L36: Valvetrain upgrades needed for 1-2 shift point of 6250? - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


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Old 04-09-2007, 01:37 PM   #1
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Default L36: Valvetrain upgrades needed for 1-2 shift point of 6250?

OK boys, give it to me straight...

While in there installing rockers (probably modified stockers, like ER rockers), what (if any) valvetrain upgrades (springs, pushrods, valve seals, etc.) would be required to "safely" get the 1st to 2nd WOT shift point up to 6250 rpm on my 1998 LeSabre L36?

(For that matter, is it safe to go to 6250 with modified stock rockers? Is a 6250 rpm shift point "safe" on an L36 beyond any valvetrain limitations?)

EDIT: current redline is 6000 rpm, according to the tach in the dash.
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Old 04-09-2007, 02:01 PM   #2
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Andy...

Call the nice folks at Intense Racing. They will be able to tell you what needs to be done. I'd think you need springs. Probably suggest valve seals.. no idea about the rockers/rods etc in your case.

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Old 04-09-2007, 05:26 PM   #3
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You definitely do not want to be reving up that high without a cam. You're only going to be moving your peak power up to 5800.


6100 would probably be more effective.
If you were to go past 6k, you would need to get 105 or 90lb springs, LSx style retainers, and new revised comp locks. (they had a problem with the angle)
The 105lb springs would be the better choice since they build pressure slower than the 90s. This will put less wear on the timing chain and damper.
You do not need to upgrade the pushrods or the lifters.
If the lifters are noisy, you may just want to pick up a low mileage L32 set off of Morad. I went that route.
It would be a good idea to replace the valve seals but if the engine is not high mileage, I wouldn't bother.
FWIW, I took stock pushrods, lifters, and 90lb springs past 6250.
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Old 04-09-2007, 11:30 PM   #4
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6000rpm tops on a stock valvetrain if you ask me. That'* an opinion, but educated from experience and seeing what valve float is like.
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Old 04-10-2007, 09:17 PM   #5
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Quote:
Originally Posted by Allmachtige
6000rpm tops on a stock valvetrain if you ask me. That'* an opinion, but educated from experience and seeing what valve float is like.
That'* exactly his question in this thread: What valvetrain mods are required?
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Old 04-11-2007, 02:56 AM   #6
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OK, after getting opinions from you guys, Intense, zzp, and 3800performance, I'm getting the picture on what'* needed now.

I've just about settled on LS6 90# springs (about $60 shipped, gmpartsdirect). 95naSTA mentioned, and I have read before, of the concern that their relatively high spring rate (380 lb/in versus 313 lb/in for CompCams) wears the timing components more...is that a concern if I really don't race that much? Besides can this really be true about LS6 springs, when the stock 3800 spring already has a rate (according to calculations from FSM data) of 355 lb/in?

Seems I'll need retainers for those springs; so, should I go with: OEM'* for LS6 springs (about $20, gmpartsdirect), or CompCams (about $30, various sources)? AFAIK, either would give a 1.800” install height with the LS6 springs…

As for keepers / locks, would there be any advantage for me to the aforementioned CompCams locks (about $25, various sources), versus replacing them all with new OEM-style keepers (about $5, Rock Auto; “Sealed Power” brand)?

As BillBoost mentioned, might as well do new valve seals (have 92k miles on the engine). So, is there any reason to go with the fancy “viton” valve seals (about $25, various sources) over OEM-style Fel-Pro’* (about $15, Rock Auto)?

I’ll be doing these springs on-car, so I imagine the standard type of valve spring compressor would be a PIA to use on the rear bank…so, does this one (designed for LS1 / LS2 / LS6) look like it’d work on the L36?:
http://cgi.ebay.com/ebaymotors/ws/eB...5801421&rd=1,1

(If that tool won’t fit, where can I get one in that style that will? Anyone got a loaner?)

Final question (for now): when I install rockers, should I use OEM rocker bolts (about $15, various sources), CompCams re-useable bolts (about $20, various sources), or Intense’* “unnamed brand” re-useable’* (about $20)?

P.*., what does valve float “feel like,” anyway…I mean, what are the symptoms? I wonder if I'm getting it now with my tired old stock springs and completing my shifts (via PowrTuner) around 5800 rpm...
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Old 04-11-2007, 03:21 AM   #7
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Definetly get re-usable bolts.

My thought reading the initial posting, is why are you aiming for 6250? ANy paticular reason?

As far as valve seals and what not go, why not get the best, as most prices aren't that far off, and if you're digging in there, do it once.
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Old 04-11-2007, 04:09 AM   #8
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Quote:
Originally Posted by BonneMeMN
My thought reading the initial posting, is why are you aiming for 6250? ANy paticular reason?
There'* all manner of shift point "theories" out there I'm planning to test, based on projections of anticipated gains after I get my rockers and (and other mods) installed.

Personally, I believe in horsepower!

6250 rpm comes from the most extreme application of perhaps the most "radical" theory I'm willing to test, wherein I would want to finish the 1 to 2 shift as high as 6250 rpm (meaning a shift set point about 6000 rpm, if current trends hold), so as to match HP at the top of 1st and HP at the rpm where it lands in 2nd (theoretically around 3250 rpm, but it won't really "pick up" from the bouncedown until around 4000 rpm...again, if current trends hold).

In short, 6250 rpm just may turn out to be too high...but I can't test it if I can't get there!
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Old 04-11-2007, 05:12 AM   #9
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LS6 springs will work just fine. I've had them on my car since Thanksgiving of '04, and I just saw my tensioner for the first time since then. It was in fine shape. In fact, I didn't have a replacement tensioner ready, so I reused the one that was on there. LS6 springs do have higher seat pressures when compressed than the CompCams 105s, but they won't require a tensioner replacement for many years. Just make sure you put a new tensioner on when you install them if your tensioner is old and tired already.

I would look for some low mile LS6 springs on Ebay. I got mine shipped to my door for $40 total including the LS6 retainers. I'm pretty sure we reused the stock L36 keepers.

I would defintely go for the reusable rocker arm bolts as Jason suggested. You never know when you might be back in there, and the cost difference is negligible. I'm glad I bought them, as I've had various reasons for loosening and retorquing my rockers over the last couple years.

Valve float is generally described as "hitting a wall" at a certain RPM. It'* like the engine is pulling nice and hard, then falls flat on its face up in the top of the powerband. I wouldn't think it would happen on a stock L36 valvetrain (even if worn), but I couldn't say for sure.
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Old 04-11-2007, 11:18 AM   #10
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Quote:
Originally Posted by agrazela
Seems I'll need retainers for those springs; so, should I go with: OEM'* for LS6 springs (about $20, gmpartsdirect), or CompCams (about $30, various sources)? AFAIK, either would give a 1.800” install height with the LS6 springs…
I wasn't 100% positive that the stock LS6 retainers would work so I got the Comp'*. If you can verify that they will, I'd say go for it.
Quote:
Originally Posted by agrazela
As for keepers / locks, would there be any advantage for me to the aforementioned CompCams locks (about $25, various sources), versus replacing them all with new OEM-style keepers (about $5, Rock Auto; “Sealed Power” brand)?
I got the comp locks as cheap insurance if anything. Others have run stock locks but I'd rather go with something designed for increased spring pressure.
Quote:
Originally Posted by agrazela
As BillBoost mentioned, might as well do new valve seals (have 92k miles on the engine). So, is there any reason to go with the fancy “viton” valve seals (about $25, various sources) over OEM-style Fel-Pro’* (about $15, Rock Auto)?
The major advantage is that they are lower. This dosn't really matter though in this situation.[/quote]
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