Vvt

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cammerfe

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Although there are giant gaps in my knowledge regarding the AJ series of engines, I do have an above average level of experience, and an ability to gain from 'hands-on' due to the stuff I've accumulated.

I've examined the VVT system in the AJ27 engine that I'm slowly re-doing and without any doubt the actuation of the variable feature is purely mechanical. There is no electric or hydraulic drive mechanism. There is a connection to the computer, but it's purely a sensor.

If anyone has information regarding the Gen 2 'LS' engine that would suggest a different actuation system than this, please give information!! As I understand, the only difference is that there is more variability in the Jag version.
KS
 
yep - the Gen2 uses an solenoid to allow more/less oil to run into the actuator on the end of the cam - making the LS's version truely continually variable. I have not had one apart - but here is my understanding -

The solenoid controlled hydraulically actuated setup varies the camshaft timing using a helical spline actuator on the camshaft, while the timing sprocket is integrated into the actuator. Oil is forced into or pulled out of the actuator - which causes it to move on its splines changing the relative position of the camshaft.
 
my understanding was that it was pure magic.... but here is my question:

how is the Jag engine more variable if the LS is "continually variable"
 
SPSully said:
my understanding was that it was pure magic.... but here is my question:

how is the Jag engine more variable if the LS is "continually variable"
Click to expand...

Perhaps the Jag engine has a larger range and the LS is "continually variable" within a smaller range. Either that or he was not correctly informed about the Jag being more variable...
 
I thought the Jag was a single-step VVT - like v-tec - it was either on the other profile or off.
 
SPSully said:
with all the confusion about the vvt on these motors.... I'm glad I have a first gen
Click to expand...
If you follow that reasoning better get an old stovebolt six with a single barrel Rochester and is still much easier to work on. LOL
Have a great day.
 
I took the Jag VVT actuation system on the front of the cam all apart yesterday in order to try to understand the process. I don't see any ingress/egress for oil into the system. I'd describe the unit as internally and externally splined, segmented gears that seem to me to move so as to alter the relationship between the sprockets on the ends of the intake and exhaust cams. A site I googled some time ago said that there's 48 degrees of variability in the system. More later.
KS

Later---I stand corrected. There's some sort of internal oil feed through the core of the cam. My source suggests locking the VVT for any sort of forced induction. 'R' model Jags do not use VVT.
 
Last edited:
Velo said:
If you follow that reasoning better get an old stovebolt six with a single barrel Rochester and is still much easier to work on. LOL
Have a great day.
Click to expand...

thanks for the advice! LOL


Ken, with new cams ground, will you need to lock anything out? I would think that the oil feed running throught the cam itself isnt there on the newly ground cams. Just a thought. I'm obviously not looking at it with ya so you wold know better.
 
There simply aren't any new cam blanks available. Therefore, the only answer is to regrind the factory items with a smaller base circle. So locking will be necessary.

I should have further info on retainers and keepers within the next few days.

KS
 
so is it safe to say that by the time you retard timing on a gen 2 so that you can run a power adder, both gen's will make the same power?
 
In one case we're talking about ignition timing and in the other, camshaft, ie valve, timing---specifically the phasing between the intake side and the exhaust side of the valve actuation system. Completely dissimilar activities in the same engine.
KS
 
I wonder what the difference in valve timing is between a locked out 2nd gen and a first gen. What about using a set of first gen cams for the second. Without the internal oil passages, it would lock out the VVT

that being said, the VVT cars have been successfully force fed. Thats the LS motor, not the Jag counterpart. Ken, maybe get ahold of ILLS and talk to him about the turbo set up on the 2nd gen and what considerations to the VVT were made.
 
the VVT makes the tuning difficult since the cam phasing changes....

have increased crank case pressure may mess up the VVT functioning - oil flow, solenoid, .... would have to try it.
 
I read that the S Type R engines did not have the vvt due to the fact that there were no gains from it on a forced induction engine.
 
Properly 'tuning' a turbo'd engine would make the VVT redundant. The boost would come on so hard as to eliminate the gain found by varying the valve timing. That's where I expect to go.
KS
 
I too would imagine that vvt on a forced induction motor wouldnt be too important considering that in performance versions which this happens to be, ford vvt system is used to build cyl pressure @ higher rpm and lower ve levels so... six to one half dozen to the other, might be worth while might not
 
Might work well for a turbo motor to keep overlap under control at different rpms an prevent manifold reversion while building off boost cylinder pressure. This would likely have to be aftermarket ECM controlled though.
 
Ills

SPSully said:
I wonder what the difference in valve timing is between a locked out 2nd gen and a first gen. What about using a set of first gen cams for the second. Without the internal oil passages, it would lock out the VVT

that being said, the VVT cars have been successfully force fed. Thats the LS motor, not the Jag counterpart. Ken, maybe get ahold of ILLS and talk to him about the turbo set up on the 2nd gen and what considerations to the VVT were made.
Click to expand...

Does anyone know how to get ahold of ILLS?
KS
 
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