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Intake Manifold Water Lines
Posted: Thu Feb 04, 2010 9:56 pm
by 71 Nova
What are the water lines running front to back on each side of the manifold on this SBC for? I assume they are for pressure equalization or ??? Are they worth adding to my small block? My intake has the bosses for them...
Re: Intake Manifold Water Lines
Posted: Fri Feb 05, 2010 8:14 am
by vegaracer
I think there to help the rear cylinders cool better. I've also seen just the two rear bosses connected together.
Re: Intake Manifold Water Lines
Posted: Fri Feb 05, 2010 11:00 am
by 71 Nova
Do you have them on your SBC?
Re: Intake Manifold Water Lines
Posted: Fri Feb 05, 2010 2:51 pm
by 1720
We have them on our 357, carried over from a 400 block based 377 that expired a while back. They are supposed to reduce air pockets forming in the heads,according to "experts".
Re: Intake Manifold Water Lines
Posted: Fri Feb 05, 2010 9:45 pm
by vegaracer
71 Nova wrote:Do you have them on your SBC?
Nope. I've thought about it, but have never followed through with it.
Re: Intake Manifold Water Lines
Posted: Mon Feb 08, 2010 9:14 am
by invegarating
I use them on my SBC but it is a street car and yes they work well,I was told that the tubes let the water that is "trapped" in the rear of the block escape to be cooled [i
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Re: Intake Manifold Water Lines
Posted: Mon Feb 08, 2010 2:18 pm
by wikd69
Almost everyone I talk to running a BBC making good HP has similar questions: How do you manage the heat ?
I ran a small AN-3 line from a waterjacket cross-connect in the back of the block forward to the outside of the thermostat housing. This pretty much 'fixed' the issue I had of boil-over with my blower build. I found that if I lifted the cap and puked water, I was in for even more problems thereafter. Adding this vent line allowed any air/steam/vapor trapped in the top/back of the block to be pushed into the top of the radiator keeping a solid slug of water in the block. I also use a Moroso high volume/fast acting thermostat up front which allows a fair amount of bleed even when closed.
The AN -3 lines and the 'leakage' through the thermostat is just enough to act as a permanent air bleed, but not enough to compromise cooling or prevent the engine from maintaining heat in the block. One mistake I made was going with a really heavy-duty Fluidyne 3-core radiator - it's so thick that it's a challenge getting air through it. I finally got the fan shrouded fairly well, and that made a big difference as well.
The pix below show how things are plumbed. I'm pretty happy with the end result.
