Corvette.

Before he went out, GM also asked him to bring a non-patented reverse-flow, water-based system he had devised. Reverse-flow cooling isn't new, and, in fact, it was pointed out in court that GM filed a patent for such a system in 1928.

The problem was that no one had figured out how to make it work as well as theoretically possible. Mr. Evans' secret, a venting system, enabled the aqueous cooling system to work, thereby allowing more horsepower, lower emissions, fewer engine problems and higher fuel economy. It also allowed for a reduced engine height for a sleeker hood line.

Understanding the value of his invention, Mr. Evans agreed to allow GM to test it if he could have an assurance that the corporation wouldn't look at how it worked. In the automotive industry, that's called a "black box" consideration, which means the car is locked and the hood is down during testing.

GM engineers were under tremendous pressure to make their own aqueous water-cooling system work by May of 1989, according to Mr. Evans's attorney, Frank Porcelli of Fish & Richardson in Boston, who said the company had plans to use it in an engine they dubbed the Gen II, which would be installed in their next generation of Camaro and Corvette models. Some $58 million had been slated for the cars' development, Mr. Porcelli claimed.

On March 16, 1989 GM ran a test on its version of the reverse-flow engine, according to court documents. The test simulated driving up a hill at 50 miles per hour in second gear. It took one minute for GM's engine to fail.

The same test was conducted on Mr. Evans' engine two weeks later. This time, the car stopped after 20 minutes, "not because there was anything wrong intrinsically with the cooling system, but because of the hook-up General Motors had required Evans to make," Mr. Porcelli noted in a Jan. 23 court hearing.

It was supposed to be a one-day test, but GM asked him to leave the car overnight, saying there was a problem with the results, Mr. Porcelli said.

"When they put their … [car] in a hot tunnel and … after one minute it overheated and failed, and it was two weeks later that they asked Mr. Evans, you know, 'Leave your-leave your car [with the un-patented vent system in it] overnight. Don't worry. It will be locked.' and they broke in," Mr. Porcelli said at the hearing.

In the morning, Mr. Evans learned that someone had been in the test area overnight, but he was told it was just for routine maintenance. "He believed them because he trusted them," commented Mr. Porcelli in a recent interview.

Mr. Evans was unaware until 1991 that GM engineers had investigated his technology. That fall, a magazine, announced GM's new Gen II engine. "Its most noteworthy feature was its reverse-flow aqueous cooling system," according to the account Mr. Evans provided. "Evans immediately knew from reading the article that he had been tricked."

He applied for a patent, which was granted in 1993, and then filed two lawsuits against GM in 1994.The second su it, for theft of trade secrets, has been ongoing for nine years, and is only now heading toward its conclusion.

FWIW, they still ran them as hot as Mobil 1 would tolerate; the fan switch didn't trigger until the coolant hit 230 degrees.

Wow! Incredible historical context.

According to Stewart components, a big issue with reverse cooling is that IF you DO get steam formation, the steam wants to rise but a reverse cooled SBC tries to send the coolant from high to low, so steam is problematic.

I'll have to go dig through my notes, but I think Stewart even put a "degrees fahrenheit temp reduction at the head" number on reverse cooling and it wasn't much... Like 2-3 degrees F if my memory is correct.

My thinking is that reverse cooling in an SBC NEEDS coolant conditions in which boiling / steam formation isn't going to happen, so waterless coolant makes sense then, but then waterless coolant itself is going to INCREASE head temps because of it's lower thermal capacity -then you need lots more flow to make up for the reduce thermal capacity and that coolant is MORE viscous, so, why not just use a high flow, regular cooling path high water race-style cooling setup?

Waterless coolant makes no sense to me if lower temps are the goal. Reverse coolant makes no sense unless you have a good and simple way to avoid any steam pockets (maybe low coolant temps and high pressures from a good pump are "good enough" mitigation).


Adam

[PackardV8]

Reverse coolant makes no sense unless you have a good and simple way to avoid any steam pockets (maybe low coolant temps and high pressures from a good pump are "good enough" mitigation). Adam

Yes, No, Maybe. All we know for certain is of all the fixes available to them, GM engineers chose reverse flow cooling as the best solution.