hungryhip-ccp

iTrader: (2)

so.... has anyone managed to wipe out a cam, take out some lifters, or break valve springs? and if so what rpm were you spinning?

i spin up to 7550 on accident sometimes, rev limit is set at 7300 but we all know you have to exceed that number before fuel is cut and with my hp levels i hit 7500 sometimes before the pcm catches up...

im wondering what kinda damage happens (what goes first) and what is the most rpm people have spun on stock valvetrain and balance shafts.

i hear the valve springs will hang to 7600-7800 but its the balance shafts that dont get enough oil to spin 15000 rpm for a long period.

anyone have some actual damage happen?

Sharkey

iTrader: (1)

a friend of mine spun his l61 to 8500 a couple times, it ended up floating a valvle and kicking out the cam follower.

hungryhip-ccp

iTrader: (2)

stock valvetrain l61?

this is refering to stock set-up only and lsj

but thank you for your input.

Sharkey

iTrader: (1)

it was stock valvetrain, and in reality the valvetrain between ecotec heads isnt that different.

im not sure if the balance shafts are an oiling issue, i thought it was more of a case of centrifical force causing them to break apart. the gm neutral balance shafts still spin in the same bearings without any oiling mods done. if its an oiling problem, you dont actualy fix it by going to the gm neutral balance shafts, you would need a balance shaft delete kit like levelzero motorsports produces.

hungryhip-ccp

iTrader: (2)

yes the same but a much much lower hp level, and i assume NA, but your right rpm is rpm.

well the balence shaft delete blocks off the oil passages and that is were i got my info on overspinning the bearings,

i dont think anyone has actually made a balance shaft come apart that would be really really hard.

level zero is what im after but it says the engine needs to be remove in order to install the bushings that block the oil passage, plus they are not reversable once there pressed in thats it for that block...

again thank you for your input

Sharkey

iTrader: (1)

rpm is rpm, it was actualy a turbo l61, and it was clayton from levelzero's cavalier. i have put the balance shaft kit in, they are a pain to put the bushings in, i had to stand the block on end. you may be able to drop the subframe down and lower the front of the motor, but its not going to be easy.

i have seen a couple pics of a balance shaft that exploded. they are just cast iron, in the end in looks kinda like a cast iron flywheel that has exploded. i dont know what they did to make it explode, but there wasnt much left of the motor in the end.

originaladrian

I was researching building my engine.


so the consensus is that if you want to spin an ecotec past 7k get a balance shaft delete kit?

ColeJJones

no, its if you consistantly spin up near 7500 or past its best to get a delete or new balance shafts

Area47

7400 on stock springs are fine.

im still on stock balance shafts and have numerous 8k runs on it at 67k miles. did you do something to yours?

hungryhip-ccp

iTrader: (2)

no, its just well i have my rev limiter set to 7300 across the board. but when the car breaks traction in first and bangs the rev limiter (ouch) it will be recorded by hpt as going as high as 7600rpm... i assume this is because the engine is revving so fast by the time it cuts fuel at 7300 it still has enough rotating mass to reach 7580rpm?


it makes a kinda loud noise coming from the intake mani as if the valves are floating or something. kinda odd. sounds kinda bad. and the over rev light comes on in the dash.

which is another thing, that is the rpm lamp correct? how come when i change it in hpt no matter how low i set it it wont go off when i want? only when over revved?

i want to do a delete kit but i hear the motor has to be out to press in the things that block the oil passages... or lower the sub frame which i will do when i do clutch and maybe ill give it a try then!

originaladrian

you just have to be able to access the timing chain area?



motor out would prob be 100x easier.

Area47

get neutral shafts and call it a day


the over spin light comes on at 7600. at least in 07's it does no matter where you set it at. you're fine man.

i use the over spin light as a shift light

hungryhip-ccp

iTrader: (2)

no, do you know what a cam bearing installation tool is? if not look it up. you have to be able to get one of those in there...


call it a mon or two, lol those things arent cheap... so is that what your running? along with the supertech's? 78lbs is plenty yeah? i was going to order these and get the head cnc'd. the only is i havent decided on is the balance shaft situation, i only wanna do this once.

also im suprised no-one has engineered a kit that allows you to retain the factory balance shafts but not spin them, that way they would still provide enough blockage to the oil system to retain pressure but not be used for anything else...

hm you would think that you could install some retaining plate possibly drill and tap the block for somthing like a cam plate in a roller block sbc 350, that would keep em in then simply use the delet kits chain and remove the sprokets from the balance shafts so there not in the way of the chain...

im going to look into this more im willing to be the test dummy here. tell me area what are your thoughts on this...

Area47

spend the money on the shafts. i wouldn't half ass anything inside the motor. im still on stock shafts right now. i need to sell some more lsj parts to cover the cost of the shafts.
you can do the shafts with the motor in the car. just with some creative use of an engine puller to get it to drop down enough

being that the shafts are chain driven along with the water pump. you lose that chain, or a gear. you lose the pump as well. not good!

78lb springs are peachy actually. zero issues with em for over 30k miles

hungryhip-ccp

iTrader: (2)

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i was thinking more of something like this but leaving the shafts in just removing the gear connected to the front of em and making a couple little retaining ears to stick out and hols down the balance shafts from coming out, like a retaing plate but just ears as ther looks to be no room for a whole plate.

but theese are just idea's i dont think they will become nothing more than that.

there is even bolt hole's in the block already...

itallionjoe did this correct?

Area47

newp. wsfrasier, witt, djt.


im not treating this one like a dsm in my past and doing that balance shaft delete bearing rotate thing. this is pretty much what seems to me you're trying to do. iono

hungryhip-ccp

iTrader: (2)

ah so it surely can be done... im start saving a little for that in my valvetrain build. thanks for your help

hungryhip-ccp

iTrader: (2)

you do the seals while you were in there? i found em for $37.

Area47

newp.

Nighthawk243

Why do you feel the need to rev the Eco that high?

Anyways... the balance shafts are actually unbalanced to vibrate in a way that counters the vibration from the normal engine operation. The shafts actually spin at twice the RPM of the engine... so basically at 7000 RPM, those unbalanced shafts are spinning at 14,000 RPM. Spin them too fast, and they'll fail from the excessive vibration.

Area47

HEY thanks! we never knew that!














































































/sarcasm

hungryhip-ccp

iTrader: (2)

so the balance shafts arent balanced? who would of thought...



but on a more serious note, im looking to rev to 7800 rpm in first to help the 1-2 transition... then i plan on taking third to the line so i wont have to shift to 4th during a pass...

Area47

you will be fine with that

hungryhip-ccp

iTrader: (2)

we shall see