Head gasket water passages

[GTM]

Hi all:

I've been noticing over the years they keep making the water passages smaller and smaller through the head gasket so that this is the major restriction.

Does anyone have any information on why this is happening besides for smog control? And what harm if those passages are opened up to match the head openings?

Cheers,
GTM

 

[Defiant]

Well, I don't know that it has anything to do with smog, but I do know if you open them up, you'll have faster coolant travel through those passages, and that's not always a good thing. You need the coolant to stick around so that it can absorb the best amount of heat, and my money's with them knowing what they're up to in those fancy offices.

Just as you can overheat an engine by running with no thermostat and no restrictor, you'd have the same effect in the head.

 

[GTM]

Originally posted by Defiant
Well, I don't know that it has anything to do with smog, but I do know if you open them up, you'll have faster coolant travel through those passages, and that's not always a good thing.

You need the coolant to stick around so that it can absorb the best amount of heat, and my money's with them knowing what they're up to in those fancy offices.
Just as you can overheat an engine by running with no thermostat and no restrictor, you'd have the same effect in the head.

I have written gasket makers and performance builders about this and no replies. Maybe they consider it propietatary info and think I'm some spy...

Engines are running hotter than ever before, pressure caps no longer at 7lbs but now 15lbs, higher t'stat temps, just try to find a 170 degree tstat. My guess it's an effort to raise the cylr head temp where they can get better burn in the lean environment. Looking at gaskets of 20 years ago they had water passages big enough to put you index finger through, now they are maybe 4, 1/4" holes for each cylinder which doesn't compute if you are trying to keep the engine cool.

I've been interested in that statement that water can flow too fast through a radiator for a lot of years. I don't know where it comes from and I've never seen it in print. The rules of physics do not support this for water because it's viscosity does not change with heat. I do know that turbulance is going to mix temps better in a turbulance induced oil cooler but not for water. I also know that in the case of a radiator the faster the water flows the the smaller the boundry layer exists. Switching to air for a moment we know the lamanar flow is much closer to sides of a rocket or space shuttle at high speeds, well the same exists in fluid dynamics. Now you get it out of the engine faster at a lower temp, you have reduced the boundry layer through the radiator by speeding it up.

Yes their are thing that can influence it like a water pump cavitating or a fluidic valve effect where the heater flow can stall the flow and make it inefficient but I've not see this since the early '70s.

The increase in hp demands a larger radiator for they didn't give you an overkill but you can't blame that on increasing the water flow speed. I see how much owners are wanting to make this mod or that mod to get more power but nobody says you just increased the HP 25% you will need to open up the head gasket water passages.

There is only so much heat excange for a finite amount of air which you have not increased speed flowing over the fins or increased the area if you have increased HP. Radiators have gotten smaller, engine temps hotter suppose there is a relationship... The white shirts are calculating what's the smallest radiator we can fit so it costs us the least while establishing we can run it this hot.

I've not looked at any of the trick head gaskets to see if they have enlarged water passages but it's my guess they have.

Cheers,
GTM

 

[Defiant]

Originally posted by GTM
I have written gasket makers and performance builders about this and no replies. Maybe they consider it propietatary info and think I'm some spy...

Well, WE all think you are.

Engines are running hotter than ever before, pressure caps no longer at 7lbs but now 15lbs, higher t'stat temps, just try to find a 170 degree tstat. My guess it's an effort to raise the cylr head temp where they can get better burn in the lean environment.

I tend to agree. Then again, compare the radiator in a DSM with that out of a Jaguar E-Type, or a Healey Six. And you couldn't get those to run if it was more than 70° out.

Looking at gaskets of 20 years ago they had water passages big enough to put you index finger through, now they are maybe 4, 1/4" holes for each cylinder which doesn't compute if you are trying to keep the engine cool.

Any energy you throw out the tailpipe or the cooling system is heat that's not moving the car.

I've been interested in that statement that water can flow too fast through a radiator for a lot of years. I don't know where it comes from and I've never seen it in print. The rules of physics do not support this for water because it's viscosity does not change with heat.

I think it's more a matter of steam pockets than viscosity. Once you get a pocket next to a plug boss or valve guide, it's tough to make calm back down. The heat localizes and tends to feed on itself.

I also know that in the case of a radiator the faster the water flows the the smaller the boundry layer exists.

You also have to figure in dwell time. Less exposure = less heat transferred.

Yes their are thing that can influence it like a water pump cavitating or a fluidic valve effect where the heater flow can stall the flow and make it inefficient but I've not see this since the early '70s.

Maybe that's why things are done differently today.

I've not looked at any of the trick head gaskets to see if they have enlarged water passages but it's my guess they have.

I'd be keen to know.

 

[Groomz]

I can already tell that I'm outgunned, but I'll throw in anyway. Cars today versus 30 years ago have become much better at control coolant temps and overall engine temperature fluctuations which leads to longer engine life, more precise tolerences and more consistent power. With cars being controlled by computers more and more ( and encroaching on the real driving experience too ) car manufacturers might be thinking that they can get away with a hotter running car only because it has a virtual nanny to make sure nothing bad happens if something does get hot ( like a limp-mode found on Ford V8s and other vehicles ). Civics have tiny little radiators because they know that their customers won't be taking their cars to peak power all the time. Cars like the MKIV Supra are incredible because of how over engineered/overbuilt they are, as apposed to Honda motors which have small radiators and weak rods, not to mention free floating cylinder liners ( thats not the technical term for it ). I guess my point is that more cooling can't be a bad thing.

Nice thread.

 

[GTM]

Originally posted by Defiant
Well, WE all think you are.I tend to agree. Then again, compare the radiator in a DSM with that out of a Jaguar E-Type, or a Healey Six. And you couldn't get those to run if it was more than 70° out.

Oh now you hit several sore spots. I sometimes feel more like an alien when trying to decipher some of these posts.

Dear lord you just had to bring up the Healey-6. I was working for Peter Satori in Pasadena before I tranfered to the Rolls shop when those things came out. I became the specialist on keeping them running and I got paid for my work. It was that damned car where I learned to grind a V notch in the t'stat and several other tricks. Actually the E type wasn't nearly as bad but remember I think we still had the basic speed law and owners would try to make the Las Vegas run to LA in under 5 hours. Someone would convince them to install Champion spark plugs recommended from Champion's book. Don't know where they did their testing but it wasn't So.Ca in the middle of summer. I also don't know how many engines they bought but it sure was a good number. I'm not knocking the company or their product just don't use the wrong heat range on a high compression Jag head.

I'll get back to the other points, someone else is knocking.

Cheers,
GTM

 

[GTM]

Originally posted by Groomz
I can already tell that I'm outgunned, but I'll throw in anyway.
...
not to mention free floating cylinder liners ( thats not the technical term for it ). I guess my point is that more cooling can't be a bad thing.

Aw, don't let a couple old farts intimidate you.

I liked the "nanny" image. Just like they took away the tool kits too.

Do you mean wet liners with "O" rings top and bottom?

Certainly having the capacity to cool beyond their current design limits needs to be re-evaluated. They give us plastic tanks, single tube radiators, and make like it's something special when you ask for a 2 tube and 3 they never heard of.

They have done their math on a sun mainframe carried out to 9 places and that should tell you something. It's all number cruntching based on how many times you sneezed today to project time lost from work. Detroit has always had the ability to build anything they want and that's just what they did.

Cheers,
GTM

 

[GTM]

Originally posted by Defiant

...
I think it's more a matter of steam pockets than viscosity. Once you get a pocket next to a plug boss or valve guide, it's tough to make calm back down. The heat localizes and tends to feed on itself.Maybe that's why things are done differently today.I'd be keen to know.

Er, um, not sure I'm following the logic that by making the water passages smaller in the head gasket it's going to get rid of steam pockets. Yes, raising the rad. cap pressure from 7 to 15 lbs will allow the engine to run about 50 degree HOTTER before it boils and or develop the steam pockets if they exist. Flooding the head with cold water most certainly will cool the surronding area including the hot spots.

Sand castings can be trickey business but the Japaneese have done a supurb job of perfecting the casting process even better than the Italians. I have almost never seen inclusions or voids in any of their castings so tend to discount they suffer from hot spots.

I have seen them in other cars for they leave pock marks from the constant bumping (when a steam bubble starts to form and the surrounding water is too cold to support it's formation it will collapse so rapidly and with such violence it will break off molecules of the surrounding metal). Sometime those heads can never be trusted so become scrap. To prevent some scrapper from selling as a good used head we would take a hammer to them so there was no way they could ever be sold except for melt down.

Those that were salvagable would be hot tanked to descale all the mineral buildup plus the galvanic interaction between the copper, brass, steel, and aluminum. Reminds me, you could take a sensitive analog volt meter and actually measure the voltage output of all those parts. Adding ground straps between the different parts greatly reduced the problem.

Back to the issue, not mentioned is the source of the heat, which if you get it out of the engine faster the less heat transfer through the exhaust port. This brings to question do you try to direct the cooled water from the intake side towards the exhaust side and then have a column flowing along that towards the t'stat?? That would suggest a gradiated flow starting at the cylinder close to the t'stat and getting larger at the furtherest point. You certainly don't want the converse to be true or you will be dumping more cold water out the path of the least resistance.

I posed the question because it's just not making sense, just looked at what was a salvagable headgasket we bagged at a wrecking yard. It has even fewer holes drilled than what we took off my son's car. You can see all the imprints from the non drilled passages which wasn't the cause of why it was there but...

Cheers,
GTM

 

[Defiant]

Originally posted by GTM
Dear lord you just had to bring up the Healey-6.

Serves them right for trying to use a delivery van motor in a sports car. At least they could have used a proper gearbox, instead of just blocking off the granny first. And the Laycock-DeNormanville was NO answer.

Actually the E type wasn't nearly as bad but remember I think we still had the basic speed law and owners would try to make the Las Vegas run to LA in under 5 hours.

Did you ever do the "fix" for the leaking rear main (rope) seal? The one consisting of three ¼" holes in the back of the [11-quart] sump, and a piece of gutter soldered on to catch the drips?

I've heard "There will always be an England". Do we HAVE to?

 

[Defiant]

Originally posted by GTM
Er, um, not sure I'm following the logic that by making the water passages smaller in the head gasket it's going to get rid of steam pockets.

"Logic"? No, no, no. These are engines. There is no logic.

 

[GTM]

Originally posted by Defiant
Serves them right for trying to use a delivery van motor in a sports car. At least they could have used a proper gearbox, instead of just blocking off the granny first. And the Laycock-DeNormanville was NO answer. Did you ever do the "fix" for the leaking rear main (rope) seal? The one consisting of three ¼" holes in the back of the [11-quart] sump, and a piece of gutter soldered on to catch the drips?

I've heard "There will always be an England". Do we HAVE to?

Wow, forgot about the blocked of granny gear. Yeah, swapping out the 180 for a 170 with the V plus there was a screw adjustment on the fan motor switch I could get the to come on sooner so you could put you arms down in there and adjust the carbs. If you attached hoses to the bowl vents and routed them close to the air intake they wouldn't boil fuel. Similar fix for the 260Z even without all the asbestos insulation we had to install.

I've used a variety of home-made and factory tools for those old flax rear seals and not just on Jags. If they had just made it like a marine prop shaft seal that you could grease with a screw cup. Wouldn't have to remove the pan or like today the tranny for the lip seal.

You know the saying about UK cars... add a bracket and develop and oil leak. Why do you have that cotter pin in your bell-housing.

Cheers,
GTM

 

[GTM]

Was watching "High Rev Tuners" and they were showing an aftermarket head from "Payne Technologies" for some DOHC 4 with 2 valve.

They had at least 4x the number of water passages and they were significantly larger. Again I wrote the gasket maker so lets see if I get a reply for this one.

Cheers,
GTM