Hey guys, I need some help. I was trying to rebuild at Gen 6.0 LQ9 with a front main bearing that spun. I took it to a machine shop and they guy said they would hopefully make it work with a align bore/hone. They later told me the block was not good. My plan was to replace the cylinders because the engine sat outside and got water in it. It had the Gen IV rods (was told it was from an 05) so I was planning on reusing those. I found another C.I. bare block, that's already machined 0.020" over. The guy had too many projects and never got to building this engine and wanted an aluminum block anyways. The problem is that it's a Gen IV block, and I don't anything about the Gen IV. He had the little towers for the AFM tapped and the gave me the AFM delete valley cover.

I would like to keep the engine as a Gen III since I already have the ECU, harness, and stuff. I'm reading I need to change my crank reluctor to a 58x, and run that racetronix 58x to 24X conversion module. Do I need to do that? I guess not since my crank is already 24x?

I also read I need to drill and tap for the knock sensors on the side, and use the harness to extend the wires for the knock sensors. What about cam position sensor? My stock cam looked good and I measured the journals and it's reusable. Do I need a Gen IV camshaft? And how does that work with Gen III harness and ECU? This is a completely stock build.

I saw a video where a guy swapped the cam sprocket from an LS2 05-06? timing chain set and modified his cam position sensor wiring to work. Is that what I need to do for mine?

Also, can someone recommend some pistons equivalent to the factory ones?

Thanks in advance.

 

use a 24X wheel crank. Get the correct 1x cam wheel. Use a front timing cover with cam sensor hole in it. Drill and tap Block for gen3 style crank sensors.

Casper's Electronics sells extension harness for the cam sensor to move to the front and the knock sensors to move down to the sides of the block.

Knock/Cam Harrness LS1 to LS2/LS7

 

Awesome. Thanks!

You meant "...drill and tap block for gen 3 style 'knock' sensors," right?

 

yes, there is already a smaller hole for the gen4 knock sensors.

 

like this

 

Nice! Are there 2 knock sensors both on the same side? Is this the threaded hole for the other sensor?

I will check out my block to see if it has the threaded holes. I believe it's an LY6 and my other engine that's junk is a Lq9 with the flat top pistons.

Are these pistons good for a stock build replacement? https://www.summitracing.com/parts/slp-h1129cpa50mm

 

The knock sensor is left and right of the block. So 1 on each side. That particular one is a gen4 aluminum 5.3L block.

Those will work just fine. Speed Pro and Silv-O-Lite are going to be the 2 predominate choices for replacement pistons. What ever you can get as there are shortages still.

You will need to have the decks machined on the block.

The replacement pistons will have a lower height.
1. To maintain the OEM compression ratio, how ever this will effect your Quench because the piston will be down in the hole in this application.
2. They also assume that the deck may need to be cleaned up during a rebuild if they are warped.

 

Oh, the front hole you circled is used as a ground point on the block. The harness grounds bolt up there.

 

Thank you sir! Great advice. I will have to do some reading on deck height. This is my first rebuild ever, so I don't really understand what Quench is (but have heard about it.)

I'm not sure if they decked the surface on the Gen IV block. I can ask the guy. Or there a way to measure? I bought a set of micrometers, but I think it only goes to 6" for the largest.

Also, I will have to look at my 317 heads in more detail. The engine had one bent push rod, in addition to a front main bearing. I took off the front cover and saw the timing chain had broken, and that's when I realize I was in trouble. I assumed I could still use the heads? Maybe have the machine shop check them?

 

You can assemble a piston and rod and install it to see if the piston is above or below the deck. Let me get you a picture

Yes the machine can check and recondition the heads as long as nothing major is wrong, shouldn't be an issue.