LE5 2.4 Cams in LAP 2.2

Cnixon160

Active Member
Honestly we would have to have both cams on a cam doctor to determine if it's even close to being an issue, your comparison is only the peak lift numbers not factoring in the ramp rates or duration, just from a visual standpoint though the valve begins and ends it's journey earlier and later the ramp rates is much softer than the factory camshaft so there is likely very little or no difference in PTV under motion, IF I decide to throw in the built short block before destruction ensues I will gladly measure the PTV but even that static measurement does not factor in the cam angles set in the tune
 

jirwin

Goblin Guru
If this is something I can do without super specialized equipment I'll do it when I get my block and head back. Not sure exactly how to do it though.
 

Cnixon160

Active Member
The "simplest" way is to get another valve either the same or preferably +1-2mm and make it into a cutter using a stop collar against the top of the valve guide to keep the depth the same, that's assuming the short block is assembled, if it is not assembled then just get a competent machine shop with a fly cutter and a Bridgeport to mill the reliefs to desired size, or go all out and call up whatever manufacturer you desire and tell them you want piston X with whatever valve relief depth you want, all of this is assuming that there is actually a possibility or risk of interference
 

Cnixon160

Active Member
I will say however that for the sake of this discussion I pulled the intake and hand turned the motor and when the valve is ~1-2mm off the seat you cannot even see the piston and it is roughly 4mm below TDC, again this is with the phasers at whatever the rest position is but in my opinion you are hugely overthinking this
 

jirwin

Goblin Guru
The "simplest" way is to get another valve either the same or preferably +1-2mm and make it into a cutter using a stop collar against the top of the valve guide to keep the depth the same, that's assuming the short block is assembled, if it is not assembled then just get a competent machine shop with a fly cutter and a Bridgeport to mill the reliefs to desired size, or go all out and call up whatever manufacturer you desire and tell them you want piston X with whatever valve relief depth you want, all of this is assuming that there is actually a possibility or risk of interference
Sorry, I wasn't referring to fly-cutting, but to measuring PTV like you were suggesting.

I will say however that for the sake of this discussion I pulled the intake and hand turned the motor and when the valve is ~1-2mm off the seat you cannot even see the piston and it is roughly 4mm below TDC, again this is with the phasers at whatever the rest position is but in my opinion you are hugely overthinking this
You're absolutely right. I'm totally overthinking it. I just don't want to make an expensive mistake. It would be different if I was running stock bottom end like you.
 

Cnixon160

Active Member
The issue lies in the VVT system almost entirely, you can effectively make the clearance go negative very easily hence the reason I did the copy pasta with the le5 ZZP tune VVT table also it wouldn't let me attach the tune file here but I'll make a drive link for it later today
 

Gtstorey

Goblin Guru
Sorry, I wasn't referring to fly-cutting, but to measuring PTV like you were suggesting.
There is always putting clay on top of the piston, but I'm not sure if there is any way to force the cams to test through the complete range of motion on a stand.
 

Cnixon160

Active Member
There is always putting clay on top of the piston, but I'm not sure if there is any way to force the cams to test through the complete range of motion on a stand.
You would have to either provide oil pressure and use something like a JimStim to trick the ECU into controlling it or get a sacrificial set of gears to open up and remove the lock pins to allow manual actuation
 

Cnixon160

Active Member
I have a sacrificial set of gears, so I'll try and crack em open later today
Pop the plastic shields off and there's a few torx screws, I believe they were T40 if you remove the lock pin and spring you could pretty easily lock them at full advance to determine absolute worst case distance
 

Ross

Goblin Guru
The issue lies in ...
also it wouldn't let me attach the tune file here but I'll make a drive link for it later today
*.hpt HP Tuner tune files can be posted here on the forum. Not sure why it didn't work for you.
So can *.hpl log files.
 

jirwin

Goblin Guru
More information. I was talking to my engine guy and I got to thinking about my pistons. I remember them being domed. Thankfully I had a video of the engine from when I disassembled it. Domes AND valve reliefs! So @Cnixon160 you're likely fine with PTV, but now I'm curious if I will be with 10:1 flat tops
 

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jirwin

Goblin Guru
Well, my engine builder won't cut valve reliefs, so I either have to do it myself and bring it back for balancing or just wait til I get it back and check the cam clearance. I just tired to take apart one of the VVT cams and I couldn't quite figure it out. I was able to actuate the "VVT" portion of the cam, but only when I didn't have all the bolts in. Does anyone know how this is supposed to work? What am I missing?

One bolt in, the bolt holes are below each of the 5 holes you see:
39134


No bolts in, VVT "actuated":
39133
 

Attachments

Cnixon160

Active Member
The small spring plunger piece is what was keeping you from actuating the phasers, it relies on a minimum oil pressure to unlock to avoid an uncontrolled movement, with it removed you should be able to semi easily move the phaser with the faceplate bolted on though for the purpose of measurement I would keep it omitted as the head and bolt will keep everything together and allow you to visualize the travel if interference occurs
 
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