valve springs

[Shimy87]

I will be changing these, from my reading seem like 2 popular choices, 980's and 981's.  Which is the better option for my combo...see sig

Thanks!!

[Steve Wood]

These days, I think I would go with the stiffer of the two

[larrym]

Yes 981s where what I used ion my flat tappets the 980s are pretty mushy after you spin it high a couple times.

[Shimy87]

Thanks guys!!

[Scoobum]

981's and don't spin the engine past 5500. I agree with Bison. Most don't  run near enuf valve spring pressure.


A lesson I learned. If you ever overboost an engine...be sure to swap in a new set of valve springs when you're changing the head gaskets.


I ran across a post from Dusty Bradfiord a while back. When he was racing these 231's back in the day...he was swapping valve springs 3 times during the race season.

[Shimy87]

ordered some 981's and borrowed a tool from a local garage, hope to have them in and installed next week  Been reading a lot on here and looks like I'm way conservative on my tune, fast guys running O2's in the 760 area. I'm in 790 area, and a few times in the first 100 ft showed some knock but figured it was from tire spin and not real knock, as it went away. I don't trailer to track, I drive and hour and a half, so I don't want to break the ol girl or I'm just chicken.

[1KWIKSIX]

Question for you?
What do Comp Cam state the 981's spring rates are at 1) closed- 1.727"  & 2) open- on the nose - 1.340"


You really should use a valve spring micrometer to check the installed heights .  Your spring pressures could be way over or under due to variances in the valve seat, valve tip , etc, etc. that will exist for each valve in your cylinder head.
I'm guessing your using a flat tapped cam?
Would hate to wipe a cam lobe.


Valve spring shims are available to help you fine tune each spring to achieve your desired numbers in your target (or at least get closer to it).


I used compressed air to keep the valves open when I recently did this change over with no problems (except you gotta watch out for those damn valve spring keepers as they will sometimes shoot out  and good luck finding them) I was lucky to have someone come to my rescue!   LOL - Thanks Brad

[Scoobum]

980's or 981's won't bring him anywhere near the valve spring pressure I'm running...and the lifters in my engine are showing zero wear after 2 years of weekend beatings...wit h no ZDDP. Oh...and I'm currently running a Fram filter. I live life on the edge...


Shimy...if you had PL...you'd be able to verify if the KR is real...or not.

[earlbrown]

I thought Comp Cams springs went to shit when they moved production to Mexico?

I have to use the hive mind here as I switched to PAC and haven't personally bought any Comp springs since all the reported problems.

[Shimy87]

Tried to install the 981's yesterday, got all but the last 3 on passenger side. Had to order the tool from Cotton's, tool I had would not fit there. I did not reinstall the metal cups that went around the old springs....was that a bad idea?

[larrym]

No you did the right thing did you measure installed hight? We usually cut a piece of wire to measure with.

[Shimy87]

Just cut wire to top of retainer or top of spring then measure? What should it be?

[Steve Wood]

I would not worry about it at all if you have installed most of them already

[Shimy87]

Got time to finish these up yesterday, put in some CR43ts gapped at .035, hope to fire it up tonight!! Those back 2 on the passenger side are kinda a pain in the ass

[Steve Wood]

yes, they are!