LQ4 / L92 Build Advice
Jul 7, 2018 | 09:44 AM
#1
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From: Bryan/College Station, Texas
LQ4 / L92 Build Advice
I am LS-Swapping my 86’ C10 Single Cab SWB W/ rebuilt TH400. What I have is a complete 2005 2500HD 6.0 LQ4 Engine, Harness & ECU. Decided to use the stock bottom end & the L92 truck top end. Already picked up a set of Bare L92 823 casting truck heads, L92 truck Intake, & LS3 42lb Injectors. Last week ordered LS3 Hollow Intake Valves, LY6 Inconel Exhaust Valves, Along w/ CompCams Beehive Springs. My parts came in yesterday & I will drop off Monday at the head shop here in town. I want to deck the heads to bump up compression ratio, does anyone know how high of a compression ratio will work fine on 93 pump gas? I was thinking around 10.5:1. From what I’ve found the L92 823 combustion chambers are 71cc. What head gasket &/or thickness? Also I’m considering roller rockers for higher rpm & less friction. I see they offer stock 1.7, 1.72, 1.8, 1.82 & 1.85 ratio roller rockers. I’m worried about PTV clearance. Stock sliding rockers are around $200 & Full Rollers are north of $500 do you think it’s worth the upgade for the cost?
I called CompCams over the phone & the cam they recommend is XR275HR .566/.568 lift & 222/224 duration @ .050” 112 LSA. I would like to order rocker arms & cam next but I can’t decide just yet. I can’t order hardened pushrods untill I assemble & measure. I still need a cam & bearings, lifters, pushrods, rocker arms & stands, torque converter(2200-2400 per CompCams rec.), timing chain kit, oil pump, oil pan, throttle body & ca Intake. I already have engine mounts & flywheel spacer kit for th400. Is there anything I’m missing? All advice is appreciated
I called CompCams over the phone & the cam they recommend is XR275HR .566/.568 lift & 222/224 duration @ .050” 112 LSA. I would like to order rocker arms & cam next but I can’t decide just yet. I can’t order hardened pushrods untill I assemble & measure. I still need a cam & bearings, lifters, pushrods, rocker arms & stands, torque converter(2200-2400 per CompCams rec.), timing chain kit, oil pump, oil pan, throttle body & ca Intake. I already have engine mounts & flywheel spacer kit for th400. Is there anything I’m missing? All advice is appreciated
Jul 8, 2018 | 12:13 PM
#2
I would contact someone else for a cam recommendation. From what i’ve seen, most square port head cams have a much larger split than that cam. Contact Brian Tooley, Jarrett Faggart, or Cam Motion.
Jul 8, 2018 | 08:56 PM
#3
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From: Bryan/College Station, Texas
Jul 13, 2018 | 09:27 PM
#4
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I'm eyeballing this Vinci "Trucker / Square Port" 216/228 .553/.553 LSA 115 Power range: 1900-6300. The website recommends Dual Valve Springs but I want to go with BTR's .560" LS6 Beehives because they are just enough for this cam profile's lift specs plus only $70 from BTR. I wish I could afford the LS1511ML Beehives but $210+ & .625" lift I think I'll go the BTR route. Anyone think this is a good idea to use beehives? Again the heads are L92 with LS3 Hollow Intake Valves. I was hoping to keep the valve side of the rocker pretty light. Considering the titanium locks they are like 4 grams a piece & just over $100
Jul 14, 2018 | 05:30 AM
#5
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From: FL
Not sure why they keep suggesting such low lift cams. Those heads really breathe and can make use of something .600" or so lift no sweat.
What is the intended use of this truck? Daily driver? Street/strip? Weekend warrior?
I have a 214/220 @ .050, .598/.604 111 LSA in my cathedral headed LQ4. It's a daily, stock converter and all. It's very tame.
If I was going square ports on my truck, I would be looking at some in the upper 220s to 230s for duration and at least as much lift as I have now.
What is the intended use of this truck? Daily driver? Street/strip? Weekend warrior?
I have a 214/220 @ .050, .598/.604 111 LSA in my cathedral headed LQ4. It's a daily, stock converter and all. It's very tame.
If I was going square ports on my truck, I would be looking at some in the upper 220s to 230s for duration and at least as much lift as I have now.
Jul 16, 2018 | 04:57 PM
#6
They're spec'ing cams pretty small for you. I would also look for around a 600 plus lift cam, especially since you spent the money on lightweight valves, seems like you want to make use of that and turn that b*** up.
How rowdy do you want it to be? If you want it pretty rowdy step the cam up to something in the 230s to 240s, get a 3600 ish stall and invest in some good rear tires.
I would call Brian Tooley or Cam motion, they're both killing it in the cam game and comp cams has had a lot of hardening issues lately and people are sending cams back to get them repaired or replaced.
Brian Tooley uses cam motion cores and I believe cam motion cuts them for him...? So either of them would be a great place to get recommendations.
I would absolutely shoot for around 10.5-11:1 if I were you, and the bigger the cam the higher that can be since generally speaking the more cam the lower the dynamic compression.
Have you considered maybe boring it to 4.065 and putting some stock LS3 pistons in it? Wouldn't cost much and you'd get quite a bit of power from the cube increase, and unshroud the valves more too. You would loose a little bit of valve clearance though since they aren't dished, except for, with only 4" pistons the valves in the LS3 head may actually come down around the higher part of the LQ4 piston and not down into the dish.
How rowdy do you want it to be? If you want it pretty rowdy step the cam up to something in the 230s to 240s, get a 3600 ish stall and invest in some good rear tires.
I would call Brian Tooley or Cam motion, they're both killing it in the cam game and comp cams has had a lot of hardening issues lately and people are sending cams back to get them repaired or replaced.
Brian Tooley uses cam motion cores and I believe cam motion cuts them for him...? So either of them would be a great place to get recommendations.
I would absolutely shoot for around 10.5-11:1 if I were you, and the bigger the cam the higher that can be since generally speaking the more cam the lower the dynamic compression.
Have you considered maybe boring it to 4.065 and putting some stock LS3 pistons in it? Wouldn't cost much and you'd get quite a bit of power from the cube increase, and unshroud the valves more too. You would loose a little bit of valve clearance though since they aren't dished, except for, with only 4" pistons the valves in the LS3 head may actually come down around the higher part of the LQ4 piston and not down into the dish.
Jul 22, 2018 | 04:03 PM
#7
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From: Bryan/College Station, Texas
So the springs comp recommended turned out to be for a sbc. Did more homework & I have a set of PAC-1219 Beehive Springs being shipped good to .625” lift 135# seat pressure & rated @ 340lbs I think those should work fine. I wanted the truck to have good low end power so that’s the reason for the smaller cam specs. I am almost ready to pull the trigger on a cam. Tell me what you think about this one..
228/238 .571”/.585” 112 LSA 1800-6600 Power Range. With 1.8 rockers it comes out to .605”/.619” lift and these heads really shine at .600”
228/238 .571”/.585” 112 LSA 1800-6600 Power Range. With 1.8 rockers it comes out to .605”/.619” lift and these heads really shine at .600”
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Jul 22, 2018 | 04:18 PM
#8
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From: Bryan/College Station, Texas
They're spec'ing cams pretty small for you. I would also look for around a 600 plus lift cam, especially since you spent the money on lightweight valves, seems like you want to make use of that and turn that b*** up.
How rowdy do you want it to be? If you want it pretty rowdy step the cam up to something in the 230s to 240s, get a 3600 ish stall and invest in some good rear tires.
I would call Brian Tooley or Cam motion, they're both killing it in the cam game and comp cams has had a lot of hardening issues lately and people are sending cams back to get them repaired or replaced.
Brian Tooley uses cam motion cores and I believe cam motion cuts them for him...? So either of them would be a great place to get recommendations.
I would absolutely shoot for around 10.5-11:1 if I were you, and the bigger the cam the higher that can be since generally speaking the more cam the lower the dynamic compression.
Have you considered maybe boring it to 4.065 and putting some stock LS3 pistons in it? Wouldn't cost much and you'd get quite a bit of power from the cube increase, and unshroud the valves more too. You would loose a little bit of valve clearance though since they aren't dished, except for, with only 4" pistons the valves in the LS3 head may actually come down around the higher part of the LQ4 piston and not down into the dish.
How rowdy do you want it to be? If you want it pretty rowdy step the cam up to something in the 230s to 240s, get a 3600 ish stall and invest in some good rear tires.
I would call Brian Tooley or Cam motion, they're both killing it in the cam game and comp cams has had a lot of hardening issues lately and people are sending cams back to get them repaired or replaced.
Brian Tooley uses cam motion cores and I believe cam motion cuts them for him...? So either of them would be a great place to get recommendations.
I would absolutely shoot for around 10.5-11:1 if I were you, and the bigger the cam the higher that can be since generally speaking the more cam the lower the dynamic compression.
Have you considered maybe boring it to 4.065 and putting some stock LS3 pistons in it? Wouldn't cost much and you'd get quite a bit of power from the cube increase, and unshroud the valves more too. You would loose a little bit of valve clearance though since they aren't dished, except for, with only 4" pistons the valves in the LS3 head may actually come down around the higher part of the LQ4 piston and not down into the dish.
Jul 22, 2018 | 04:30 PM
#9
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From: Bryan/College Station, Texas
Not sure why they keep suggesting such low lift cams. Those heads really breathe and can make use of something .600" or so lift no sweat.
What is the intended use of this truck? Daily driver? Street/strip? Weekend warrior?
I have a 214/220 @ .050, .598/.604 111 LSA in my cathedral headed LQ4. It's a daily, stock converter and all. It's very tame.
If I was going square ports on my truck, I would be looking at some in the upper 220s to 230s for duration and at least as much lift as I have now.
What is the intended use of this truck? Daily driver? Street/strip? Weekend warrior?
I have a 214/220 @ .050, .598/.604 111 LSA in my cathedral headed LQ4. It's a daily, stock converter and all. It's very tame.
If I was going square ports on my truck, I would be looking at some in the upper 220s to 230s for duration and at least as much lift as I have now.
