Wet 1

iTrader: (4)

I'm going to be using 2.200" intake valves in a LS7 style head. The manufacture is suggesting that the SS valves they will be suppling (Racemaster?) should be fine for my application. This FI engine is going to be spun to 7K and I expect to keep the lift on the hyd cam around .590" to .620". Will these SS valves be okay for this application and if so what would I need for springs to keep everything under control?

I'm very sceptical about spinning the engine to 7k using SS valves of this size w/o using some major elephant springs (which I don't want to use either).

Do you guys agree that I should be okay as the manufacture is suggesting, or should I follow what my common sense is telling me... that a 2.200" SS valve just sounds too heavy to me, I'm having a hard time believing this won't be an issue. Is Ti the way to go here (of course I don't want to spend the money if I don't have to)???

TIA!

MrDude_1

iTrader: (4)

well the first thing i would want to know is...... what does the valve weigh?

Wet 1

iTrader: (4)

Unfortunatly, I don't know. They haven't nailed down the exact specs for the heads yet so I don't have any details to share... I wish I did. Although, I'm guessing a SS valve of that size has to be pretty heavy.

DAPSUPRSLO

iTrader: (14)

Not as heavy as 3/8 or 11/32 big block stainless valves though. Although I don't know how they fair at 7000rpm with stainless valves and a hydraulic roller. Just get yourself some morel lifters, throw some good spring pressure at them, don't go too crazy with the ramp rate of the cam, and have some fun

steve2001sh

In order to answer your question, you'll need to know:
weight of the valves
ramp rates
other special mods to the valvetrain (like springs)
lift hights (you did list that)

I don't know enough to answer your question, but whoever does will want to know those things.

Solid or liquid filled valvles will make a difference in weight and cooling.

Don't get too caught up in titanium. Good steel can stronger both per inch and per pound.

SStrokerAce

iTrader: (2)

Order up one valve and weight it... that's what the real world does.

You have to realize that BBC stuff or anything that is 5.5+" long and 2.20"+ in diameter is going to be big and it can be controled with conventional springs.

Your looking at 140-150g valves here anyways, which are heavy.

BTW the whole lobe shape matters not just the "ramp rate" when people mention that it makes me wonder if they understand what's going on in the valvetrain at all.

Bret

DavidNJ

For the engine you're building, it is time to bite the bullet an expect to spend $750-800 for Ti intakes and $250-400 for Special/Super Alloy exhausts.

SStrokerAce

iTrader: (2)

You could have hollow stems made.... the problem here is that there are easily some Ti valves that come out of a some professional racing classes that would be pretty close to being drop in valves.

What you have to realize, and I don't think people here do.... a stainless hollow stem valve SBC gets buzzed to 9,000rpm weekly in our country in a circle track series. We are talking over 70 cars, 30-40 times a year are doing this without a problem.

You are only doing 7000rpm, a BBC with SS valves can do that without a problem and they have valves that have the same mass. You need to look at the setup a lot like a BBC though, good lifters and the right springs to do the job would help.

In the end a lighter Ti valve would be better, but look at things a little closer before you blow $80+ a valve on that, and you ONLY need intakes not exhausts.

Bret

DavidNJ

Its not the valve, its the hydraulic lifter. Those guys run springs that are 250-300# on the seat and over 600# on the nose. Not something that a hydraulic roller will like. Also, aren't those 7mm stems, 2.15" intakes, and replaced every race?

It would be fine in a 6000rpm, and Comp has big beehive springs (26055 and 26095) that could be used. That heavy a valve just seems like a lot for a hydraulic lifter.

SStrokerAce

iTrader: (2)

A hydro can take that pressure if you do everything right... hence the lifter comment.

FWIW you can't get a 7mm shelf SS valve that will fit this application.

I've been able to take stainless standard valve SBC's with hydro rollers to 7500rpm without problems, that's without hollow stems, small stems or cheater lifters.

Bret

Wet 1

iTrader: (4)

Bret, what size valves though? 2.02"? 2.08"? 2.200" is a big valve.

Thanks for your input guys...

steve2001sh

Did I use "ramp rate" incorrectly? My understanding is that "ramp rate" describes the acceleration from different points. A valve may open faster than it closes or visa versa. Maybe it will start opening quickly, but then stay somewhat level until time to close. Any changes from the standard sinusoidal pattern would affect the acceleration of the valve, which would test its strength. Does "ramp rate" describe something else?

87gnx

iTrader: (3)

I would go w/Titanium; spend the money(tax return maybe) it'll be worth it with that combo IMHO.

SStrokerAce

iTrader: (2)

Ramp is just one part of the lobe, and in terms of valve control it's not the be all end all... which is the way guys talk about it. The shape of the nose and the flanks of the lobe both have a lot to do with it as well.

2.08" is the valve size I was speaking of.... Probably a 125g valve if it wasn't hollow stem, and closer to 105g when it is.

Bret

DavidNJ

Actually, this might require a step back. The LS7X seems to have a 5.5" valve for a 2" spring. When a 5.4" or 5.5" valve is factored in, any valve may need to be custom. World didn't specify their stock length, however it has to be in the 5.3-5.5" range based on their drawings. They may have ordered batches of custom valves for their setup. Rev has a 5.45", 5/16" stem vavle with 2.2 intake and 1.625 exhausts, sot that may be what they are using.

Interestingly, listed as LS1 valves, the exhausts have a 22 1/2° angle.

SStrokerAce

iTrader: (2)

Yeah the exhausts need more tulip to the head....

There is a Ferrea BBC 5/16 valve that's 2.250" head diameter that you could cut down but it's a ton shorter (5.325)

There are a lot more choices with 11/32 stems, but whats new.

Bret

Wet 1

iTrader: (4)

When I talked to Manley yesterday, they said they do not stock a 2.200" and that it will need to be custom. I 'believe' WP is going to be using Manley valves... SD series I would hope. So regardless, I think they are going to have to be custom made.

airflowdevelop

5.400 OAL x 11/32 x 2.250 intakes in BBC HR motors is a pretty common deal. You need to watch everything else in the valvetrain package, and give it a fair amount of spring pressure.

This also brings up another interesting question...what size bore is this motor going to be?

Dennis

Wet 1

iTrader: (4)

4.125"

DavidNJ

These seem to be a special long 5/16" x 5.45" stem big head valves designed for LS1 aftermarket heads. Rev seems to be actively going after the aftermarket head business.