PTV clearance with LQ4, milled 243s, and EPS cam
06-01-2011, 12:54 AM
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PTV clearance with LQ4, milled 243s, and EPS cam Laptop is broken and i cant use the search from my phone! lol. I have a stock LQ4 6.0 with 50k on it that i'm putting in my TA. I also have an EPS cam (234/246 .602/.607 111 lsa) and ported 243's. The 243s are going to the shop to get freshened up and i also want to get them milled to compensate for the lower CR of the lq4 motor. About how far can i mill these heads down before PTV becomes a big issue? thanks
06-01-2011, 03:02 AM
#2
Your best bet would be to ask Geoff at EPS. Honestly, since he ground the cam, he'd be able to give you the best answer. That cam doesn't have the "PTVC must be checked" warning on the EPS site, but when you start milling, who knows. Have you checked PTVC before with that cam on the motor? How much do you want to mill?
06-01-2011, 04:16 AM
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How much are you going to mill the heads?
I think with a cam that big you better not mill the heads at all.
I know, your compression will suck. But that's the problem with LQ4 short block, it drops your compression without giving you more PTV clearance (no valve reliefs)
It looks like LQ4 engines are better for forced induction projects while LQ9 short blocks are better for NA builds (flat pistons).
I think with a cam that big you better not mill the heads at all.
I know, your compression will suck. But that's the problem with LQ4 short block, it drops your compression without giving you more PTV clearance (no valve reliefs)
It looks like LQ4 engines are better for forced induction projects while LQ9 short blocks are better for NA builds (flat pistons).
06-01-2011, 09:01 AM
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if you don't want to flycut the pistons then i wouldn't mill the heads. i'm going through that right now.
my combo consists of an lq4, ported 243's milled .040, .051 gasket. cam is 23x/24x .6xx/.6xx 110. i checked the piston to valve clearance over the weekend. intake valve has .082 clearance and the exhaust has .057, so i will have to cut the exhaust.
my combo consists of an lq4, ported 243's milled .040, .051 gasket. cam is 23x/24x .6xx/.6xx 110. i checked the piston to valve clearance over the weekend. intake valve has .082 clearance and the exhaust has .057, so i will have to cut the exhaust.
Last edited by bluecajun5.3; 12-09-2011 at 04:10 PM.
06-01-2011, 09:39 AM
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damn..not the answers i was expecting lol. i wanted to mill them enough to atleast get a CR of 10.5:1 or 11.0:1. I will contact Geoff at EPS later on, thanks for the recommendations guys
