I have decided to go with a set of shimmed 910 valve springs. I'm getting my order together and would like to know if there is anything else I may need that I should get.
Riffraff Diesel: Comp Cams 910-16 Valve Spring Set
Riffraff Diesel: Ford Valve Stem Seal
Riffraff Diesel: Comp Cams 4737-16 Valve Spring Shims .015"
Riffraff Diesel: Comp Cams 4743-16 Valve Spring Shims .030"
Proform 66902 Proform Valve Spring Height Mic

 

new set of Push Rods since you'll have the Rocker Arms off?

Riffraff Diesel: Smith Brothers Push Rods

 

Small tube of engine assembly grease. If you get .030 shims, it is not likely you would need the .015, however they are pretty cheap if you want to land on the cautious side. Don't forget the spring compression tool! I got free shipping on my springs, which saved me quite a bit of money.

 

Ok I am wondering why the shims? I ask because I bought a set of 910's off another guy on here and it came with shims I think the .015 ones. Shimming them would give you more spring tension, why would you need both sets?

 

Hopefully Roland comments here...

As I understand it, you can measure and individually shim each spring to get the heights exactly the same across the engine. You would need an assortment of different shims to accomplish this (e.g. .005, .010, .015 and .020). This should give you the same seat pressure across all 16 valves. Or you can put the .030 shims in and take a blanket approach to a target of a 125lb across the board valve seat pressure (approx but pretty darn close) with the known spring strength of the Comp 910. If you don't shim at all with the 910, Comp Springs says to expect about 115 lbs of seat pressure. In the end, the idea is to get those valves to close more firmly and concisely to eliminate valve float on a modified or tired engine, since the stock springs leave a lot to be desired. Mine were ridiculous soft when I pulled them out, and were probably only giving about 63-70 lbs of seat pressure based on wear averages for what Ford put in there. Valve springs do get weaker over time, and my engine is getting older at 13 years.

All that said, if you go too far with the seat pressures, you will wear out the valve seats and end up re-working the head. I have read that 140 lbs is that threshold on the 7.3L. Once you go to 140 or beyond, you don't have a daily driver any more that the valves will last in. The stock pushrods on these engines have a good reputation for holding up under some serious horsepower.

 

Stock valve springs have a seat pressure of 71-79 lbs @ an installed height of 1.833". The Comp Cams 910 have 92 lbs @ 1.85". Installing them no shim at all would give you an increase in seat pressure of ~20 lbs over stock. Adding the .030" shim would decrease the installed height to ~1.80 and put you at 110-115 lbs. Due to wear on the valve face and seat, spring height may vary from valve to valve. Checking height will allow you to compensate for the wear by adding shims to equalize the seat pressure for all the valves. Most seem to not have to add more than an additional .015" to get them somewhat equal. I doubt you would be able to see, or feel, any noticeable difference in performance with a variance of ~ .015'' between valves. have been running stock push rods with .030'' shimmed 910's for over 25k miles and am well pleased with the outcome. IMHO, going the "extra mile" to shim them all, individually, is up to you. I'll worry about "exactness" when it comes to rebuild time and there'll be alot more going on than just valves.

 

thanks for the info guys, I plan on doing them on my tired f450... she is not happy when i get over 2500rpms it sounds like the valves float, or an intake valve hangs open.... it could just be injectors bleeding oil pressure, and not being able to maintain enough icp to fire them properly. Under 2500 rpms it runs just fine, with a slight miss, It has steadily gotten worse over the past 25K miles. I just need to pony up the funds and send my core set in for rebuild, then spend a day or so swapping sticks and springs.