*continued*




Measuring the intake centerline is similar to the procedure used to find TDC. First rotate the crank until the indicator reads 0.050-inch before peak lift. Note the reading on the degree wheel, in our case 66 degrees (at this point, negative and positive don't apply, keep it simple with positive. Other degree wheels may require using negative and positive). Next we rotate around until the indicator reads 0.050-inch after peak lift. Again, we note the reading on the degree wheel of 162 degrees. To find the center point between these two readings, we simply add them together and divide by 2. 66+162 = 228 228 divided by 2 = 114 The intake lobe centerline is set at 114 degrees. This number matches our cam data card packaged with the cam. The cam is degree'd as ground and as specified, and installed with no advance or retard. It is possible for a cam to degree somewhat different than specified, especially in the case of a custom-ground cam. When necessary, the timing set can be adjusted to correct the cam position.



Degreeing a camshaft when the engine is still in a car or with the cylinder heads installed is generally more time consuming and more difficult. Comp's Sportsman Degree kit, PN 4796, is perfect for in-car or head-on degreeing.




Locating TDC with the cylinder head on requires a spark plug type piston stop. For Gen III and IV engines (or most any 14mm spark plug head), Comp's PN 4795 unit works fine.



The piston stop screws in the spark plug hole and the center of the stop is screwed further down into the combustion chamber to provide a stop for the piston. Remember the stop is only for touching the piston, not poking holes in it! Disconnect the battery before even thinking about using these. If the engine is rotated via the starter, you'll either rip threads out of the head or poke a hole in the piston.




The smaller diameter degree wheel pays dividends when used in the car. The larger wheel simply won't fit.



Since the Gen III and IV engines use a metric threaded valve cover bolt, you'll need to make a custom fixture mounting stud. A piece of 5/8-inch tubing, some washers and an extra long metric bolt will do the trick if you can't fabricate something.


http://ourworld.cs.com/ls1info/0506htp_degree_26_z.jpg

The head-on cam fixture mounts using a valve cover bolt hole in the head--pretty slick. It is possible to align the indicator with the lifter, as shown, but it is very difficult to see the contact point between the two.




The alternative to setting the indicator on the lifter is setting the tip on the valve retainer. First, it is necessary to swap in some light checking springs, so the lifters don't collapse when the engine is rotated. Comp's PN 4758-2 springs do the job. Degreeing is completed the same way as described out of the car with the heads off. A little more patience is required when doing it in the car. Remember to double check all measurements, mistakes are easy to make. And lube up that number one intake lobe now!

 

gmblack3 - Guide for Dual Spring Swaps

Here is my "how to" when I installed crane duals with the crane tool. From what it sounds like the "more performance" tool is different, but this should get you there.

Instead of grease we used one of those pen magnets to make sure the keepers didn't go anywhere. Sounds like the other guys used grease to keep the keepers in place during reassembly, use the pen magnet when removing the keepers.

Remove the stock rockers. You can see the rocker here and the broken spring:



Should look like this when you get all the stock rockers and rail removed:



Sorry didn't get any pics of the old spring removal. You should be able to figure it out from the install pics.

Apply 15psi of air to the cylinder where the springs are being removed from. Some say that more should be applied but it worked for us.

Give a few taps to the valve spring with a dealblow hammer. You just want to make sure that the valve is not going to follow the spring down. If it is let the spring compression tool back up and a few more taps with the hammer on the spring/valve. Once the spring locks are looking free, grab them with a pen style magnet. This is the best way to ensure that you don't drop them. Let the spring tool back up and remove the two springs.

Then it will look like this:



If you have some miles on the car, I suggest changing out the valve seals. GM part # 12457652 this is the part # for the brown (exhaust=high-temp) seals. I suggest getting 2 sets (8 in a set) of these. They list at $17.50 a set. There are also seals that are black, they are used for intake seals (not high-temp). They are the same price so you might as well have the higher temp seals (brown) on all 16 valves.

If you are replacing the springs with aftermarket springs you will need to remove the spring seats. The new springs will need a different valve seats as the aftermarket springs will not sit on the stock valve seats.

Here is a pic of the stock valve seat being removed. You can also use your pen magnet to remove these as well:



The valve seals can be removed by using a set of pliers. Careful not to scare the side of the valve when removing the valve seals.

Grab a new valve seal and lube it with oil on the inside and top, carefully slide it down over the valve. You don't want to damage the seal.



Slide the 2 new spring seats on and make sure they are flush on the head:



With a socket and extension tap the valve seal into place. You will feel a click:





Check again to make sure the spring seats are flush against the head.

The place the new spring with retainers in place:



Then get the spring tool and retainers lined up. Start to slowly compress the spring. Make sure the valve does not get caught on the retainer.



See how the valve is centered in the retainer:



Here are your spring locks. Notice how one side is bigger. The bigger/thicker side will go up.



Place them in place like this:



Slowly release pressure on the spring tool:



After you remove the tool they should look like this:



Give a few lite taps again on the spring/valve to make sure that everything is good. Remove the air from that cylinder and move on to the next set of springs.

gmblack3