[Formulajones]

Originally Posted by Formulas

One thing that caught my mind is

Doesn't the LSX engines operate with less spring pressure's than race Pontiacs?

They operate with less spring pressure than a "street" Pontiac in stock form!!

For starters, The very low mile LS engines I've done camshaft swaps in have stock beehive springs in them that were lucky to check just over 90 lbs. seat pressure, which is why those rollers live a long happy life. You can't even successfully run a decent flat tappet camshaft in a Pontiac with those springs pressures. So we don't even have to talk about race engines here.

When upgrading the camshafts in them years back, we went straight for a double spring with about 130 lbs. on the seat. The valvetrain in the LS engines are much lighter than Pontiacs, so they work well with a little less spring pressures on aftermarket camshafts than what you would typically see today, especially in engines with heavier valvetrains. I've run those engines like that for another 80,000 miles with the original lifters still in place without a problem, and spin them near 7000 rpm.
In a Pontiac with a pretty heavy valve train you are looking at 150 lbs. on the seat and somewhere around 360-380 open on a fairly mild hydraulic roller to control the valvetrain, even at lower 5-6000 rpm levels. I've had no issues with this either. My BBC has been together for the last 20 years with those springs without failure.

[blueghoast]

So how ya keep them from spining?

GT.

[krisr]

Originally Posted by Formulajones

The valvetrain in the LS engines are much lighter than Pontiacs, so they work well with a little less spring pressures on aftermarket camshafts than what you would typically see today, especially in engines with heavier valvetrains.

When I had my LS3 apart to do a valve spring and camshaft swap, I weighed the intake valves to compare against my 2.11 stainless valves.

Stock LS3 - 88 grams
F6189 (machined down to 2.11 w/30deg seat)- 147 grams

And that's JUST the valve!

[Murf]

Originally Posted by krisr

When I had my LS3 apart to do a valve spring and camshaft swap, I weighed the intake valves to compare against my 2.11 stainless valves.



Stock LS3 - 88 grams

F6189 (machined down to 2.11 w/30deg seat)- 147 grams



And that's JUST the valve!

Good info krisr! I have a couple questions for anyone that cares to reply.

1. Does the weight of the complete valvetrain affect the spring pressure required? I assume it does.

2. Would the use of beehive springs help fight the possibility of overloading the lifters & are there compatible beehives available?

3. Are there any relatively light 2.11 intake valves available at a somewhat reasonable price?

Thanks
Murf



Sent from my iPhone using Tapatalk Pro

[Formulajones]

Yes the weight of the valve train has a huge affect on spring pressures needed to control it.

On the beehive's, today there are many more options that work. Back when I was playing with them on LS engines there wasn't, so the go to solution then was a typical double spring swapped onto the LS engines. Beehive's have a few advantages though (smaller retainer being lighter is one of them) so if I could find a beehive spring package to work with a particular combo I was building today I'd go that direction.

Yes there are lighter valves than stock available. You could even get into hollow stem or sodium filled stuff (GM did this on some LS engines)
It just depends on how much money you want to spend. Personally I prefer to go with either titanium or tool steel retainers on all engine builds to lighten things up, and lighter valve assemblies when I can, even on a typical street engine build. Spring pressure will also be a result of how aggressive the lobe profile is. Even on a mild street engine build the valvetrain ends up being a somewhat spendy part of the build.

[slowbird]

Originally Posted by krisr

When I had my LS3 apart to do a valve spring and camshaft swap, I weighed the intake valves to compare against my 2.11 stainless valves.

Stock LS3 - 88 grams
F6189 (machined down to 2.11 w/30deg seat)- 147 grams

And that's JUST the valve!

I don't know the ls stuff that well, do they run titanium valves? What size valves are they?