LS1 valves

[03GC]

Has anyone tried to put stock LS1 valves in yet? The stems are about .0015-.002 larger than stock,so the guides would need to be reamed.The head sizes are 2.00 and 1.55 (stock jeep is 1.91 and 1.5 I believe). The valve overall lengths are slightly longer (intake .042 ,exhaust.016).

I know some will think oversize valves are a waste of time. Some flow bench data would be awesome to prove or disprove this( right up 1bolts alley )

I am on the fence right now . The machine shop says they will do whatever I want , but thinks it is a waste of time.

Any opinions?
Paul

[dwg86]

Someone here has done it. I used SBC 1.94/1.50 stainless undercut valves. My head needed guides and most of the valves were worn. I bought a set of stainless, undercut, swirl polished valves off Ebay for around $60.00. The machine shop reamed the guides for the 11/32 valves. The SBC valves are the same length as the 4.0, and the intake valves are only .030 bigger than stock (thats not adding that much to valve shrouding). If you use the SBC valves, you can choose just about and spring/retainer combo you want.

[6TIME]

I actually just finished up a 7120 head for a stroker build with stock GM LS1 valves/springs/retainers. The nice thing about the LS valves is that they are tuliped on the underside of the head so they actually give you a few cc's of chamber volume allowing the quench height to be tightened up a bit. I had bronze liners installed and also had to cut the spring seats deeper to accommodate the 1.8" install height. I purchased all of the parts on Ebay for less than $50 bucks, and they are a very lightweight valvetrain combo for the 4.0 head. I'll try to post pics when I can.

[6TIME]

Ok here's some pics! There are some pretty distinct differences between the stock valve/keeper and the LS setup that affect the install height quite a bit.

[Plechtan]

I used the chevy valves on a head, we machined the head down about .100 the used some +.050 locks to get the corect height. Here are some examples of special locks

http://www.pppcenter.com/06Catpgs/C010.pdf


I think the big reason to use the LS valves is cost. I got 16 valves, springs, retainers, abd locks for $100 off of ebay.

[StroktWJ]

Nice! I have had a set of Gen III 5.3L heads hanging out in the garage for sometime and was think the same idea for my next Jeep stroker.

[Dmondeac]

I have not tried the LS valve but I went with 2.02/1.64 SBC valves and just machined the heads to get the proper installed high for the springs.

[zeekracing]

This is awsome news. I have a few sets of ls1 heads in the garage. This will save some money if I can use the behieve style springs. Are the stock ls1 springs good enough for an aftermarket cam? How much would I exspect to pay a machine shop to modify the head for this ls1 setup?

[03GC]

Just picked up my head today from machine shop.
Stock LS1 valves, 505 Performance springs, retainers,locks.
Had to cut sping pockets about .100.....closed pressure about 105-110 ,about 280 at .490 lift.
Kinda high pressure, but this is similar to what Comp and Crane(before they closed) called for. I know a lot of people think this is too much, but I will trust a cam vendors opinion (till it bites me in the ass!!)
I am going to break the cam in with Comp Cams Break in oil, then use Summit (re-badged Spectro...good stuff) 10-40 high zddp oil for the first couple oil changes.
Probably use Mobil 5w-40 Turbo Diesel after that
Paul

[Desertjr]

woah....1.8" install height? I think we are installing mine at 1.7" using 100% ls6 stuff..valves, retainers, springs, everything!....whats the differences here?

[6TIME]

All LS type conical springs aren't created equal. They all look similar but there can various differences in spring rate and height depending on the motor and year. I setup my springs using a Rimac spring tester to get them dialed where I wouldn't have excessive spring loads. I set them up at about 80lbs seat @1.8" and open they were around #240ish. I did have another set that could have been setup @1.70-1.75 just fine. Factory LS1 specs for springs are around 75-80 seat and 220-230 install ht can vary from 1.76-1.80" depending on the motor. Install ht. all depends on where you want the seat/open pressure to be...

[Desertjr]

All LS type conical springs aren't created equal. They all look similar but there can various differences in spring rate and height depending on the motor and year. I setup my springs using a Rimac spring tester to get them dialed where I wouldn't have excessive spring loads. I set them up at about 80lbs seat @1.8" and open they were around #240ish. I did have another set that could have been setup @1.70-1.75 just fine. Factory LS1 specs for springs are around 75-80 seat and 220-230 install ht can vary from 1.76-1.80" depending on the motor. Install ht. all depends on where you want the seat/open pressure to be...

So for a stock cam and 1.7 ratio rockers. What should I be looking at for spring pressure? Springs are out of a lq4.

[6TIME]

Your lift with 1.7 rockers and Lq4 cam (depending on yr) will be right in the ballpark for stock LS engines. I'd say, with the mellow factory 4.0 cam and light LS valvetrain parts, you'd be fine with stock LS pressures. From what I've seen, the factory specs for LQ4 springs are 76lbs seat and 220lbs open. Just make sure to test every spring for installed/open pressures and bind ht. to make sure you're dialed.

[troy5118]

Has anyone had any problems cutting .100" out of the valve spring seat for these springs. Getting close to water??

Thanks