firechicken2k

my dyno looks sorta like a heart monitor

Matt @ TTP said it might be because a lifter (or a few from what i understand) might be collapsing.

Seems like everything is breaking around me..

So..

My question is - if it is in fact a lifter, what will happen if it will collapse as I am driving? will it damage anything, and take something with it?

I am just curious, cause I am broke right now, and dont have the money to tear into the engine.. I'd like to change at least a cam, hopefully heads too, while we'll be in the engine.. so saving up for that.

So. What will a collapsed lifter take with it, if anything, if I wait until it breaks before fixing it?

Demon_Speeding

iTrader: (24)

I collapsed a few lifters on my old Chevelle, granted it was a Gen I 283cid motor. I wound up with a messed up exhaust valve on one of them. I don't think the lifter collapsing caused it though...It was more related to the fact of the valve sinking into the head. <--Non hardened valve seats.

I'd just watch my driving and keep the RPMs low.

firechicken2k

how do rpm's even matter, with a lifter?
correct me if i'm wrong, but camshaft's lobes move the lifter up and down.. doesn't really matter if you're going 2 mph or 200 mph - your lifters are working at pretty much the same rate

ArKay99

iTrader: (1)

Inertia.

firechicken2k

elaborate?

Cstraub

iTrader: (1)

As the engine turns faster the cam turns faster. As the revs increase the velocity at which the lifter follows the lobe increases. At peak lift the inertia mass of the lifter increases exponetially exerting more force on the valve spring which must control and dampen the inertia. RPM is not a friend to hyd roller lifters.

Chris

Adrenaline_Z

Don't forget the lash/preload clearances also get thrown out the window.

You may risk the chance of bending pushrods, breaking rockers, etc.

That would be the difference of a lifter moving up and down at ~20 times per second, or 200+ times per second.

Which case would cause more damage if a lifter collapsed?

Force/Velocity explained:
http://othello.mech.northwestern.edu...h5/Sources.htm

ls1powrdta

well how do know if you have collapsed lifter though without pulling off the heads?just wondering cause im thinking i may have one.

spy2520

iTrader: (3)

200+ times per second is kinda fast dont you think? Isnt it every crank rpm = half a cam rpm. At 6000rpms the cam should be spinning at 3000 rpms which would only allow for about 50 times per second. The range would be between 6 and 60 times per second, realistically. But you could have always just been exaggerating.

Adrenaline_Z

I wasn't making a reference to the frequency per second as it applies to RPM
( I didn't list RPM).

I was just stressing the extreme of his example (2 MPH to 200 MPH) to highlight
the effective mass, inertia, and job of the valve springs to control all of that
reciprocating weight.

But in any case, you're correct. Sorry for the confusion.