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L33 heads have good enough springs for low boost?

 
Old 07-09-2019, 08:18 AM
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Default L33 heads have good enough springs for low boost?

I have read that a salvaged L33 with 799 heads won't need upgraded valve springs on factory L33 cam when boosted since the springs are same as LS2/LS6 or whatever. Is this true? Only planning on boosting 10psi or less for absolutely as cheap as possible initially.
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Old 07-09-2019, 08:56 AM
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New LS6 springs are only like $60.

Springs soften up over time. If the stock springs are high mileage, its not worth messing with them.
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Old 07-09-2019, 09:17 AM
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L33's do not have the "good" springs as the OEM cam is barely more than the LM7 cam.
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Old 07-09-2019, 10:13 AM
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Originally Posted by JoeNova View Post
New LS6 springs are only like $60.

Springs soften up over time. If the stock springs are high mileage, its not worth messing with them.
Sorry wasn't clear, idea is to have the engine as "modular" as possible in time/effort as well as cheap.

Motor blows, swap another with minimal effort/time/money with another salvage, and dial in the tune. Would be nice to not even need to open valve covers LOL.. I understand I'll of course need the typical MAP/injectors and am planning on swapping over entire LS6 intake, accessories and and oil pan (Fbody) but otherwise not open the engine at all. Just seeing how far from reality this idea is. This idea is obviously "Sloppy" inspired.

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Old 07-09-2019, 10:16 AM
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Originally Posted by G Atsma View Post
L33's do not have the "good" springs as the OEM cam is barely more than the LM7 cam.
But I guess my question is are the valve springs good enough with the factory L33 cam to work with occasional single digit PSI boost?

Not shooting for the moon, just maybe push upwards towards 500hp. This is for a daily driver that will see a lot of miles, say 50k per year.

EDIT: this thread seems to indicate that it would be fine:

https://ls1tech.com/forums/dynamomet...urbo-6psi.html

Last edited by mk3cn4; 07-09-2019 at 10:23 AM.
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Old 07-10-2019, 08:05 AM
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Based on the thread linked below, it seems most (all?) 799 heads very likely have LS6 springs from the factory, although not all were colored yellow.

Assuming I go this route, I will check for yellow coloring on the springs. If no color, I'll decide at that point which way to go.

If anyone has tested the non-colored springs on stock 799's and found them to not be LS6 springs I'd like to know.

Thanks.

https://www.ls1.com/forums/f7/799-heads-155748/
"Also 2001 243 z06 heads have blue springs which had less lift capability, .525 instead of.570 the yellow springs came out in 02 because the ls6 was upgraded in that year the yellow springs were were used from there on up on the 243 and 799 heads however I have seen some heads that just have regular springs with no color on them and 'supposed to be the same but no one has confirmed it."
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Old 07-10-2019, 10:21 AM
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Originally Posted by mk3cn4 View Post
Based on the thread linked below, it seems most (all?) 799 heads very likely have LS6 springs from the factory, although not all were colored yellow.

Assuming I go this route, I will check for yellow coloring on the springs. If no color, I'll decide at that point which way to go.
That would be a bad assumption. As said, the L33 came with a cam that is TWO points in duration bigger and SLIGHTLY more lift than the LM7 cam. GM isn't gonna stick their really good (to them..) springs in heads that don't need them. Keep in mind the 243/799 heads came in all truck engines after 06. The L33 cam did not warrant the good springs.
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Old 07-10-2019, 12:08 PM
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You can try them, but when I tested 200k mile springs against replacement stock springs, there was a significant decrease in seat pressure and spring rate.
Worst case, you just have trouble making power.

Its near impossible to blow an L33.
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Old 07-10-2019, 03:18 PM
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Ok, thanks guys. Appreciate the input. I have an L33 available near me for $600. Haven't eyeballed it yet but assuming it has 799 heads then the heads alone are worth half that I figure, might just go grab it and start this turbo build.

Swapping better springs isn't that big a deal I guess especially for an engine already out of the car. Would just be nice if it already had ones on it that would work out of the box, not just for this build but for future replacements.

PLUS it would have been cool to tell the dude I just beat at the track that it's just a L33 Vortec with a turbo, never even opened the valve covers!!

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Old 07-10-2019, 04:34 PM
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You don't need to assume. IF it IS an L33 it WILL have 243/799 heads. Into which you should put some LS2-LS3 valve springs minimum.
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Old 07-10-2019, 07:20 PM
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I'd rather buy springs than a new used engine.
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Old 07-11-2019, 07:58 AM
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Originally Posted by G Atsma View Post
You don't need to assume. IF it IS an L33 it WILL have 243/799 heads. Into which you should put some LS2-LS3 valve springs minimum.
I actually searched for that answer and couldn't confirm, and didn't want to ask the guy if it had 799 heads because I didn't want him to google that and raise his price. Thanks for that info, confirmed that the VIN has "B" at 8th digit so I think I'm good then, will be trying to eyeball it later today. Thanks,
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Old 07-11-2019, 08:18 AM
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I recommended stepping up to 5:16 comp pushrods. Higher cylinder pressures with boost. Last thing you want is rods flexing
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Old 07-11-2019, 03:35 PM
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Welp, as it turns out I *think* my current DD cammed LQ4 has a lifter eating a cam, had enough shavings to plug up my oil pressure relief valve two weeks ago, rather than doing that diagnostic and repair I might as well just replace that engine with this new L33 turbo instead of doing a slow convenient parallel build, which means I'd have the existing LQ4's 799 heads with PAC springs and trunion rockers and push rods to swap over to this L33. Not sure yet. Need to cut open a few more filters before I know how bad the LQ4 problem is.

Was hoping to DD the LQ4 for a while and grab a BMR Kmember, plop the L33 on there and get it all done then just do a "quick swap" (as quick as a swap can be since it needs tuned etc.), without having the additional down time of working on the engine in the middle to swap all the parts around etc.

This is all good food for thought. Appreciate all the input.
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Old 07-11-2019, 09:03 PM
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Even if the springs work it's really ridiculous result, a stock cam 5.3L engine on 8psi of boost makes like 300hp to the tire through 4l80e

Engine camshaft needs a lot more duration and a bit more lift to make use of the full displacement, then 8psi will make much more power as it should

and with that camshaft upgrade comes spring upgrade
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Old Yesterday, 09:45 AM
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Originally Posted by mk3cn4
Sorry wasn't clear, idea is to have the engine as "modular" as possible in time/effort as well as cheap.

Motor blows, swap another with minimal effort/time/money with another salvage, and dial in the tune. Would be nice to not even need to open valve covers LOL.. I understand I'll of course need the typical MAP/injectors and am planning on swapping over entire LS6 intake, accessories and and oil pan (Fbody) but otherwise not open the engine at all. Just seeing how far from reality this idea is. This idea is obviously "Sloppy" inspired.
An LM7 might be a better fit for this project. Finding an L33 engine can be tough. If you blow this one, it might be hard/expensive to find another one. The heads are great though
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Old Yesterday, 10:55 AM
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There is nothing unique about any of the L33 parts. It's just a good combo. Aluminum block shared with LM4. 243/799 heads can be had anywhere. Meh cam. Gen 4 rods now very common.
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Old Yesterday, 11:27 AM
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Originally Posted by JoeNova View Post
You can try them, but when I tested 200k mile springs against replacement stock springs, there was a significant decrease in seat pressure and spring rate.
Worst case, you just have trouble making power.

Its near impossible to blow an L33.
What he said.

Even when these engines were brand new, it was often possible to find evidence of valve float with Stock valve springs with the Stock rev limit in dyno testing. Back in they day, we saw it many times at the local dyno.

OP, I'd hate to do all the work even for a sloppy build and risk being down 5-30 whp over $60 worth of valve springs. I think if you run 10# of boost that basically takes 10# of spring pressure away due to the pressurized intake tract. The spring has an extra 10# of pressure to work against. So actually the valve will have less than stock spring pressure for the stock cam under boost.

I've tested valve like JoeNova and also found they lose pressure over time. The ones I test lost 10-25 pounds of spring pressure. Remove some more spring pressure due to boost conditions and it's easy to see some well used stock springs could be down 10-30 pounds of spring pressure.

Being that your building for 50,000 miles of daily driving it sounds like the stock springs will continue to see a lot of normal wear and tear, so the spring pressures will likely continue to drop over time and use.

Best wishes with your project,
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