Gen V Engine
02-07-2006, 01:58 PM
#21
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Forged pistons expand more than a cast piston. Therefore, when the engine is cold, there is more clearance between the piston and the bore. I am not sure how Ford has dealt with this, but it would be interesting to see.
I think you may be able to get rid of the slap with a properly placed offset pin or a very good skirt coating.
I am not saying at all that a forged piston would be a bad thing, I think it would be great. But the fact is that GM is gun shy to do this. Plus, they are so strapped for cash right now, adding any more cost into an engine is out of the question for them.
I think you may be able to get rid of the slap with a properly placed offset pin or a very good skirt coating.
I am not saying at all that a forged piston would be a bad thing, I think it would be great. But the fact is that GM is gun shy to do this. Plus, they are so strapped for cash right now, adding any more cost into an engine is out of the question for them.
02-07-2006, 02:01 PM
#22
Remember the piston slap of the LS1's. Yeah, that cost GM some money. The people driving thevehicles complained of noise from the engine, GM told the dealerships it was normal, customers, knowing more than the engineers, decided it wasn't. Therefore, GM got the bad end of that deal.
Are forged pistons really that noisy?
I thought the piston slap was due more to the fact that when cold the piston had room in betweent he cylinder walls and caused the slapping noise until the cylinder walls warmed up so how would that neccessarily have anything to do with the forged pistons?
Hence 06 Z06 = cast pistons.
Besides, most people want forged so they can add nitrous with "no worries".
GM isn't about to upgrade to forged so people can "spray" thier oem warrantied car.
02-07-2006, 02:03 PM
#23
Originally Posted by MSURacing
Forged pistons + GM = Lawsuits!!!!
They have already had this problem. And it wasn't even with forged pistons. Remember the piston slap of the LS1's. Yeah, that cost GM some money. The people driving thevehicles complained of noise from the engine, GM told the dealerships it was normal, customers, knowing more than the engineers, decided it wasn't. Therefore, GM got the bad end of that deal.
I think the only thing they can do to handle the power levels is to have piston squirters like they do on the Ecotec 2.0L supercharged engines. This will allow the piston to handle more heat by cooling the backside of the piston.
They have already had this problem. And it wasn't even with forged pistons. Remember the piston slap of the LS1's. Yeah, that cost GM some money. The people driving thevehicles complained of noise from the engine, GM told the dealerships it was normal, customers, knowing more than the engineers, decided it wasn't. Therefore, GM got the bad end of that deal.
I think the only thing they can do to handle the power levels is to have piston squirters like they do on the Ecotec 2.0L supercharged engines. This will allow the piston to handle more heat by cooling the backside of the piston.
Yeah, I don't know if that is the case. Plenty of people have forged internals, and they aren't any louder than stocker's. And the piston slap in the LS1 had nothing to do with forged internals, since the LS1 doesn't have forged internals ....
02-07-2006, 02:10 PM
#24
Yeah, I don't know if that is the case. Plenty of people have forged internals, and they aren't any louder than stocker's. And the piston slap in the LS1 had nothing to do with forged internals, since the LS1 doesn't have forged internals ....
Last edited by NO-OPTION-2002; 02-09-2006 at 11:05 AM.
02-07-2006, 04:31 PM
#25
Oh ok, yea i dont know a ton about forged pistons, just in the few cars that ive seen/heard with forged pistons they havent been any louder than any other car in my experiences with them. I agree though GM isnt quite on the up-and-up right now so i cant see them making any of their vehicles more expensive (adding more expensive engine parts) but it would be awesome to see them go that route. Also, there are tons of guys on the board who spray on their stock ls1/ls6/ls2 engines so I dont think that by adding a completely forged bottom end would open the flood gates to people spraying on their oem engines, because if they are gonna spray they are gonna spray.
02-08-2006, 10:20 PM
#28
Back to the topic...GM could learn alot from the Germans. Take a look at the technology Mercedes is using, espeally in the AMG line. How about clean diesels? esp in the 3-4L range, perfect for most trucks and utes. . How about 75-100 HP/L like the Japanese and Europeans. Cars are getting heavier with all the near luxo gadgets and safety bits. How about a new Camaro that weighed in at 3200 lbs and had 400HP from an all aluminum 4L V6/8. Remember the folks here are an exception to the rule. For the economies of scale in engine lines, GM needs to address the concerns of the other 98%. But many of these technologies I've mentioned can make us hot rodders happy too.
--JMarsa
--JMarsa
02-09-2006, 04:13 AM
#29
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Originally Posted by MadBill
DOD deactivates both valves and the injectors in the affected cylinders, so there is no effect on O2 sensors, just more exhaust per cylinder from the remaining 4, as they work harder and more efficiently.
Also, E85 is really no better for emissions (stories to the contrary notwithstanding) than gasoline. Different concerns, but no better overall.
Also, E85 is really no better for emissions (stories to the contrary notwithstanding) than gasoline. Different concerns, but no better overall.
Just wondering how DOD deactivates the Valves? does it remove the lobe from the cam?
Cam lobe control's the valve so the valves will open and close in a DOD motor (especially in a single cam OHV motor like the Gen III / IV motors).
DOD controls Fuel feed from the Injector and spark... Cylinder should still do a complete cycle due to the cam. It would be induction, compression, decompression (due to no combustion), then exhaust.
So a DOD motor from GM will actually feed air into the exhaust line for the cylinders that do not have fuel and spark going on (deactivated pistons).
That increase in air flow in the exhaust line could cause the O2 sensors to read off, which if GM hasn't programed the computer correctly it would try to richen up the mix to compensate for the Lean reading the O2 sensors would give off.
Unless GM has something special going on to stop the cam from pushing the lifters which push the push rods which in turn move the rocker arms that open the valves... DOD still opens the valves.
02-09-2006, 11:17 AM
#34
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Originally Posted by Bring the Noise
Unless GM has something special going on to stop the cam from pushing the lifters which push the push rods which in turn move the rocker arms that open the valves... DOD still opens the valves.
02-09-2006, 08:54 PM
#36
DOHC? Heh, that doesn't sound like GM. Remember a DOHC motor is going to cost tons more. Much much harder to work on, more cramped, higher mass, takes up more space.
Pushrods define GM v8's! Personally, I like easy to work on motors. GM has put so much money and effort into pushrods why turn back now. It is traditional. If you want DOHC get a Honda or a Mustang. DOHC? Yea, but a set of cams in that bitch. Real fun. lol
I don't understand why everyone is so up-ity about DOD. It is already being used with no problems in several GM cars. O2 sensors look at ratios, don't they? What has to be reprogrammed?
Pushrods define GM v8's! Personally, I like easy to work on motors. GM has put so much money and effort into pushrods why turn back now. It is traditional. If you want DOHC get a Honda or a Mustang. DOHC? Yea, but a set of cams in that bitch. Real fun. lol
I don't understand why everyone is so up-ity about DOD. It is already being used with no problems in several GM cars. O2 sensors look at ratios, don't they? What has to be reprogrammed?
02-10-2006, 06:54 AM
#37
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Or how about some coates heads...
A new spherical port-type rotary valve system is incorporated with conventional reciprocating engines by replacing the traditional noisy cumbersome high pumping-loss poppet valve-train.
The operation of this new economical valve package has been proven durable (in extended dynamometer and road tests) and shown to deliver many superior engine performance features.
The only moving element in the new mechanism is one set of rotating spherical valves per cylinder mated with respective floating ports whose sealing actions are linked to the cylinder pressure variation. This creative concept has become a proven engineering reality thanks to recent advancements in design and some new material technology.
Among the beauty of the new invention is no need for costly modification in the existing manufacturing line of the present engine block. It is truly an engine technological breakthrough which offers revolutionized performance and convenience.
Absence of poppet valves and other operating accessories normally housed under the valve cover has permitted elimination of both oil lubrication and cooling water flow in the upper portion of the cylinder head. This reduces the overall engine height by as much as 20 cm from that of its conventional counter part, and maintains a clean engine.
The new, patented simple valve-train unit has minimized the area of contact for fluid flow through the gas exchange ports by making use of wide-open circular cross-sections. This significantly cuts down the pumping loss and unmatchable increases the volumetric efficiency to achieve a high torque/power-density engine.
The new dynamically balanced rotating spherical port valve eliminates entirely mechanical noise produced by current poppet-valve components. Hissing sound generated as gas flow squeaks through the narrow annulus valve opening in the conventional cylinder head is no longer audible. At the same time, the new unit cuts down, by an order of magnitude, the need for power out of the crankshaft. Normally a big parasitic power drain is required in conventional engines to drive the valve train.
Performance & Excellence
SUMMARY
Many production engine blocks mounted with Coates rotary port-valve cylinder heads have been operated in the original host vehicles to implement extensive tests. For example, one of them has successfully been driven over 150,000 miles and shows many performance advantages. Some proven engine characteristics are listed below along with the best probable reasons for the observed results.
LOW MANUFACTURING COST:
• Far fewer parts in simple valve mechanism
• Simple cylinder head
• No costly change in manufacturing line of the existing engine block
• Shorter assembly time
LOW MAINTENANCE COST:
• Simple package to produce fewer troubles
• No oil in the cylinder head to burn or leak
• No liquid lubrication in any part of the rotary valve
• No cooling water in the upper portion of the split cylinder head
LOW NOISE:
• Absence of noisy reciprocating valve train smooths intake
• gas flows and no valve bounce
LOW PARASITIC POWER CONSUMPTION:
• Low pumping loss in gas exchange process
• Low power required for rotary valve operation
HIGH EFFICIENCY ENGINE:
• High critical compression ratio - No hot exhaust valve
• Low parasitic power consumption
• Low pumping loss
HIGH VOLUMETRIC EFFICIENCY:
• Fully opened circular valve ports
• Low-temperature intake port
• No back flow of residual gas
• No need for valve overlap
FLEXIBILITY OF GAS MOTION CONTROL:
• Near zero tradeoff problem between gas motions and volumetric efficiency
• Fully opened circular cross-sectional port|
• Staggered variable valve openings
HIGH TORQUE/POWER-DENSITY ENGINE:
• High volumetric efficiency
• Fewer parts in the engine and simple cylinder head
• High thermal efficiency
• High engine speed-dynamically stable rotating valve with no valve floating problem
HIGH EFFICIENCY IN PART-LOAD OPERATIONS:
Low pumping work
• Use less than 10% power to operate the poppet valve mechanism
LOW KNOCK TENDENCY:
• No high-temperature wall, e.g. exhaust poppet valve
• Low filling work to the intake charge
LOW POLLUTANT EMISSIONS POTENTIAL:
• No oil burned in the valve ports
• Absence of valve overlap
• Low-temperature cylinder head wall
• High exhaust gas temperature
CLEAN ENGINE BLOCK AND COMPARTMENT:
• No oil leakage from the valve cover
• No coolant leakage from the cylinder head/gasket
• No need for valve cover ventilation
FLEXIBILITY OF AUTO-BODY STYLING:
• Low overall height- Absence of valve cover
• No water jacket in upper portion of the cylinder head
• Compact and clean engine package
-Sly
A new spherical port-type rotary valve system is incorporated with conventional reciprocating engines by replacing the traditional noisy cumbersome high pumping-loss poppet valve-train.
The operation of this new economical valve package has been proven durable (in extended dynamometer and road tests) and shown to deliver many superior engine performance features.
The only moving element in the new mechanism is one set of rotating spherical valves per cylinder mated with respective floating ports whose sealing actions are linked to the cylinder pressure variation. This creative concept has become a proven engineering reality thanks to recent advancements in design and some new material technology.
Among the beauty of the new invention is no need for costly modification in the existing manufacturing line of the present engine block. It is truly an engine technological breakthrough which offers revolutionized performance and convenience.
Absence of poppet valves and other operating accessories normally housed under the valve cover has permitted elimination of both oil lubrication and cooling water flow in the upper portion of the cylinder head. This reduces the overall engine height by as much as 20 cm from that of its conventional counter part, and maintains a clean engine.
The new, patented simple valve-train unit has minimized the area of contact for fluid flow through the gas exchange ports by making use of wide-open circular cross-sections. This significantly cuts down the pumping loss and unmatchable increases the volumetric efficiency to achieve a high torque/power-density engine.
The new dynamically balanced rotating spherical port valve eliminates entirely mechanical noise produced by current poppet-valve components. Hissing sound generated as gas flow squeaks through the narrow annulus valve opening in the conventional cylinder head is no longer audible. At the same time, the new unit cuts down, by an order of magnitude, the need for power out of the crankshaft. Normally a big parasitic power drain is required in conventional engines to drive the valve train.
Performance & Excellence
SUMMARY
Many production engine blocks mounted with Coates rotary port-valve cylinder heads have been operated in the original host vehicles to implement extensive tests. For example, one of them has successfully been driven over 150,000 miles and shows many performance advantages. Some proven engine characteristics are listed below along with the best probable reasons for the observed results.
LOW MANUFACTURING COST:
• Far fewer parts in simple valve mechanism
• Simple cylinder head
• No costly change in manufacturing line of the existing engine block
• Shorter assembly time
LOW MAINTENANCE COST:
• Simple package to produce fewer troubles
• No oil in the cylinder head to burn or leak
• No liquid lubrication in any part of the rotary valve
• No cooling water in the upper portion of the split cylinder head
LOW NOISE:
• Absence of noisy reciprocating valve train smooths intake
• gas flows and no valve bounce
LOW PARASITIC POWER CONSUMPTION:
• Low pumping loss in gas exchange process
• Low power required for rotary valve operation
HIGH EFFICIENCY ENGINE:
• High critical compression ratio - No hot exhaust valve
• Low parasitic power consumption
• Low pumping loss
HIGH VOLUMETRIC EFFICIENCY:
• Fully opened circular valve ports
• Low-temperature intake port
• No back flow of residual gas
• No need for valve overlap
FLEXIBILITY OF GAS MOTION CONTROL:
• Near zero tradeoff problem between gas motions and volumetric efficiency
• Fully opened circular cross-sectional port|
• Staggered variable valve openings
HIGH TORQUE/POWER-DENSITY ENGINE:
• High volumetric efficiency
• Fewer parts in the engine and simple cylinder head
• High thermal efficiency
• High engine speed-dynamically stable rotating valve with no valve floating problem
HIGH EFFICIENCY IN PART-LOAD OPERATIONS:
Low pumping work
• Use less than 10% power to operate the poppet valve mechanism
LOW KNOCK TENDENCY:
• No high-temperature wall, e.g. exhaust poppet valve
• Low filling work to the intake charge
LOW POLLUTANT EMISSIONS POTENTIAL:
• No oil burned in the valve ports
• Absence of valve overlap
• Low-temperature cylinder head wall
• High exhaust gas temperature
CLEAN ENGINE BLOCK AND COMPARTMENT:
• No oil leakage from the valve cover
• No coolant leakage from the cylinder head/gasket
• No need for valve cover ventilation
FLEXIBILITY OF AUTO-BODY STYLING:
• Low overall height- Absence of valve cover
• No water jacket in upper portion of the cylinder head
• Compact and clean engine package
-Sly
02-10-2006, 06:56 AM
#38
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The Coates Spherical Rotary Valve Engine is the most advanced in the world, with the most positive valving system ever built. The breathing capabilities of the system are almost double that of a poppet valve. For instance: a static test of a five-litre poppet valve engine on an airflow machine produced a reading of 133 cubic feet per minute (CFM) with valve fully opened. The five-litre Coates Spherical Rotary Valve Engine on the same machine, however, produced a reading of 319 CFMs fully opened; a colossal advantage in airflow comparison. A five-litre poppet vavle engine tested on a dynomometer under the same loads and conditions at 5500 produced 480 BHP and 454 foot pounds of torque. The maximum RPMs on the poppet valve engine were 5700 RPMs; the Spherical Rotary Valve Engine in comparison reached 14,850 RPM's, The Coates Spherical Rotary Valve comprises two spherical rotary valves assembled on two separate shafts - one for inlet and one for exhaust. They rotate on ceramic carbon bearing with no oil lubrication, the spheres do not make contact with any part of the housing. The seals are a floating type and are also made of a ceramic material. They have two piston rings and are floating in a small cylinder-type chamber, they are activated by the compression and the combustion strokes of the engine which allows 100 percent sealing effectiveness, when compressed.
02-10-2006, 06:56 AM
#39
GM has done pushrod V8 but its also done some mighty fine DOHC engines! the "Red top" 2.0 ltr four was outstanding! you can get 300bhp out of one N/A. that 150bhp per Ltr!!!! so they do know how to do it and can make it work! also they have done some nice V6's.
Chris.
Chris.
02-10-2006, 08:46 AM
#40
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Originally Posted by chuntington101
GM has done pushrod V8 but its also done some mighty fine DOHC engines! the "Red top" 2.0 ltr four was outstanding! you can get 300bhp out of one N/A. that 150bhp per Ltr!!!! so they do know how to do it and can make it work! also they have done some nice V6's.
Chris.
Chris.