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NOTE: This How-To guide is neither endorsed by or property of Corvette Forum or myself in any way/shape/form. All liability stemming from any actions taken in relation to this guide is solely placed upon the end user. (This means you!)
When doing a cam upgrade on a C7, you may be required to install a cam phaser limiter. If you are installing a DoD delete cam, then you need to limit the variable computer controlled gear used to adjust timing given different driving scenarios such as “eco mode”.
This device works by usage of oil pressure which is fed into the cam gear through a series of passageways in the block, heads, and cam. The ECM controls the oil flow through a valve which increases or decreased the amount of oil in the cam phasers oil chambers. This can allow the cam to retard up to 60 degrees.
By installing a cam phaser limiter, we can restrict the range of movement for the cam phaser to around 20 degrees which retains the VVT functionality, but still provides for the necessary valve clearance for performance cams with different LSA profiles.
For this process we will be using Comp Cams phaser limiter kit, part number 5456. Here are all the parts you should need. (1 Corona is require to complete this process
So, you’ve take you front cover off, and are ready to take off the main cam gear. On the LT1, in order to remove the timing chain and cam gear, you must also remove the oil pump, which also means the oil pan on the LT1/LT4 unfortunately. I won’t go into the details of that in this guide as this guide is specific to the cam phaser limiter itself, but I will make mention that if you are going to be reusing your existing oil pump, you need to mount the oil pump align tool BEFORE removing the pump! These are the blue things on the block in the picture below.
Ok now that we are past that, remove the main bolt on the front of the cam gear. This bolt is known as the Camshaft Position Actuator Solenoid Valve (CMP). This bolt MUST be replaced once it is removed!
Now that we have that bolt out, you can slide the crank timing gear, timing chain, and the cam phaser gear off the motor. Put the crank gear aside for now. For the timing chain, now would be a good time to replace it with a C5R timing chain if you haven’t thought ahead on it already.
Before we go any further, you need to know that the cam phaser has a spirally-wound spring inside of it so extreme caution must be taken during this procedure to make sure you do NOT release the spring! Also, never handle the cam phase by the front, thin metal trigger wheel!
Ok, before we clamp it into the vise, you need to install the safety bolt, washers, and nut into the phaser. This will ensure that the trigger wheel will not explode off on you during our process. Take the cam phaser over to your vise, and first wrap it with a red rag to prevent any damage, and now clamp it down so that you are only clamping the gear portion down itself. Do not over-tighten the vise; use just enough pressure to hold the cam phaser in place. Make sure you turn the cam phaser so that the pin bolt is at the 2-3 o’clock position:
In the next picture, you will see the cam phaser pin bolt as I have pointed out in yellow, and the cam phaser spring, which is shown with the red arrow.
Now that we know what parts are what, and we have the gear clamped into the vise, go grab the “C” shaped spring compressor tool that came with the kit, and your ratchet, and the little spring lock tool. The tool is used with the ratchet as shown below:
The “C” shaped spring compressor tool needs to be put onto the cam phaser so that the tooth I am pointing to with the red arrow above will grab the cam phaser spring that I showed in the previous picture. It goes on there like this:
Below you can also see how the little “C” spring lock tool hooks into the big “C” spring compressor tool and goes around the metal trigger wheel. Make sure you are using the square holes in the tool for the lock, not the round ones. You’ll need to use the compressor tool so it grabs the spring where it makes an “L” shaped bend by the pin bolt, and then compress the spring about an inch (when looking it at from the rear, turn clockwise). Make sure the compressor tool is centered on the phaser spring “L” so that it does not slip off.
While you have it compressed, slide the spring lock tool into the slots in the spring compressor, around the metal trigger wheel as shown, and it will hold the spring in place for the next phase of the procedure.
By this time, you should have consumed approximately 50% of your Corona. Now its time to start removing the bolts for the phaser. First, loosen the pivot bolt ½ turn, but do NOT remove the bolt. Remember that is this bolt that we want to loosen ½ turn:
Remove the other four bolts completely:
Now remove the safety bolt in the middle, and slide the front ring open. It will leak some oil, this is normal:
Now we get to install the actual phaser limiter block. Make sure to install the block so that the slotted end goes in first, and the longer part towards the bottom:
Now slide the cover back over, and install the safety bolt again, and then install all the remaining Torx bolts making sure that you install the pin bolt in the 2-3 o’clock position! Torque these bolts to 85 in. Lbs.
Once these bolts have been torqued, you can remove the cam phaser spring compressor lock tool and the compressor, followed by the safety bolt. The cam phaser is now ready to go back onto the motor/cam! When installing the new Camshaft Position Actuator Solenoid Valve (CMP), you will need to torque it to the following specs:
It should be noted that there are 2 cam phasers designs. I have seen a difference between the LT1 and LT4. There are also 2 different kits available from Comp depending on what phaser you have. You can see from the pictures below the LT4 has 2 small spiral springs vs. the single on the LT1. The bolts holding the unit together as well as their orientation is different.
It should be noted that there are 2 cam phasers designs. I have seen a difference between the LT1 and LT4. There are also 2 different kits available from Comp depending on what phaser you have. You can see from the pictures below the LT4 has 2 small spiral springs vs. the single on the LT1. The bolts holding the unit together as well as their orientation is different.
This is great information, thank you for supplementing the guide!
I am checking the torque on the final 90 degrees and I am getting 110 ft #, from 12 oclock to 12:30. Any one check the torque on this? So I have gone form 48 to 110 pounds in 1/16 of a turn, ie its tight. Yes, I know its not stated a torque value, but I snapped a head bolt trying this method, ended up using a tap to clean threads and used ARP studs. Fxxx the factory head bolts and 60 degrees then 40 degrees.
Tightening this past 110 ft pounds makes me real real nervous, the neck down before threads looks breakable.
I am checking the torque on the final 90 degrees and I am getting 110 ft #, from 12 oclock to 12:30. Any one check the torque on this? So I have gone form 48 to 110 pounds in 1/16 of a turn, ie its tight. Yes, I know its not stated a torque value, but I snapped a head bolt trying this method, ended up using a tap to clean threads and used ARP studs. Fxxx the factory head bolts and 60 degrees then 40 degrees.
Tightening this past 110 ft pounds makes me real real nervous, the neck down before threads looks breakable.
I followed the recommended specs and it was fine. Just make sure you use a new CMP bolt and don't reuse the old one.
NOTE: This How-To guide is neither endorsed by or property of Corvette Forum or myself in any way/shape/form. All liability stemming from any actions taken in relation to this guide is solely placed upon the end user. (This means you!)
When doing a cam upgrade on a C7, you may be required to install a cam phaser limiter. If you are installing a DoD delete cam, then you need to limit the variable computer controlled gear used to adjust timing given different driving scenarios such as “eco mode”.
This device works by usage of oil pressure which is fed into the cam gear through a series of passageways in the block, heads, and cam. The ECM controls the oil flow through a valve which increases or decreased the amount of oil in the cam phasers oil chambers. This can allow the cam to retard up to 60 degrees.
By installing a cam phaser limiter, we can restrict the range of movement for the cam phaser to around 20 degrees which retains the VVT functionality, but still provides for the necessary valve clearance for performance cams with different LSA profiles.
For this process we will be using Comp Cams phaser limiter kit, part number 5456. Here are all the parts you should need. (1 Corona is require to complete this process
So, you’ve take you front cover off, and are ready to take off the main cam gear. On the LT1, in order to remove the timing chain and cam gear, you must also remove the oil pump, which also means the oil pan on the LT1/LT4 unfortunately. I won’t go into the details of that in this guide as this guide is specific to the cam phaser limiter itself, but I will make mention that if you are going to be reusing your existing oil pump, you need to mount the oil pump align tool BEFORE removing the pump! These are the blue things on the block in the picture below.
Ok now that we are past that, remove the main bolt on the front of the cam gear. This bolt is known as the Camshaft Position Actuator Solenoid Valve (CMP). This bolt MUST be replaced once it is removed!
Now that we have that bolt out, you can slide the crank timing gear, timing chain, and the cam phaser gear off the motor. Put the crank gear aside for now. For the timing chain, now would be a good time to replace it with a C5R timing chain if you haven’t thought ahead on it already.
Before we go any further, you need to know that the cam phaser has a spirally-wound spring inside of it so extreme caution must be taken during this procedure to make sure you do NOT release the spring! Also, never handle the cam phase by the front, thin metal trigger wheel!
Ok, before we clamp it into the vise, you need to install the safety bolt, washers, and nut into the phaser. This will ensure that the trigger wheel will not explode off on you during our process. Take the cam phaser over to your vise, and first wrap it with a red rag to prevent any damage, and now clamp it down so that you are only clamping the gear portion down itself. Do not over-tighten the vise; use just enough pressure to hold the cam phaser in place. Make sure you turn the cam phaser so that the pin bolt is at the 2-3 o’clock position:
In the next picture, you will see the cam phaser pin bolt as I have pointed out in yellow, and the cam phaser spring, which is shown with the red arrow.
Now that we know what parts are what, and we have the gear clamped into the vise, go grab the “C” shaped spring compressor tool that came with the kit, and your ratchet, and the little spring lock tool. The tool is used with the ratchet as shown below:
The “C” shaped spring compressor tool needs to be put onto the cam phaser so that the tooth I am pointing to with the red arrow above will grab the cam phaser spring that I showed in the previous picture. It goes on there like this:
Below you can also see how the little “C” spring lock tool hooks into the big “C” spring compressor tool and goes around the metal trigger wheel. Make sure you are using the square holes in the tool for the lock, not the round ones. You’ll need to use the compressor tool so it grabs the spring where it makes an “L” shaped bend by the pin bolt, and then compress the spring about an inch (when looking it at from the rear, turn clockwise). Make sure the compressor tool is centered on the phaser spring “L” so that it does not slip off.
While you have it compressed, slide the spring lock tool into the slots in the spring compressor, around the metal trigger wheel as shown, and it will hold the spring in place for the next phase of the procedure.
By this time, you should have consumed approximately 50% of your Corona. Now its time to start removing the bolts for the phaser. First, loosen the pivot bolt ½ turn, but do NOT remove the bolt. Remember that is this bolt that we want to loosen ½ turn:
Remove the other four bolts completely:
Now remove the safety bolt in the middle, and slide the front ring open. It will leak some oil, this is normal:
Now we get to install the actual phaser limiter block. Make sure to install the block so that the slotted end goes in first, and the longer part towards the bottom:
Now slide the cover back over, and install the safety bolt again, and then install all the remaining Torx bolts making sure that you install the pin bolt in the 2-3 o’clock position! Torque these bolts to 85 in. Lbs.
Once these bolts have been torqued, you can remove the cam phaser spring compressor lock tool and the compressor, followed by the safety bolt. The cam phaser is now ready to go back onto the motor/cam! When installing the new Camshaft Position Actuator Solenoid Valve (CMP), you will need to torque it to the following specs:
First Pass: 48 Lb. Ft.
Final Pass: 90 degrees
Bottom’s up!
Stay tuned for more How To guides!
Ant
how do you keep the engine from turning over when torquing this bolt to the right spec. I cant find any types of lock or pin holes
how do you keep the engine from turning over when torquing this bolt to the right spec. I cant find any types of lock or pin holes
I believe when I did mine I locked the crank from turning over by putting two flywheel bolts in, and using a prybar placed between then that rested against the mounts of the engine stand.
I believe they actually require drilling and pinning the phaser from what a well trusted shop told me. But maybe there are different methods?
BTR sells something called "AMP GEN V VVT PHASE LOCKOUT (LT engines)" which looks like a plug, and description makes me think it locks it out completely...
I will email and ask but i wish someone here could confirm. I wanna upgrade to a cam which requires more than kit i currently have (one you show here)...
BTR sells something called "AMP GEN V VVT PHASE LOCKOUT (LT engines)" which looks like a plug, and description makes me think it locks it out completely...
I will email and ask but i wish someone here could confirm. I wanna upgrade to a cam which requires more than kit i currently have (one you show here)...
When you hear back from them please let us know what you find out. Thanks Osman!
HOW TO: Installing a Cam Phaser Limiter
