Yea, i was thining of asking you to today at work, just in case.

More goodies arrived today, thanx Andrew.

wow nice are those springs use so i think that L36 will see 6000 plus RPM

Yea they are used. They have about 15K on them, but were tested and came out great. Well it may see over 6000. I will probably start out at around 6100 and jump on a dyno and see how the curve looks, if it is still pulling i may up it a little more. I know the 4t60e'* dont like high revs so i am not going to push it but i would like to capture as much of the cams powerband as i can.


PS- the springs do not look anything like that right now. Andrew cleaned them up and they look sparkling new. That was the pic he sent me, i took another one but dont have the time to let it upload and what not.

Actually, they are pretty much in the same shape they were when I bought them...that picture is just a bit dark.

Terry, if you can still make out the numbers in red Sharpie on the springs, here are the exact Instron test results:

Spring...Uncompressed ht (in)...Spring rate (lb/in)...Seat pressure at 1.800" (lb)
1..............2.153.............................. ..245............................86.4
2..............2.136.............................. ..240............................80.5
3..............2.164.............................. ..238............................86.6
4..............2.136.............................. ..251............................84.5
5..............2.164.............................. ..252............................91.7
6..............2.143.............................. ..260............................89.3
7..............2.146.............................. ..246............................85.1
8..............2.156.............................. ..246............................87.5
9..............2.139.............................. ..242............................82.1
10............2.174............................... .249............................93.1
11............2.142............................... .246............................84.2
12............2.156............................... .249............................88.5

Spring rate:
Avg: 247 +/- 6 lb/in (<3% RSD)
Min, Max: 240 lb/in, 260 lb/in

Seat pressure at 1.800" install height:
Avg: 86.6 lb +/- 3.7 lb (<5% RSD)
Min, Max: 80.5 lb, 93.1 lb

These springs have lost, on average, about 20% of their spring rate and seat pressure versus new specification (313 lb/in and 105 lb, respectively). This is to be expected on valvesprings used some 15k miles or so. They probably won't change much more than this with further use. No single spring is vastly different from the others.

For comparison, a set of stock springs with 30k miles on them tested at 52 lbs average seat pressure at 1.800" install height, for a loss of over 25% from original specification.

I would be interested in some gearheads' opinions on whether the "stronger half" of this batch of springs should go on the intake side or the exhaust side (or if it even matters)...

i would say on the intake because there more lift and duration on the intake side

I would say the stronger springs should go on the exhaust...because the intake has more lift, and will compress the spring more, I'm thinking putting the lower spring rates on the intake might help even out camshaft wear...

my thinking is that why do you change springs in the first place .because the new cam or the rocker as more lift .so if more lift need stronger spring why not put the stronger springs where there more lift just my 2 cents

Yeah, but they're still stronger than stock...ah well, let'* wait to see what the experts say

I think either way it will be more than enough to take care of valve float. It'* not like it has a crazy */c ramp rate or anything.

I would throw them on the intake if anything though since it weighs more.