Adding Ls/gear reduction to a dd rigging

[12ftgso480]

Here's where I currently am with mine. I don't like the thought of my water lines attaching right behind my head, I'll do some diggin through the threads and oriely. See if I can get it setup differently. Headers supposed to be in tomorrow. Getting excited about starting

 

[12ftgso480]

Cage a little tight up front on me but it was very minimal modifying it.

 

[One Eyed Gator]

You can use a corvette water pump or an F body pump but you have to change the pulleys, balancer and alternator to the same spacing.

Truck spacing, f-body spacing or y-body/corvette spacing

Corvette style comes straight out the from the front of the pump also the alternator usually sits low on the drivers side of the motor instead of up top

 

[12ftgso480]

Chopping up harness trying to get it all cleaned up. May have to redo my bars to cage, running a little close to tensioner pully. Got fuel lines done up, was pretty happy with how it turned out. Anyone got a pic of your radiator hoses ? Wanting some ideas on high point. Headers came back a little further than I wanted but thinking we can put a hard 90 and pull it off.

 

[12ftgso480]

You can use a corvette water pump or an F body pump but you have to change the pulleys, balancer and alternator to the same spacing.

Truck spacing, f-body spacing or y-body/corvette spacing

Corvette style comes straight out the from the front of the pump also the alternator usually sits low on the drivers side of the motor instead of up top

Ending up running a waterpump off a 13 chevy 2500.

 

[Slidin Gator]

Ending up running a waterpump off a 13 chevy 2500.

Corvette setup would probably give you good clearance but cage mods are cheaper. I don’t know who sits the rear seat but I assume they are important. I suggest an SFI rated balancer system, you don’t want that thing shredding under the seat.

 

[One Eyed Gator]

If that is a Corvette Fuel filter regulator I personally have never had good luck with them.

I also like the fuel pressure regulator and a gauge close to the fuel rail.

58 PSI at the tank level maybe not be the same at the fuel rail

 

[12ftgso480]

Anybody have a good pic of their fill high point/reservoir for radiator? Been going rounds with cousin about how we should do it

 

[12ftgso480]

In some of my first pictures of the boat with the small block you can see they did it with main radiator hose lines, if I'm understanding it right we can do it with heatercore lines off the water pump and not be so bulky? Thoughts

 

[Slidin Gator]

Anybody have a good pic of their fill high point/reservoir for radiator? Been going rounds with cousin about how we should do it

144",

I have been mulling this same question for a bit. I drilled, tapped and plugged the heater ports on my water pump, then forgot about it for a while before I found this in my dad's stash.

Coolant Reservoir with:

• Radiator cap with overflow at top
• 3/8" NPT at bottom
• 1/4" NPT port up high.

Friggin Perfect





My present plan is below:

• Pump high return direct to top of radiator with big hoses, no stupid detours.
• Radiator outfitted with cap relief defeat (pull relief spring and relief plat out, open relief port to 2 way).
• Connect 3/8" port on this reservoir to the defeated overflow on the radiator.
• Connect LS Steam Ports to 1/4" high port on reservoir.
• Add in 1/4" Reservoir "T" for secondary vacuum pump port.
• Install radiator pressure cap on this remote reservoir
• Connect this Remote Reservoir purge port to additional coolant overflow tank.

This setup should make it easy to vacuum fill the cooling system. I plan to put a mechanical temp gauge sensor into the engine side port on the heater outlet (plugged previously). The head port feeds the EFI the info it needs, but the circulation port provides more trouble shooting information for the user.

My thinking so far.

 

[12ftgso480]

144",

I have been mulling this same question for a bit. I drilled, tapped and plugged the heater ports on my water pump, then forgot about it for a while before I found this in my dad's stash.

Coolant Reservoir with:

• Radiator cap with overflow at top
• 3/8" NPT at bottom
• 1/4" NPT port up high.

Friggin Perfect

View attachment 98392

View attachment 98393

My present plan is below:

• Pump high return direct to top of radiator with big hoses, no stupid detours.
• Radiator outfitted with cap relief defeat (pull relief spring and relief plat out, open relief port to 2 way).
• Connect 3/8" port on this reservoir to the defeated overflow on the radiator.
• Connect LS Steam Ports to 1/4" high port on reservoir.
• Add in 1/4" Reservoir "T" for secondary vacuum pump port.
• Install radiator pressure cap on this remote reservoir
• Connect this Remote Reservoir purge port to additional coolant overflow tank.

This setup should make it easy to vacuum fill the cooling system. I plan to put a mechanical temp gauge sensor into the engine side port on the heater outlet (plugged previously). The head port feeds the EFI the info it needs, but the circulation port provides more trouble shooting information for the user.

My thinking so far.

Well hell yea dude! Sounds like you got a plan, the big hoses are bulky, so my cousin is voting to order a different reservoir and run small lines. Wondering at this point if the bigger lines will get air out easier.

 

[Slidin Gator]

Well hell yea dude! Sounds like you got a plan, the big hoses are bulky, so my cousin is voting to order a different reservoir and run small lines. Wondering at this point if the bigger lines will get air out easier.

I'm full on "Your Cousin Vinny" on this one. Air don't need much to get out, ever had a tire leak?

But, if you want to try stuff like my old man, I also found a few of these in the stash. Like I said, I been thinking. You are welcome to whatever I don't use.

 

[One Eyed Gator]

12ftgso480 I sent you a PM

 

[Slidin Gator]

Found the instructions for the Jegs expansion tank. I will probably add the connection from the heater port on the water pump (radiator return side) using a 1/2" hose to the bottom port on tank. The steam port hose will still run to the 1/4" port. As long as the radiator sits below the engine and radiator return hose does not have an airlock point, probably no need for a connection between the expansion tank and radiator.

On the subject of getting the air out, note the earlier point about a vacuum pump connection point. I plan to put a valve on the bottom of the radiator (ball valve instead of pep cock). Run a hose from that valve into a jug of coolant. Pull a vacuum on the system and then open the bottom valve to pull in coolant. Fill until the pump spits out coolant. I use a venturi type air driven vacuum pump, works for this and AC service.

That should solve the air issue quickly.

 

[12ftgso480]

Found the instructions for the Jegs expansion tank. I will probably add the connection from the heater port on the water pump (radiator return side) using a 1/2" hose to the bottom port on tank. The steam port hose will still run to the 1/4" port. As long as the radiator sits below the engine and radiator return hose does not have an airlock point, probably no need for a connection between the expansion tank and radiator.

On the subject of getting the air out, note the earlier point about a vacuum pump connection point. I plan to put a valve on the bottom of the radiator (ball valve instead of pep cock). Run a hose from that valve into a jug of coolant. Pull a vacuum on the system and then open the bottom valve to pull in coolant. Fill until the pump spits out coolant. I use a venturi type air driven vacuum pump, works for this and AC service.

That should solve the air issue quickly.

View attachment 98395

Nice ! I that sounds like it's gonna be legit, I really have grown fond of my vacuum pump aswell. I've got a kubota side by side that I could not burb the air out after a water pump Job so I was forced to buy one. Now I know there's no better way . I guess the thought in my head that still lingers is an issue on the fly and need to add water and burp it without a pump handy.

 

[Slidin Gator]

I guess the thought in my head that still lingers is an issue on the fly and need to add water and burp it without a pump handy.

From the perspective of an old school SBC that's a reasonable (but resolvable) concern. But to understand how the expansion tank solution simplifies things you have to consider the details of the LS cooling system. The highest point of the old SBC cooling system is the Intake manifold and related thermostat outlet. This means air will make its way to the thermostat housing and eventually flow into the radiator, which in automotive applications is usually a bit higher than the thermostat. In the SBC system, for most applications the radiator makes for a convenient place to capture and vent air. Expansion tank solutions make sense when the radiator is lower than the thermostat (aka an airboat).

On ANY LS application, the highest point of the engine cooling system is the heads and ultimately the steam ports. This is a function of GM eliminating coolant in the intake manifold. The Dry intake is what drove GM to re-design the thermostat, cooling and steam port system. The thermostat is low on the inlet side of the coolant circuit and air venting is via the steam ports. Plug the steam ports and you will never vent an LS engine sufficiently.

My point is that the full radiator flow through expansion tank kinda makes sense for the old SBC you are deleting, it makes no sense for an LS application. Air venting is a function of the steam ports, full stop. The only other connection needed is a line big enough to vent excessive pressure through the Expansion tank (from overheating) and not choke flow when topping off (refill flow is not limited by expansion tank volume). A 1/2" hose connection from the pump radiator side heater port meets all criteria other than air removal.

 

[12ftgso480]

From the perspective of an old school SBC that's a reasonable (but resolvable) concern. But to understand how the expansion tank solution simplifies things you have to consider the details of the LS cooling system. The highest point of the old SBC cooling system is the Intake manifold and related thermostat outlet. This means air will make its way to the thermostat housing and eventually flow into the radiator, which in automotive applications is usually a bit higher than the thermostat. In the SBC system, for most applications the radiator makes for a convenient place to capture and vent air. Expansion tank solutions make sense when the radiator is lower than the thermostat (aka an airboat).

On ANY LS application, the highest point of the engine cooling system is the heads and ultimately the steam ports. This is a function of GM eliminating coolant in the intake manifold. The Dry intake is what drove GM to re-design the thermostat, cooling and steam port system. The thermostat is low on the inlet side of the coolant circuit and air venting is via the steam ports. Plug the steam ports and you will never vent an LS engine sufficiently.

My point is that the full radiator flow through expansion tank kinda makes sense for the old SBC you are deleting, it makes no sense for an LS application. Air venting is a function of the steam ports, full stop. The only other connection needed is a line big enough to vent excessive pressure through the Expansion tank (from overheating) and not choke flow when topping off (refill flow is not limited by expansion tank volume). A 1/2" hose connection from the pump radiator side heater port meets all criteria other than air removal.

I hadn't done any research but have been wondering about the steam ports. I've been told you can just cap them, their not that important. In my head I'm thinkin well shit they put them on there but we delete stuff from motors all the time thank you for the thorough explanation. So what we concluded is this is not just a high point circulation tank, there's more to it than that? We are venting pressure here so it will have to be a radiator cap and run to an overflow tank ? Hope I'm picking up atleast some of what your laying down

 

[Slidin Gator]

I hadn't done any research but have been wondering about the steam ports. I've been told you can just cap them, their not that important. In my head I'm thinkin well shit they put them on there but we delete stuff from motors all the time thank you for the thorough explanation. So what we concluded is this is not just a high point circulation tank, there's more to it than that? We are venting pressure here so it will have to be a radiator cap and run to an overflow tank ? Hope I'm picking up atleast some of what your laying down

You got it, the expansion tank becomes the top of the radiator and has the radiator cap with relief connected to overflow tank. Radiator itself should not have a relief point. Steam ports are important on LS, much more so than the old 400 SBC.

This is my first round with LS stuff myself. Folks should know to call BS if I’m wrong on something. The pump and thermostat system is different vs. SBC too. I covered that some in my engine thread.

 

[Slidin Gator]

I came up with a couple graphics that I hope explains the LS cooling system. I made them for me cause this system has thrown me for a few loops getting it straight.

The LS thermostat has 2 functions:
#1 is Thermal portion that blocks pump inlet when the engine is cold.
#2 is relief valve portion that opens when cold and meters radiator flow when hot.

When the engine is cold, the thermostat blocks the pump from picking up coolant from the bottom of the radiator. Nature abhors a vacuum so the relief valve at the end of the thermostat holds back pressure, but something's gotta give, so it opens and feeds the pump. The point is when it is cold the engine cooling system circulates coolant through the engine, but it is blocked off from the radiator. This solves an old SBC problem where engines would overheat before enough coolant got to the thermostat to open it up. The old circuit required a bypass of some kind so the thermostat would actually see the hot temps (bypass in the block, from the pump or with holes in the thermostat).

The LS system, on startup coolant re-circulates at full flow through the engine, with the thermostat in the loop. As soon as the engine reaches operating temp, the thermostat can react and open. At this point the pump can finally breath and start pulling coolant from the radiator. That thermostat relief valve is equally important here. If the relief opens it will divert hot coolant back into the pump inlet. The relief valve has to stay closed now so all coolant can route out the top of the pump to the top of the radiator.

So here is the critical part, you don't want to restrict the flow from the top of the pump back to the radiator, or through the radiator and back to the pump for that matter. The pressure relief in the thermostat regulates the amount of pressure that you got to push however much flow the pump makes through the radiator vs. dumping hot coolant back through the Engine! Routing full size coolant lines through a bunch of 90-degree fittings just to get to a high side tank and then back down to the radiator is a great way to add back pressure, leading to more opening of the bypass relief, leading to things running hot. A thermostat appears to be an essential spare now that I think about it!

The whole concept of a high flow water pump without an easier flowing radiator circuit is useless from what I can figure. It's the opposite of what anyone with a SBC brain would think! As I see it, the secret to a good LS cooling system is to minimize the twists and turns between the water pump and radiator and let the parts do their job.

I'm still thinking about if I can get away without a direct radiator to expansion tank connection. Keep in mind the JEGS tank instructions are for a SB Ford, so they may not be exactly correct for an LS. The primary issue I am seeing is when the engine is cold (when you would normally fill the system), the thermostat will be closed so flow may be restricted. The vacuum fill should eliminate that concern for the shop, but it's the refill with cooler and swamp water scenario I gotta keep in mind. Can't just yank the thermostat when she's giving you trouble or you will overheat!

 

[12ftgso480]

I came up with a couple graphics that I hope explains the LS cooling system. I made them for me cause this system has thrown me for a few loops getting it straight.

The LS thermostat has 2 functions:
#1 is Thermal portion that blocks pump inlet when the engine is cold.
#2 is relief valve portion that opens when cold and meters radiator flow when hot.

When the engine is cold, the thermostat blocks the pump from picking up coolant from the bottom of the radiator. Nature abhors a vacuum so the relief valve at the end of the thermostat holds back pressure, but something's gotta give, so it opens and feeds the pump. The point is when it is cold the engine cooling system circulates coolant through the engine, but it is blocked off from the radiator. This solves an old SBC problem where engines would overheat before enough coolant got to the thermostat to open it up. The old circuit required a bypass of some kind so the thermostat would actually see the hot temps (bypass in the block, from the pump or with holes in the thermostat).

The LS system, on startup coolant re-circulates at full flow through the engine, with the thermostat in the loop. As soon as the engine reaches operating temp, the thermostat can react and open. At this point the pump can finally breath and start pulling coolant from the radiator. That thermostat relief valve is equally important here. If the relief opens it will divert hot coolant back into the pump inlet. The relief valve has to stay closed now so all coolant can route out the top of the pump to the top of the radiator.

So here is the critical part, you don't want to restrict the flow from the top of the pump back to the radiator, or through the radiator and back to the pump for that matter. The pressure relief in the thermostat regulates the amount of pressure that you got to push however much flow the pump makes through the radiator vs. dumping hot coolant back through the Engine! Routing full size coolant lines through a bunch of 90-degree fittings just to get to a high side tank and then back down to the radiator is a great way to add back pressure, leading to more opening of the bypass relief, leading to things running hot. A thermostat appears to be an essential spare now that I think about it!

The whole concept of a high flow water pump without an easier flowing radiator circuit is useless from what I can figure. It's the opposite of what anyone with a SBC brain would think! As I see it, the secret to a good LS cooling system is to minimize the twists and turns between the water pump and radiator and let the parts do their job.

I'm still thinking about if I can get away without a direct radiator to expansion tank connection. Keep in mind the JEGS tank instructions are for a SB Ford, so they may not be exactly correct for an LS. The primary issue I am seeing is when the engine is cold (when you would normally fill the system), the thermostat will be closed so flow may be restricted. The vacuum fill should eliminate that concern for the shop, but it's the refill with cooler and swamp water scenario I gotta keep in mind. Can't just yank the thermostat when she's giving you trouble or you will overheat!


View attachment 98406


View attachment 98408

Well said sir !