best bang for buck coolant bypass?

[thisguy65]

I've been looking at these after a few friends experince with their 5.0 mustang (coycote motors) where they would pop due to a lean condition in the ECM programming and that rear cylinder being the hottest. I saw the fleece kit and while it's very nice, for what I'm doing it's out of price range.

I did happen to find this guy
Dodge 5.9L Cummins Cylinder #6 Cooling Kit Improves Coolant Flow

I assume it can be installs to the port can face the driver or passenger side.
Just run a line from the rear of the block to where the metal heater hose bolts to the thermostate housing.

any other ideas?

[jimbo486]

Many here have built homemade bypass kits using a Watts 530c adjustable pressure relief valve that dumps into the upper radiator hose. There's another relief valve others have used that you can buy at fixed pressures. I think it's Aquatrol.

I recently built a bypass kit for my engine. I bought a 94-98 thermostat housing, used a Keating Machine billet rear plate, stainless tubing, compression and misc. fittings, the Watts LF530C valve set at 50psi, a stainless braided hose to run the length to the thermostat housing where it would dumps/relieves pressure.

[thisguy65]

Very nice!

Why is a pressure relief valve used and why not just let it circulate?

What paint did you use for your block? How has it held up?

[jimbo486]

I asked that question here before I put mine together and what comes up is that it's somewhat dependent on what you plan to do with the truck. What kind of RPM range the engine will see. Usually, just replacing all of the large expansion plugs in the block with billet pieces is the remedy to preventing a blow out. At that point, I suppose a bypass may not be necessary anymore. Others might have opinions and reasons why it is.

Even though I installed billet freeze plugs, my thinking shifted to the concern of coolant flow. Which is when I began asking which was most concerning; relieving pressure, promoting flow or are they both important? Pressure seemed to outweigh flow. My thinking is that if enough pressure does build up prior to or after the thermostat is opened, the valve opens and dumps some pressure while simultaneously allowing some coolant flow until the valve closes again. Granted, it's only through a 1/2" hose and ultimately a 1/4" NPT fitting into the thermostat housing so the volume and rate may be small and not continuous.

Majority of the time, a pressure relief is used because of the rapid expansion from heat in the system around #5 and #6. As you're probably aware, the circulation of coolant lacks around those 2 cylinders. From the rapid expansion, excessive pressure is possible. Especially when running the engine hard when not up to normal operating temperature with the thermostat still closed. Expansion plugs can and have blown out.

I had the shortblock rebuilt by a machine shop and I don't recall what paint was used, other than a gloss. It just went back together last week so no telling yet how well it'll hold. The shop tells me it holds up good from what they've experienced.

[thisguy65]

The valve is just to dump pressure ahead of the thermostat, see and understand that. However, why not just run it with out, there will be a constant flow (small a mount) Might take a half of a mile more to get warmed up completely but there is always something bleeding off.

[95cummins5.9]

The engine won't build good heat with it constantly bypassing the stat.

[wildbill144]

What did you do to the block side where that jiggle valve was.

[wildbill144]

wow are you supporting it across the manifold. im trying to figure this out my self

[thisguy65]

Originally Posted by 95cummins5.9

The engine won't build good heat with it constantly bypassing the stat.

I would think it would. The amount (volume) that would be going through a 1/4npt is pretty small. Then add pressure and volume decreases, by passing only thing doing is giving the pressure a means of escaping before building up to pressure.

Originally Posted by wildbill144

What did you do to the block side where that jiggle valve was.

Jiggle valve?

[gman99]

I built this for my coolant return. I used the same rear plate and Watts valve. The main difference is my setup isn't fighting the flow of the engine at the thermostat housing and maintains a full 5/8" all the way through the system.

Bottom line his is prettier; mine flows more. Whether or not that makes a difference is anyone's guess though.

[thisguy65]

Originally Posted by gman99

I built this for my coolant return. I used the same rear plate and Watts valve. The main difference is my setup isn't fighting the flow of the engine at the thermostat housing and maintains a full 5/8" all the way through the system.

Bottom line his is prettier; mine flows more. Whether or not that makes a difference is anyone's guess though.

Did you notice your motor taking longer to warm up?

[Redrider2911]

Originally Posted by thisguy65

Did you notice your motor taking longer to warm up?

The Watts valve will only open with excess pressure... Usually you wont have excess pressure during warm up because you will be keeping the RPMs down.

[Financial Mistake]

Mine is almost the same as Jimbos, just not quite as refined because I suck at tape measure and have been too lazy to shorten the lines.

I run all engineered diesel freeze plugs, including the rear plug with the 1/2" outlet, into a watts 530c regulator, thru -10an line, and into a engineered diesel thermostat housing spacer with a 1/2" inlet. I honestly can't remember if I have my thermostat before or after the bypass, but I'm pretty sure the bypass bypasses the thermostat, but can't say with 100% certainty.

I run dual derale fans on a toggle, that I never use since the one thing dodge did right was implement a good cooling system, that just having air run thru the rad period keeps the engine well within operating temps. I stay around 185-200° even in stop and go traffic in N Texas heat.

So, no, no problem getting the engine to warm up, even in the dead of winter, all 2 weeks of it.


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[jimbo486]

Originally Posted by wildbill144

What did you do to the block side where that jiggle valve was.

What's this jiggle valve you speak of?

Originally Posted by wildbill144

wow are you supporting it across the manifold. im trying to figure this out my self

No support along the manifold.

To add a little more info, the stainless braided hose was a custom piece ordered through and made by Swagelok. They have a premade hose listed on their website with the correct length and fittings I wanted but it had to be custom made, for reasons I can't remember. It has tube adapters (for compression fittings) crimped at both ends. That alone was about $95. All of the fittings, excluding the PRV, are stainless which added to the overall cost as well. I don't like rust.

[biggy238]

Jimbo, what brand are the compression fittings you used? I just installed my Fleece kit and the soft hose is kinked from the poor bend radius (I bought it used so I can't blame them much) and the metal tube is the solution I arrived at also.

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[joefarmer]

Originally Posted by biggy238

Jimbo, what brand are the compression fittings you used? I just installed my Fleece kit and the soft hose is kinked from the poor bend radius (I bought it used so I can't blame them much) and the metal tube is the solution I arrived at also.

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Discount Hydraulic Hose I plumbed my last dual CP3 setup using most all hardline with their parts and a flaring tool.

[jimbo486]

All of the fittings I used are Swagelok. They use dual ferrules, a front and back. I have an assortment of them in a Rubbermaid container in my garage.

[biggy238]

-8, - 10?

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[jimbo486]

1/2", -8.

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[wildbill144]

Sorry thisguy65 I just saw you ask about the jiggle valve, funny name but that's what the service manual called it, its the one way brass fitting that the small hose that comes off the thermostat housing to the manifold go's to. It bleed's off excess air pressure, If you have it off shake it up and down and you'll hear the valve inside jiggling, guess that's where the name comes from. Lol..