LT4 Hot Cam Question
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Joined: Jun 2003
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From: san antonio tx
LT4 Hot Cam Question
I have a LT4 and am anticipating installing the LT4 Hot Cam. Do I need the whole kit or is just the cam itself necessary? I understand the rocker rollers are 1.6 and the springs and retainers are already on the LT4 heads. The car has 47K and how about replacing the cam timing chain.
All recommendations greatly appreciated.
All recommendations greatly appreciated.
Le Mans Master
Joined: Jan 2003
Posts: 8,596
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From: Portland Oregon
Re: LT4 Hot Cam Question (owen lancaster)
While you are in there, you may as well install a decent timing set. Use the GM LT4 extreme timing set. It is expensive but well worth the peace of mind. Especially if you see the difference in the chain itself. The original will appear to be a cheap necklace with its anemic looking links.
The Extreme timing set is GM PN 12370835
The "Kit" included new 1.6 roller rockers that converts the zero lash style rockers to adjustable. However that would necessitate replacing the rocker arm studs with GM PN 12371058. Or you can use a ARP 3/8 rocker arm stud kit that is designed for heads without push rod guidel plates.
Using the adjustable rockers gives you better control over the amount of preload on the lifters. Not all cylinder heads are machined exactly the same. So even if you "Zero" lash the lifter using the old rockers, some lifters maybe preloaded more than others or not enough.
For the price of the kit its a good deal. You can sell the extra parts on the here as well to recoup a little of the cost. And don't forget to look over the Opti Crap unit and be careful when removing the water pump take care not to dump antifreeze on the Opti. I always drain the block by removing the knock sensors. That way it prevents any additional coolant from draining on the floor when the water pump is removed.
The Extreme timing set is GM PN 12370835
The "Kit" included new 1.6 roller rockers that converts the zero lash style rockers to adjustable. However that would necessitate replacing the rocker arm studs with GM PN 12371058. Or you can use a ARP 3/8 rocker arm stud kit that is designed for heads without push rod guidel plates.
Using the adjustable rockers gives you better control over the amount of preload on the lifters. Not all cylinder heads are machined exactly the same. So even if you "Zero" lash the lifter using the old rockers, some lifters maybe preloaded more than others or not enough.
For the price of the kit its a good deal. You can sell the extra parts on the here as well to recoup a little of the cost. And don't forget to look over the Opti Crap unit and be careful when removing the water pump take care not to dump antifreeze on the Opti. I always drain the block by removing the knock sensors. That way it prevents any additional coolant from draining on the floor when the water pump is removed.
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: LT4 Hot Cam Question (Nathan Plemons)
Nope :( It is unfortunately the anemic chain set up.
http://www.hashmarks.com/techtips/ca...tor%20ring.jpg
That is the set up on Jims 96 GS when he installed his HOT cam.
http://www.hashmarks.com/techtips/ca...tor%20ring.jpg
That is the set up on Jims 96 GS when he installed his HOT cam.
Drifting
Joined: Jul 2000
Posts: 1,661
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From: Phoenix, Arizona
Re: LT4 Hot Cam Question (tjwong)
:iagree: Technically speaking, all you need is the cam. However, the Extreme Duty Timing Set is a great recommendation. Also, draining by removing the knock sensors - be careful not to overtighten when putting them back.
The stock LT4 springs are OK with the Hot Cam, but they are close to their limits.
JMHO, but the stock LT4 studs are 10mm. That is between 3/8 and 7/16. I would not recommend going to smaller 3/8 studs. If you change, go to 7/16 and different rockers = greater strength & stability.
The stock LT4 springs are OK with the Hot Cam, but they are close to their limits.
JMHO, but the stock LT4 studs are 10mm. That is between 3/8 and 7/16. I would not recommend going to smaller 3/8 studs. If you change, go to 7/16 and different rockers = greater strength & stability.
Race Director
Joined: Apr 2000
Posts: 15,344
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From: Texas
Re: LT4 Hot Cam Question (tjwong)
Just a random thought or two or three or...
- If money is no object, buy the Extreme Duty (ED) set. Keep in mind it's a couple hundred dollars minimum.
- If you intend to beat the living poopie out of the engine on a weekly basis (i.e. 4 grand clutch dumps with drag radials out back), buy the ED set
- If the first two don't apply, stick with the stock chain (I did)
- The LT4 has a pretty good/light valvetrain. It's good to 6800rpm with the stock pieces.
- My stock LT4 chain with 68k miles was perfect. Realistically, it could have been reused. My engine has seen drag racing, autocrossing, aggressive street use, and the road course.
Just my opinions.
- If money is no object, buy the Extreme Duty (ED) set. Keep in mind it's a couple hundred dollars minimum.
- If you intend to beat the living poopie out of the engine on a weekly basis (i.e. 4 grand clutch dumps with drag radials out back), buy the ED set
- If the first two don't apply, stick with the stock chain (I did)
- The LT4 has a pretty good/light valvetrain. It's good to 6800rpm with the stock pieces.
- My stock LT4 chain with 68k miles was perfect. Realistically, it could have been reused. My engine has seen drag racing, autocrossing, aggressive street use, and the road course.
Just my opinions.
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Racer
Joined: Apr 2003
Posts: 260
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From: Palm Bay Fl
Re: LT4 Hot Cam Question (tjwong)
Nope :( It is unfortunately the anemic chain set up.
That is the set up on Jims 96 GS when he installed his HOT cam.
That is the set up on Jims 96 GS when he installed his HOT cam.
-Dave C.
Le Mans Master
Joined: Jun 2002
Posts: 6,097
Likes: 2
From: Cincinnati Oh
Re: LT4 Hot Cam Question (Nathan Plemons)
The LT4 has a "Heavt Duty" timing chain, not the Extreme Duty set.
LT1: Chain, Timing Powdered metal butt link #10128485
LT4: Single Roller (made for GM by Cloyes) Steel #12555887
The ED # has already been posted. I would get it since you'd already be in there for the cam.
Race Director
Joined: Apr 2000
Posts: 15,344
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From: Texas
Re: LT4 Hot Cam Question (Dave C. '97 Z28)
Nope :( It is unfortunately the anemic chain set up.
That is the set up on Jims 96 GS when he installed his HOT cam.
That picture is the Extreme Duty chain. If that's the stock LT-4 chain, then the LT-4 has the extreme duty already.
-Dave C.
That is the set up on Jims 96 GS when he installed his HOT cam.
That picture is the Extreme Duty chain. If that's the stock LT-4 chain, then the LT-4 has the extreme duty already.
-Dave C.
Burning Brakes
Joined: Jun 2003
Posts: 1,229
Likes: 1
Re: LT4 Hot Cam Question (96GS#007)
I know this is a little off topic, but I have an L98.
I was also told that an LT4 Hotcamkit could be installed in my engine.
What if the LT4 hotcam and 1.6 lifter and better springs, and Ram air intake were installed in my engine, and the same on an LT4.... I know that the LT4 woudl make more power then my L98....
But what exactly is the reason for the LT4 for making more power.
Lets say both engine had also the same exaust manifold and exhaust system.
Just a question for you expert out there :cheers:
I was also told that an LT4 Hotcamkit could be installed in my engine.
What if the LT4 hotcam and 1.6 lifter and better springs, and Ram air intake were installed in my engine, and the same on an LT4.... I know that the LT4 woudl make more power then my L98....
But what exactly is the reason for the LT4 for making more power.
Lets say both engine had also the same exaust manifold and exhaust system.
Just a question for you expert out there :cheers:
Race Director
Joined: Apr 2000
Posts: 15,344
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From: Texas
Re: LT4 Hot Cam Question (TheStef)
Given that you've normalized everything (i.e. intake, exhaust), the LT4 will make more power primarily for the following two reasons...
- Higher compression ratio (10.8:1 vs ~10:1 for the L98)
- The LT4 has much better cylinder heads
- Higher compression ratio (10.8:1 vs ~10:1 for the L98)
- The LT4 has much better cylinder heads
Racer
Joined: Apr 2003
Posts: 260
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From: Palm Bay Fl
Re: LT4 Hot Cam Question (96GS#007)
Oops... Well, the gears look like the gears from the extreme duty setup. I guess that's what threw me off. The LT-1 gears look different than those LT-4 gears, which are solid. The LT-1 gears have slots in them like the standard Chevy timing gear, and the chain is a PM non-roller chain. At least the LT-4 came with SOME kind of roller chain.
My Bad....
-Dave C.
[Modified by Dave C. '97 Z28, 3:10 PM 9/17/2003]
My Bad....
-Dave C.
Nope :( It is unfortunately the anemic chain set up.
That is the set up on Jims 96 GS when he installed his HOT cam.
That picture is the Extreme Duty chain. If that's the stock LT-4 chain, then the LT-4 has the extreme duty already.
-Dave C.
I can assure you the chain in the pic that Tom linked to is the Stock LT4 chain and not the Extreme Duty Chain. Why? It's my car/engine/chain in the picture :)
That is the set up on Jims 96 GS when he installed his HOT cam.
That picture is the Extreme Duty chain. If that's the stock LT-4 chain, then the LT-4 has the extreme duty already.
-Dave C.
I can assure you the chain in the pic that Tom linked to is the Stock LT4 chain and not the Extreme Duty Chain. Why? It's my car/engine/chain in the picture :)
[Modified by Dave C. '97 Z28, 3:10 PM 9/17/2003]
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: LT4 Hot Cam Question (TheStef)
I know this is a little off topic, but I have an L98.
I was also told that an LT4 Hotcamkit could be installed in my engine.
What if the LT4 hotcam and 1.6 lifter and better springs, and Ram air intake were installed in my engine, and the same on an LT4.... I know that the LT4 woudl make more power then my L98....
But what exactly is the reason for the LT4 for making more power.
Lets say both engine had also the same exaust manifold and exhaust system.
Just a question for you expert out there :cheers:
I was also told that an LT4 Hotcamkit could be installed in my engine.
What if the LT4 hotcam and 1.6 lifter and better springs, and Ram air intake were installed in my engine, and the same on an LT4.... I know that the LT4 woudl make more power then my L98....
But what exactly is the reason for the LT4 for making more power.
Lets say both engine had also the same exaust manifold and exhaust system.
Just a question for you expert out there :cheers:
The stock TPI intake is the single largest restriction in the L98 engine design where top end horsepower is concerned, it simply cannot flow the volume of air required above about 4500 RPM's. So even if you had identically flowing heads with the same compression ratio coupled to the same exhaust system the TPI would make far less top end horsepower. It would probably have a fair advantage in low RPM torque though. It's just the nature of the intake.
BTW the LT1/LT4 have a reverse flow cooling system, which means the cooler water from the radiator comes to the cylinder heads first, keeping them cooler and allowing for the higher compression ratio.
Burning Brakes
Joined: Jun 2003
Posts: 1,229
Likes: 1
Re: LT4 Hot Cam Question (Nathan Plemons)
Sorry Nathan, I ment SuperRam.
Thats what I wanted to know about the differences between LT1 or LT4 and L98
So the heads are cooled first
cool, anything else different?
[Modified by TheStef, 9:38 AM 9/17/2003]
Thats what I wanted to know about the differences between LT1 or LT4 and L98
So the heads are cooled first
cool, anything else different?
[Modified by TheStef, 9:38 AM 9/17/2003]
Burning Brakes
Joined: Oct 2000
Posts: 897
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From: My Own Private Idaho
Re: LT4 Hot Cam Question
http://grandsportregistry.com/lt1vslt4.htm#CHAIN
ROLLER TIMING CHAIN
Stock LT1 has powdered metal butt link chain drive for the camshaft and water Pump. LT4 has smaller but stronger steel roller chain. Although it seems that the new chain and sprockets would reduce mass, The cam sprocket was left solid, rather than webbed, specifically for additional mass. Increased inertia in the system reduces the tendency for cam torsion.
ROLLER TIMING CHAIN
Stock LT1 has powdered metal butt link chain drive for the camshaft and water Pump. LT4 has smaller but stronger steel roller chain. Although it seems that the new chain and sprockets would reduce mass, The cam sprocket was left solid, rather than webbed, specifically for additional mass. Increased inertia in the system reduces the tendency for cam torsion.
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: LT4 Hot Cam Question (TheStef)
The super ram makes brutal low end torque and a fairly decent midrange. It does still fall off in the upper RPM's though. A MiniRam is VERY similar to an LT1/LT4 intake in appearance and design. It will give up some low end torque but it'll flow all the air at higher RPM's you could ever want.
Any other differences. Well the reverse flow cooling actually routes coolant in such a way that it doesn't flow through the intake. That's really cool because you don't have to drain the coolant to pull the intake, and the coolant doesn't serve to heat up the intake any. Performance wise there probably isn't a whole lot else. The internals are basically interchangeable. The LT motors had a gear driven water pump, which was kinda cool. If your belt breaks you can still drive it so long as you've got a hot battery.
The block has some minor differences, the LT's have no provision for a mechanical fuel pump.
In most respects the LT1/LT4 is just an improved L98. The only drawback is the distributor location, which wouldn't be a problem in itself if it wasn't so fragile.
Any other differences. Well the reverse flow cooling actually routes coolant in such a way that it doesn't flow through the intake. That's really cool because you don't have to drain the coolant to pull the intake, and the coolant doesn't serve to heat up the intake any. Performance wise there probably isn't a whole lot else. The internals are basically interchangeable. The LT motors had a gear driven water pump, which was kinda cool. If your belt breaks you can still drive it so long as you've got a hot battery.
The block has some minor differences, the LT's have no provision for a mechanical fuel pump.
In most respects the LT1/LT4 is just an improved L98. The only drawback is the distributor location, which wouldn't be a problem in itself if it wasn't so fragile.
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Re: LT4 Hot Cam Question (Nathan Plemons)
You can install a LT1/4 intake manifold on a L98. It has been done, effectively giving you the same benefits of that manifold or the miniram for a lot less money.
http://www.lt1intake.com/services.htm
http://www.lt1intake.com/services.htm