The "official" LS1/LSx/5.3/6.0 tech thread

What are y'all doing for radiator overflow tanks? I assume you need a tank with pressurized cap instead of the jeep tank that's not pressurized. The gm tank is huge, so aftermarket tank?
 
LBarr2002 said:
What are y'all doing for radiator overflow tanks? I assume you need a tank with pressurized cap instead of the jeep tank that's not pressurized. The gm tank is huge, so aftermarket tank?
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I've never had an issue with a non pressurized. If you must, a surge tank can be had from summit or jegs. The idea behind a surge is that it's the highest point of the system, relying on it as a fill point and air escape.
If your radiator is the highest point, a typical radiator overflow bottle will work. Mine I sourced from a 1500 v8 Dodge ram. Tall, squarely cylindrical and plenty of capacity.
 
LBarr2002 said:
What are y'all doing for radiator overflow tanks? I assume you need a tank with pressurized cap instead of the jeep tank that's not pressurized. The gm tank is huge, so aftermarket tank?
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If it’s going in a Jeep eBay is literally full of ls conversation radiators for cheap


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XJsavage said:
I've never had an issue with a non pressurized. If you must, a surge tank can be had from summit or jegs. The idea behind a surge is that it's the highest point of the system, relying on it as a fill point and air escape.
If your radiator is the highest point, a typical radiator overflow bottle will work. Mine I sourced from a 1500 v8 Dodge ram. Tall, squarely cylindrical and plenty of capacity.
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Having a pressurized system would increase the boiling point. Wasn't sure if it was necessary.

Loganwayne said:
If it’s going in a Jeep eBay is literally full of ls conversation radiators for cheap


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Yeah, I know what radiator I'm going to use, just didn't know what tanks work well or if needed at all. The radiator has a cap built in, which I don't thing the gm truck radiators do.
 
Having a non pressurized burp tank won't hurt a thing, the cooling system will still be pressurized.
 
I've been collecting parts since October 2017, but bit the bullet and tore into it last weekend. LM4 is sitting in it's new home, but have a couple issues to address.

Has anyone been able to find a good reference of what stock manifolds look like off different vehicles? My motor came out of a Buick Ranier. Manifolds are block hugger rear dump. Passenger side fits great but driver side dumps into the driveshaft. I have a HP axle and very little lift which complicates this further. Hoping to find a driver side manifold that is a center dump or dumps under 3rd cylinder to go in front of oil pan.
 
LBarr2002 said:
I've been collecting parts since October 2017, but bit the bullet and tore into it last weekend. LM4 is sitting in it's new home, but have a couple issues to address.

Has anyone been able to find a good reference of what stock manifolds look like off different vehicles? My motor came out of a Buick Ranier. Manifolds are block hugger rear dump. Passenger side fits great but driver side dumps into the driveshaft. I have a HP axle and very little lift which complicates this further. Hoping to find a driver side manifold that is a center dump or dumps under 3rd cylinder to go in front of oil pan.
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LS3 Corvette manifolds or the LS1 Camaro Manifold.

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Corvette C6 LS2 LS3 Exhaust Manifold LH '05-'13 | eBay

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NEW OEM Firebird Camaro Exhaust Manifold Left Drivers Side 5.7L LS1 350 | eBay
 
For the price of those manifolds, you can pick up some cheap block hugger shorties with 3/8” flanges on eBay. Around $80 shipped.
 
Chris_Keziah said:
LS3 Corvette manifolds or the LS1 Camaro Manifold.

s-l1600.jpg

Corvette C6 LS2 LS3 Exhaust Manifold LH '05-'13 | eBay

s-l1600.jpg

NEW OEM Firebird Camaro Exhaust Manifold Left Drivers Side 5.7L LS1 350 | eBay
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The ls3 one may be too far forward. The ls1 one would probably work and I have a friend that's supposed to get back to me if he still has a set. The O2 bung is going to point directly at the motor mount and I'd have to block of the egr stuff, but it's an option.

iwaxmyjimmy said:
For the price of those manifolds, you can pick up some cheap block hugger shorties with 3/8” flanges on eBay. Around $80 shipped.
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Yes, but will they warp and leak?
 
LBarr2002 said:
The ls3 one may be too far forward. The ls1 one would probably work and I have a friend that's supposed to get back to me if he still has a set. The O2 bung is going to point directly at the motor mount and I'd have to block of the egr stuff, but it's an option.



Yes, but will they warp and leak?
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About 2k miles on mine so far, that’s why I mentioned the 3/8” flanges less likely to warp and leak. Also I used studs instead of header bolts.
 
iwaxmyjimmy said:
About 2k miles on mine so far, that’s why I mentioned the 3/8” flanges less likely to warp and leak. Also I used studs instead of header bolts.
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Thanks, I'll think about that a little more then. It would be difficult for me to run studs with the clearance I have to get them on and off, but I do have ARP bolts to replace the stock ones.

Are these what you have?
Pro Stainless Steel Truck Headers Fits Chevy 5.0l 5.7l 305 327 350 400 V8 Pop for sale online | eBay
 
LBarr2002 said:
Thanks, I'll think about that a little more then. It would be difficult for me to run studs with the clearance I have to get them on and off, but I do have ARP bolts to replace the stock ones.
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Fits Chevy LS1 LS6 Stainless Steel Block Hugger Tight Exhaust Headers LS 1 LS 6 800995742134 | eBay

These are the ones I used, they only have 2.5” collectors. They worked great for my application, square body 5.3/sm465. You should be able to route the exhaust in front of the oil pan much like I did and take it all back on the passenger side. I had to use them to clear the slave cylinder on the driver side. And yeah studs can make it it a little bit of a pain to get them off but it helps keeping them sealed.
 
iwaxmyjimmy said:
Fits Chevy LS1 LS6 Stainless Steel Block Hugger Tight Exhaust Headers LS 1 LS 6 800995742134 | eBay

These are the ones I used, they only have 2.5” collectors. They worked great for my application, square body 5.3/sm465. You should be able to route the exhaust in front of the oil pan much like I did and take it all back on the passenger side. I had to use them to clear the slave cylinder on the driver side. And yeah studs can make it it a little bit of a pain to get them off but it helps keeping them sealed.
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That looks like what I need... did you coat them?
 
LBarr2002 said:
That looks like what I need... did you coat them?
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Also get 135 degree spark plug wires. Stock AC Delco ones will get burnt up on them. But Taylor’s are what’s on mine I found on amazon for $28 shipped. Also I run the fancy heat boots too.
 
iwaxmyjimmy said:
Also get 135 degree spark plug wires. Stock AC Delco ones will get burnt up on them. But Taylor’s are what’s on mine I found on amazon for $28 shipped. Also I run the fancy heat boots too.
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I have a set in my summit cart.

Another question. I was set on reusing the factory hard line for fuel supply and using one of the evap lines for the return. While trying to design a crossmember that would allow me to drop the skids independent of the trans mount, a friend helping said this would be much easier if those lines weren't there.

Thoughts? Reuse factory lines with adapters to AN or run new Summit PTFE braided lines from tank to fuel rail?
 
LBarr2002 said:
I have a set in my summit cart.

Another question. I was set on reusing the factory hard line for fuel supply and using one of the evap lines for the return. While trying to design a crossmember that would allow me to drop the skids independent of the trans mount, a friend helping said this would be much easier if those lines weren't there.

Thoughts? Reuse factory lines with adapters to AN or run new Summit PTFE braided lines from tank to fuel rail?
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For simplicity and choice of routing locations I would do all new line braided line with AN fittings.
 
I'd probably run braided lines if I was doing a swap. Just makes life easier.

I definitely agree on the plug wires. The stock ones with the heat boots fit fine with the headers on my 99, but I needed a new set anyway. I wound up with MSD wires that have bendable plug boots and some boot guards that are made of something like header wrap. Plus...they look cool and are 8.5mm.

If you go with the LS1 manifold, I'd plug the 02 bung and weld new ones in wherever you need them. If you go with headers that are stainless, I'd leave them alone or maybe have them ceramic coated if you wanted to lower under hood temps.
 
On the subject of fuel lines... I'm going to run new supply and return. I plan to plumb the return into one of the existing evap lines in the tank. I want to remove the charcoal canister in the passenger wheel well and block off the evap stuff. What do I need for a vent/rollover valve?

Something like this up in the wheel well I assume?
https://www.summitracing.com/parts/...BdC7p9Qbd9HkfpE7ta56HFCf5VJOdkmhoCKQsQAvD_BwE
 
Is it normal to not have the gm oil pressure sensor plug in a cut down harness?
 
LBarr2002 said:
Is it normal to not have the gm oil pressure sensor plug in a cut down harness?
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Mine uses a 3 wire ECT and Oil pressure sensor for these reasons. From a 4th gen Camaro I believe.
 
iwaxmyjimmy said:
Mine uses a 3 wire ECT and Oil pressure sensor for these reasons. From a 4th gen Camaro I believe.
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I have coolant temp, but no oil pressure. I guess its not an issue. Sucks that I already drilled and tapped the oil cooler bypass plate for the jeep sensor though. I guess I'll plug that port and move the jeep sensor up top...
 
LBarr2002 said:
Is it normal to not have the gm oil pressure sensor plug in a cut down harness?
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Depends on who does it. I think the factory plug on the front of the driver side only communicates through the PCM, and the additional added sensor is what communicates with the gauges. In factory application the one sensor does both.
 
I have my LM4 5.3/4l60 combo up and running in my 04 LJ. I'm trying to use the stock gauges but none of the gauges are responding and the obdII port is showing no connectivity. The lj was originally an automatic and we cut out the trans wiring and removed the tcm. I know the tcm is connected on the bus, and we're wondering of this is the issue.

Anybody have experience with a factory auto pcm and using the stock gauges?
 
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