casias

iTrader: (1)

Last week, I swapped an LS9 cam into this is a daily driven truck. It is a 1999 Dakota R/T with an LY6, 6.0 litre Gen IV ls engine with 6L90 transmission swapped in a couple of years ago. Without any modifications, this drivetrain was tuned to run about 13.1 at 107-ish on 30 psi street tires. The only time it went to a 1/4 mile track, it was tuned with a diablosport tuner, and ran 13.4 at 103 on street tires.



The goal of this truck has always been reliable, performance with street manners. It is still a truck. It tows, hauls, carries, and commutes.

The LY6 engine retained variable valve timing. This, coupled with the 6l90 six-speed transmission and 3.92 rear gears made it a torque monster in low to mid RPM's. When it was tuned by CHENRY Motorsports, he pulled timing out to keep the rear wheels planted. With more timing, slicks and cal-tracs, this would have been a 12 second track truck.

But.... that wasn't my goal.

Time for a new phase.

This is how it looked when I tore it apart a week ago. For those of you that don't know, the intake is made from 4" PVC pipe, and a toilet flange from Lowe's. Screw the $200+ CAI, this worked great. I had replaced the water pump with a 2010 camaro pump, and put a dirty dingo bracket to relocate the belt.





So, on with the standard, LS cam swap write-up.

After exposing the timing gear, I pulled off the original VVT cam gear.



After locking the tensioner in place with an allen tool, and spinning the cam, I put wood dowel rods to hold the lifters up, and swapped the cam.



Ran into a little trouble trying to do springs in the car. I can tell you, it is not as easy as people make it out. Normally, I would pull heads and have Clearwater Cylinder Heads freshen them, but I wanted to try this.

First, these valve locks are smaller, and slipperier than you can imagine.



They are $2.75 each half, and 30 minutes round-trip to the dealer to replace. At least for me.

Second, the air compressor trick didn't work when I bumped the end of the fourth valve, and it dropped into the cylinder. Of course, the cylinder was at bottom dead center, so the valve went all the way down. So, whip off the heads. Put in Comp Cams 918 springs. Time for LS9 head gaskets also.



Scrape the crud out of the block. Not a perfect job, but I think it will be ok. This motor has 170k miles on it.



Back together with new cam gear, LS9 cam. I reused the chain and tensioner because they seemed ok.



GROAN! I can here it now. The LS9 cam is not great. More on that later.

On goes the LS3 timing cover.



You have to remove the wiring harness from the old cover and reuse it, because you need a 5-pin plug. This is self explanatory when you see the parts. Save money and buy only the LS3 cover. The cam sensor and wiring harness are reused.



And on goes the LS3 intake.




Results:

The LS9 cam, which is more aggressive lift and duration, has a super lazy LSA. My thought was to decrease some of the torque initially, and get the truck moving without wheel spin, then the power would grow quickly at 2,500 rpm on. Using this cam NA is not a great choice.

If I were going to keep this truck NA, I would keep the original LY6 cam and VVT. Really. It was perfect with the 6l90 and 3.92 gears on the stock torque converter.

But, this is the beginning of phase two. I am told is is damn near impossible to tune the vvt for a boosted application. This is from a very reliable source. So this is why the cam was swapped.

That, and I wanted to try something new for a while. This is probably the best thing about the LS platform. Options are endless.

bonecrrusher

iTrader: (1)

I have a similiar build as you - I have a LS2 6.0 bottom end - GMPP CNC lS3 heads - and an LS9 cam, Kooks long tubes - and an aftermarket intake.

I went from 375 RWHP to 450 RWHP - and from what I noticed - especially with my T56 - the LS9 cam sucks ***** at low rpm.

Sitting in 6th gear at 65 mph - the car has no power at all - with my old LS2 cam I could throttle it in 6th and pass - now I'm downshifting a few gears.

But like you - I'm just starting phase 2. I'm installing some 918's myself - and installing an Edelbrock E-force LS3 blower - hopefully boost makes up for the crap bottom end feeling!

casias

iTrader: (1)

I agree. I haven't had it tuned yet, so we will see what it brings. I have read so many conflicting views on this cam, I wanted to try it for myself. But most of these are in the LS3 camaro.

Cam swap is so easy, though. It may come out for something different.