maxplusten

iTrader: (4)

Ok guys, to make a long story short my build is in my sig. Few weeks ago i had a lifter break appart on me (ls7 gm lifters) and wipe the cam. Im to the point where its time to order new ones. I dont wanna put the same thing back in and want to opt for something stronger with higher RPM potential.

Just a breakdown of the valve train. The cam is a custom grind from CamMotion (see below for cam specs). Im running 1.6 Comp Gold rockers, polylocks (which are becoming a nightmare and are a big part of this reoccurring problem), All comp rocker studs and guide plates , hardened comp push rods standard length. Valve springs are matched to the cam and they set on top of Dart pro 1 200cc chambers.

When Clayton and me originally discussed it this motor was suppose to be able to spin up to 7500 with no issues. This break occurred at 6700. I want to make sure I put the right stuff back in it before it ever goes boosted. The more i read about LS7 lifters this seems to be a reoccurring problem. I'm inclined to go with the comps but anything i can do to bulletproof this setup would be great. What do you guys recomend?

I really want to get rid of the polylocks in favor of something a little more maintenance free. Any suggestions there?

Also since i have the motor out, anything else i should upgrade while im at it that maybe im overlooking or forgetting?

Cam Specs:
Intake and exhaust
Lobe seperation =114.1 cam deg
Valve overlap= 2.4 crank deg
Intake
Valve open=2.5 BTDC
Centerline= 110.1 ATDC
Valve Close 42.5 ABDC
Duration: 225 Crank Deg
Lobe lift : .34882
Valve Lift: .52323
Lobe Area: 26.99
Exhaust
Valve open=55.4 BBDC
Centerline= 118.1 BTDC
Valve Close .2 ATDC
Duration: 235.2 Crank Deg
Lobe lift : .3335
Valve Lift: .50026
Lobe Area: 27.81

maxplusten

iTrader: (4)

Also as far as lifters go i would like to keep the budget under the $600 mark... cams already got me on the hook for 360 as well as a new oil pump so im already deeper into this headache than id prefer to be

td1168

iTrader: (2)

I'm running LS7's in my build. How many miles were on yours when the lifter broke?

maxplusten

iTrader: (4)

not even 7000 miles yet... only seen full throttle maybe 10 times

sweetbmxrider

iTrader: (13)

Morel/lunati link bars.

SAPPER

iTrader: (10)

how high when you say "high rpm"?
According to you cam specs, 6500 looks like your peak with a good tune. After alot of research and seeing what comes into the dealer here, stay away from these so-called "LS7" lifters. I need to upload a pic of one that came out of a 2011 ZR1 with 18k on it.

maxplusten

iTrader: (4)

yea i can only imagine, i know how mine looked lol, and yea thats kinda what i was figuring on that cam too... I dont think it needs to spin any harder than 6500 myself but Clayton informed me it would be around 7k on 15lbs of boost if and when we did it.

nitrous2fast

iTrader: (2)

I don't think that cam would peak at 7000, let alone 7500. Besides with boosted motors you don't need to spin to the moon to make amazing power. Spinning faster just requires better top end stuff that really isn't needed with reasonable rpm. How are you having problems with polylocks? They don't require any maintaince....

maxplusten

iTrader: (4)

ive had the same polylock back off 3 times on me now, I know were adjusting them right at this point and weve even replaced the lock and the stud... i dont understand it. It happens to be the same lifter that disingrated so i'm assuming theres a connection

Yea i agree though, i dont think she needs to wind that hard.

leadfoot4

iTrader: (1)

I've used ARP studs and their polylocks without issue. They recommend tightening the set screw in the lock to 22 ft/lbs. Did you do this?

Canada

iTrader: (2)

I'd go with the Comp Cams Short Travel Race Link Bar Lifters. Good for hi revving and heavy valve trains. Will cost you about $630.