LQ4 Rebuild Plan and Questions
04-24-2017, 10:37 AM
#1
LQ4 Rebuild Plan and Questions Long time listener, first time caller. Bought a couple things from here. Anyways, this is my 2nd engine. So I in no way claim to be an expert but think I know enough to screw up something.
Bought an LQ4 that the seller claims "ran when pulled". Whatever, I know better. I tore it apart.
My plan for rebuild is the following (attempting to keep budget reasonable):
- Clean block and crank. Crank inspection, possibly polish. Cylinder bores look great - only planning on a flex hone.
- Clean and reuse piston assemblies. Any recommendations on best way to clean these?
- Replace main and rod bearings with Clevite H Series. Line hone - necessary?
- Reuse main cap bolts. These are torque to angle not TTY.
- ARP cracked rod bolts
- HEADS: 243 heads shaved to 61cc chambers. Ported .600 PAC 1218. COMP trunion upgrade. Stock rockers. Stock lifters. LS2 trays. Brian Tooley push rods. ARP Head bolts.
- Cam: Id like a mild to medium cam (future plan is to purchase some unshaven 243s to brind SCR back down to boost) that would work well with boost in a couple of years after the motor is broken in. Plan is to have Brian Tooley spec the cam. Not wanting to fly cut pistons if I dont have to.
- Truck intake. Maybe upgrade to gen4 with 92mm TB (still trying to keep the budget in check).
- Other non major items: LS2 timing chain upgrade. GM Muscle Car oil pan. D585 coils. Melling 10296 Oil Pump. 8.1 injectors (I understand stock LQ4 injectors are near their limit)
Looking forward to your thoughts and justifications on this build. Using LS1tech and Potaks book for references.
Bought an LQ4 that the seller claims "ran when pulled". Whatever, I know better. I tore it apart.
My plan for rebuild is the following (attempting to keep budget reasonable):
- Clean block and crank. Crank inspection, possibly polish. Cylinder bores look great - only planning on a flex hone.
- Clean and reuse piston assemblies. Any recommendations on best way to clean these?
- Replace main and rod bearings with Clevite H Series. Line hone - necessary?
- Reuse main cap bolts. These are torque to angle not TTY.
- ARP cracked rod bolts
- HEADS: 243 heads shaved to 61cc chambers. Ported .600 PAC 1218. COMP trunion upgrade. Stock rockers. Stock lifters. LS2 trays. Brian Tooley push rods. ARP Head bolts.
- Cam: Id like a mild to medium cam (future plan is to purchase some unshaven 243s to brind SCR back down to boost) that would work well with boost in a couple of years after the motor is broken in. Plan is to have Brian Tooley spec the cam. Not wanting to fly cut pistons if I dont have to.
- Truck intake. Maybe upgrade to gen4 with 92mm TB (still trying to keep the budget in check).
- Other non major items: LS2 timing chain upgrade. GM Muscle Car oil pan. D585 coils. Melling 10296 Oil Pump. 8.1 injectors (I understand stock LQ4 injectors are near their limit)
Looking forward to your thoughts and justifications on this build. Using LS1tech and Potaks book for references.
Last edited by SmokeyCheese1; 04-24-2017 at 02:47 PM.
04-24-2017, 05:22 PM
#5
I'd just make a few small changes. Consider the bushing style Trunnion upgrade such as the Straub ones vs the Comp ones you mentioned. Another recommendation would be to get 11/32" pushrods (or at least when you switch to your permanent heads, since you will likely need new lengths then). Lastly would be to look into Morel or Johnson drop in lifters.
04-25-2017, 09:11 AM
#6
Ok, so lifter upgrade? I'll check those out.
I'll upgrade pushrods both times. With this motor and the final heads. I would just build this car boosted now but my thought process is boosting a looser motor is better. So I think breaking this build in is a better way to go about it. Plus, I already have the shaved heads from a previous build.
What about flex plate? Factory ok?
Also, lesser known but quality torque converters for 4L80E?
I'll upgrade pushrods both times. With this motor and the final heads. I would just build this car boosted now but my thought process is boosting a looser motor is better. So I think breaking this build in is a better way to go about it. Plus, I already have the shaved heads from a previous build.
What about flex plate? Factory ok?
Also, lesser known but quality torque converters for 4L80E?
04-25-2017, 11:59 AM
#7
I wouldn't use H series bearings on stock crank and rods. H series are made for aftermarket cranks with larger fillets. The P series would be fine.
Seriously email us, we can get you set up with everything you need.
A high quality 4l80 stall will run about $800+
Seriously email us, we can get you set up with everything you need.
A high quality 4l80 stall will run about $800+
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05-10-2017, 08:06 AM
#10
New plan - machine shop HAS to bore .030 so reusing the pistons is out.
Now, without replacing pistons and rods to a forged set up using 6.125" rods, it appears as if my options are limited to hypereutectic for direct replacements.
I wasnt planning on dropping an extra $1000 on this build. Are there any piston options out there that allow me to reuse the stock rods?
Now, without replacing pistons and rods to a forged set up using 6.125" rods, it appears as if my options are limited to hypereutectic for direct replacements.
I wasnt planning on dropping an extra $1000 on this build. Are there any piston options out there that allow me to reuse the stock rods?
05-10-2017, 02:42 PM
#11
All of the aftermarket pistons will require a floating pin rod. We have a very nice hyper e piston in a 4.030 for stock pressed pin or floating pin rod. We also have a few piston sets for 4.030 and stock rod in forged but again require a floating pin rod.
If you want more info, like i said shoot me an email.
Rpmspeedtech@gmail.com
If you want more info, like i said shoot me an email.
Rpmspeedtech@gmail.com