GMCproject

Hey yall. Bought a cam and new valve springs to go along with it. I've done one cam swap but it was on a mustang. Anyone have a good set of instructions on R&R'ing the cam on a 4.3L V6 truck? How do I go about removing the intake manifold and fuel rails and crap? Will I need an impact wrench? I remember it helped on the stang a lot. I guess that answers that question. Will I need to remove the radiator to pull the cam? Didn't have to on the stang. Any hints, tips or degreeing the cam once I get ready to put it in? How bout the springs? Pull the rocker arms off, compress the spring, pull out retainer, replace spring, reverse order. Basic idea? On adjusting the rocker arms (I'm staying with the stock one's for now), do I just sit there and tighten them down until the pushrod stops moving and then back it off a 1/4 turn or so? Sorry for all the questions but the Stang seems to be an easier task than the truck is going to be. I plan on doing the install next week sometime. Figure give myself about 3 or so days just to be safe. Also, will MTI tune the truck once I get it running? I'm getting the Comp Cam 56-460-8 cam. I'm also getting the 986-12 valve springs with it. I plan on running nitrous or FI later on down the line (headers are on my list of things to do next). Thanks for the help yall.

Also. What about the lifters? How do I keep them from falling out of their homes? How bout the valves when I replace the springs? Should I pull the heads off to do it? I'm gonna have limited access to air tools so screwing an air hose in to the cylinder isn't really an option. Thanks for the help yall.

P.S. Should I go and buy a service manual for this?

GMCproject

Anyone?

TnTrk53

You do not remove intake. Pull fan,waterpump, crank pulley,valve covers,rocker arms,and pushrods. timeing cover.Radiator comes out easily,trans lines are held in by removable clips.airconditioning condenser does not need to come out.Put pully bolts back in can and spin several times,retainers will hold lifters up.Grease new cam very well before install.
About 8-10hr job.Springs are more difficult and require air fitting to inflate cylinder to hold valves up and you will need a spring depressor for ls1.(More Racing has a nice tool and there are others available on line) Good luck.
I'm no mechanic and was successfull with both swaps.

GMCproject

Thanks for the help. I don't know how I'm gonna do the springs since I won't have access to an air compressor (hopefully I can find one). How bout setting the timing up? Just match the dots up? How bout finding TDC on #1? Which cylinder is #1? Isn't it front left if your looking at the truck? Thanks for the help.

TnTrk53

Jusy match the dots, pcm takes care of timing. If your lift isn't over .540 you may not need to change springs.

GMCproject

The lift is only like .500 but comp recommends changing the springs anyways. I've got 60K+ miles on the stock springs. So I thought it would be a good idea to change them anyways.

TnTrk53

60K's not many miles if you've kept good oil in it. Stock spring handle more lift than that when you use longer rockers. The spring swap is tougher than the cam swap,have plenty of extra retainers when you start they get away easily.

Black02Z71

Ok this is a 4.3L, your going to have to remove the intake, and pull the lifters out. Just disconnect the fuel lines and injector plugs from the intake, the fuel rail and injectors are inside the manifold. The balance shaft is driven by a gear behind the cam sprocket, just line up the dots.

For timing there is one notch in the timing cover at the 2:00 position, and another 90 degrees down from the first, there will be 2 marks on the balancer 90 degrees apart, bring the motor to TDC on #1 compression stroke, line up the marks on the balancer to the notches on the timing cover, then drop the distributer in making sure the rotors lines up with the arrow with the #6 on it (the distributer has no adjustment, when its bolted down it can not turn).

Valve adjusting, what I do is, turn the motor over, watching the lifters, when one lifter is up in the bore, adjust the other lifter on that cylinder, thats in the down position. Spin the pushrod as you tighten the nut, when you can't turn the pushrod any more, give it 1/2 a turn more.

Max lift on vortec heads is only .480

Black02Z71

I just looked into max lift on vortec heads. According to Chevy High performance mag, max lift with stock springs is only .420" (allows 0.030-inch retainer-to-seal) you have to machine the top of the valve guide down, so the retainer doesn't hit the valve seal, and the spring seat needs to be cut around the guide for larger springs.

TnTrk53

I completely missed the 4.3 v6 part, owh ta foo liam.