rockymountain1999

Can’t really find an answer to this question:

Are .660” dual springs okay for an OEM LS7 cam with OEM LS7 lifters?

Is this too much pressure on the lifters or am I not thinking about this correctly?

Thanks!

Undy

My only question is.. Why?

OEM springs control the valve train with an OEM cam just fine. No need to go with stiffer springs. You'll actually suffer a tad more parasitic HP loss for no reason too.

SPDKLZ1

I have PAC 1207 dual springs, 155 lb closed, 436 lb open, with OEM LS7 lifters recommended and installed by Richard at WCCH and build completed by DRM (Doug Rippie Motorsports) and they to an enormous amount of LS7 builds every year. But yeah with the stock cam I don't see the purpose unless maybe to prevent a dropped valve.

rockymountain1999

Thanks for your reply. My 2009 ZO6 had a lifter fail that wiped the camshaft so I’m in the middle of making the repair. I bought this car a couple of years ago which had the heads done by WCCH/Vengeance Racing (see attached invoice). This was done about 25,000 miles ago. I had the car reflashed back to the OEM tune thanks to the liberals here in Colorado. Anyway, I’m thinking I should go back to an OEM spring (or same spec) just for peace of mind. Any suggestions? Thanks!

rockymountain1999

And I’m also wondering about the 7.750 push rods that are in there…..

grinder11

Undy nailed it. Stock springs have been tested to 7,000rpm+. No need to tempt fate on even more sideloading of LS7 guides by going to stiffer springs on a stock cam. Are you worried about over revving, or???

rockymountain1999

I’m worried about digging into this engine again! Just a weekend toy car. Looking now for new springs. I guess I should go back in with stock push rods too.

grinder11

I would definitely go with at least an .080" wall, 3/8" diameter hardened pushrod.....

1972bluelt1

How much did they mill the heads?

rockymountain1999

Not completely sure about that. This “head repair” was completed 9 years ago.

I spoke with Vengeance Racing and they couldn’t advise any further other than explaining they probably cleaned up the surfaces and still remained within “specs” for the ZO6 heads while keeping the stock cam.

They now send out heads for this type of work.

Armando Estrada

What lifters were you running? And every when would you change the oil? 10w-40 seems a little too thick, when 5w-30 is whats recommended. I personally use 0w-40 Pennzoil Ultra Platinum with great results over Mobile 1 5w-30, that also caused a couple of failed ls7 lifters when I did a cam swap, 20k miles into the HCI build. I did switched over to Johnson 2116 lifters, Manton Push Rods, Pennzoil 0w-40 vs Mobil 1 5w-30, and change my oil every 2500-3000 miles on e85, "waters down the oil faster" My engine has never been soo quite! Ls7 lifters with stock trays are junk on big cam builds with heavy spring pressure, even stock c6z06's can start chirping the lifters under normal driving, its the plastic trays that suck! "I did replace my trays when i did my HCI the 1st time around" and still failed!

rockymountain1999

Lifters were LS7s. Upon purchase about 12,000 miles ago, I switched to Amsoil 5W-30. Changed at about 4200 miles intervals.

I have a new set of GM LS7 lifters and waiting on a new OEM LS7 cam. Trying to justify the $700 - $800 for Johnson lifters at the moment.

Armando Estrada

Do yourself a favor and ditch those ls7 lifters, and move onto Johnson Linkbar lifters, those plastic trays are no good. I would also change oil every 3k miles at least and 0w-40 or 5w-40 for oil, more heat from mods require thicker oil. 750$ dollars is better than having failed lifters once again, you would just have to measure for pre load on pushrods through Manton. If you already failed once, why use them again.

1972bluelt1

I think you also have to check each pushrod length if you are using short travel lifters and may need more than one length pushrod.

rockymountain1999

Understood. However, this is what I’m trying to avoid; changing things too much in this car. No real modifications other than “repaired” heads.

Winter is upon us so I have plenty of time to figure this out.

Armando Estrada

You cheap out on these cars, you pay way more down the line. Heavy lesson learned.

grinder11

Let me say up front that it's hard to say anything bad about Johnson lifters. One of the very best, if not THE best. But the question is whether or not you need a set of $800 lifters in a pretty much stock engine. Now, I'll give you my experience. I have a modded LS7 in my C5. Running PAC dual springs with 425lbs@max lift, 165lbs on the seat. Running genuine LS7 lifters and genuine GM trays. Cam is spec'd by Futral, ground by Cam Motion. It has .603"/.608" lift, 232°/250° duration, on a 112° LSA. I have 52,000 miles on the build, never a problem with the trays OR lifters. I have a 7,000rpm shift point.

Undy

Similar experience here... Put 88K on my tune 'n header w/ CAI 07 Z06 with stock lifters and never had one single problem with them. IMO Johnson lifters are an extreme over-kill with a stock cam.

encasedmetal

Aftermarket springs would be an option to consider if you moved to a SS exhaust valve as so many of us do. more weight requires more spring control for the valve.

KennyPowers

I see stainless exhaust valves listed... oe exhaust valves are TI.. WCCH would change the spring given the heavier stainless valve?? Give them a call to confirm