AFR 165s PS3 install issue

I have the PS3 kit and I am having problems with the set-up. The stock AFR spring installed height that the heads originally have is 1.800-1.815. Ed Curtis set up the PS3 kit with shims that will get you .030 longer than the stock height. So since the kit shims off of the stock height the installed height for the new springs is 1.830-1.845. So here is the problem. My origional-installed height is around 1.775-1.785 which is too short according to specs. So when I install the kit as prescribed in the instructions it sets my installed height .030 longer than stock which since my stock is actually 1.775-1.785 it now sets the PS3 springs to 1.805-1.815. This is far under the suggested 1.830-1.845. I don't know why the original installed height is so far off? I don't know if I should install the kit as prescribed and be under specs, or re-shim every valve to get the suggested 1.830-1.845? Ed Curtis is on vacation and I need to get these heads together.

95opal said:

Did you leave the stock AFR shims in and just take out the spring locator cups?

Click to expand...

The first thing I did is follow the instructions from the kit and just removed the spring cups and left the shims. But after I did this and re-measured the installed height ranged from 1.809 to 1.817. Which is too tight according to the specs of 1.830-1.845.

The next thing I did was measure the shims under the cups. The exhaust shims were all .030 and the intake were all .060. So I took the .030 out completely and left only the hardened shim from the kit on the exhaust valves. I then took the .030 shim that was originally on the exhaust, and installed them on the intake side. This raised my installed height to around 1.839 to 1.847 range. This is where I am at right now. I just don't know if I should run them long at the 1.839-1.847 range or put the shims back to their original location and run them short at 1.809-1.817? I am also wondering if AFR intentionally runs them tight because maybe they will loosen after they are ran on the motor? My cam is a Comp XE270HR-14 with only .512 of lift so I would think I would be ok with having them tight with my cam since it doesn't have much lift and these springs are supposed to be good to .635 lift without binding issues?

My last option is to just re-shim all the valves to attain the 1.830 installed height?

I am not using hardened shims (shims with the AFR heads not hardened). But the .030 shims with the kit are hardened so I am putting the non-hardened shims under the hardened shim from the kit. According to the PS3 instructions this is fine as long as the hardened shim is the last shim installed. Yes, I am using a height micrometer and I also have been pulling up on the retainer to make sure the locks are fully seated confirm and accurate reading.

At lunch today I put the PS3 springs on a spring checker to see what kind of pressures I would get at different heights. At 1.825 I got 140lbs, and at 1.850 I got 135lbs. This tells me that .025 changes in installed height only changed my closed pressure by 5lbs. I am starting to think I will be ok running these springs at 1.839-1.847 range and I will be fine. (AFR stock springs are 120lbs at the seat) I already installed my seals so I do not want to remove the seals (damage the seals) to install more shims if I don’t need to. But I will re-shim as you suggested if I definetly need to. I am also in the required installed height range of 1.830-1.845. Just at the higher end.

Rick, you also mentioned that the stock AFR spring would be ok with my cam. I was told by AFR that the springs are rated to 6000 rpms. I called AFR and they said that rating is for hydraulic cams not hydraulic roller cams. Due to the aggressive ramp profile of hydraulic roller cams that I probably have valve float issues at or around 5500. This is also consistent with an article on AFRs website that was conducted by muscle mustangs and fast fords where they compared heads and the AFRs did the best as far as gains, but did get valve float at 5700. http://airflowresearch.com/articles/ultimate/Group1/Part2/A-P10.htm This was with a Comp XE266HR14 cam that is not quite as aggressive as my XE270HR14 cam. I plan to rev to 6000 so that is why I upgraded.

I did not know there is a PS2 kit.

You are right about the seals. I was able to gently pry them off carefully without damaging the seals in order to reshim the springs. I first took a pocket screwdriver and gently popped off the garter spring on the seal. I then coated the valve stem with oil and gently slid off the seal. By removing the garter spring that helped the seal slide off the valve. The machine shop carries .015/.030/, and .060 thick shims. There are none in between. I bought a bunch of .015. Again, I am not 100% sure what the installed height actually is. Ed does not clearly specify an installed height specification, he just gives a range. I am just going to use the 1.830 as my installed height spec. Most spring manufactures give a single installed height spec and then the rule of thumb is + or minus .010. So I reshimmed all the springs with an installed height spec of 1.830 and + or minus .010.

Here are the final installed height measurements after installing the .015 shims: 1= 1.828 2=1.820 3=1.828

4=1.823 5=1.829

6=1.820 7=1.827 8=1.828 9=1.832 10=1.820 1=1.834 12=1.829 13=1.824 14=1.822

15=1.835 16=1.820

I can now start focusing on my degreeing my cam and setting my pushrod length.



Thanks for the help on this Rick, you insight was very helpful.