Will checking PTV like this work?
Thread Starter
TECH Enthusiast
Joined: Jan 2004
Posts: 539
Likes: 1
From: Grand Rapids, MI
Will checking PTV like this work? I've been told I can't use a hydraulic lifter to check PTV clearance and since that's what I have under my half installed heads I figured this might work.
Can I just check cam lobe lift at 8* multiply it by 1.7 and then subtract that from my valve drop at 8* to get my clearance?
How accurate would this be? I was pretty convinced after degreeing in my cam last night and "attempting" to install the rockers with the checker springs I have on the #1 cylinder right now that it wasn't gonna fit.
So far I have this, at TDC my valve drop is .125, lobe lift is .064... So .064x1.7=.109 and so I would have .016 clearance at TDC right? At 8* ATDC I have .148 valve drop and .093 lobe lift and that comes out to .148-.093x1.7= -.010
What do you guys think is this pretty accurate way to check or is there something I'm not taking into consideration? Looks like flycutting .100 to me
Can I just check cam lobe lift at 8* multiply it by 1.7 and then subtract that from my valve drop at 8* to get my clearance?
How accurate would this be? I was pretty convinced after degreeing in my cam last night and "attempting" to install the rockers with the checker springs I have on the #1 cylinder right now that it wasn't gonna fit.
So far I have this, at TDC my valve drop is .125, lobe lift is .064... So .064x1.7=.109 and so I would have .016 clearance at TDC right? At 8* ATDC I have .148 valve drop and .093 lobe lift and that comes out to .148-.093x1.7= -.010
What do you guys think is this pretty accurate way to check or is there something I'm not taking into consideration? Looks like flycutting .100 to me
ok must be the larger vavles then, most guys have no issues at all on 2.02 vavles and unmilled. thats strange though still i would think it would have some clearance, did you install the cam dot to dot or with any advance?
Thread Starter
TECH Enthusiast
Joined: Jan 2004
Posts: 539
Likes: 1
From: Grand Rapids, MI
I installed it dot to dot, but it does have 4 degrees advanced timing ground in. I think with that and the bigger valves it's causing me problems. Thanks for the responses WS6firebirdTA00 
So no one else has an opinion on checking PTV clearance this way, c'mon fellas I know this isn't one of the important threads like "what cam to get" and "how much power will this combo make" but c'mon
So no one else has an opinion on checking PTV clearance this way, c'mon fellas I know this isn't one of the important threads like "what cam to get" and "how much power will this combo make" but c'mon
Last edited by f-bodman; May 19, 2005 at 03:06 PM.
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Thread Starter
TECH Enthusiast
Joined: Jan 2004
Posts: 539
Likes: 1
From: Grand Rapids, MI
The motor won't turn over by hand, well it will but it hangs up around TDC , that's what made me realize I might have clearance problems to begin with. I could clay it but it would just cut it in half 
, that's what made me realize I might have clearance problems to begin with. I could clay it but it would just cut it in half LS1 Tech Stories
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Verdad Gallardo Thread Starter
TECH Enthusiast
Joined: Jan 2004
Posts: 539
Likes: 1
From: Grand Rapids, MI
I have the stock graphite gaskets on, the worst part is I haven't done the torque to yield part yet I just have new GM bolts torqued to ~22lb. I think after I pull the heads off I might get some MLS gaskets. Well I've got a flycutting kit on the way from TSP right now, wish me luck.