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GM LQ4 rebuild

Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
RockChucker said:
Pretty. I remember parts day pickup. My stack looked very similar to yours but I also had cleggs go through my L92 heads
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I love the look of freshly machined engine parts! I'll have a local shop go thru my 243 heads, that shouldn't be too hard to get done.


Tacoma said:
$1800?! been awhile since I had engine machine work done. :eek: Good to know though, since I"ll be doing this, probably there, soon enough. :D
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Parts were $900, looks like the pistons were half of that cost. FelPro gasket set, oil pump, bearings, rings and 2 new connecting rods... it adds up quick. They claimed their prices for parts were pretty competitive with Summit, etc.

Labor for the machine work was $700, which is about right. If I sourced the parts myself, the total from the machine shop may have been more affordable.... but I'd still need the other parts.

Building an engine isn't cheap!
 
Tacoma

Tacoma

Et incurventur ante non
Location
far enough away
yeah, that's not a crazy price, at all. I haven't built an engine ground up in quite a while though LOL so it's good to have some ballpark OT hours to aim at hahah.
My engine is going to be mostly a stock rebuild, with a cam and headers, nothing "rowdy". :D Should be plenty for a CJ7 MOOAHAHAH
 
Dominic

Dominic

Well-Known Member
Location
Salt Lake City
Howdy Greg,
Stumbled upon this thread this weekend while doing some cam research. My son bought me a Brian Tooley truck Norris cam kit for Christmas. We bought a really clean 2006 GMC Sierra 2500HD this past spring. It has an LQ4 with 192K miles. Everything about it has been great, we put 10k miles on it this past summer. Only things I have done are muffler, Diablew tune (which as been fantastic) and an Air raid intake and filter. I have not had the motor opened up but sent off the oil for analysis and things looked great. Oil pressure has been consistent up around 40 psi at idle. From everything I can tell, the motor is healthy.

This cam is supposed to be mild enough to work with the stock stall converter. The kit does come with new valve springs caps, spacers and pushrods.

I am a bit overwhelmed by all the opinions online. I wondered if I might get your input on a WWGD (What would Greg Do) :)

If you had a seemingly healthy LQ4 and were going to put a cam in would you and top end refresh what would you do? I have 317 heads that at the very least we would pull and have a machine shop check them. It would be awesome to find some 243 heads but does not have to happen if our heads are in good shape I suppose.

The Truck is a tow rig and above all else I just want it to be reliable. I probably wouldn't be doing a cam on it if my son was not so eager to learn how to take apart an engine.

So far I am planning on:
Cam install,
Pull heads
inspect valves and have machine shop check for leaks and cracks
Timing chain and Oil pump
ARP head studs
Dyno and Tune after cam install.


Thank you for your time and for always sharing knowledge with us all.

Cheers,
Dom
 
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Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
Dominic said:
Howdy Greg,
Stumbled upon this thread this weekend while doing some cam research. My son bought me a Brian Tooley truck Norris cam kit for Christmas. We bought a really clean 2006 GMC Sierra 2500HD this past spring. It has an LQ4 with 192K miles. Everything about it has been great, we put 10k miles on it this past summer. Only things I have done are muffler, Diablew tune (which as been fantastic) and an Air raid intake and filter. I have not had the motor opened up but sent off the oil for analysis and things looked great. Oil pressure has been consistent up around 40 psi at idle. From everything I can tell, the motor is healthy.

This cam is supposed to be mild enough to work with the stock stall converter. The kit does come with new valve springs caps, spacers and pushrods.

I am a bit overwhelmed by all the opinions online. I wondered if I might get your input on a WWGD (What would Greg Do) :)

If you had a seemingly healthy LQ4 and were going to put a cam in would you and top end refresh what would you do? I have 317 heads that at the very least we would pull and have a machine shop check them. It would be awesome to find some 243 heads but does not have to happen if our heads are in good shape I suppose.

The Truck is a tow rig and above all else I just want it to be reliable. I probably wouldn't be doing a cam on it if my son was not so eager to learn how to take apart an engine.

So far I am planning on:
Cam install,
Pull heads
inspect valves and have machine shop check for leaks and cracks
Timing chain and Oil pump
ARP head studs
Dyno and Tune after cam install.


Thank you for your time and for always sharing knowledge with us all.

Cheers,
Dom
Click to expand...

Dom, good to see you back on here!

You're definitely on the right track, with 200k miles a top-end refresh will help that LQ4 last another 200k+ miles.

I was going to suggest a new timing set, oil pump, etc. If you can find a set of 243 heads, you'd see some significant gains over the 317's. There's a lot of power made in better cyl heads!

I'd have the heads disassembled, cleaned up, milled a little, valve job and new valve seals installed, since it'll be apart for the new valve springs anyway.

The ARP headbolts are overkill, but I've made that upgrade on a previous engine myself. The factory style TTY head bolts are pretty cheap, but ARP's are high quality.

Did the cam kit come with new lifters too? I'd highly recommend new lifters with a new cam, the old rollers have probably worn-in to the individual lobes on the stock cam after 200k miles.

Lastly, I'd upgrade the rocker arms with trunnion bearings, the needle bearings are a known failure point on a LS and it's good insurance in the long run. You can buy rockers with trunnion upgrades or you can buy a kit and install them yourself, saving a little money.

Hope that helps, let me know if you have any other questions!

And far as this thread goes, I still have my LQ4 sitting in my shop, bagged up. I haven't done much with my LQ4 since buying a TJ with a crate LS3... but I have a couple vehicles I could put it into. 😁
 
I Lean

I Lean

Mbryson's hairdresser
Vendor
Location
Utah
One thing to consider, if you're thinking of putting money Into those heads...you can buy a set of aftermarket heads that will bump compression, flow better than stock, and come with valves already installed with better-than-stock valve springs. They are fairly cheap-ish, and especially if you deduct the cost of machine work or other things from the cost.

Also, Hi! 😁
 
Dominic

Dominic

Well-Known Member
Location
Salt Lake City
Greg/Carl, Wonderful to chat with you both and thank you both for the feedback and advice. I am going to do some compression tests and see if I can tell how the current heads are doing. This kit came with an adapter to pressurize the cylinder and hold the valve up and an adapter to change the spring, seal and hat with the heads on. It is possible I won't need to remove the heads if.... that all went correctly.

I know this will never be a 8.1 or LBZ. I got a great deal on the truck and it is so so clean and simple . The tune was a game changer. Adding a little torque from a cam seemed like a fun idea to pick up a little power but it might make sense to start setting up a replacement motor built the way we want and swap it in when we are ready.

Just for fun I will check in when I get some compression testing done.

Best to you and yours and Happy Holiday. Talk to you guys soon!
 
Dominic

Dominic

Well-Known Member
Location
Salt Lake City
Well this certainly escalated quickly. This morning an add on KSL popped up for a rebuilt LQ4, 243 heads valve job and cleaned up but not ported or anything and tbss intake with 92mm throttle body, new rockers, springs and a big Texas speed cam and arp head bolts for $1500. It seemed to good to be true but as it turns out it was just priced to sell quickly. The builder had run it in a truck for 30k then swapped in a ln ls3. The builder/seller was very nice and had plenty of projects that showed me he knew his stuff.

So we brought it home. Plan is to disassemble a bit and ensure it is in the shape we think it should be in. Clean up things that need attention, new lifters and oil pump, truck norris cam and some different valve covers :p and get it ready to swap in.

All of this seemed serendipitous. None of this was on my mind last week and it has all fallen into place. I think Greg might be the patron saint of LS based motor Miracles 😂.
 

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Dominic

Dominic

Well-Known Member
Location
Salt Lake City
Insides looks pretty good. About what I would expect. No evidence of metal fragments. Does look like perhaps some valve and piston kissing took place. The valves look perfect though so not sure what to make of that. I would think the valves would show evidence of interference?

We still need to extract the cam but so far so good.
 

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Dominic

Dominic

Well-Known Member
Location
Salt Lake City
I wrote the guy I bought it from. My guess is that maybe these pistons were reused as they were not that damaged? Perhaps the damage came from the last head which is why he rebuilt it.
 
Greg

Greg

I run a tight ship... wreck
Admin
Location
Grand Junction, CO
I'd be leary of "30k miles on a rebuild", it's looking like the start of my "recently rebuilt" LQ4 this thread started with!

Do the valves on the corresponding cylinder look like they've hit the piston? I have a lot of questions and doubts myself. I'd be hauling it to a machine shop for a full inspection at this point, and probably a proper rebuild.
 
UNSTUCK

UNSTUCK

But stuck more often.
I’d spend a few dollars getting some Amazon measuring tools. Check cylinder taper and out of round. That will give you a good idea of engine condition. But @Greg is right. It’s not a 30k motor. Invest a couple grand into it and you’ll sleep better at night. It’s a great platform to build off of.
 
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