3500 valves floating

[Barry]

At what rpm are you 3500 people feeling valve float?
I had my rev limit set at 6k and it pulls hard up to it. I bumped it up to 6500 and things changed. It seems to fall on its face around ~6200, it feels like the valves are floating. The whole sound of the engine changes.

Is this normal?

[1meanz]

whats the use in 6500 rpms? if it doesnt fell right up there, put it back to 6k or even 6200. im not sure at where they float, but i know if they do, and it looses power ater 6200 rpms, no need to pull it to 6500.

[Superdave]

the springs are similar in spec to the 3400 springs so float around 6K would be normal. There were rumors of the 3500 springs being better but after some research that seems to be false.

There was also some issues on the '05 models with the springs causing excess valvetrain noise and triggering knock events.

Comp 26915's would fix that real quick. Mine's seen past 7K with no float at all.

[Barry]

I was just curious if this is a ignition related issue or injectors maxing out or something.

It pulls hard, then just dies at around 6200. Its like it just pulls 10* timing all the sudden. I know it isnt(looking at the logs) but thats what it feels like.

Are those comp's still availible?

[Superdave]

Yep, Redbird just brought a set over for me to put on his 3500 heads Friday.

26915-12 on Summit

the stock cam isn't going to do much at that high of RPM, but with LS1 springs on my mild ported 3400 back in '06 it would rev past 6500 no problem.

[asylummotorsports]

I have dozens and dozens of runs on mine, and with the stock cam and springs the best times have all been achieved shifting at 6,000.

There is no power above that with the stock stuff so why bother anyway.

Having said that, I have had it to 6500 without any issues. It's not doing anything but making noise, but I didn't notice any parts compromises.

If you have enough cam to go past 6000 then get the better springs. If you still have the stock cam, IMO you don't require the springs.

Now if these proposed higher ratio rocker arms ever show up, that may change.

[3400-95-Modified]

6750 FTW LOL

And I'm running the 26986 springs from the WOT-Tech store.

Why are you guys going with 313 rate springs? The 280's I have seem to be working find and use stock parts all around... no LS1 seats necessary.

[Superdave]

6750 FTW LOL

And I'm running the 26986 springs from the WOT-Tech store.

Why are you guys going with 313 rate springs? The 280's I have seem to be working find and use stock parts all around... no LS1 seats necessary.

the 915/918 springs use the stock hardware too.. no LSx seats needed.

[IsaacHayes]

I wonder how far it will pull once the valve float is fixed.

[Barry]

Yeah im curious too. If it would pull to 6500 it seems to leave me in a better position in the next gear.

[3400-95-Modified]

the 915/918 springs use the stock hardware too.. no LSx seats needed.

Not According to ben... also the diameter's listed on Summit are smaller, thats why I assumed it was more like the Yellow springs.

26915's These Comp springs are designed for the LS1, and as such require the LS style seats and different seals to fit the 60V6 pushrod motors

136# @ 1.700" and 262# @ 1.300.

26918's These springs are very stiff and should only be used on an extreme build. Recommeded for .550 max lift, these springs also require LS style spring seats as the stock seat/seal of the 3100, 3400, and 3500 will not work.

161# @ 1.700" and 287# @ 1.300"

I ask again thou... Why the 915's?

They only support up to 500 max lift... I can't use them according to that spec alone, and the 918's are said to be very stiff and for an extreme build only.

My springs are Rated at 140# @ 1.7 and 250# @ 1.3 Very close to the 915's but support more lift.

[Superdave]

i have 915's installed with stock 3500 seats, Ben just hasn't updated his info.

I went with the 915's because they offered the better spring rate and they actually coil bind at 1.08 which allows for .570 safe lift. 120# @ 1.7 and around 300 lbs at 1.15.


If you want the real specs of a product you should always go to the manufacturer. http://www.compcams.com/technical/Ca...07/282-306.pdf

[3400-95-Modified]

.570 still cuts it too close for me...

I'm still not understanding the benefit of using such a stout spring on a stock setup... the 915 as your recommending for him.

[SappySE107]

I just got some 915s in and they do not fit the stock stem/seal combo. Its tight on the bottom and the spring does not touch the bottom unless perhaps with the spring installed on the head and the pressure forces it down more. I don't know what this does to the spring to force it on the stock seat.

[3400-95-Modified]

Ok, I was simply questioning it going by the specs even on the comp cams sheets... My springs have a seat OD of 1.412 where the others are only 1.290 I figured that had bring them close to the seat center if not forcing them into place.

Also LS6's are 1.290 and I know for a fact that I used Toyota Land Cruiser seats and Cavi 2.2 seals on my old setup to get those to work since they wouldn't fit the stockers.