PTV checking with VVT cam
PTV checking with VVT cam I'm mocking up my stock short block L92 right now for the first time. I have two cams here to choose from. The first I bought a while ago when I first bought the engine:
222/236 .566/.578 114 LSA Comp Cams 156-403-13 OR
TSP VVT3 230?? .620 lift?? cam which I bought after they were released.
I would have just thrown it all together but my heads are PRC CNC heads that have been milled .035", so I don't want to built it without checking PTV first.
I'm thinking the VVT actuator should be checked at full advance (the way it is at rest ) as well as fully retarded. Has anyone done this somehow and how did you temporarily lock the VVT actuator to fully retarded to check it that way?
Typically, retarding cam timing decreases exhaust valve clearance, and increases intake clearance, and vice versa for advancing timing.
222/236 .566/.578 114 LSA Comp Cams 156-403-13 OR
TSP VVT3 230?? .620 lift?? cam which I bought after they were released.
I would have just thrown it all together but my heads are PRC CNC heads that have been milled .035", so I don't want to built it without checking PTV first.
I'm thinking the VVT actuator should be checked at full advance (the way it is at rest ) as well as fully retarded. Has anyone done this somehow and how did you temporarily lock the VVT actuator to fully retarded to check it that way?
Typically, retarding cam timing decreases exhaust valve clearance, and increases intake clearance, and vice versa for advancing timing.
Teching In
Joined: Nov 2011
Posts: 12
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I modified an old phaser by removing the spring , sensor plate and locking pin, which is inside the phaser. I then drilled and tapped holes through the sides for two set screws that will move it by pushing on one of the vanes. One set screw advances it and the other retards it.
I'm mocking up my stock short block L92 right now for the first time. I have two cams here to choose from. The first I bought a while ago when I first bought the engine:
222/236 .566/.578 114 LSA Comp Cams 156-403-13 OR
TSP VVT3 230?? .620 lift?? cam which I bought after they were released.
I would have just thrown it all together but my heads are PRC CNC heads that have been milled .035", so I don't want to built it without checking PTV first.
I'm thinking the VVT actuator should be checked at full advance (the way it is at rest ) as well as fully retarded. Has anyone done this somehow and how did you temporarily lock the VVT actuator to fully retarded to check it that way?
Typically, retarding cam timing decreases exhaust valve clearance, and increases intake clearance, and vice versa for advancing timing.
222/236 .566/.578 114 LSA Comp Cams 156-403-13 OR
TSP VVT3 230?? .620 lift?? cam which I bought after they were released.
I would have just thrown it all together but my heads are PRC CNC heads that have been milled .035", so I don't want to built it without checking PTV first.
I'm thinking the VVT actuator should be checked at full advance (the way it is at rest ) as well as fully retarded. Has anyone done this somehow and how did you temporarily lock the VVT actuator to fully retarded to check it that way?
Typically, retarding cam timing decreases exhaust valve clearance, and increases intake clearance, and vice versa for advancing timing.
Ive done it 3-4 times....
1. Install any phaser limiter your using. (Comp limiters allow 20* total movement, get the right one, there are two phaser part numbers and two different phaser limiters)
2. Install something to lock the phaser advanced while your in there. I milled a piece of stock to fit precisely.
3. Check PTV with it advanced
4. Open it back up and retard it against the phaser limiter
5. Make a new piece to lock it in place retarted
6. Measure PTV with the phaser retarded
1. Install any phaser limiter your using. (Comp limiters allow 20* total movement, get the right one, there are two phaser part numbers and two different phaser limiters)
2. Install something to lock the phaser advanced while your in there. I milled a piece of stock to fit precisely.
3. Check PTV with it advanced
4. Open it back up and retard it against the phaser limiter
5. Make a new piece to lock it in place retarted
6. Measure PTV with the phaser retarded
ptv Thanks, makes total sense. I'll be doing it today. It would be nice if I had a spare, but no big deal to do it with the original. Mine's the early actuator, so it's 62 deg stock I believe. Got the right comp limiter kit, and just have to make a solid lifter from one of the old ones so I can do ptv and check my pushrod length.
I want to run the VVT3 TSP i've got. I could probably run the Comp Cam as is without any issues. It's under 600 lift and Comp uses a lot less spring press.
I want to run the VVT3 TSP i've got. I could probably run the Comp Cam as is without any issues. It's under 600 lift and Comp uses a lot less spring press.
Last edited by kballs; Jan 22, 2012 at 01:35 PM.
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ptv checking I'm doing this right now. Took apart my phaser and took a few pics to make it clearer for everyone. I didn't have to take the spring apart, but all 5 bolts have to come out to free the movement of the phaser. I put the comp limiter in and sacrificed some drill bit ends to make the internal stops to check ptv. I ended up using 21/64 and M letter drills for mine. This is what S10 was talking about.
Now I can head to the shop and see what i'm looking at for clearances.
Now I can head to the shop and see what i'm looking at for clearances.
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Verdad Gallardo Thanks for the photos - makes perfect sense to cut the end off an old drill bit if you have the right size. I see the shape is a little different going advanced and retard which I assume is the reason you're using two different drill bits.
Are you going to use clay on the pistons or some other method for measuring PV clearance?
Are you going to use clay on the pistons or some other method for measuring PV clearance?
Phaser # 12585994 uses Comp limiter kit #5456
Phaser # 12606358 uses Comp limiter kit #5460
Be very careful when reinstalling the phaser for the final time, take extra time to be absolutely sure the alignment pin is aligned with the hole on the back of the phaser. Hope you have a 5 ft breaker bar! IIRC its 48lb*ft plus 90 degrees!!!!
Does the Texas speed cam come with the long bolt, like Comps does?
My TSP cam came with the long bolt. It is manufactured by Comp Cams. I assume this si the bolt that you're refering to needing 48ft-lb plus 90*? Is that that resisted by the timing chain and crankshaft/flywheel stop? I wonder if I'll end up turning my engine stand over.
My TSP cam came with the long bolt. It is manufactured by Comp Cams. I assume this si the bolt that you're refering to needing 48ft-lb plus 90*? Is that that resisted by the timing chain and crankshaft/flywheel stop? I wonder if I'll end up turning my engine stand over.
That bolt/valve takes some serious torque upon final installation.
VVT cam choice Thanks for the feedback guys. This is my first LS, but i've built many engines from old big blocks, to M5 reblocks when I was working for BMW to 2500hp QSK Cummins engines at my current job.
Info on VVT stuff is far between and well protected it seems, so if I can help more VVT engines stay that way, i'll do what I can do help people want to keep it.
I haven't even looked at my VVT3 cam yet so I don't know if it's got the long bolt in it. I did buy a new cam bolt/valve since it's supposed to be a single use piece.
Info on VVT stuff is far between and well protected it seems, so if I can help more VVT engines stay that way, i'll do what I can do help people want to keep it.
I haven't even looked at my VVT3 cam yet so I don't know if it's got the long bolt in it. I did buy a new cam bolt/valve since it's supposed to be a single use piece.
Teching In
Joined: Nov 2011
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I'm doing this right now. Took apart my phaser and took a few pics to make it clearer for everyone. I didn't have to take the spring apart, but all 5 bolts have to come out to free the movement of the phaser. I put the comp limiter in and sacrificed some drill bit ends to make the internal stops to check ptv. I ended up using 21/64 and M letter drills for mine. This is what S10 was talking about.
Thanks. My brain wasn't functioning so well when I wrote that before.
ptv checking I ended up using the smaller comp cam I had. PTV is well in the safe now with about .110". I'm selling the VVT3 cam now in classifieds if anyone is looking. If not i'll just keep it until I build a stroker short.
I'm working on the math to degree my VVT-2 cam and check PTV. The catch is that the phaser I sacrificed for testing is my original L92 one, and I have a new L99 phaser, cam, and limiter that the motor will run on. My notes (all deg values related to crank):
The L92 phaser has 62deg of freedom, from 17deg advance to 45deg retard
The L99 phaser has 52deg of freedom, from 7deg advance to 45deg retard
Both phasers have 44 timing chain teeth, for 8.18 deg per tooth.
According to a CompCams Technical Note:
The L99 cam (189- core) alignment pin is 13deg retarded in relation to the L92 (156- core) pin.
So I want to set up the unsprung L92 phaser to represent the L99 phaser
The L92 phaser has 62deg of freedom, from 17deg advance to 45deg retard
The L99 phaser has 52deg of freedom, from 7deg advance to 45deg retard
Both phasers have 44 timing chain teeth, for 8.18 deg per tooth.
According to a CompCams Technical Note:
The L99 cam (189- core) alignment pin is 13deg retarded in relation to the L92 (156- core) pin.
So I want to set up the unsprung L92 phaser to represent the L99 phaser
Last edited by 85MikeTPI; Jun 15, 2012 at 08:19 PM.
Ideally you would lock the cam at 0deg for degreeing, but full advance is easiest. You have to adjust the values for the advanced value, and know what the base setting is for your phaser.