#181  
Old 05-02-2022, 11:21 AM
78w72 78w72 is offline
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mike, you can google all the info you want, it is a fact that changing the valve seats wont change the temp the engine runs at, all youre doing is changing to hardened seats, they still function & cool the valve the same, only difference is hardened can use unleaded fuel. so you have not proven anything & for the last time im not trying to make this personal or " USING THIS FORUM TO DISCREDIT YOU" just trying to provide accurate info to some of the things you have said here.

splash shields: you googled up some info regarding splash shields on other cars, they even categorize them as "skid plates" or engine shields that go under the engine, which are entirely different than the ones we are talking about here that you claim are there for heat related purposes... further research will show that these splash shields were not very common on 2nd gen firebirds & t/a's & were not part of the fender air extractors function... they are for water & debris, period. i have owned a lot of these cars & very few had these shields stapled on from the factory, pretty sure they were more common on bigger cars or early camaros etc. if the splash shields were for heat purposes they would have been installed on all of these cars.

the OP has left this thread back on the first page or 2, so i will leave mike to carry on with his googling, sounds like he has it all figured out.

  #182  
Old 05-02-2022, 11:33 AM
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Quote:
Originally Posted by P@blo View Post
What about how far your pistons sit down in their holes at TDC?
Zero decking these things certainly helps in many ways. It most definitely helps with power output and efficiency, and generally needs less ignition timing with good quench, and makes an all around happy engine. A happy engine is much easier to tune. Likely will have the ability to run cooler as a result with all things being considered.

Cam timing is another big player when it comes to that stuff. Degreeing the cam and making sure the events happen when they should, and the cam is suited for the combo being used.

I hinted at these things in one of my earlier posts. You can have a killer cooling system but if you have an engine that just isn't happy with the parts selected and/or down on efficiency for one reason or another, it's going to be more of a struggle.

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  #183  
Old 05-02-2022, 12:33 PM
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Zero deck is overrated.Tom

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  #184  
Old 05-02-2022, 02:33 PM
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Agree. Unless the piston is down far enough to fall into the detonation zone said to start about .050" (and probably closer to .055") including gasket, there won't be any difference between a total chamber volume made up of either a zero deck 90 cc combustion volume or a .006" down 90 cc combustion volume, or any other combination.

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  #185  
Old 05-02-2022, 03:57 PM
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.006" down won't do much of anything.

I usually do .005" down or in that area and use a .038" head gasket or there about.

Point being zero deck is just a term thrown around not meant literally, at least when I say it, but it does get the point across. What you don't want is a piston .030 or .040 in the hole......unless you don't want to run a head gasket lol, Or you just don't care about quench and mixture motion, and you're not trying to run this piss poor pump gas on a decent compression ratio.

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  #186  
Old 05-02-2022, 09:02 PM
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Mike said:

"The Heat from those valves sinking into the Head and then Block and into the Engine compartment is most of my problem. Since I have not installed those seats, I feel lucky that I got past Vapor lock and under hot hood temps., at all."

Mikes Proof:

When it comes to engine cooling, the radiator is kind of a showoff. It sits right up front, catching the best breeze, dominating the conversation. And when it erupts in a cloud of coolant and steam, everyone knows about it.

"However, the engine valves (particularly the exhaust valves) shouldn’t be overlooked for the role they play in keeping an engine cool. The exhaust valves take 75 percent of the heat from the combustion chamber and the valve seats have the responsibility of helping to cool them off by drawing heat away from the valves and conducting it into the cylinder head".


Originally Posted by 78w72 View Post
Why do you disagree about the exhaust seats? Can you explain how exhaust seats cause or contribute to over heating or vapor lock? Those heads exhaust seats are just not hardened for unleaded fuel, changing to hardened seats, from what the heads have now, will make zero difference in how hot the under hood or engine temps. are. Same goes for Using the splash shields over the A-frames.


78w72, Was just explaining, that valve seats have nothing to do with vapor lock or overheating. Mike said: Something like he was going to change the exhaust seats & "can you imagine all the heat those valves are sending into the heads & block"... that's not how that works. Those heads have non- hardened exhaust seats, if they haven't been changed to run on unleaded gas. Changing to hardened valve seats won't have any effect on heat from the engine. I was asking mike to explain his statement, but now Mike doesn't have the answers...: confused:


MIKE SAID SEE POST # 171 FOR URL, EXPLAINS WHY!

People after reading this URL above, you can make your own determination about what Exhaust Valves Temp, range has to do with Hot under the Hood Temps.


Last edited by TRADERMIKE 2012; 05-02-2022 at 09:51 PM.
  #187  
Old 05-02-2022, 09:47 PM
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Quote:
Originally Posted by TRADERMIKE 2012 View Post
Mike Reply:

"However, the engine valves (particularly the exhaust valves) shouldn’t be overlooked for the role they play in keeping an engine cool. The exhaust valves take 75 percent of the heat from the combustion chamber and the valve seats have the responsibility of helping to cool them off by drawing heat away from the valves and conducting it into the cylinder head".
What I've highlighted in bold is INSANE.

Valves DO NOT "take 75% of the heat from the combustion chamber". I'm not sure they even get to 75% of the peak TEMPERATURE of combustion. We do know the difference between heat and temperature...right?

And even if they did--which I am not acknowledging as fact--iron vs. aluminum has almost no effect on engine compartment temperature.

Well-known if somewhat inaccurate estimation is that the cooling system removes 1/3 of the heat produced by combustion, the exhaust system removes 1/3 of the heat produced by combustion, and the remaining 1/3 does useful work, driving the piston down and moving the vehicle.

Valves cannot take 75% of the heat of combustion, if ~33% of the heat is doing useful work, and another ~33% of the heat is going out the tailpipe. Then there's some heat going into the cooling system via the interior surface of the combustion chamber other than the valves, and the oil.

Then there's the failed idea that "valves have a role to play in keeping the engine cool." No, they don't. They are cooled by the engine, not the other way around.

This thread has become filled with information that isn't true.

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  #188  
Old 05-02-2022, 10:09 PM
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Quote:
Originally Posted by 78w72 View Post
Mike, you can google all the info you want, it is a fact that changing the valve seats won't change the temp the engine runs at, all you're doing is changing to hardened seats, they still function & cool the valve the same, only difference is hardened can use unleaded fuel. So, you have not proven anything & for the last time I'm not trying to make this personal or " USING THIS FORUM TO DISCREDIT YOU" just trying to provide accurate info to some of the things you have said here.

splash shields: you googled up some info regarding splash shields on other cars, they even categorize them as "skid plates" or engine shields that go under the engine, which are entirely different than the ones we are talking about here that you claim are there for heat related purposes... further research will show that these splash shields were not very common on 2nd gen firebirds & t/a's & were not part of the fender air extractors function... they are for water & debris, period. I have owned a lot of these cars & very few had these shields stapled on from the factory, pretty sure they were more common on bigger cars or early Camaros etc. If the splash shields were for heat purposes, they would have been installed on all of these cars.

the OP has left this thread back on the first page or 2, so i will leave mike to carry on with his googling, sounds like he has it all figured out.
Mikes Reply:

For your information my 1979 Pontiac Firebird TA has those "A"-frame Splash Shields, I will find the Article That I read that depicts the other function of the splash shields and that is to keep air from entering the under-hood air flow as your vehicle is moving forward, Turbulence is a killer under the hood. The name of the splash shields evaded me at the time I wrote that first statement, I am only human.

  #189  
Old 05-02-2022, 10:14 PM
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Mick,the first engine I had built after coming back to the hobby about 23-24 years ago, was built by a shop in Garden Grove.Came with great marks.I supplied most of the SD parts for the engine and explained I wanted 9.5 CR.Built the engine dynoed at Verbansics(spelling).Made right at 500 HP with a Isky 505d magnum roller cam.About 3 years after, I decide to freshin it up and took it apart.It had TRWs in and they were down 100.Ran great raced it some back then,drove the hell out of it on the street with no issues.Everything looked good inside.Ordered a set of Ross dished pistons and put it back together.Running today about 19 years later,heads have not been off,a few cam changes over the years.I guess,hemis and 409s do well without quench.Got lucky again I guess.Tom

  #190  
Old 05-02-2022, 10:57 PM
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Originally Posted by tom s View Post
I guess,hemis and 409s do well without quench.Got lucky again I guess.
My understanding of quench distance is that the danger zone is from .050 to about 0.100 or so.

I suppose the amount of quench area may affect the detonation-resistance of a given quench distance.

Quench distance less than .050, preferably less than .045 makes for good in-chamber turbulence, a fast burn, and leaves little end-gas that can detonate.

Greater than 0.100 is essentially an "open" chamber, the flame front goes completely across--again leaving no end-gas to detonate. The chamber tends to have little turbulence. It probably needs additional spark advance to make up for the slower burn--but the burn is fairly complete. It's not an "efficient" chamber, but it'll work OK.

But between those figures, the piston-to-head gap is too small for effective flame travel, too large to push the end-gas into the "burning" part of the chamber inducing turbulence and therefore faster burn. So the superheated end gas "pops" under the pressure and heat of combustion.

Even if the end-gas doesn't detonate, the chamber needs additional spark advance due to the lack of turbulence and the resulting slower burn.

  #191  
Old 05-03-2022, 12:03 AM
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Mikes Reply:

I use this product, "Red Line (80204) Water Wetter" - Coolant Additives - 12 Oz Bottle.
Ultimate cooling performance - Coolant additive with a unique agent that lowers temperatures by reducing and eliminating bubbles or vapor barrier that form on hot metal surfaces.
Water Wetter is a unique wetting agent for cooling systems which reduces coolant temperatures by as much as 30 degrees Fahrenheit.
Elimination of any hot-spots that might encourage knocking.
Redline says this is supposed to decrease the chance of corrosion and improve the thermal conductivity of your engine coolant, thereby transferring heat away from your engine block more effectively.

I have read in the past, so don't quote me, that Water Wetter will work at the cylinder walls. When there are water vapor bubbles adjacent to the cylinder walls cavitating, it will break down those bubbles and make the walls more slippery and the complete Radiator solution can touch the wall (better contact) to carry the heat away.

OR


EVANS WATERLESS COOLANT:

WHY EVANS
Evans Waterless Coolant provides distinct advantages over traditional water-based coolant. The absence of water avoids the formation of vapor, high pressure and boil-over, and prevents corrosion and electrolysis. Evans’ high boiling point and lower freeze point allow a wider and safer operating temperature range. The benefits derived from Evans can be achieved in most vehicle applications and engine types, although Evans’ performance may vary depending on cooling system configurations.

The Benefits of Using Evans Waterless Coolant
Heat Management: Evans high boiling point virtually eliminates vapor in the engine, ensuring constant liquid-to-metal contact. Evans draws more heat from the engine, which may lead to slightly higher coolant gauge temperatures (by 10 to 20 degrees). Heat management is improved as engine component temperatures are kept under control.

Lower Pressure: Evans’ lower system pressure reduces stress on hoses, seals and gaskets.

Corrosion Protection: The absence of water also means no corrosion and electrolysis. This is particularly important for cars stored for long periods of time.

What is the right coolant for my use?
High Performance Waterless Coolant: Cars and light duty trucks.
Heavy Duty Industrial Waterless Coolant: Superior temperature management and protection for industrial applications
Powersports Waterless Coolant: Motorcycles, ATVs, UTVs, and snowmobiles.

How much coolant will I need?
EWC is a stand-alone coolant, not to be mixed with water. You need enough to completely fill the entire cooling system. Check your owner’s manual for coolant capacity.

How much Prep Fluid do I need?
If you cannot fully drain the system; Open the lower radiator hose and block drain plugs if accessible, and heater core. Allow to empty and force high volume air to purge remaining coolant. Fill with Evans Prep Fluid, run the vehicle to circulate and drain again. This would require approx. 75% of the system volume of Prep. Alternately, smaller quantities of Prep can be used to flush through a component, or plumbing.

Will I need to use a chemical flush or will Prep Fluid be sufficient?
For neglected cooling systems or high mileage vehicles, a chemical flush may be necessary to remove rust, scale and residue prior to using Prep or Evans Coolant. Evans offers a Cooling System Flush for neglected cooling systems.

Will Evans lower my engine temperature?

Typically, no. Vehicles running under normal operating conditions should show either no change or a slight increase in temperature, but that will depend on cooling system configuration as well as driving conditions. Certain systems that use incompatible components, have an existing problem, or are poorly designed could run hotter. The ability to lower the operating temperature depends on multiple factors, primarily coolant flow volume and air flow temperature. For example, multi pass radiators will result in higher temperatures due to decreased coolant flow volume vs. large tube multi row radiators that improve coolant flow. Different thermostats may increase flow volume because of less restriction.
Water-based coolant boils at a temperature only slightly higher than the operating temperature of the coolant. Localized boiling releases water vapor that can only condense into coolant that is colder than the boiling point of water. Vapor that doesn’t condense occupies a volume that displaces liquid coolant. Hot engine metal, insulated by water vapor, becomes an engine “hot spot” that can cause pre-ignition and detonation. Evans’ high boiling point means it will not turn to vapor.

  #192  
Old 05-03-2022, 12:18 AM
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Originally Posted by Schurkey View Post
What I've highlighted in bold is INSANE.

Valves DO NOT "take 75% of the heat from the combustion chamber". I'm not sure they even get to 75% of the peak TEMPERATURE of combustion. We do know the difference between heat and temperature...right?

And even if they did--which I am not acknowledging as fact--iron vs. Aluminum has almost no effect on engine compartment temperature.

Well-known if somewhat inaccurate estimation is that the cooling system removes 1/3 of the heat produced by combustion, the exhaust system removes 1/3 of the heat produced by combustion, and the remaining 1/3 does useful work, driving the piston down and moving the vehicle.

Valves cannot take 75% of the heat of combustion, if ~33% of the heat is doing useful work, and another ~33% of the heat is going out the tailpipe. Then there's some heat going into the cooling system via the interior surface of the combustion chamber other than the valves, and the oil.

Then there's the failed idea that "valves have a role to play in keeping the engine cool." No, they don't. They are cooled by the engine, not the other way around.

This thread has become filled with information that isn't true.
Mikes Reply, please read:

https://www.enginebuildermag.com/201...s-valve-seats/


Last edited by TRADERMIKE 2012; 05-03-2022 at 12:38 AM.
  #193  
Old 05-03-2022, 12:30 AM
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Quote:
Originally Posted by tom s View Post
Mike, the first engine I had built after coming back to the hobby about 23-24 years ago, was built by a shop in Garden Grove. It came with great marks. I supplied most of the SD parts for the engine and explained I wanted 9.5 CR. Built the engine dynode at Verbanics (spelling). Made right at 500 HP with an Isky 505d magnum roller cam. About 3 years after, I decided to freshen it up and took it apart. It had TRWs in and they were down 100. Ran great raced it some back then, drove the hell out of it on the street with no issues. Everything looked good inside. Ordered a set of Ross dished pistons and put it back together. Running today about 19 years later, heads have not been off, a few cam changes over the years. I guess, hemis and 409s do well without quenching. Got lucky again, I guess. Tom
Mikes Reply:

I have read that when you keep the CR down to your 9.5:1 that you can run on pump gas, is that not the reason you chose that specific CR to begin with? No luck in that, you made an educated choice. Tom S. I know you're the engine builder and I am not, just repeating what I have read. Following you on Hesster1976 post, you have at least 3-4 cars in the Magazine's and you were involved in that special Tempest build. You're the man...Also the dished pistons you used, like what should be what is in my car, is the key to lower CR, no luck, you know what you are doing?


Last edited by TRADERMIKE 2012; 05-03-2022 at 12:37 AM.
  #194  
Old 05-03-2022, 12:53 AM
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Quote:
Originally Posted by TRADERMIKE 2012 View Post
I read it. It's wrong in the areas I pointed out.

The rest of the article isn't relevant to this discussion.

  #195  
Old 05-03-2022, 01:11 AM
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Mikes Reply:

The next step up is a high alloy seat material, for applications where high heat resistance is required, such as a propane or natural gas fired stationary engine but also for high performance engines, heavy-duty and extreme duty engines where longevity is a must. Seats are made out of high-speed tungsten carbide tool steel, which gives it ceramic-like characteristics for extreme temperature resistance.

Conversely, because they tend to run much cooler than exhaust valves, low alloy seats work well with intake valves in performance applications, even in such extreme cases as offshore racing boats that run for hours on end.

Anything that interferes with a seat’s ability to cool the valves (such as a loose fit, poor surface finish or deposits between the seat and its counterbore) can lead to premature valve failure and expensive comebacks, so a cylinder head job often requires valve guide and seat work to restore it for service or to improve performance. In order for a valve to seat correctly, for efficiency and power, engine builders must replace or bring back to spec all valve seats and guides.

https://www.enginebuildermag.com/201...s-valve-seats/


Mikes second Reply:


I chose this passage from this "URL", that I want you to read please. I thought at the time that I made my statement, "wouldn't it be nice to have a ceramic type phenolic valve seat to keep the head from having to transfer so much heat"? Also, when I made my statement, I had not read this "URL" yet, so I was speaking purely from speculation, turns out my intuitions are good.

  #196  
Old 05-03-2022, 01:28 AM
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I feel a little guilty for interrupting the discourse on valves - but only a little.

I was going to add in my last post that the detonation area to avoid was .050" to .080" down but had deleted it when I proof read it. Tom's piston depth at .100" down in the hole would not only have been totally safe, but might have added power. I've been told that the successful short course racers have found that there is better power in an open shaped chamber than a high quench chamber. If I had to venture a guess I'd say that quench is better for low RPM running to get the most efficient combustion mixture, but at mid to high RPM the quench area becomes a detriment since the speed and turbulence of the incoming mix is all that is needed and the open chamber is then more efficient. So in short, these racers have moved away from the D-shaped piston top to the old fashion open dish.

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  #197  
Old 05-03-2022, 01:54 AM
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Mikes Reply:

How do the Exhaust Seats Work?

"The seats draw heat away from the valves and conduct it into the cylinder head. This provides most of the cooling that the valves receive and is absolutely critical with exhaust valves".

"One point everyone does seem to agree upon is that valve seats play a critical role in the longevity of the valves. The seats draw heat away from the valves and conduct it into the cylinder head. This provides most of the cooling that the valves receive and is absolutely critical with exhaust valves. Anything that interferes with the seat's ability to cool the valves (such as a loose fit or deposits between the seat and its counterbore) can lead to premature valve failure and expensive comebacks".

https://www.aa1car.com/library/ar993...haust%20valves.

Mikes second Reply:

"We have found that most of the original equipment seats in aluminum heads are not much more than cast iron, which is very easy to cut. But most aftermarket seats 18 to 20% chromium and are a monster to cut, which is ridiculous. You do not really need that hard of a seat in an (aluminum head because the seats never get very hot). So that is why we are introducing a softer material that will be easier to machine, easier on tooling and give a more precise seat."

"Some people are still trying to use plain cast iron seats in unleaded engines. It just will not work because it is too soft. They are a thing of the past so that is why we have discontinued plain cast iron seats in our line."

"Keon said Well-Tite seats are not heat treated, but are machined and sold "as cast." He says this allows them to handle high temperatures without danger of grain inversion. He also said the unique Well-Tite ally has an excellent memory characteristic that allows a seat to return to its original size after heating without distortion, which means the seats will not loosen or fall out if an engine overheats.
Keon said rebuilders should be especially careful about the quality of the seats they buy. He said many offshore suppliers are less than thorough about their quality control measures, yet charge as much for cast iron seats as ones that contain superior alloys".

VALVE SEAT INSTALLATION
Once the counterbore in the head has been machined for the desired interference fit and a replacement has been selected, the next step is to install the seat.

As mentioned previously, the hole must be clean and have a smooth surface finish. The seat should be placed with the radius or chamfer side down and lubricated (ATF works fine) prior to being pressed or driven in with a piloted driver (recommended to prevent cocking).

If the replacement seat has a sharp edge, it should be chamfered or rounded so it won't scrape any metal off the head as it is being driven into position. If metal gets under the seat, it will create a gap that forms a heat barrier. This, in turn, will interfere with the seat's ability to cool the valve and premature valve failure will likely result.

Preheating the head and/or chilling the seats with dry ice or carbon dioxide (do not use Freon because it damages the ozone!) will make installation easier and lessen the danger of broaching the counterbore as the seat is being installed.
If you choose to peen or stake the seats after they have been installed as added insurance to prevent them from falling out (which should not be necessary if the seats have the correct interference and were properly installed), several engine rebuilders we interviewed recommended rolling or peening rather than staking. Their reason? Staking creates stress points and potential hot spots.

machining valve seats
Finishing valve seats after installation.
The final step is to machine the valve seats once they have been installed in the head. This may involve cutting a 45-degree seat, or a 3-angle valve job (30-45-60 degrees), or a multi-angle valve job for better performance. Valve seats must be cut concentric to the center of the valve guide for proper alignment and sealing. Lack of concentricity in the valve seat itself can also prevent the valve from sealing tightly against the seat causing a compression leak and a possible misfire. Valve-to-seat sealing can be checked by applying vacuum to the intake and exhaust ports.


Last edited by TRADERMIKE 2012; 05-03-2022 at 02:34 AM.
  #198  
Old 05-03-2022, 02:55 AM
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Quote:
Originally Posted by lust4speed View Post
I feel a little guilty for interrupting the discourse on valves - but only a little.

I was going to add in my last post that the detonation area to avoid was .050" to .080" down but had deleted it when I proof read it. Tom's piston depth at .100" down in the hole would not only have been totally safe, but might have added power. I've been told that the successful short course racers have found that there is better power in an open shaped chamber than a high quench chamber. If I had to venture a guess, I'd say that quench is better for low RPM running to get the most efficient combustion mixture, but at mid to high RPM the quench area becomes a detriment since the speed and turbulence of the incoming mix is all that is needed and the open chamber is then more efficient. So, in short, these racers have moved away from the D-shaped piston top to the old fashion open dish.
Mikes Reply:

I am stuck with the 1967 670 "D"-Port Heads for now, as I am keeping this 428 ci HO stock, besides with Posi-traction my wheels spin and I have to add weight in the trunk for safety, in the rain. I have no idea what my deck is at for I never removed the Head, since I bought this second-hand project. It just runs too well to fool with. The motor is immaculate internally. I like to run transmission fluid in my second-hand projects that I have modified and sold. I ran it for 15 minutes with a new filter, then I installed the correct oil and a new filter. A Transmission rebuilder told me that when he bought his brand-new vehicle, he filled it with trans. fluid and ran it, went 300 K miles and when he opened the Engine it looked new inside. So, I figured it can't hurt to run Trans. fluid for 15 min. hot and change. Also, my 1967 670 D-Port "closed chambered" Heads are a one year only design or so I have been told.


Last edited by TRADERMIKE 2012; 05-03-2022 at 03:14 AM.
  #199  
Old 05-03-2022, 03:10 AM
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Someone in this thread has got stuck in the snake oil swamp from the advertisers in the HotRod magazines and accepted just about every incredible tip after another and instead of learning the combustion engine principles or at least learned to service their engine according to the service manual. We have all been beginners and done similar but thankfully learned what is correct on the journey to a well-functioning car.

FWIW

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Old 05-03-2022, 03:31 AM
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Quote:
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Mikes Reply:

I have read that when you keep the CR down to your 9.5:1 that you can run on pump gas, is that not the reason you chose that specific CR to begin with? No luck in that, you made an educated choice. Tom S. I know you're the engine builder and I am not, just repeating what I have read. Following you on Hesster1976 post, you have at least 3-4 cars in the Magazine's and you were involved in that special Tempest build. You're the man...Also the dished pistons you used, like what should be what is in my car, is the key to lower CR, no luck, you know what you are doing?
Mike replied to Tom S.:

I thought you spelled my name wrong, but I now see you were speaking to Mick, my bad, this is why I announce myself the way I do, up late, sorry.

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The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




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