Vortec Coolant Bypass - Can't you just drill a hole in the head?

[K5ride]

I'm installing some Summit Racing vortec heads on my 75. I've read and searched a lot regarding the coolant bypass issue. Many different opinions and experiences, along with a lot of misinformation. I don't wish to debate whether or not one is needed and for my application, I have decided to use one. The question I have is why people don't just drill a hole in the head to match the factory internal coolant bypass that is in all the pre 96 blocks? It seems this would correct all the issues and not have to run the coolant hose from the intake to the water pump. Am I missing something? Has anyone done this? Thanks for the input.

 

[77 K20]

Well- at least for myself drilling into a brand new head and being unsure of measurements is enough of a deterrent.

Cheaper and easier to run a bypass hose or just drill some holes in a $10 thermostat.

 

[K5ride]

Well- at least for myself drilling into a brand new head and being unsure of measurements is enough of a deterrent.

Cheaper and easier to run a bypass hose or just drill some holes in a $10 thermostat.

I have the measurements. I can just use the head gasket for a template and drill the same size hole as the gasket has. The thermostat holes are not nearly as effecient as a bypass. I plan on running a bypass, either in the head or a coolant hose from the intake to water pump like GM states is required.

 

[77 K20]

Drilling the head should work- I'd just be too chicken.

And the coolant bypass can be difficult depending on what water pump and what intake manifold you have. When I first tried the hose bypass the GM performance intake manifold made it very difficult to hook everything up. (location and size wise).

This was when I was test fitting a hose bypass:

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I couldn't use the other port near the thermostat as I needed that for the intake coolant temp sensor for the fuel injection.

I bought some fancy silicone hose. It kept seeping.

 

[K5ride]

Drilling the head should work- I'd just be too chicken.

And the coolant bypass can be difficult depending on what water pump and what intake manifold you have. When I first tried the hose bypass the GM performance intake manifold made it very difficult to hook everything up. (location and size wise).

This was when I was test fitting a hose bypass:

You must be registered for see images attach

I couldn't use the other port near the thermostat as I needed that for the intake coolant temp sensor for the fuel injection.

I bought some fancy silicone hose. It kept seeping.

Wow that looks real tight to get the hose on. I'm sure my Edelbrock manifold will be the same. I think I'll call the local machine shop and get some advice before I do anything I may regret.

 

[bucket]

Drilling the head should work- I'd just be too chicken.

And the coolant bypass can be difficult depending on what water pump and what intake manifold you have. When I first tried the hose bypass the GM performance intake manifold made it very difficult to hook everything up. (location and size wise).

This was when I was test fitting a hose bypass:

You must be registered for see images attach

I couldn't use the other port near the thermostat as I needed that for the intake coolant temp sensor for the fuel injection.

I bought some fancy silicone hose. It kept seeping.

Why not just use the lower, forward facing port for the temp sensor and the one next to the thermostat for the bypass?

 

[bucket]

Now that you fellas pointed out that there's no bypass hole in the vortec head and it's not just the block/water pump surface like I originally thought, I have so many questions.

If drilling a hole in the thermostat and running a standard heater system is not a sufficient bypass, how do so many people, such as myself, get away with it? What did GM do with the original vortec-headed crate motors that used a standard block and water pump? The single outlet on the water pump must be used for a heater if there is no port on the radiator, which most cars don't have. Did GM drill the hole into the head on the early crate engines? Now I also wonder about the current crate engine offerings...


P.S. I deleted the duplicate thread.

 

[K5ride]

Drilling the head should work- I'd just be too chicken.

And the coolant bypass can be difficult depending on what water pump and what intake manifold you have. When I first tried the hose bypass the GM performance intake manifold made it very difficult to hook everything up. (location and size wise).

This was when I was test fitting a hose bypass:

You must be registered for see images attach

I couldn't use the other port near the thermostat as I needed that for the intake coolant temp sensor for the fuel injection.

I bought some fancy silicone hose. It kept seeping.

Did the vortec heads make a big difference? Is it worth all the $$? Would you do it again? I've already purchased everything but just wondering if regular gen 1 aftermarket heads would do the same without the bypass headache and expense of the new intake manifold.

 

[K5ride]

Now that you fellas pointed out that there's no bypass hole in the vortec head and it's not just the block/water pump surface like I originally thought, I have so many questions.

If drilling a hole in the thermostat and running a standard heater system is not a sufficient bypass, how do so many people, such as myself, get away with it? What did GM do with the original vortec-headed crate motors that used a standard block and water pump? The single outlet on the water pump must be used for a heater if there is no port on the radiator, which most cars don't have. Did GM drill the hole into the head on the early crate engines? Now I also wonder about the current crate engine offerings...


P.S. I deleted the duplicate thread.

I've read that "getting away with it" depends on a few factors. If your talking about the temp gauge, there are multiple sending units with different specs and installation locations both in the head and manifold. Some have managed to get their temp gauge to quit fluctuating but still maintain the hot spots in the passenger head which can cause damage. The GM crate engines that use the vortec heads do not have the hole drilled and come with a warning in the instructions that you MUST use the bypass from the manifold to water pump. I trust that GM knows about the engines they manufacture and believe them when they state a bypass MUST be used. I'm just trying to decide which bypass to use.

 

[SquareRoot]

I put vortecs on my gen 1. Ran a short hose from intake to water pump. Easy Peasy. No issues. Before I learned I needed a bypass. my temps would bounce around on my EFI and DD Fan conrtoller. Add bypass hose-boom fixed. Some say the factory heater hose acts as a bypass? I don't know but in my Vintage Air setup they use a solenoid to block off water flow to the heater core unless the heat is actually called for. Keeping hot coolant out helps the A/C cool better. To your point, why drill new heads when you can add a $10 part and fix it?

 

[SquareRoot]

My setup. FYI

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[K5ride]

My setup. FYI

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That looks much easier to hook it up that way instead of fighting the smaller hose when using the front port. Even easier than drilling holes in my head....LOL.

 

[bucket]

I know I've seen crate engines on display with vortec heads and the bypass port in the block. The early 330 hp version for sure. I pulled the following pic from Summit, which I'm assuming is from GM's own advertising. Notice it has vortec heads and even appears to be a vortec block as well (plastic timing cover, fewer bolt holes) but it has the bypass port.

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[K5ride]

The problem is the vortec heads don't have a bypass hole to circulate the coolant.

 

[bucket]

The problem is the vortec heads don't have a bypass hole to circulate the coolant.

That's what I'm trying to determine for sure. Why would GM specifically drill a bypass into a vortec block but not the head? If they did actually do something like that, what about all the people without a heater hose port on the radiator? How are they supposed to run a heater and a bypass hose from the water pump if there is only one port? Vortec headed engines are a super popular swap, where's all the people with a rigged up bypass hose and a heater hose T'd in? Do they just all have temperature swings and nobody complains about it? Why don't my own two engines have temperature swings?

Like I said, I've got so many questions now. It's just as well, I'm currently sitting in a hotel room 600 miles from home and nothing to do, at least now I have something to research.