PTV? LS1 BTR Stage 2 cam, Livernois Stage 3 243s
02-04-2017, 05:15 PM
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PTV? LS1 BTR Stage 2 cam, Livernois Stage 3 243s Putting together my heads/cam on my LS1 (5.7)...went to check PTV today and the results are...odd. I almost wasn't going to check because I assumed I'd be safe choosing a smaller cam.
0.07 intake and 0.115 exhaust.
Seems really off...so I checked it twice and got the same results both times. I checked PTV on #1, using clay with the Livernois Dual springs installed on the heads. Converted 2 lifters to solid, set rockers to zero lash, rotated crank a number of times. Did I miss something?
BTR Stage 2 cam: 227/234 .614"/.576" 113+2
Livernois Stage 3 243 heads: milled 0.15, 2.02 SS intake valves, 1.575 exhaust valves
GM MLS gaskets: 0.51
Am I safe to run this with these clearances, or does something seem wrong?
0.07 intake and 0.115 exhaust.
Seems really off...so I checked it twice and got the same results both times. I checked PTV on #1, using clay with the Livernois Dual springs installed on the heads. Converted 2 lifters to solid, set rockers to zero lash, rotated crank a number of times. Did I miss something?
BTR Stage 2 cam: 227/234 .614"/.576" 113+2
Livernois Stage 3 243 heads: milled 0.15, 2.02 SS intake valves, 1.575 exhaust valves
GM MLS gaskets: 0.51
Am I safe to run this with these clearances, or does something seem wrong?
02-04-2017, 06:33 PM
#2
Seems legit to me from what others report with a slightly milled head, slightly larger intake valve diameter, and a 227/228 sized intake lobe.
.070" is fine on the intake.....most prefer .080" but plenty of "cam only" guys have reported as tight as .040'-.060' range
.070" is fine on the intake.....most prefer .080" but plenty of "cam only" guys have reported as tight as .040'-.060' range
02-05-2017, 08:00 AM
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Seems legit to me from what others report with a slightly milled head, slightly larger intake valve diameter, and a 227/228 sized intake lobe.
.070" is fine on the intake.....most prefer .080" but plenty of "cam only" guys have reported as tight as .040'-.060' range
.070" is fine on the intake.....most prefer .080" but plenty of "cam only" guys have reported as tight as .040'-.060' range
I suppose as long as I have plenty of exhaust clearance, I'm ok running slightly tighter intake...?
Oh wow, that's a really good question, and would explain the results I'm seeing. Maybe I'll give them a call tomorrow.
02-06-2017, 02:18 AM
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The heads really are a work of art. I'd almost rather hang them on the wall.
I bought them off craigslist, brand new with protective film still on the decks...which has me somewhat worried that they're milled more than I was told. I guess as long as my exhaust clearance is ok I'll be fine.
02-06-2017, 02:02 PM
#7
Did you check PTV? That's quite a bit more intake duration than I'm running.
The heads really are a work of art. I'd almost rather hang them on the wall.
I bought them off craigslist, brand new with protective film still on the decks...which has me somewhat worried that they're milled more than I was told. I guess as long as my exhaust clearance is ok I'll be fine.
The heads really are a work of art. I'd almost rather hang them on the wall.
I bought them off craigslist, brand new with protective film still on the decks...which has me somewhat worried that they're milled more than I was told. I guess as long as my exhaust clearance is ok I'll be fine.
Im running the heads right out the box. No issues.
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02-08-2017, 10:54 AM
#9
.070" is okay. The bigger issue is the exhaust clearance. And you're good there.
One thing I would caution - did you torque the head down? I didn't my first time when I did measurements and when I torqued down, I was off about .015" everywhere because the Cometics I had squished down when torqued. If using ARP head bolts, it's easier to do since you can reuse them. And you just need to do the 4 around the cylinder you are checking.
One thing I would caution - did you torque the head down? I didn't my first time when I did measurements and when I torqued down, I was off about .015" everywhere because the Cometics I had squished down when torqued. If using ARP head bolts, it's easier to do since you can reuse them. And you just need to do the 4 around the cylinder you are checking.
02-08-2017, 11:49 AM
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.070" is okay. The bigger issue is the exhaust clearance. And you're good there.
One thing I would caution - did you torque the head down? I didn't my first time when I did measurements and when I torqued down, I was off about .015" everywhere because the Cometics I had squished down when torqued. If using ARP head bolts, it's easier to do since you can reuse them. And you just need to do the 4 around the cylinder you are checking.
One thing I would caution - did you torque the head down? I didn't my first time when I did measurements and when I torqued down, I was off about .015" everywhere because the Cometics I had squished down when torqued. If using ARP head bolts, it's easier to do since you can reuse them. And you just need to do the 4 around the cylinder you are checking.
Might be worth torquing to do a final check considering that I'm kind of tight on the intake. Thanks for the heads up!