LE5 2.4 Cams in LAP 2.2

jirwin

jirwin

Goblin Guru
Alright this has bugged me long enough. I thought I could enlist the help of the forum to see what you all think. There's a lot of smart people on here, so maybe we can figure it out together.

The question I'm looking to answer is: Can you use LE5 cams (and performance cams) in the LAP?

Straight away ZZP says no, but after tearing into my LAP I couldn't help but wonder why. I saw an LE5 stamped head gasket during teardown and got curious. The heads are the same! So, while I wait for it to get back from the shop I decided to dig into this a little more. I wouldn't bother digging if there were performance LAP cams, but sadly there are not. I found this infamous thread where OP tries OEM 2.4 LE5 cams in his 2.2 LAP and bends all 16 valves. Many in the thread are skeptical that it was timed right, and to be honest I am too.

All specs were pulled from a 2006 2.4 LE5 and 2010 2.2 LAP.

Specs:
2.2 LAP2.4 LE5Notes
HeadGM GENUINE 12624550GM GENUINE 12624550The 2.2 LAP has other heads for California emissions, but this should be irrelevant
Intake ValvesGM GENUINE 12622329GM GENUINE 12622329
Exhaust ValvesGM GENUINE 12615936GM GENUINE 12615936Confirmed via GM Parts Direct
VVT Sprocket (Cam Gear) IntakeCLOYES VC107CLOYES VC106Cloyes is GM's provider. I just got my full timing kit from RockAuto for my 2.2 LAP and there are 2 VC107's
VVT Sprocket (Cam Gear)
Exhaust		CLOYES VC107CLOYES VC107Cloyes is GM's provider
Intake VVT SolenoidGM GENUINE 12679099GM GENUINE 12679099
Exhaust VVT SolenoidGM GENUINE 12679100GM GENUINE 12679100
Hydraulic Lash AdjusterGM GENUINE HL129 GM GENUINE HL129
Rocker ArmGM GENUINE 12693909GM GENUINE 12693909
Valve SpringGM GENUINE 90537032GM GENUINE 90537032
Camshaft SealGM GENUINE 12574477GM GENUINE 12574477
Intake CamGM GENUINE 12621516GM GENUINE 12578511Confirmed via GM Parts Direct
Exhaust CamGM GENUINE 12604896GM GENUINE 12578512

Stock Camshaft Specs:
2.2L LAP2.4L LE5
Intake Cam Peak Lift~66.2551
Intake Valve Peak Lift?10.54252068
Intake Valve Timing?135
Intake Valve Duration @1mm Lash?210.30
Exhaust Cam Peak Lift~65.95143
Exhaust Valve Peak Lift?10.03908697
Exhaust Valve Timing?-125
Exhaust Valve Duration @1mm Lash?195.40
LE5 Specs Gathered from here. LAP were crudely measured by yours truly with a Harbor Freight set of digital calipers. I could not find any specs online, and have no real way of measuring anything more than lift myself.

As you can see, almost all the head parts are the same. The cams themselves, and the phasers were the only difference I could find. The 2.4 uses a Cloyes VC106 and VC107, whereas the full timing kit I just got for my 2.2 uses 2 VC107's. Maybe this has something to do with it? I would be interested to see a base 2.4 LE5 tune to see if there is something different in the cam phasing there (Though, I'm not exactly sure where to look. Still new to tuning). Please share if you have one. Maybe its possible with using the LE5 phasers and taking its tune into account.

What do you guys think?
 
Joebob

Joebob

Goblin Guru
I would look for piston face position as well as the head components. I don't know if the 2.4 is only a bored 2.2 or if there are crank, connecting rod, wrist pin height differences that might affect valve clearance beyond head components.
 
jirwin

jirwin

Goblin Guru
The crank rod and pistons are all different. Bigger bore and stroke and slightly higher (10.4:1 vs 10:1) compression
 
jirwin

jirwin

Goblin Guru
95Blitz said:
You also need to look at the valve relief pocket on the piston.
Click to expand...
It might be as simple as that. Looking at ZZPs pictures, the LE5s have reliefs, but the LAP are just flat top.

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95Blitz

95Blitz

Goblin Guru
Yup that would bend valves for sure. You can have some made with the reliefs cut into them.
 
Cnixon160

Cnixon160

Active Member
Okay so I am running this exact setup, I have the LE5 ZZP cams in my 2010 LAP 2.2, first off, the head itself is identical but you will need to get the cam phasers aka gears from a LE5 as the dowels are in different locations IF YOU TRY TO USE THE LAP GEARS YOU WILL DESTROY EVERYTHING. I have attached a photo showing both gears and the dowel locations. Any other questions just ask.
 

Attachments

Cnixon160

Cnixon160

Active Member
Also a side note, it will be drivable with no tuning changes albeit poorly, but if you needed to drive it to a tuner it will be fine, I also did the neutral balance shafts and a set of OTTP 80lb springs and it will happily smack the 8150 limiter if your not paying attention
 
Cnixon160

Cnixon160

Active Member
Desert Sasqwatch said:
8150 RPM redline, that's screaming!!! o_O
Click to expand...
It was initially an experiment to see what the LAP could handle, HP tuners hard coded limit is 8192 but it either hit the limiter and completely shut off or blasted right past the limiter like it didn't exist with no predictability so I backed it down just a smidge, I have a built LE5 on standby for when the inevitable happens
 
jirwin

jirwin

Goblin Guru
First off, thank you so much for taking the time to reply. Awesome to see someone figured this out! My wallet is not happy about this new information.

Cnixon160 said:
Okay so I am running this exact setup, I have the LE5 ZZP cams in my 2010 LAP 2.2, first off, the head itself is identical but you will need to get the cam phasers aka gears from a LE5 as the dowels are in different locations IF YOU TRY TO USE THE LAP GEARS YOU WILL DESTROY EVERYTHING. I have attached a photo showing both gears and the dowel locations. Any other questions just ask.
Click to expand...
Looking at part numbers again, the intake cam phaser on the LE5 seems to be a different part number (according to RockAuto anyway) but the exhaust is the same. Your picture makes it look like they are both different. Thoughts?

Cnixon160 said:
Also a side note, it will be drivable with no tuning changes albeit poorly, but if you needed to drive it to a tuner it will be fine, I also did the neutral balance shafts and a set of OTTP 80lb springs and it will happily smack the 8150 limiter if your not paying attention
Click to expand...
Any special considerations to take into tuning? As you can see we were thinking there would be valve clearance issues, hence the valve reliefs on the LE5 pistons.

That redline is awesome haha. Your piston speeds are very high! My math says that's aproaching current F1 cars!
38995
38997
 
Cnixon160

Cnixon160

Active Member
Honestly I never even pulled the head, I fed about five feet of climbing rope into each cylinder individually and rotated the engine to hold the valves up while changing the springs, it doesn't make any strange noises so I assume PTV is okayish maybe, I would strongly recommend not turning it as hard as I am if you expect it to survive for a reasonable period, the exhaust is identical I believe the gear material had changed between 2006 and 2010 based on the gears pictured, as far as tuning I copied the LE5 VVT map from what was advertised as a ZZP tune before HP tuners wiped the modified tunes from the repository otherwise it tunes like any other setup
 
Cnixon160

Cnixon160

Active Member
Here's the uncolored on photo, the red line is the index tooth on each gear, the photo is rotated 90° from the labeled version but somewhat more clearly illustrates the difference if you blow it up
 

Attachments

Tinkles

Tinkles

Well-Known Member
8150 rpms, that is the territory for when you should start looking into the Jezel goodness for Ecotecs.
 
Cnixon160

Cnixon160

Active Member
jirwin said:
You had me onboard until I saw the price. One place was ~$135 per follower lol.
Click to expand...
Typically people doing the thing I am doing have significantly more money invested in their setup, worst case I'm out a $100 ebay turbo and a few hours of labor to swap in the spare engine, my biggest concern is the clutch coming apart but I just have half of my plate carrier hanging behind the seat as a quasi scatter shield
 
jirwin

jirwin

Goblin Guru
More information because I got curious again. Found this CSS thread with rod & piston info.

Copied from the thread for our purposes:
LE5LAP
Bore88mm86mm
Stroke98mm94.6mm
Rod Length143.74mm146.5mm
Wrist Pin Diameter20mm20mm
Compression Height28mm26.75mm
Total Bottom End Height220.74mm220.55mm

So effectively you have 0.25mm extra of deck clearance. Thicker Cometic head gasket nets a tint bit more.

Still have concern with the valve relief in the stock LE5 pistons though. Diamond Racing lists the pistons with 0.140" (Intake) and 0.130" (Exhaust) valve pockets. Its obviously working for you @Cnixon160, I'm just scared that I could potentially screw up a fresh forged build if it doesn't work for me for some reason. Not to mention the ZZP LE5 cams are hella expensive.
39045
 
G

Gtstorey

Goblin Guru
I think it's possible to cut valve reliefs in most forged pistons. Either by a machine shop prior to (or probably really during) or even after assembly of bottom end (look up piston fly cutter).
 
jirwin

jirwin

Goblin Guru
Gtstorey said:
I think it's possible to cut valve reliefs in most forged pistons. Either by a machine shop prior to (or probably really during) or even after assembly of bottom end (look up piston fly cutter).
Click to expand...
Interesting! That was much easier than I thought it would be (with the right tool of course). I wouldn't imagine balancing would be an issue with that since in theory you'd be taking the same amount off each piston.
 
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