5.3 transplant question
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5.3 transplant question I have a 2000 burb with a 5.3. Last year the motor went south due to a oil pump failure 
I have purchased a used motor that I am in the process of refreshing and installing.
First off, I know this is an LM7 but i don't see an lm7 section on the forum but i believe this is gen 3 motor correct? Is the lm7 the same as an LSx? I was hoping someone could clarify for me.
So among other things I am replacing the rear main. I bought the felpro rear main kit. The seal that came with it had a shorter depth than the original. I wasn' sure whether to flush it with the outer face or the inner seat. I went with the inner seat and not sure if that's correct or if it even matters.
Also I was kind of a DA and didn't realize what the plastic center piece was for and installed it without it. I was a little hard and I had to manhandle it a bit. I don't know if I ruined it or not. Should I replace it?
I have purchased a used motor that I am in the process of refreshing and installing.First off, I know this is an LM7 but i don't see an lm7 section on the forum but i believe this is gen 3 motor correct? Is the lm7 the same as an LSx? I was hoping someone could clarify for me.
So among other things I am replacing the rear main. I bought the felpro rear main kit. The seal that came with it had a shorter depth than the original. I wasn' sure whether to flush it with the outer face or the inner seat. I went with the inner seat and not sure if that's correct or if it even matters.
Also I was kind of a DA and didn't realize what the plastic center piece was for and installed it without it. I was a little hard and I had to manhandle it a bit. I don't know if I ruined it or not. Should I replace it?
Your truck originally came with a 5.3 LM7. This is a genIII engine so you're in the correct section. We do not have sections for every iteration of these engines, so we keep it to genIII, genIV and now genV.
What is the engine that you bought? If you can't ID it, tell us more about it like what vehicle did it come out of.
What is the engine that you bought? If you can't ID it, tell us more about it like what vehicle did it come out of.
Last edited by Paul Bell; Aug 23, 2015 at 04:20 PM.
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The motor i bought came out of an 02 suburban. It's a 5.3 as well. Block is identical but there are few minor differences on the intake. The motor appears to be in good shape.
I swapped lots of 350's back in the day but don't really have too much experience with the newer motors.
I swapped lots of 350's back in the day but don't really have too much experience with the newer motors.
It should be pretty much identical-including the intake manifold. If not, swap on the parts from the original.
No doubt both engines suffered with poor performing PCV systems. I suggest you pull the intake and clean up the ports and soak the manifold in de-greaser. It's always a GREAT idea to do the LS6 PCV swap: http://www.ls1howto.com/index.php?article=18
New knock sensors because they're under the valley cover AND intake manifold. A new ACDELCO oil pressure sending unit, because it's a bitch to change later.
Next pull the oil pan and check for excessive gunking. Consider a new timing chain and oil pump. Front & rear crank seals are waay easy now.
No doubt both engines suffered with poor performing PCV systems. I suggest you pull the intake and clean up the ports and soak the manifold in de-greaser. It's always a GREAT idea to do the LS6 PCV swap: http://www.ls1howto.com/index.php?article=18
New knock sensors because they're under the valley cover AND intake manifold. A new ACDELCO oil pressure sending unit, because it's a bitch to change later.
Next pull the oil pan and check for excessive gunking. Consider a new timing chain and oil pump. Front & rear crank seals are waay easy now.
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It should be pretty much identical-including the intake manifold. If not, swap on the parts from the original.
No doubt both engines suffered with poor performing PCV systems. I suggest you pull the intake and clean up the ports and soak the manifold in de-greaser. It's always a GREAT idea to do the LS6 PCV swap: http://www.ls1howto.com/index.php?article=18
New knock sensors because they're under the valley cover AND intake manifold. A new ACDELCO oil pressure sending unit, because it's a bitch to change later.
Next pull the oil pan and check for excessive gunking. Consider a new timing chain and oil pump. Front & rear crank seals are waay easy now.
No doubt both engines suffered with poor performing PCV systems. I suggest you pull the intake and clean up the ports and soak the manifold in de-greaser. It's always a GREAT idea to do the LS6 PCV swap: http://www.ls1howto.com/index.php?article=18
New knock sensors because they're under the valley cover AND intake manifold. A new ACDELCO oil pressure sending unit, because it's a bitch to change later.
Next pull the oil pan and check for excessive gunking. Consider a new timing chain and oil pump. Front & rear crank seals are waay easy now.
I have pulled the pan and front timing cover. Doesn't look too bad. I replaced the oil pump but kept the timing chain because it looked good and was nice and tight.
Replaced the front and rear seals and got schooled in removing in re-installing the harmonic.
I pulled the intake tonight and cleaned up the mating surface.
Did you see my question about the oil seal? Not sure if i should leave it as is or replace it.
The original LS rear main seals were dual lip and needed a tool to set them right. New seals are single lip.
If your original engine had a EGR setup, you'll need to replicate it on the replacement engine. Your PCM will look for it.
If your original engine had a EGR setup, you'll need to replicate it on the replacement engine. Your PCM will look for it.
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All of these engines have the same architecture. LS1 was the original 5.7L, the LM7 is a 5.3 with an iron block and a different intake manifold with a higher throttle body to clear water pump mounted fans that trucks use.
GenIII LS engines have a 24x crank reluctor ring and a 1x cam reluctor. GenIV LS engines use a 56x & 4x system.
GenIII LS engines have a 24x crank reluctor ring and a 1x cam reluctor. GenIV LS engines use a 56x & 4x system.
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Crank & cam sensors are passive components and generally don't go bad. If they work, no sense spending good money on new ones.
I suggest the knock sensors because over time their metal bodies rust & rot.
I suggest the knock sensors because over time their metal bodies rust & rot.
Thread Starter
Teching In
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Thread Starter
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Can anyone tell me the size on the hex head torque converter bolts? Pretty sure there metric and my 5/16 was a hair small. My book doesn't list it and could find it with a google search.
Update: It's an 8mm. I stripped the first one. Used a little heat and a punch and got it out. The other two came out with some heat.
Update: It's an 8mm. I stripped the first one. Used a little heat and a punch and got it out. The other two came out with some heat.
Last edited by larrybud; Aug 29, 2015 at 12:05 PM.