PI Headswap..Degree/Retard Comp Cams 262ah???

[97GTSTANG]

PI headswap is underway, its a stage 2 port and polish pi heads with SS Valves (thinner) and Comp Cams Stage 1 262AH. Do i just follow the basic cam installation or do i have to degree/retard the cams so i dont have any PTV issues? I have read from many sites that i just drop them in and bolt them down, but i have also read i have to degree/retard the cams. So which is it?

I was told the SS Valves will help with clearance issues, will the port and polish help and will i be clear from any PTV issues .

Thanks

 

[Lugnuts]

If I were you, I'd consult Comp Cams - they are always helpful - and then do my own check on piston to valve clearance regardless of the answer they give you. The first time you do not check this you will likely learn a pricey lesson.. Advance and retard are not typically something that you just arbitrarily change - you need a reason. While clearance is a reason, it is not what I am talking about.

Will the port and polish help what? Certainly you are not referring to clearance. Porting will help produce more power when done right for the application. Polishing is debatable but a common practice.

 

[trinity_gt]

I don't believe the 262AHs are aggressive enough to worry too much about PTV. I would degree them after the install to verify the timing but wouldn't worry about advancing or retarding them.

You might consider upgrading the springs while you're that far into it...

 

[N8Dogg98]

I'd want to degree them to ensure they are installed properly. They could be off by a few degrees either side and that has a negative impact on performance. As far as retarding or advancing them, you won't really know which direction to go until you actually degree them properly. FWIW, a set of trick flow adjustable crank gears would be quite helpful and allow you to advance or retard in 2* increments up to 8* either side.

Trick Flow® Replacement Adjustable Crank Sprockets, Timing Gears - trickflow.com

 

[97GTSTANG]

Thanks for the advice guys. So its just a good practice to degree the cams after install. So when they are installed, they are placed in the position that is required by comp cams and then the degree tool is used to check if they are in the right positions? I am not mechanically inclined so i gave the job to a mechanic to complete. So what setup should the cams be at to be at peak performance?

 

[Lugnuts]

Unfortunately there is no cut and dry answer for that either. The requirements for different combinations driven under different conditions determine the best orientation of the cams. Your set up may respond better with advance, retard or straight up. You would have to look at your combination, how you intend to use it and the cam specs to make the most educated guess but sometimes you just gotta get it close and adjust from there to find your peak performance.

 

[N8Dogg98]

Thanks for the advice guys. So its just a good practice to degree the cams after install. So when they are installed, they are placed in the position that is required by comp cams and then the degree tool is used to check if they are in the right positions? I am not mechanically inclined so i gave the job to a mechanic to complete. So what setup should the cams be at to be at peak performance?

You want the cams to be degreed to the appropriate intake centerline (ICL)that comp designed them to be run at. This is especially important with a PI engine because you run the risk of PTV if they happen to be advanced more than a few degrees from their designed ICL. If the cams are retarded a few degrees from their designed ICL it hinders your engines maximum potential.

The issue with the OHC engines is you have 2 separate cam gears and the tooth on the gears can often be off by a few degrees either side. FWIW, my cams are supposed to be run at 106* intake centerline, and when the gears were installed the actual centerline was 108* on one side and 113* on the other side, so I had to use the adjustable crank gears to advance timing by 2* and 6* (respectively).

 

[97GTSTANG]

N8 thanks for the tip. So even if you line up the cams dot to dot, it might be off the mark? What should the centerline be at? Is that the only number i have to worry about?

Thanks

 

[N8Dogg98]

N8 thanks for the tip. So even if you line up the cams dot to dot, it might be off the mark? What should the centerline be at? Is that the only number i have to worry about?

Thanks

Yep you can line the mark on the cam sprocket and the crank sprocket and it still may be off slightly. Ford just had fairly loose production tolerances with regard to the cam gears. Get yourself a degree wheel, a set of Trick Flow adjustable crank gears, a case of beer, and search for "how to degree ford 4.6 V-8"

 

[97GTSTANG]

Just spoke with the mechanic, he said the swap is completed and just doing some final checks. He said the car started up just fine and is running well. he said it just needs to be driven to set a base idle. How long should it be driven to get a base idle. He said he will be driving it tonight and tomorrow to check everything before i pick it up. He said he will keep it under 4K RPM until it has some break in time. Is that accurate or does it matter?