Advise for Engine build LQ9
Thread Starter
Teching In
Joined: Dec 2019
Posts: 31
Likes: 8
Advise for Engine build LQ9 Greetings, Picked up a used LQ9 today and wanted to get a few suggestions/advise on my build. the Lq9 came out of a 02 Escalade with 190K miles. engine will be going in my 87 Monte Carlo SS with a 4l80e behind it. First order of business is to tear down and label everything this weekend. I'm still in the process of finding a machine shop but spoke with a few and am narrowing down my selection.What questions do i need to be asking these potential machinist? I'm shooting for a daily derivable street rod with around 425- rwhp. I have a set of 799 heads off a 5.3 I'm planning to send to AI and get the 226 head package. Going to run the torquer V4 cam (231/234 .629"/.615" 111 LSA) from Texas Speed with dual valve springs. The rockers I'm still doing research on, hearing a lot of mixed reviews and a lot of horror stories from my findings but thinking about going with CHE LS/LT trunion kit on the stock rockers. Will this combo put me at my target of 425 rwhp??? The piston selection I'm defiantly in need of some direction. I'm thinking about going with GMPP Hypereutectic LS2/ LQ9 replacement pistons. They run about $70 each and rings $40ea for a single set. This combo with the 799 head will put me around 11.1 compression. My theory behind going with the GM replacements is that the LQ9 was a stout motor from the factory lasting over 300k miles if taken care of. Why change it??? plus to my knowledge hypereutectic is superior over forged for a street/ daily driver. Please correct me if I'm wrong. Is there a better option out there around the same price point? Any other upgrades i should consider?? all input is greatly appreciated
TECH Senior Member
Joined: Jun 2016
Posts: 22,291
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From: Central Cal.
I would first make sure it needs overhauling. These engines see 300K miles with dull regularity. Before removing heads, check compression and oil pressure. Your short block might be usable in present form.
Thread Starter
Teching In
Joined: Dec 2019
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At 190K i would imagine it would be in need of a overhaul. Would hate to do all the rest of the work for the bottom end to fall out.... I'm pretty sure ill be beating the **** out this engine. Kinda just want a fresh start.
TECH Fanatic
Joined: Dec 2017
Posts: 1,467
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From: Bossier City, Louisiana
For my 150,000 mile truck engine, it was mostly just a few sensors, one bad injector and valve seals. No need to tear into the bottom end. As advised, check your compression, oil pressure and you might take a look at the interior of the oil pan for chunkage. Mine was all good . . . maybe yours, too.
Rick
Rick
Thread Starter
Teching In
Joined: Dec 2019
Posts: 31
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I figure the engine is out the car. for longevity and ease of mind why not re do it now..... just curious how would you check oil pressure on a engine thats out of the vehicle and not running?? I can see a way to do compression by bolting a starter the the block and using a jump box for power...... please advise
TECH Fanatic
Joined: Dec 2017
Posts: 1,467
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From: Bossier City, Louisiana
Remove all spark plugs. Install a manual Autometer plastic tube oil pressure gauge and then vigorously crank the engine using a good battery. Mine cranked on cold oil up into the 35-40 PSI range which made me plenty happy. Once I got it running, I had 50 PSI or so on cold oil but those earlier oil pressure and compression tests gave me the confidence to proceed with mounting my engine.
I think I've heard more bad stories around here of engine trouble AFTER a rebuild than simply installing Mr Goodwrench's good work and running it.
Rick
I think I've heard more bad stories around here of engine trouble AFTER a rebuild than simply installing Mr Goodwrench's good work and running it.
Rick
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I have seen WAY more rebuilt Ls engines fail than 300K stock untouched bottom end engines.
The ONLY time I would recommend it would be if something was known to be wrong with it.
BUT, even then if your goal is under 500RWHP I would just get another clean junkyard shortblock.
Only time it makes sense financially is if your going to be boosting the engine and in need of some forged internals.
And if thats not enough ......why in the world would you replace the pistons with the same thing that is already in there for $70 EACH!!!???? and rings for $40 each?????!!!! Thats ludicrous!
The ONLY time I would recommend it would be if something was known to be wrong with it.
BUT, even then if your goal is under 500RWHP I would just get another clean junkyard shortblock.
Only time it makes sense financially is if your going to be boosting the engine and in need of some forged internals.
And if thats not enough ......why in the world would you replace the pistons with the same thing that is already in there for $70 EACH!!!???? and rings for $40 each?????!!!! Thats ludicrous!
TECH Fanatic
Joined: Nov 2011
Posts: 1,367
Likes: 144
From: Woodstock, GA
I have seen WAY more rebuilt Ls engines fail than 300K stock untouched bottom end engines.
The ONLY time I would recommend it would be if something was known to be wrong with it.
BUT, even then if your goal is under 500RWHP I would just get another clean junkyard shortblock.
Only time it makes sense financially is if your going to be boosting the engine and in need of some forged internals.
And if thats not enough ......why in the world would you replace the pistons with the same thing that is already in there for $70 EACH!!!???? and rings for $40 each?????!!!! Thats ludicrous!
The ONLY time I would recommend it would be if something was known to be wrong with it.
BUT, even then if your goal is under 500RWHP I would just get another clean junkyard shortblock.
Only time it makes sense financially is if your going to be boosting the engine and in need of some forged internals.
And if thats not enough ......why in the world would you replace the pistons with the same thing that is already in there for $70 EACH!!!???? and rings for $40 each?????!!!! Thats ludicrous!
The bottom end has never been touched other than timing chain, gears ....oil pump ....
On The Tree
Joined: Nov 2013
Posts: 106
Likes: 3
From: Omaha, NE
I am running a LQ9 with a smaller 227/232 with under .600 lift, AI 226 ported 243's, truck intake and throttle body and 8.1 marine injectors and made 405hp/400tq on a previous tune that has since been improved. I havent gotten it dyno'd with the new tune but wouldnt be surprised if I was at 415hp now. My setup has a 2800 stall converter and a built 4l70e and 3.73's. I can see 425 being very achievable with the cam you spec, and I know my intake and TB are my choke points right now, but I'm running 92% duty cycle on my injectors as it is and don't feel it necessary to spend all the extra $$ with how fun it is on the street already.
Thread Starter
Teching In
Joined: Dec 2019
Posts: 31
Likes: 8
So i know these motors do 300k miles all day in a stock truck that rarely spins over 4000rpm. But how do they hold up with high mileage spinning 6500 rpm with increased cylinder pressure?? any thoughts or experiences??
Not sure where you are getting your information from but plenty of work trucks see higher than 4k RPMs. We have one in our fleet that has 250k+ on the LQ4. Nothing has been done to the motor. It hauls a full bed of tools and supplies every M-F since 2006.
TECH Enthusiast
Joined: Feb 2018
Posts: 640
Likes: 297
From: Michigan
If a little 1.8 liter with a turbo can handle that kind of beating, an LS certainly can.
Last edited by Bob570; Dec 4, 2019 at 08:56 PM.
Nothing wrong with rebuilding the LQ9 if your up for it. But what these guys are trying to say is that it will cost you a couple grand after machine work and all is said and done. Minimum. You prolly didn’t pay half that for the engine. My advice is pull the valve covers and the pan. Those gaskets are reusable, no problem. If it isn’t sludged over badly, put it back together and run it. If it looks terrible, like never maintained terrible, then I’d pull it all down and go through it. Personally I enjoy the rebuild process, and find it relaxing and therapeutic.
These engines don’t rebuild cheap. Gaskets are expensive. Bearings are expensive. Piston kits are expensive. Send a PM to WS6Store here on Tech and tell them your thoughts. They will give you rock bottom pricing on a complete rebuild kit. Then get an estimate from the machine shop of your choice. You likely can buy 2 or 3 LQ9’s for the price of a rebuild, but you don’t know what you’ve got til you start it up. If you rebuild it, and measure everything as you assemble, you know exactly what you have.
I love a Monte SS. Post pics!
These engines don’t rebuild cheap. Gaskets are expensive. Bearings are expensive. Piston kits are expensive. Send a PM to WS6Store here on Tech and tell them your thoughts. They will give you rock bottom pricing on a complete rebuild kit. Then get an estimate from the machine shop of your choice. You likely can buy 2 or 3 LQ9’s for the price of a rebuild, but you don’t know what you’ve got til you start it up. If you rebuild it, and measure everything as you assemble, you know exactly what you have.
I love a Monte SS. Post pics!
Thread Starter
Teching In
Joined: Dec 2019
Posts: 31
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Just picked it up a week ago. The fun begins!!! Did an LS Swap in a 70 Chevelle for a customer. In love with the car but that swap left a bad taste in my mouth. Want to do mines right. He went with a Bone stock LQ4 and a bone stock 4l80. Turned out to be a mess because the owner was a cheap ***. Showing up with sub par parts other than what i suggested for the build, didn't want to paint the engine, didn't want to clean up and paint the engine bay, didn't even want to reseal the engine. Running the car with around with the original rear end with 2.56 gears and drum brakes in the front. complete mess
