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camshaft upgrade

  
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camshaft upgrade

 
jtunny jtunny
I love my Chevy Chevette! | Posts: 5 | Joined: 10/12
Posted: 11/23/12
11:41 AM

have 2010 camaro w/vvt, is it possible to exchange camshaft without relieving pressure on lifters, i.e. removing rockers? ref:article in october 2009 super chevy magazine.  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 11/23/12
03:13 PM

jtunny
I'm going to have to look into that. Crane Cams has after market roller lifters. When you releave the pressure on the valve train, you can remove the cam from the block. Then reinstall a replacement. I don't know about production engines?

Bob  

jtunny jtunny
I love my Chevy Chevette! | Posts: 5 | Joined: 10/12
Posted: 11/24/12
11:50 AM

i think it's do too active fuel management system. the lifters must be different. i know mast cams have upgrades for this car.  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 11/25/12
12:22 AM

jtunny
  Yes they do have upgrade cams. If it was my car and I was going to change the cam. Get the service manual for it. I remember when the VVT's first came out. I was a consulting engineer with a  Chevy dealer. I noticed the guys where taking the whole top of the engine off. Plus there are Tech. Tips.
 
  There is a lot of tricky things you need to watch for. GM also had a problem with the 5.3 VVT's losing oil pressure. I had a Impala SS with an oil pressure problem. It turned out the lifter fell apart.
  If your doing a cam change in a VVT I would recommend you take it apart, and take pictures as you go along. Get a service manual.
  Back when the 3.4 twin OHC cam was out. It was a real PITA to work on. If you didn't have the tools to lock the Cams.

  The dealership where I was working had one come in on a hook. They gave it to one of their super Techs...LOL... He played with that thing for (2) solid days. The car was out of Warranty, but the car dealer that sold it paid the bill.
  I was asked to look at it. I went got the manual an in 1 hour I knew what it was. Someone changed the inside timing belt, and took the Cams off. They didn't mark anything. I managed to get the cams where they belonged. They had the Intake Cam on the exhaust and Visa. Versa. Put things where they belonged and that was it...Good Luck they didn't make it easy. If it was easy everyone would be fixing them...LOL...

Bob  

jtunny jtunny
I love my Chevy Chevette! | Posts: 5 | Joined: 10/12
Posted: 11/27/12
08:00 AM

the new camaro's that have active fuel management,during this process they shut down 4 of the 8 cylinders while the car is running, the values don't open letting fuel/air mixture in. the lifters must be design to accomadate?  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 11/27/12
08:37 PM

No they keep pumping their little hearts away. When they shut down the fuel. It simply shuts off those injectors until the demand goes up for the other 4 cylinders.

Look at it this way. As long as the valaves are opening and closing they are still cycling. No fuel so there is No combustion, No Combustion it doesn't use fuel.

It's not a new system! Cadillac had it back in the 1980's. It was called 2-4-6 or a 1-3-5?
Thanks
Bob  

jtunny jtunny
I love my Chevy Chevette! | Posts: 5 | Joined: 10/12
Posted: 12/04/12
12:17 PM

dod {displacement on demand} they call it. during the process 4 of the 8 cylinders  values stay close using the special lifters and the use of oil pressure system {i.e. solenoids}. the trapped gases inside the cylinders work with each other to prevent drag. i found out they have kits you can install to delete dod.  

BuzzLOL BuzzLOL
V-6 Camaros rule! | Posts: 39 | Joined: 05/10
Posted: 12/31/12
02:08 AM

.. Cadillac engine was a 4-6-8... gave a lot of problems... a one year engine... had computer MPG readout... cruised about 30 MPG as I recall on 4 cylinders... think it raised the rocker arms to de-activate cylinders...

.. I think you have to relieve the pressure on the lifters on LSx engines, but the lifters stay up in the holders after you rotate the cam so you can pull it out...