This weekend I'll be installing my first valve train in a Flathead, needless to say, I'm looking for as much knowledge and specs about it as I can and going through the process in my head before I take a stab at it. The operation seems pretty standard, as I've been read through a lot of great threads like "Flathead Porting: Soup to Nuts . . . Pictures, Details and Opinions" - by Bored and Stroked. However, I can't seem to find any examples including the 400 jr cam and Zephyr Springs. The other threads and articles have included the Isky Max-1 and the Potvin 3/8 grind, just not the 400 Jr. I know the cams are close to the 400 jr, but I know it has more lift than the others. Everyone says the LZ springs work great, but if you use them with SBC pro-flo valves, you need to shim them, which leads me to my quesion. How much do you need to shim the spring to achieve the adequate installed spring height, and how much pressure are you trying to achieve on the valve; using a 400 Jr Cam, SBC valves and Zephyr Springs?
Found this on the HAMB, not sure if it helps. "Don't buy double valve springs - they are a complete waste of time for your setup and a royal pain in the ass to work with. Buy a set of Lincoln Zephyr springs or Isky 185G springs. With the Zephyr springs, set it up with about 70 lbs on the seat with the 185G, about 80 lbs on the seat. You don't need a lot of spring pressure with your setup . . . all it does is wear out your cam/lifters!"
Dale pretty much lays it all out in this thread http://www.jalopyjournal.com/forum/showthread.php?t=420484 I machined my block at milford SCC Motor building class. Later when i went to install the valve assembly i found that i couldnt get the proper valve lash. I debated on new valve seats durring the class but the machinest reassured me that they looked great. Problem is that they had been ground to deep over the years. so i had to tear down the block and take it to a machine shop to get new seat put it. I used H&H Potvin 3/4 cam with isky springs, H&H adjustable lifters and proflow 1.5 valves.
Thanks F-6, that'll help but, I'm still looking for the installed spring height measurement for the Zephyr Springs. Thanks CC. Fortunately or unfortunately however you look at it, I'll be running new seats so that might help that the seats shouldn't be cut to deep. That really couldn't have been to fun. I've been trying to infer here as well, the differences between the 185g springs and Zephyrs, but I can't find any tech specs on the zephyrs either...
I'm no expert, but I think you need to put the spring in a pressure gauge, there's no magic height as all the springs have different rates, you use the shims to get the right pressure.
Exactly, its more involved than just sticking a shim under each spring, you also have to know what your springs installed height is in the block, without that, you have no way to know if you need to shim them or if you have too much already. You need a height mic or small telescoping gage, checking spring,valve, retainer & locks and of course, a way to compress the springs to R & R them.
Guys thanks for the input. I understand its not going to be as simple as sticking a shim under the valve. Otherwise I wouldn't have posted the thread... Let me rephrase the question. Im wanting to see if there exists, somewhere, an installed spring height recommendation for Zephyr springs that will be used with chevy valves and a 400 jr cam. The other threads I have read recommend 1.95 to 2.10 inches of installed height. However these figures came from a max 1 and potvin 3/8 grind cam. Neither of which have as much lift as the 400. Ive found in the past its better to know a range to work in rather than not...
my 2cents... install your valve assy into the block ..using the install bar pull the assy down and install the retaining keeper making sure it is seated as intended in the block .. measure the now installed height from spring end to end .wright it down.. remove the assy ,take the spring off and put it in your spring tester ..duplicate the installed spring measurement and see where you are. If its less than 80 lbs then you need shims if its more than 80 lbs your valve seats will need cut ...in other words each assy needs to be installed and measured in order to get it right..its a lot of work but thats how its done to perfection...80 lbs is plenty in my opinion..Isky springs will come very close to that if your valve seats are not cut to deep..I hope this helps
Thanks John! That does make sense and help answer some questions. Id rather do it right the first time. Now regarding a spring tester. I ran across a thread on the Ford barn where someone made one out if a drill press and standard weigh scale. Any harm in this since im without a true spring tester? My only concern would be the possible inaccuracy.
Just bit the bullet and picked up a valve spring tester. If I'm going to do this I want to do it right. Thanks for everyone's input, I'll update when I go about assembling everything.
oldsboy, your on the right track with the tester however I think the scales idea would work just fine
I agree, the right way is going to win out. I have no real input here, just cant wait to hear this flatty come to life.
Just to cap this thread I wanted to post an update. I'm currently working on the setup of the valve assembly after the valve spring tester showed up. I have photos and an update on my build thread showing photos of how its going. Thanks again for the instruction from everyone. I believe I'm on the right track now. http://www.jalopyjournal.com/forum/showthread.php?t=549465&page=19
Hi "olds", you need to be careful when "shimming" the installed spring height, you will only be able to use possibly (1) .060" and (1) .030". If you need any more shims to get the desired height you will have no "register" left to keep the springs stable. The amount of room in total from the spring seat to the top of the register is only about .125" (1/8"). Using 1 each on the shims (.060"/.030") leaves little "register" for the springs. (I have a photo below here with 2 shims in place. The small black line above the shim is what is left for the spring) The Isky spring's give 80# @ 2.000". The stock springs (late '52/'53) give 45# @ 1.875", and the stock ones (early '49/'51) give 55# @ 2.000". (Add) Watch the spring design also, some are "progressive" wound and get installed with the "stacked" end on the bottom of the guides. Thanks, Gary in N.Y. P.S. Have never used the "Zephyr" springs, for us probably unnecessary?? The Isky's (185G's) work fine.
Gary, thanks for the heads up. I did send you a PM regarding this but I wanted to see if anyone else could weigh in on as well. Since I'm running a longer the (the chevy 1.6's) how do you go about retaining the register on the guide and retainer if you have to use more shims? Anyone?
Hi "olds", if you absolutely need more shims, the only option I see is making a type of "sleeve" (preferably steel) about .400" long with a .670" O.D. x .530" I.D. The guide could be machined to the .530" dimension (on the topside) totally eliminating the existing register. You would slide the sleeve over the (.530") guide and have the .400 height to work as the new register and shim locater. You would be able to use numerous shims with this method. It would simply be some lathe work, could be done right at home on a small bench-lathe! Whoever is mfg the new replacement Flathead guides, I believe they are of "Chinese" origin now, should have had the foresight to change this dimension and incorporate it into the new design, would have been very simple. All, that would have been needed is add .200" add'l to that original .125" height. It would actually have made it an excellent selling point. (Add) I have read your P.M. Thanks, Gary in N.Y. P.S. While we are on valve springs and guide issues, I really strongly recommend havng the guides (old or new) bronzed-lined and machined for Viton stem seals. You'll never have a valve "hang" anymore!
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