Ly6 in 2004 gmc 2500hd

[charles farquhar]

So I blew the factory lq4 and was given a short block ly6 (heads from it are currently on my lq4)

Already pulled the VVT cam out of the ly6. it is a non DOD motor. Is it possible to swap all my existing parts of the lq4 straight on to the ly6 (already know about the knock sensors) and drop it straight in after I get non-vvt cam?

[swathdiver]

19 minutes ago, charles farquhar said:

So I blew the factory lq4 and was given a short block ly6 (heads from it are currently on my lq4)

Already pulled the VVT cam out of the ly6. it is a non DOD motor. Is it possible to swap all my existing parts of the lq4 straight on to the ly6 (already know about the knock sensors) and drop it straight in after I get non-vvt cam?

The computer architecture is different and doesn't talk to one another.  So if you swap all the Gen III stuff onto the Gen IV block and heads you'll be fine.  The camshaft grinds between your LQ4 and the LY6 are basically identical save for VVT and the latter being 1-bolt versus 3.

[charles farquhar]

31 minutes ago, swathdiver said:

The computer architecture is different and doesn't talk to one another.  So if you swap all the Gen III stuff onto the Gen IV block and heads you'll be fine.  The camshaft grinds between your LQ4 and the LY6 are basically identical save for VVT and the latter being 1-bolt versus 3.

So then everything that I'm reading about harnesses and flashing pcm is irrelevant?

[davester]

Yes, as you are removing most/all of the bits that make it an LY6, and putting on the bits that make it an LQ4, so you can just install it in your truck that is expecting an LQ4.

[CamGTP]

You guys are forgetting the most important thing, he can swap it in but it will never run.

 

The LQ4 is a 24/1x crank trigger. The LY6 is a 58/4x crank trigger. He must swap the reluctor wheel on the crank and change to a 1x cam gear to make it work.

 

Or I think there is a really expensive converter box that can be bought to make it run.

 

Past that you still have to extend the wiring for the knock sensors and for the cam sensor because it's on the front cover a LY6. Then if you swap camshafts to a non VVT camshaft you need to buy a non VVT front cover.

 

I guess you'll have to see how it runs after that. A tune may be needed to sort out some little stuff but it will be 100% required if a stock camshaft is not what goes back into that engine.

 

 

[charles farquhar]

5 hours ago, CamGTP said:

You guys are forgetting the most important thing, he can swap it in but it will never run.

 

The LQ4 is a 24/1x crank trigger. The LY6 is a 58/4x crank trigger. He must swap the reluctor wheel on the crank and change to a 1x cam gear to make it work.

 

Or I think there is a really expensive converter box that can be bought to make it run.

 

Past that you still have to extend the wiring for the knock sensors and for the cam sensor because it's on the front cover a LY6. Then if you swap camshafts to a non VVT camshaft you need to buy a non VVT front cover.

 

I guess you'll have to see how it runs after that. A tune may be needed to sort out some little stuff but it will be 100% required if a stock camshaft is not what goes back into that engine.

 

 

What's the difference in using my lq4 cam vs the factory ly6?

[CamGTP]

Other than the LY6 using VVT, likely not much. I don't have the cam grind specs at the moment.

 

You could use a stock LQ4 camshaft with the correct 3 bolt cam gear. Then just figure out the reluctor wheel on the crank and it should fire up.

[charles farquhar]

Just now, CamGTP said:

Other than the LY6 using VVT, likely not much. I don't have the cam grind specs at the moment.

 

You could use a stock LQ4 camshaft with the correct 3 bolt cam gear. Then just figure out the reluctor wheel on the crank and it should fire up.

Just did some research and found that they are the same cam only difference is single bolt vs 3 bolt. Question now is if I can just swap the crank right into the ly6 block 

 

[swathdiver]

15 hours ago, CamGTP said:

You guys are forgetting the most important thing, he can swap it in but it will never run.

 

The LQ4 is a 24/1x crank trigger. The LY6 is a 58/4x crank trigger. He must swap the reluctor wheel on the crank and change to a 1x cam gear to make it work.

 

Or I think there is a really expensive converter box that can be bought to make it run.

 

Past that you still have to extend the wiring for the knock sensors and for the cam sensor because it's on the front cover a LY6. Then if you swap camshafts to a non VVT camshaft you need to buy a non VVT front cover.

 

I guess you'll have to see how it runs after that. A tune may be needed to sort out some little stuff but it will be 100% required if a stock camshaft is not what goes back into that engine.

 

 

You're right, I completely forgot!  Duh!

10 hours ago, charles farquhar said:

What's the difference in using my lq4 cam vs the factory ly6?

 

10 hours ago, CamGTP said:

Other than the LY6 using VVT, likely not much. I don't have the cam grind specs at the moment.

 

You could use a stock LQ4 camshaft with the correct 3 bolt cam gear. Then just figure out the reluctor wheel on the crank and it should fire up.

The grinds are essentially the same.

 

LY6

12625440

196

208

0.466

0.478

116

 

LQ4

12561721

196

207

0.467

0.479

116