rsicard
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Posts posted by rsicard
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When someone calls your assertions "Bullshit pure and simple" then it is time to provide proof to prove a point. To your point about about technical discussions I agree that is what it should be. As to the grooves, the only time that I can see that they provide benefit is when squish and swirl are already optimized. In addition the grooves will increase the travel time of the combustion chamber flame in conjunction with good squish. That increases combustion efficiency. Good swirl and squish are only accomplished by way of a good piston and cylinder head configuration. I suspect that Robello engine builders already knows about this science in that they order specific pistons and modify cylinder heads to get to a specific configuration.
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The above link is NOT "Bullshit pure and simple". Comments?
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No it is not a conspiracy theory. The SBC was designed before 1958. All later designs were an evolution from the earlier original design. Don't care about whether you think it's "Bullshit pure and simple". I have talked to others in the industry that experienced type of stealing. It is not UNIQUE. The advantages of reverse flow cooling are well understood. For the SBC GM used it only a few years. With its advantages one would think that the design aspect would be carried forward but was not.
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If Smokey and Vizard are your standards of the best combustion technology gurus then you're at least 10 years behind where things are now. The best engineers right now probably work for Ferrari, Renault, Mercedes, and Cosworth. There are also a lot of OEM senior engine design engineers deep in the bowels of the OEM manufacturers that have forgotten more the Smokey and Vizard put together. They have vast computer and lab resources at their disposal.
Regarding direct injection and turbulence: Spraying a precisely calibrated fine mist at 3,000psi into a combustion chamber at exactly the right spot near the end of the compression stroke does not require a lot of turbulence.
John:
The basics are the basics for ICE regardless of time, Ferrari, Renault, Mercedes, and Cosworth. The basics do not change over time. Combustion efficiency is likely not advanced by theory, CFD or a team of inexperienced engineers. It is only gained by testing, documenting, trial and error. Using Ferrari, Renault, Mercedes and Cosworth Formula one engines as an example is like comparing apples and oranges. OEM have never learned as much as Smokey and Vizard! Genius is not taught, it is instilled by constant questioning! Computer Modeling does not yield EXPERIENCE. It is only the refining of science that matters no matter what the process.
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John C:
Purchase David Vizard's latest book and read it thoroughly. The master of combustion science was Smokey Yunick who has since passed on. The next best these days is David Vizard. Read what he says about domed pistons. The fuel injectors emits FUEL only. It need to combine with incoming air. Even with CFD, it is doubtful that Ford can come up with good squish and swirl with that configuration. Maybe they are counting on tumble to do the job instead. Would like to see David Vizard's assessment of this design. Ford has come up with MANY differing engine designs mostly dual overhead cam engines. They are just following in the footsteps of Honda and Toyota wherein the power is developed at higher RPMs with turbrochargers i.e. force feeding the fuel mixture.
Comments?
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Tony D:
Apparently you do not understand large corporation tactics. Concerning stolen technology the gentlemen at Evans cooling was the one that created reverse cooling design.
Go see http://www.evanscooling.com/company-background. I will try to find the original article on this subject.
As far as Mr. Singh grooves I have already commented on that. Its simple KISS. They increase combustion flame travel thus more efficient burn of mixture. Not difficult to grasp.
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Tony D:
I purchased a 1994 Buick Roadmaster. It had a Gen II Small Block Chevrolet known as the LT-1. Found a design defect in the fuel pump to line interface within the tank. Went back to doing it the older way and everything worked out OK. Just before that, replaced the fuel injectors, Opti-Spark distributor, Plug wires and Spark Plugs. The wife took it to emissions and there were so few emissions the certification sheet read zero HC and zero NOx. That is how good a design that engine is. GM stole the cooling system design from someone who already had the design registered. GM team of lawyers settled the matter even though they were at fault. Heard of similar litigation situations and the results are the same. Does not matter who is right or wrong, just who has the deepest pockets and the most lawyers. It was the cylinder head design, compression ratio and cooling system that made the difference. The Vortec heads were an off-shoot of that cylinder head design with conventional cooling.
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Huh? OEMs can't get good squish and swirl in their combustion chambers? What about the Honda F20C engine - 120 hp per liter and meets Bin2 emisisons standards? Maybe the Honda B16 engine - 100 hp per liter and meets PLEV standards? Or how about Ford's new EcoBoost 3.5L V6 - direct injection which is the ultimate in swirl technology? Nissan's VQ and VK engine series...
It seems there is a basic misunderstanding at to what squish and swirl are, what they look like in physical configuration, and how they promote combustion efficiency. Looked at the Ford Ecoboost 3.3 V6 piston and cylinder head configuration and am unable to see the science of combustion efficiency. Supercharging or Turbocharging is a whole different science altogether. It is force feeding combustion. There seems to be a comparison between NA and Boosted Engines which is not a good comparison. Once a SBC Gen I is boosted to 12 inches it likely to produce overwhelming power per cubic inch (super efficiency) just like the more modern engines with boost but with much less moving parts.
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Good squish and swirl will NOT be obtained by using production tolerances. It may not be attained using mass production parts. There needs to be specific configuration pistons and cylinder heads to attain good squish and swirl. OEMs are interested in how much it costs to produce to keep the profit margin up. OEMs will keep the tolerances on the conservative side to keep reliability up with CHEAP parts to hold down warranty costs. It is only when assembling and testing each Corvette and Camaro engine that particular attention will be paid to assembling a high performance and quality product and still keep warranty costs in line. With better performance comes better emissions.
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You two need to get a properly tested GOOD ECU with a baseline software load to try in place of yours. Also all sensors need to be tested as well as the interconnect wiring to be correct.
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X64v is or was a University of Arizona student. Have not seen any of his posts here in quite some time. As far as cooling the L28 6 cylinder there appears to be insufficient cooling of the cylinder heads of these type cylinder heads. The only way out of this situation is to carefully cut open scrap cylinder heads to see if it was a design defect or workmanship problem at the point of manufacture. Then figure a way to modify the supposed good cylinder heads to increase coolant effectiveness and flow.
As far as general engine cooling, there is an air gap at the top of the radiator support and the bottom of the hood that needs to be closed up. Also other holes in the radiator support need to be closed up such that most all of the air flow goes through the radiator. Then try removing the inspection covers to see if these fixes provide adequate cooling.
Personally, I am going to do all of this plus fabricating a tunnel from smaller opening in the front grille inlet to a large outlet at the radiator. This get the air flow from a higher to a lower pressure area and confines the flow though the radiator. With good flow through the radiator and out through the top of the inspection panel openings should provide good cooling.
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The older Z cars are exempt from the smog laws. The 240Z is one of the lightest of the older Z cars. Also the wiring was simpler on the older Zs. Three good reasons to go after the older Zs.
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It's not complicated. If the grooves increase the combustion flame rate of travel, then it is a design improvement no matter what duty cycle or power band. If there is more complete combustion in lesser amount of time the EGT will likely decrease. Something has to be sacrificed at higher loads and speeds.
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I need to take Tony D's advice and work through the cooler night.
Right now there are more aspects to the project and need to tackle them one a time. Need to align the rear of the T56 transmission and R200 rear end to get the angles just right then finish fabing the rear trans mount. Need to remove the existing subframe rails, straighten the floors and weld in the Bad Dog Frame Rails. Suspect the floor pan steel is real thin and needs great care in welding the new Frame Rails. Would also like to weld in "L" channel on the top side to the Bad Dog Sub-frame Rails with a spacing such that I can weld a "C" channel to the two "L" rails on top of the floor to gain much added strength. Likely cleco the whole mess together during the process, then plug weld through the "L" rails through the original floor to the Bad Dog rails. This should allow for a GOOD STRONG weld. Then add the "C" channel on top for added strength.
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Correction: "When this gap is reduced the resistance to detonation is GREATLY INCREASED."
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Did you put Gapless rings on the pistons?
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Good combustion is a combination of aspects. Using the Small Block Chev as a baseline, the best pistons for combustion flame travel are flat tops. Admittedly there needs to be valve reliefs cut into them for valve clearance. For real good squish an all forged bottom end is necessary as it provides the least flexing of reciprocating components. Then the block can be decked to near zero wherein the piston is flush with the top of the block. Then the cylinder head flat face of the combustion chamber can be torqued to within 0.025 to 0.030 inches of the top of the piston with thin head gaskets. When this gap is reduced the resistance to detonation is significantly reduced. Additionally, swirl is enhanced also. With good squish and swirl the incoming fuel and air mixture is homogenized more thoroughly and therefore the flame front will migrate much faster through a homogenized mixture than a richer mixture portion of the combustion chamber. Adding grooves directs the mixture on the opposite side of the chamber towards the flame front caused by the spark plug thereby speeding up the burning of the total combustion chamber mixture of air and fuel.
The LT-1 Small Block Chevrolet (Gen II SBC) engines were 10.0 to 1 compression from the factory and ran very well on 87 octane fuel. I had one of these in a 1994 Buick Roadmaster and went to emissions and there was so little of it that emissions equipment reported zero zero. Best running engine I have every had and kept it that way well past 100K miles and still running strong passing most everything in sight. From Tucson to Phoenix and return at 80 MPH it got 24 MPG and it was a HEAVY vehicle! When the tune is right, the emissions will be exceptional! It is really hard to beat a good design engine that has a good Electronic Fuel Injection (EFI) with a very precise Ignition System.
Now I have an even better (more tunable) EFI system for my 240Z which is getting a 383 SBC.
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Ray:
Very nicely documented application of Bad Dog rails. Need to do the same to my 240Z except the passenger floor is buckled upward. Same on drivers side but to lesser extent. Need to remove existing frame rails then use portapower to push floors back into position and anchor same with new Bad Dog rails that are on hand. Want to add 90 degree and "C" channel on top side for more strength. Right now it is TOO HOT in Arizona to do much of anything outside.
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Sounds as though it is running too rich. Need to check both unregulated and regulated fuel pressure. Then the injectors need to be tested for proper operation. If there was an ignition miss that may be the product of the Opti Spark distributor or coil for same. Not certain about tunercat but may need to lean out the fuel map in same.
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You must have said that the LT-1 engine was out of a 1996 GM. If that is the baseline they are testing for then O2 sensors need to be installed front and rear of CAT converters. For CARB approved air cleaner go to the junk yard and get an intake system + MAP sensor off of a 1994-1996 LT-1 equipped vehicle and install same. Tell them it came stock on donor vehicle. The looking for CARB approved accessories ignores what is really coming out of the tailpipe which is the most certain test that can be performed. An LT-1 in proper tune should come out with NO measurable emissions!
1975 and older vehicles are EXEMPT from smog regulations. A 240 or 260Z is a better starting point for folks in California.
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Mull:
The craftsmanship is exceptional! Care to elaborate on the sequence for welding the cabin roll cage assembly. The sequence is key to putting the cage together.
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Swirl and quench have just as much or more to do with combustion efficiency in a Wedge design cylinder head. A lot depends upon the design of the cylinder head combustion chamber and a piston to complement same. Adding the groove will likely aid in flame front travel speed. It may NOT aid swirl. GM has done a considerable amount of work on the newest Corvette cylinder heads to enhance swirl. Quench is easier to achieve. Both work together to atomize the fuel mixture for a more complete burn and therefore better efficiency. Automobile manufacturers may tweak combustion chamber design with CFD software but even that is hard to validate its benefit in the design.
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Nathan:
I have a T-56 trans that I am putting into a 1971 Datsun 240Z. I purchased it on Ebay and believe it to be from a 1996 vehicle and don't know how many miles are on it. It seems to shift OK as it is not in use as yet. Would like to use you as a source of knowledge. In the process of fitting the trans and 383 SBC stroker into the 240Z. In the process of fabbing rear trans mount.
The goal is to go through the trans and replace what is necessary and beef up the weak spots. Have my own shop and would entertain rebuilding it myself. Would need to fab fixture to hold trans and tools necessary to disassemble and reassemble the trans after replacing weak and worn parts. Are you willing to be a mentor? Have experience in rebuilding engines and small fabrication. Live in Tucson Arizona far away from where you are.
Testing Fuel Injectors
in Trouble Shooting / General Engine
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Because th injector reads 0 ohms does not necessarily mean that it is defective. Just says that the ohmmeter may be of low quality. A crude check of the injector would be to apply fuel under pressure at 45 psi and apply 12 volts to the terminals of the injector. This would represent 100% duty cycle, a crude way to test the injector. To properly check injectors requires a fixture with large lab test tubes to capture the fuel emitted by the injector(s) by timing and measuring by applying a measured +12 volts pulse train. Timing and measuring for a given pulse width applied.