LQ4 rehab with L92 heads
05-06-2011, 09:15 PM
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LQ4 rehab with L92 heads I have an LQ4 that I am going to put L92 heads on. I have a complete LS3 intake setup already. I haven't bought the heads yet. I plan on switching over to a 98-02 Fbody accessory setup. I have a few questions as I go forward:
Is the Fbody water pump different then the truck waterpump? I think the inlet on the truck pump will interfere with the throttle body on the LS3 setup. Also, the truck pump sits out from the block a little further doesn't it?
Do I need to switch to an LS3 valley pan? I have looked at the LQ4 and LS3 pans next to each other and there are some differences.
Am I going to have any issues with piston clearance with the new heads? I plan on going with a mild cam.
Finally, I am going to put new bearings in at the very least, while I am at it, would you put in new rod bolts and head bolts?
Thanks in advance, looking to build a nice street motor and I have always gotten great info from this site.
Is the Fbody water pump different then the truck waterpump? I think the inlet on the truck pump will interfere with the throttle body on the LS3 setup. Also, the truck pump sits out from the block a little further doesn't it?
Do I need to switch to an LS3 valley pan? I have looked at the LQ4 and LS3 pans next to each other and there are some differences.
Am I going to have any issues with piston clearance with the new heads? I plan on going with a mild cam.
Finally, I am going to put new bearings in at the very least, while I am at it, would you put in new rod bolts and head bolts?
Thanks in advance, looking to build a nice street motor and I have always gotten great info from this site.
05-08-2011, 08:50 PM
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Anybody? It looks like on the LQ truck engines that the sensors that are mounted in the valley pan are knock sensors and maybe a cam position sensor. I am not sure how to deal with this after looking at the LS3 valley pan. Are people leaving the LQ valley pan with the Car intake when they swap to the LS3 style heads? It looks like these two sensors can be repositioned on the side of the block. I am having a hard time finding info on this.
05-08-2011, 09:49 PM
#3
Ok Yes the truck water pump is different than the car... YOu need to run the F body water pump... The water neck is different and so is the pulley spacing...
No you can use the LQ4 valley cover and leave the Knock sensors in there.. that is have the LS1 cars are anyway... and this will work fine with the LS3 heads...
You won't have as much PTV issues as an LQ9 would since your pistons have a little dish...But your compression will drop.... Call Geoff at EPS and he can get you a cam speced out that will work great and have no PTV issues..
If you are going to put new bearings in you may as well go with ARP rod bolts or Katech... some say you can't re use your crank bearings some say you can... you can just buy some stock ones for reassurance...
Head bolts you can go ARP or New OEM ones...your call both work good but of course the ARP is much more costly but can be re used....
Let me know if I can be of anymore help as I just finished an LQ9 with LS3 swap into my Trans am
No you can use the LQ4 valley cover and leave the Knock sensors in there.. that is have the LS1 cars are anyway... and this will work fine with the LS3 heads...
You won't have as much PTV issues as an LQ9 would since your pistons have a little dish...But your compression will drop.... Call Geoff at EPS and he can get you a cam speced out that will work great and have no PTV issues..
If you are going to put new bearings in you may as well go with ARP rod bolts or Katech... some say you can't re use your crank bearings some say you can... you can just buy some stock ones for reassurance...
Head bolts you can go ARP or New OEM ones...your call both work good but of course the ARP is much more costly but can be re used....
Let me know if I can be of anymore help as I just finished an LQ9 with LS3 swap into my Trans am
05-08-2011, 10:18 PM
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Thanks for the reply. After I posted, I found one of my LS books. Looks like the OEM head bolts are essentially a one time torque cycle item. Sounds like they are relatively cheap. I will likely run with them since I am not going to run boost and my compression should be close to stock. The rod bolts seem like a no brainer the more I think about it.
I got the LS3 lifter valley pan along with my LS3 intake, but it looked like the LQ style would work. I think I would rather leave the sensors where they are.
I got the LS3 lifter valley pan along with my LS3 intake, but it looked like the LQ style would work. I think I would rather leave the sensors where they are.
05-09-2011, 08:26 AM
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stick with the lq4 valley cover or use this as an opportunity to upgrade to the newer LS6 one to cut down on oil in the intake. if you don't want to buy new valve covers, you will need to cut the baffles inside the passenger side cover (very easy to do with a dremel or air tools)
05-10-2011, 06:22 PM
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However I don't have an LQ4 pistons sitting in front of me to check and see if that would be a problem....I just know the have a dish...
Either way if he Calls Geoff at EPS or Pat G or any of the well known companies like I had suggested they will know and set him up with a cam that will not have clearance issues.....
So a simple answer to the original post......NO PTV won't be an issue with a Mild cam....
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05-11-2011, 08:55 PM
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I have done some research on the PTV issues and it seems like picking the right cam is key. That being said, I do have access to somebody who works at a machine shop so I will probably have them flycut when they take the block to do the bearings and rod bolts.
05-12-2011, 08:36 PM
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Mild cam is the plan. I want good streetable horsepower. I am not building the car to drag race, more for myself and occasional autocross. I want it to have a nice lope but have good manners.
06-15-2011, 11:14 AM
#13
I would definitely replace your bolts with ARP hardware, that includes head bolts. I ended up using ARP head studs. Also the crank bolt is a 1 time use bolt. The truck waterpump has a longer curved neck instead of coming straight out. LQ4 pistons are in fact dished and would likely have plenty of PTV clearance however the compression ratio is quite a bit lower. I would definitely use the LS6 valley cover as these motors need all the help they can get to prevent oil pooling up in the intake manifold. Good luck with your build, it's the same combo I am running 1300hp with, different rods, crank, pistons and a couple big *** T4 turbos.
06-17-2011, 03:17 AM
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"You won't have as much PTV issues as an LQ9 would since your pistons have a little dish...But your compression will drop..."
What would the compression be with the L92/LS3 heads on a LQ4?
What would the compression be with the L92/LS3 heads on a LQ4?
06-17-2011, 10:05 AM
#15
Well stock ls3 heads have 70cc chambers, take it from there to see. If you use gm MLS gaskets they are .051 thick.
Here is a calculator http://www.angelfire.com/fl/procrastination/motor.html
Here is a calculator http://www.angelfire.com/fl/procrastination/motor.html
06-26-2011, 04:06 PM
#16
Im considering a lq4 swap with ls3 heads & intake.
Im looking for some input on what people think about a torquer type cam to take advantage of these heads and intake (also what tb do I use with the ls3 intake?)..
I would like to eventually build a bigger cube lqX shortblock for a more max-effort setup, but right now I want an extremely driveable vehicle.
My car: 98 Z28, A4 stock tranny, 2.73 gears, street tires.
I am looking for a lower budget setup right now just to get the car back on the road.
Ive been trying to search to find info but picking through hundreds of threads sometimes to simply have someone have 'ls3 intake' in their sig and lq4 be on the same page.
Anyways, can I get some small, long duration large split cams suggestions from people? I dont care about what it sounds like but I would like to run a stockish exhaust. I do not want the car to be loud.
Im looking for some input on what people think about a torquer type cam to take advantage of these heads and intake (also what tb do I use with the ls3 intake?)..
I would like to eventually build a bigger cube lqX shortblock for a more max-effort setup, but right now I want an extremely driveable vehicle.
My car: 98 Z28, A4 stock tranny, 2.73 gears, street tires.
I am looking for a lower budget setup right now just to get the car back on the road.
Ive been trying to search to find info but picking through hundreds of threads sometimes to simply have someone have 'ls3 intake' in their sig and lq4 be on the same page.
Anyways, can I get some small, long duration large split cams suggestions from people? I dont care about what it sounds like but I would like to run a stockish exhaust. I do not want the car to be loud.
04-02-2012, 07:50 AM
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I have a LQ4 with L92 heads milled .030 and run around 10:1. Stock LQ4 pistons are a 7cc dish. At least on mine they were. If you keep the heads stock your compression would be below that. If you plan to boost it, it would be good. I like a little spray myself.
