Thicker head gaskets/ less compression...

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We agree on him needing a camshaft and the affects of head materials on cylinder pressure and compression ratios.


Ok - no more being a pussy for me...lol. You didn't explain crap. You made bold proclamations with no engineering behind it. In terms of the talking about head materials you are flat out wrong. Here's my attempt at education:
Power is only created by the conversion (combustion) of chemical energy (air and fuel) into thermal energy (heat), and that thermal energy being converted into mechanical energy by the reciprocating and rotating assemblies that results in torque at the back of the crank. Anything that potentially removes heat from the combustion event will reduce that torque at the crank. The combustion event temperature is affected by several things: fuel type, effectiveness of mixing, mechanical compression ratio, materials, amount of surface area, and shapes that make up the sealed area where the combustion happens. The materials and shape include the piston design and material ( 2nd largest single surface area), the block (top of the bore), the head material (the largest surface area), chamber shape, valve material, and head gasket fire ring. Anything steel will not remove heat very well. Anything aluminum will and as I note - the largest surface areas are aluminum. This ability to transfer heat is why aluminum heads "need" more static compression, and why KB hyper pistons break when the top ring gets overheated and the gap closes. Hypothetically because there are no possibilities to do this with mopars - If two engines are built IDENTICAL, and one has aluminum heads and one has iron, the iron will show more torque at the crank because there will be more thermal energy converted to power.

now leave my wife (ex) out of this...lol
 
Frankenduster said:
Thanks, but I actually do drive the car long distances. I make an annual 1000 mile round trip to Los Angeles and back every year.
I have already decided against the gasket swap. I have been grasping at straws in an effort to fix this problem. Sometimes I feel like the sick patient that is willing to see a witch doctor to find a cure, trying all sorts of unconventional remedies!
Thanks to everyone who offered help, Greg
Click to expand...


Greg - the ideas about looking a the carb and timing curves are all good. I've been able to "fix" higher compression engines by simple tuning. Like you mention - check the power valves especially because if they are late, and pinging starts - it won't stop until you let off. Also look into slowing the advance down. Some engines won't feel "slow" or lose power if you bring them up to max advance at 2800 - or 3K, or 3200. Keep a close eye on the spark plugs for signs of detonation too. You're close, not way over the accepted limits so it might be just that. you might also look into something like Water Wetter to lower the engine temps (internally).
 
I have never run anything higher than 93 octane in my aluminum headed small block and so far have never had any detonation. It had from 191 to 201 cylinder pressure and I checked with 2 different gauges while the engine was warm. It is 10.9 -1 compression and the cam is 255/266 duration at .050.
 
moper said:
[
We agree on him needing a camshaft and the affects of head materials on cylinder pressure and compression ratios.


Ok - no more being a pussy for me...lol. You didn't explain crap. You made bold proclamations with no engineering behind it. In terms of the talking about head materials you are flat out wrong. Here's my attempt at education:
Power is only created by the conversion (combustion) of chemical energy (air and fuel) into thermal energy (heat), and that thermal energy being converted into mechanical energy by the reciprocating and rotating assemblies that results in torque at the back of the crank. Anything that potentially removes heat from the combustion event will reduce that torque at the crank. The combustion event temperature is affected by several things: fuel type, effectiveness of mixing, mechanical compression ratio, materials, amount of surface area, and shapes that make up the sealed area where the combustion happens. The materials and shape include the piston design and material ( 2nd largest single surface area), the block (top of the bore), the head material (the largest surface area), chamber shape, valve material, and head gasket fire ring. Anything steel will not remove heat very well. Anything aluminum will and as I note - the largest surface areas are aluminum. This ability to transfer heat is why aluminum heads "need" more static compression, and why KB hyper pistons break when the top ring gets overheated and the gap closes. Hypothetically because there are no possibilities to do this with mopars - If two engines are built IDENTICAL, and one has aluminum heads and one has iron, the iron will show more torque at the crank because there will be more thermal energy converted to power.

now leave my wife (ex) out of this...lol
Click to expand...

The iron will show more at the crank, eh? Is that so? Maybe one should read these tests and then decide.

http://www.carcraft.com/techarticles/ccrp_0602_iron_versus_aluminum_cylinder_heads_test/viewall.html

http://www.chevyhiperformance.com/techarticles/83858_iron_vs_alloy_engine_heads/
 
Thanks for those links, IQ. Pretty interesting when a theory gets debunked after hearing it for years.
Next up, engines NEED backpressure!
 
LOL.....I just read the rest of this post.

Just trying to help ya...all is cool....or hot ...i mean....lol


I think what IQ52 posted is very interesting....

I would love to see more information on the subject of aluminum vrs steel and the way heat works in a engine using different materials.

You would need the same head casting in steel and aluminum plus both heads would need to be totally even--- as far as flow and velocity goes.

I have always heard this to be true.....could we all learn something new??

Someone better call up Hughesengines with the news....

FROM HUGHESENGINES SITE INFORMATION..........


Aluminum heads dissipate (get rid of) heat much faster than iron heads. The rapid heat loss from the combustion chamber results in reduced combustion chamber pressures (heat equals pressure); similar to the effect that lowering the compression ratio which lowers cylinder pressure. When switching to aluminum heads you MUST raise the compression ratio to prevent a power loss.
 
I still maintain there's no difference in compression or power. Compression is a ratio. It makes zero difference what the head is made out of.

Also, about the heat dissipation. My opinion on it is that the heat the aluminum head dissipates is residual heat and not directly combustion heat. Although it is left over from combustion, in order to dissipate pure combustion heat, a metal would have to dissipate heat at an impossibly fast rate, since the actual combustion process is less than a second. Iron holds more residual heat in and this I believe is the reason people have it in their minds iron heads make more power. They don't. They never have. We should stop this stupidness on this thread and take it up elsewhere. This is doing nothing for Greg's original question. He already has his heads. He's not making that decision. Make a thread about the difference between iron and aluminum heads and be done with it.
 
Since we strayed off the topic, I must admit that the woman in RustyRatRods avatar is strangely arousing. Herman Munsters wife ?? Really ???
 
Yup. That's her. The argument rages as to whether it's photoshopped. I think it could go either way. I have a big copy too and all the shadows are right. If it's fake, it's a goodun. They did a show called Munsters After Dark in the UK that was more risqué. That is one theory as to where the pic came from. Who knows? She was a hottie either way.
 
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