i know from when they claimed the trailvoy in 02 had 270hp and then in 03 they revised the head and cams design to get the extra 5 hp. What actually did they do. Was the head worked over a lil bit, and the cams completely changed.
IceN
From what I recall reading, the cam phaser has a few degrees more authority starting in '03 than the original '02 unit. I don't recall the heads being changed, however the head-gasket was reworked.....the diagrams I saw indicated there was less material between the cylinders (ie: less gasket and more openning) and it appeared to be a move to reduce the cost of the gasket more than anything else. (They claimed better sealing, but with less material not sure how that would work). Also modified was the oil pump, which was supposed to aid in quieting the engine along with the poly coated pistons.
I don't think the gasket was thinner it just had more cut-out of it between the cylinders and passages......head gaskets aren't thick by any stretch of the imagination to begin with. (For the most part they're a thin sheet of steel with a teflon sealer/coating applied to them). Even if they managed to make them 'thinner', it would be a negligible affect on compression.
Now for 2006, they did raise the compression a tad to help get the additional 16 hp and still managed to keep it running regular 87 octane fuel.
Now for 2006, they did raise the compression a tad to help get the additional 16 hp and still managed to keep it running regular 87 octane fuel.
does that mean all i need to do to get that extra 15hp is take the crank out, shave it down by lets say 3mm and that would give me a higher compression ratio?? right now my '02 is 10:1
Curious, what would you shave on the crank? If you shave the journals, the over-sized bearings would re-center it and the compression would still be the same. - Shaving it wouldn't affect the compression ratio.
What you would need to do is install a higher compression piston or slightly longer connecting rods in order to reduce the volume above the piston at full stroke. Milling the heads a bit to reduce the combustion chamber size would also be an option to increase the compression ratio. (Either way you'd need to check the clearances before firing things up, to make sure the pistons aren't going to hit the valves...also known as blue-printing the motor).
Keep in mind that increasing spark advance also increases the static compression and thus creates add'l power.....which is in part how a PCM tune works. (Whole lot easier to play with spark advanced than tear down a motor to increase the mechanical compression ratio....the '06 only increases from 10 to 10.3:1).
What you would need to do is install a higher compression piston or slightly longer connecting rods in order to reduce the volume above the piston at full stroke. Milling the heads a bit to reduce the combustion chamber size would also be an option to increase the compression ratio. (Either way you'd need to check the clearances before firing things up, to make sure the pistons aren't going to hit the valves...also known as blue-printing the motor).
Keep in mind that increasing spark advance also increases the static compression and thus creates add'l power.....which is in part how a PCM tune works. (Whole lot easier to play with spark advanced than tear down a motor to increase the mechanical compression ratio....the '06 only increases from 10 to 10.3:1).
Here are the changes for 2006 (LONG!)
VORTEC 4200 4.2L I-6 (LL8)
2006 model year summary
• Increased horsepower and torque outputs
• Higher 10.3:1 compression ratio
• Improved air flow
• Mass air flow sensor
• Improved A.I.R. system
• Improved ignition coils
• Piston rod squirters
Full descriptions of new or changed features
Increased horsepower and torque
The Vortec 4200, already noted for providing peak power and torque emulating that of competitors’ larger-displacement V-8s, delivers 16 more horsepower for 2006. Its new rating is 291 hp and 277 lb.-ft. of torque. The power increase resulted from a higher compression ratio and improved engine breathing. GM Powertrain’s participation in the new SAE test certification procedure provides more accurate readings of in-vehicle performance by using more exact measures of exhaust backpressure and also accounting for loads put on the engine by the accessory drive.
Increased compression ratio
The Vortec 4200’s compression ratio increased to 10.3:1 as a result of changes to its piston profile, which lowered the volume in the combustion chamber. Even with its higher compression ratio, the engine continues to maximize fuel economy by allowing customers to use regular or unleaded fuel.
Improved air flow
Improved performance also results from increased airflow into and through the engine. A larger (38.7 mm) intake valve and larger (33.5 mm) exhaust valve allow more air to flowthrough, and the camshaft also provides more lift to allow the valves to stay open longer.
Mass air flow sensor
A mass air flow system helps reduce emissions, allowing the Vortec 4200 to meet California LEV II emissions requirements while also improving its fuel economy.
The mass air flow (MAF) sensor (replacing a previous speed density fuel control system) more accurately measures air flow into the engine, eliminating variability in a number of conditions including changes in altitude and temperature, and allows more precise fuel and spark response.
The MAF is lightweight and has a modular design, using an integrated intake air temperature sensor. The electronics, located in the center of the sensor’s flow tube, are air cooled by the intake air. The output calibration is precisely programmed into the module.
A.I.R. system
The Air Injection Reaction (A.I.R) System, which pumps air into the port of each cylinder head, has also been upgraded to assist in reducing emissions. During the casting process, the A.I.R. port is now cast right into the cylinder head for improved air flow.
Ignition coils
The ignition system uses more compact coils, which also provide better reliability/ durability and make better use of its energy. Their more compact size saves an entire coil’s worth of weight. Enhanced durability has been proven from the coils’ use in other Gen III engines.
Piston rod oil squirters
The piston, inside the cylinder bore of the engine block, transfers energy through the connecting rod to the crankshaft. For improved durability and quietness the piston rod is now drilled with a tiny (less than 1/8th mm) hole, which allows oil to be sprayed on the cylinder wall, providing a cushioning layer on the sides of the piston which rides on the film of oil.
The oil is originally pumped into the crankshaft, whose journals have cross-drilled holes. As the crankshaft rotates, pumping oil through the journals, the oil is fed from the journals through the piston rod bearing into the piston rod itself. Its open orifice then allows the oil to be sprayed into the cylinder wall.
Overview
The award-winning Vortec 4200 4.2L I6 (LL8), which won rave reviews in virtually every automotive media outlet when introduced in 2002 and awards, including three consecutive appearances on Ward's Auto World's 10 Best Engines list, has continually been refined to optimize value and performance.
During the five years since the engine’s launch, virtually every system and technology, from emissions control to engine management to sealing, has been examined and refined. In 2003, the Vortec 4200 was fitted with polymer-coated pistons that reduce engine noise and enhance durability. The oil pump was refined to limit noise; and the cam-chain tensioner was improved for quieter operation. For model year 2004, the Vortec 4200 was introduced in the all-new Buick Rainier and Isuzu Ascender. In ’05 its variable valve timing, or cam phasing, system was equipped with a new state-of-the-art vane phaser. Along with previous GM midsize SUVs, ’05 also saw the Vortec 4200 introduced in the Saab’s first 9-7X SUV.
The Vortec 4200 originally debuted as the first inline six-cylinder engine in GM Powertrain’s lineup in nearly 20 years. While the industry largely had turned away from the inline six, GM recognized that, given careful design and development, the inherent advantages of inline six-cylinder architecture were perfect for the new millennium. With the technical sophistication of premium passenger car engines and the power of competitors’ V-8s, the Vortec 4200 is no ordinary inline six. Its flexible architecture provides the foundation for a range of inline engines, maximizing the return on corporate investment while exceeding customers’ performance expectations.
An exceptionally light, rigid engine block and cylinder head combination, cast with the GM's patented lost foam process, provide the foundation for the Vortec 4200’s success. All-aluminum construction means less weight than conventional cast-iron truck engines, and less weight means improved fuel economy. The bottom end of the engine derivesstrength through many features, starting with a bearing beam, or ladder, that connects the seven main bearing caps to further stiffen the engine’s structure. The oil pan bolts to the transmission bell housing as well as the engine block, eliminating points of vibration and making the complete engine more like a single casting. The oil pan also gives “pan-axle” all-wheel drive capability to trucks equipped with the Vortec 4200. A passage cast through the width of the oil pan allows a drive axle to pass through it rather than under it, allowing the engine to be placed lower in the vehicle for a more compact package that improves the vehicle’s handling dynamics and gives designers greater styling flexibility.
The Vortec 4200's feature list reads like those for premium luxury/performance car engines: dual-overhead cam cylinder head, four valves per cylinder, roller-follower valve actuation and exhaust-cam phasing; a 10.3:1 compression ratio that delivers the seemingly incompatible benefits of high compression and regular-grade fuel; Electronic Throttle Control (ETC); and direct accessory mounting.
Vehicle platform teams recognize the Vortec 4200’s strengths, yet its design advantages and premium features mean little if the finished product doesn’t deliver what customers demand, like low maintenance. With Vortec 4200, oil changes are the only scheduled maintenance during the first 100,000 miles of operation, and even those are as stress-free as possible. GM’s Oil Life System (GMOLS) advises an oil change when it’s actually needed, based on real-world vehicle operation, rather than a predetermined mileage interval. The oil filter is easily accessible from underneath Vortec 4200-equipped vehicles and is mounted pointing straight down, reducing the potential for spilling oil during removal.
Most of all, customers demand performance and economy. Along with delivering even more peak horsepower and torque comparable to competitors’ larger-displacement V-8s, the Vortec 4200 also has higher EPA mileage ratings (based on published figures available in March 2005).
The Vortec 4200 is produced in Flint, Michigan.
VORTEC 4200 4.2L I-6 (LL8)
2006 model year summary
• Increased horsepower and torque outputs
• Higher 10.3:1 compression ratio
• Improved air flow
• Mass air flow sensor
• Improved A.I.R. system
• Improved ignition coils
• Piston rod squirters
Full descriptions of new or changed features
Increased horsepower and torque
The Vortec 4200, already noted for providing peak power and torque emulating that of competitors’ larger-displacement V-8s, delivers 16 more horsepower for 2006. Its new rating is 291 hp and 277 lb.-ft. of torque. The power increase resulted from a higher compression ratio and improved engine breathing. GM Powertrain’s participation in the new SAE test certification procedure provides more accurate readings of in-vehicle performance by using more exact measures of exhaust backpressure and also accounting for loads put on the engine by the accessory drive.
Increased compression ratio
The Vortec 4200’s compression ratio increased to 10.3:1 as a result of changes to its piston profile, which lowered the volume in the combustion chamber. Even with its higher compression ratio, the engine continues to maximize fuel economy by allowing customers to use regular or unleaded fuel.
Improved air flow
Improved performance also results from increased airflow into and through the engine. A larger (38.7 mm) intake valve and larger (33.5 mm) exhaust valve allow more air to flowthrough, and the camshaft also provides more lift to allow the valves to stay open longer.
Mass air flow sensor
A mass air flow system helps reduce emissions, allowing the Vortec 4200 to meet California LEV II emissions requirements while also improving its fuel economy.
The mass air flow (MAF) sensor (replacing a previous speed density fuel control system) more accurately measures air flow into the engine, eliminating variability in a number of conditions including changes in altitude and temperature, and allows more precise fuel and spark response.
The MAF is lightweight and has a modular design, using an integrated intake air temperature sensor. The electronics, located in the center of the sensor’s flow tube, are air cooled by the intake air. The output calibration is precisely programmed into the module.
A.I.R. system
The Air Injection Reaction (A.I.R) System, which pumps air into the port of each cylinder head, has also been upgraded to assist in reducing emissions. During the casting process, the A.I.R. port is now cast right into the cylinder head for improved air flow.
Ignition coils
The ignition system uses more compact coils, which also provide better reliability/ durability and make better use of its energy. Their more compact size saves an entire coil’s worth of weight. Enhanced durability has been proven from the coils’ use in other Gen III engines.
Piston rod oil squirters
The piston, inside the cylinder bore of the engine block, transfers energy through the connecting rod to the crankshaft. For improved durability and quietness the piston rod is now drilled with a tiny (less than 1/8th mm) hole, which allows oil to be sprayed on the cylinder wall, providing a cushioning layer on the sides of the piston which rides on the film of oil.
The oil is originally pumped into the crankshaft, whose journals have cross-drilled holes. As the crankshaft rotates, pumping oil through the journals, the oil is fed from the journals through the piston rod bearing into the piston rod itself. Its open orifice then allows the oil to be sprayed into the cylinder wall.
Overview
The award-winning Vortec 4200 4.2L I6 (LL8), which won rave reviews in virtually every automotive media outlet when introduced in 2002 and awards, including three consecutive appearances on Ward's Auto World's 10 Best Engines list, has continually been refined to optimize value and performance.
During the five years since the engine’s launch, virtually every system and technology, from emissions control to engine management to sealing, has been examined and refined. In 2003, the Vortec 4200 was fitted with polymer-coated pistons that reduce engine noise and enhance durability. The oil pump was refined to limit noise; and the cam-chain tensioner was improved for quieter operation. For model year 2004, the Vortec 4200 was introduced in the all-new Buick Rainier and Isuzu Ascender. In ’05 its variable valve timing, or cam phasing, system was equipped with a new state-of-the-art vane phaser. Along with previous GM midsize SUVs, ’05 also saw the Vortec 4200 introduced in the Saab’s first 9-7X SUV.
The Vortec 4200 originally debuted as the first inline six-cylinder engine in GM Powertrain’s lineup in nearly 20 years. While the industry largely had turned away from the inline six, GM recognized that, given careful design and development, the inherent advantages of inline six-cylinder architecture were perfect for the new millennium. With the technical sophistication of premium passenger car engines and the power of competitors’ V-8s, the Vortec 4200 is no ordinary inline six. Its flexible architecture provides the foundation for a range of inline engines, maximizing the return on corporate investment while exceeding customers’ performance expectations.
An exceptionally light, rigid engine block and cylinder head combination, cast with the GM's patented lost foam process, provide the foundation for the Vortec 4200’s success. All-aluminum construction means less weight than conventional cast-iron truck engines, and less weight means improved fuel economy. The bottom end of the engine derivesstrength through many features, starting with a bearing beam, or ladder, that connects the seven main bearing caps to further stiffen the engine’s structure. The oil pan bolts to the transmission bell housing as well as the engine block, eliminating points of vibration and making the complete engine more like a single casting. The oil pan also gives “pan-axle” all-wheel drive capability to trucks equipped with the Vortec 4200. A passage cast through the width of the oil pan allows a drive axle to pass through it rather than under it, allowing the engine to be placed lower in the vehicle for a more compact package that improves the vehicle’s handling dynamics and gives designers greater styling flexibility.
The Vortec 4200's feature list reads like those for premium luxury/performance car engines: dual-overhead cam cylinder head, four valves per cylinder, roller-follower valve actuation and exhaust-cam phasing; a 10.3:1 compression ratio that delivers the seemingly incompatible benefits of high compression and regular-grade fuel; Electronic Throttle Control (ETC); and direct accessory mounting.
Vehicle platform teams recognize the Vortec 4200’s strengths, yet its design advantages and premium features mean little if the finished product doesn’t deliver what customers demand, like low maintenance. With Vortec 4200, oil changes are the only scheduled maintenance during the first 100,000 miles of operation, and even those are as stress-free as possible. GM’s Oil Life System (GMOLS) advises an oil change when it’s actually needed, based on real-world vehicle operation, rather than a predetermined mileage interval. The oil filter is easily accessible from underneath Vortec 4200-equipped vehicles and is mounted pointing straight down, reducing the potential for spilling oil during removal.
Most of all, customers demand performance and economy. Along with delivering even more peak horsepower and torque comparable to competitors’ larger-displacement V-8s, the Vortec 4200 also has higher EPA mileage ratings (based on published figures available in March 2005).
The Vortec 4200 is produced in Flint, Michigan.
ok i know i wont be able to increase the bore of the intake and exhaust valves without spending $$$$$$$$$$$, but note how the quote below says the camshaft allows more lift to allow the valves to stay open longer. The particular part i was thinking of shaving was where the connecting rods join on the crank shaft. Don't know if this will work, but was an idea.ylab said:
tblazed said:
'06 head
All,
The '06 and up head is way better than the earlier parts - a head with seat and guide installed is not that much $$$ from GM, do a minor clean up on the intake ports ( to remove the casting flash lumps) and port the exhaust out to the exhaust gasket size and you will easily add 50HP using the stock '06 cams. I just had my ported '06 head flow tested. The intake flowed 310cfm and the exhaust 215 cfm - now go look and see what an aftermarket SBC aluminum head flow numbers are say AFR or Brodix both excellent heads .... And these are to fill a bigger cylinder than the 4200.
Want to make power with this engine other than a turbo its all in the head and camshafts. Gerry Arnold is running the 4200 in comp eliminator and is make 600HP NA with it - mind you this is a full out race engine running 10200 rpm through the top end of the 1/4. Not exactly a street engine but it illustrates what is possible. I think 400 HP (flywheel)with cams and a good head port is well within the capabilities of this engine.
There is a small nucleus of hard core folks that are racing and making parts for this engine.
If more people started ordering camshafts from Comp cams they said they would consider making 1 or 2 part numbers available - but these are not your $200 cams - your looking at around $1700 for a pair of billet cams - why so much?
Well GM has flat out refused to sell unground cam blanks - no blanks - no cams. That is until recently when a bunch of the above mentioned folks designed a CNC program to get billet steel cores cut. From these round blanks Comp can cut finished cams but its not a cheap process. I know first hand as I have a set of custom cams waiting on the shelf to go into the turbo engine.
I'm considering leaving the turbo on the shelf initially and dyno testing just the head and cams with a stock '06 exhaust manifold ( untouched) to see how much balls this engine will have NA. Then put the turbo on it.
Its a chicken and egg situation - no parts - no demand... no demand == no parts. The way to break that endless circle is to start asking for parts. I know about the endless header quest here so I can understand the frustration. Actually the stock exhaust manifold is not a bad piece - just get it extrude honed and it will do quite well.
If folks decided they wanted cams as a group buy I'll take on the task of talking to Comp.
All,
The '06 and up head is way better than the earlier parts - a head with seat and guide installed is not that much $$$ from GM, do a minor clean up on the intake ports ( to remove the casting flash lumps) and port the exhaust out to the exhaust gasket size and you will easily add 50HP using the stock '06 cams. I just had my ported '06 head flow tested. The intake flowed 310cfm and the exhaust 215 cfm - now go look and see what an aftermarket SBC aluminum head flow numbers are say AFR or Brodix both excellent heads .... And these are to fill a bigger cylinder than the 4200.
Want to make power with this engine other than a turbo its all in the head and camshafts. Gerry Arnold is running the 4200 in comp eliminator and is make 600HP NA with it - mind you this is a full out race engine running 10200 rpm through the top end of the 1/4. Not exactly a street engine but it illustrates what is possible. I think 400 HP (flywheel)with cams and a good head port is well within the capabilities of this engine.
There is a small nucleus of hard core folks that are racing and making parts for this engine.
If more people started ordering camshafts from Comp cams they said they would consider making 1 or 2 part numbers available - but these are not your $200 cams - your looking at around $1700 for a pair of billet cams - why so much?
Well GM has flat out refused to sell unground cam blanks - no blanks - no cams. That is until recently when a bunch of the above mentioned folks designed a CNC program to get billet steel cores cut. From these round blanks Comp can cut finished cams but its not a cheap process. I know first hand as I have a set of custom cams waiting on the shelf to go into the turbo engine.
I'm considering leaving the turbo on the shelf initially and dyno testing just the head and cams with a stock '06 exhaust manifold ( untouched) to see how much balls this engine will have NA. Then put the turbo on it.
Its a chicken and egg situation - no parts - no demand... no demand == no parts. The way to break that endless circle is to start asking for parts. I know about the endless header quest here so I can understand the frustration. Actually the stock exhaust manifold is not a bad piece - just get it extrude honed and it will do quite well.
If folks decided they wanted cams as a group buy I'll take on the task of talking to Comp.
head comparison
Though I'd post some pix of the early and late head
Late head with perf springs installed
Late head - ported with OEM exhaust gasket installed. Close up.
Stock early head with late OEM exhaust gasket installed
Stock early head top - ported late head bottom - exhaust ports
Stock early head top - ported late head bottom intake ports
Late head with inconel valves installed - turbo ready
Though I'd post some pix of the early and late head
Late head with perf springs installed
Late head - ported with OEM exhaust gasket installed. Close up.
Stock early head with late OEM exhaust gasket installed
Stock early head top - ported late head bottom - exhaust ports
Stock early head top - ported late head bottom intake ports
Late head with inconel valves installed - turbo ready
Wow man, if I could get an 06+ engine Id swap it in after seeing those pics. Looks like theres a lot left on the table, and nice p'n'p job. Wonder if I could just swap an 06+ head onto my 02 block? Think there'd be a nice performance bump with that port and polish job for sure.
Just wish I had the $$$ for a 06+ motor so I could get a set of custom cams and follow your turbo build a little more for my TB. But man thats a lot of money for me to drop as a college student into my (still) parent's car. Ill end up with a new(er) car before long, probably about a year or so that will be mine and then it'll get a lot of "goodies" added on.
Just wish I had the $$$ for a 06+ motor so I could get a set of custom cams and follow your turbo build a little more for my TB. But man thats a lot of money for me to drop as a college student into my (still) parent's car. Ill end up with a new(er) car before long, probably about a year or so that will be mine and then it'll get a lot of "goodies" added on.
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