Rebuild LS1 or drop in LQ4
06-20-2010, 05:47 PM
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Rebuild LS1 or drop in LQ4 I have a 98 M6 Z28 and my rings appear to be fried. I found a LQ4 engine for $600 So I was just wondering about what all I have to do to put the LQ4 in. Ive been told I would need a newer model computer, but I would think the motor itself would just bolt right up. I was thinking ported/polished/milled L92 heads (pretty sure Ill have to flycut the pistons), LS3 intake, and regrinding my cam (the shop I called told me they could get .570 lift from my LS1 cam so I guess they could regrind the LQ4 cam to that too.) Or would I be better off just rebuilding my LS1? And cost is an issue as I am on a budget 
06-20-2010, 07:16 PM
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If you are looking for a budget build, then that LQ4 is certainly the way to go. What year LQ4 will you be getting? You won't need a newer model computer and pretty much everything bolts right up other than a few minor things. As far as the cam goes, don't do a regrind, do it the right way and buy the whole complete cam package from someone like TSP. You should definately measure PTV either way though. Safe over sorry...
06-20-2010, 07:18 PM
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Here are some things to know when doing the swap:
-You will need your oil pan and intake off of the LS1 - the intake off of the trucks is too tall and the oil pan doesn't fit the F-bodies.
-The TB coolant lines are different than the LS1. You will have to buy about 6 inches of rubber hose and slightly (and GENTLY) tweak the metal coolant line to clear the intake.
-I had problems getting the truck coils to clear the small evap thingy on the fuel rail (correct me if that isn't what its called lol)
-The oil filler neck that was on the trucks is too tall and you will need one from an F-Body.
-The oil pressure sending unit that comes on the truck engines is a 3 wire and not a 1 wire like the LS1's so you will need one off of an LS1.
-The alternator bracket will only be held in by 2 bolts unless you tap the other one. I did not, and I haven't had any problems.
-You may want to use the pulley off of the truck power steering pump. It is metal unlike the cheap plastic that the F-bodies use and it is the same size, just more durable and you don't have to worry about it cracking when you hammer it on the pump.
-Make sure you keep all of your accesories and brackets as I don't think the truck ones will work without modification. Also, you will need the crankshaft pulley off of the LS1 since the truck pulley won't line up with the rest of the accesories.
Some of the above may not apply to you but for me they did since I bought a complete LQ9 from intake to pan.
-You will need your oil pan and intake off of the LS1 - the intake off of the trucks is too tall and the oil pan doesn't fit the F-bodies.
-The TB coolant lines are different than the LS1. You will have to buy about 6 inches of rubber hose and slightly (and GENTLY) tweak the metal coolant line to clear the intake.
-I had problems getting the truck coils to clear the small evap thingy on the fuel rail (correct me if that isn't what its called lol)
-The oil filler neck that was on the trucks is too tall and you will need one from an F-Body.
-The oil pressure sending unit that comes on the truck engines is a 3 wire and not a 1 wire like the LS1's so you will need one off of an LS1.
-The alternator bracket will only be held in by 2 bolts unless you tap the other one. I did not, and I haven't had any problems.
-You may want to use the pulley off of the truck power steering pump. It is metal unlike the cheap plastic that the F-bodies use and it is the same size, just more durable and you don't have to worry about it cracking when you hammer it on the pump.
-Make sure you keep all of your accesories and brackets as I don't think the truck ones will work without modification. Also, you will need the crankshaft pulley off of the LS1 since the truck pulley won't line up with the rest of the accesories.
Some of the above may not apply to you but for me they did since I bought a complete LQ9 from intake to pan.
06-20-2010, 09:35 PM
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Man thats awesome. Im not sure what year it is from. I have bypassed the coolant lines for the throttle body so that shouldnt be a problem and I was thinking of relocating the coils to the firewall if I could find enough room for them. I think ill probably just go ahead and go with the MS3 or MS4 cam. And it sounds like as long as I have all the stuff off my LS1 I should be good to go. And the LS3 intake will take care of the huge truck intake problem. But I think the 98 computer is different than the other years, the red and blue connectors are reversed or somethin like that, but a new one cant cost but so much.
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06-21-2010, 12:56 AM
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Here are some things to know when doing the swap:
-You will need your oil pan and intake off of the LS1 - the intake off of the trucks is too tall and the oil pan doesn't fit the F-bodies.
-The TB coolant lines are different than the LS1. You will have to buy about 6 inches of rubber hose and slightly (and GENTLY) tweak the metal coolant line to clear the intake.
-I had problems getting the truck coils to clear the small evap thingy on the fuel rail (correct me if that isn't what its called lol)
-The oil filler neck that was on the trucks is too tall and you will need one from an F-Body.
-The oil pressure sending unit that comes on the truck engines is a 3 wire and not a 1 wire like the LS1's so you will need one off of an LS1.
-The alternator bracket will only be held in by 2 bolts unless you tap the other one. I did not, and I haven't had any problems.
-You may want to use the pulley off of the truck power steering pump. It is metal unlike the cheap plastic that the F-bodies use and it is the same size, just more durable and you don't have to worry about it cracking when you hammer it on the pump.
-Make sure you keep all of your accesories and brackets as I don't think the truck ones will work without modification. Also, you will need the crankshaft pulley off of the LS1 since the truck pulley won't line up with the rest of the accesories.
Some of the above may not apply to you but for me they did since I bought a complete LQ9 from intake to pan.
-You will need your oil pan and intake off of the LS1 - the intake off of the trucks is too tall and the oil pan doesn't fit the F-bodies.
-The TB coolant lines are different than the LS1. You will have to buy about 6 inches of rubber hose and slightly (and GENTLY) tweak the metal coolant line to clear the intake.
-I had problems getting the truck coils to clear the small evap thingy on the fuel rail (correct me if that isn't what its called lol)
-The oil filler neck that was on the trucks is too tall and you will need one from an F-Body.
-The oil pressure sending unit that comes on the truck engines is a 3 wire and not a 1 wire like the LS1's so you will need one off of an LS1.
-The alternator bracket will only be held in by 2 bolts unless you tap the other one. I did not, and I haven't had any problems.
-You may want to use the pulley off of the truck power steering pump. It is metal unlike the cheap plastic that the F-bodies use and it is the same size, just more durable and you don't have to worry about it cracking when you hammer it on the pump.
-Make sure you keep all of your accesories and brackets as I don't think the truck ones will work without modification. Also, you will need the crankshaft pulley off of the LS1 since the truck pulley won't line up with the rest of the accesories.
Some of the above may not apply to you but for me they did since I bought a complete LQ9 from intake to pan.
06-21-2010, 02:39 AM
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I was going to do a build thread and use all of the pics I have but I am too lazy right now to do a write up lol.
06-21-2010, 08:48 AM
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Yea, I am about to do this swap. I plan to try to take a lot of pictures but we'll see. It seems to be a pretty straight forward install. One question, you said you had trouble getting the truck coils to clear. Does that mean you used the LS1 coils or made clearance for the truck coils?
06-21-2010, 04:27 PM
#12
Truck Coils They are taller and I think the bracket is also a lil taller. You may have to adjust (bend) your fuel connection up at the rail.
Usual size of the TB on the trucks was 75 or 78mm. I think all the ones with L92 heads had a 90. Though not 100% sure on that.
Usual size of the TB on the trucks was 75 or 78mm. I think all the ones with L92 heads had a 90. Though not 100% sure on that.
Last edited by davidws6; 06-21-2010 at 04:27 PM. Reason: .
06-21-2010, 08:57 PM
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Yea, I am about to do this swap. I plan to try to take a lot of pictures but we'll see. It seems to be a pretty straight forward install. One question, you said you had trouble getting the truck coils to clear. Does that mean you used the LS1 coils or made clearance for the truck coils?
06-22-2010, 04:09 PM
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I talked to the guy about the LQ4 and he said it came out of a Tahoe, but I thought all the Tahoes came with 5.3s??? And he didnt know what year, late 90s early 00s and had like 90,000 miles. Does a 5.3 look like a 6.0?
06-23-2010, 02:41 PM
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http://en.wikipedia.org/wiki/GM_Vortec_engine
According to Wikipedia, the Tahoes came with 4.8's and 5.3's but that's what Wiki says. I'm sure someone on here will chime in who knows for sure.
It also looks like the Tahoe Hybrid came with a 6.0L but that was in 08 and on.
According to Wikipedia, the Tahoes came with 4.8's and 5.3's but that's what Wiki says. I'm sure someone on here will chime in who knows for sure.
It also looks like the Tahoe Hybrid came with a 6.0L but that was in 08 and on.
06-23-2010, 04:55 PM
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Yea my uncles 03 Tahoe had 5.3. And the guy didnt have much info on the engine so I might just stick with my LS. At least that way I know for sure what Im workn with, I just hope its not too scarred up inside when I tear it down.
08-06-2010, 12:17 PM
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