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Author Topic:   External water lines
posted January 05, 2004 02:44 PM
Did a search on this, but didn't really find what I wanted. As I read it there's 2 ways to externally plumb a SBC.

1. 6AN lines from back of intake manifold up to thermo housing.

2. 8AN lines from pressure side of waterpump to center of heads (just above deck surface, but below header flange).

Question: Can both of these be done together? Is this effective on cast-iron parts? Or is this an aluminum head only option? And the most important question, does it help?


posted January 05, 2004 06:38 PM           
3. plumb from water pump to the sides of the block between the center cylinders.

I ran water to my heat exchanger then into the sides of the block, but that was for 100 lap mains.

posted January 05, 2004 08:04 PM
He is correct, drill and tap for 3/4" pipe thread and don't run the tap in very far at all, then you can run the pump outlets into each side and then out from the manifold back to the radiator. I have seen some that are now drilling and tapping 3 holes on each side to get a better spread of the flow, but I dont know how much more that would help, not to mention create a mess of lines and fittings. Thats how I do it on my sprint motor, of course I block off the front inlets to do it that way, I also only use 3 of the 4 outlets on the injection because to use the one by the mag makes getting in there almost impossible when using AN fittings and such. I have seen no spots that have a higher temp because of this either, so it must be doin ok..
M.Harris 44H

posted January 05, 2004 09:20 PM           
M harris

Are you saying you block the water pump inlets on front. I just bought a Adams alum water pump from a winston cup used parts dealer and it has some very nice o ring plugs in it, blocking the stock water inlets 100%. Then had hose fittings out the side of the pump.

I got the idea of the side hoses from a sprinters system I didnt know that was their only water inlet though if Im understanding you.

I also ran the hoses from the rear of the manifold to the water neck.

Istock59, personally I was going to run the side hoses again, and maybe tap the rear for hoses in alum intakes. But considering the mains are usually only 15 laps I wasnt thinking it would be necessary, right away? Im also running a elect fan and alternator.

posted January 06, 2004 06:30 AM
dirtrace, I dunno if it's really necessary, but then again I've never tried it! I was thinking about just drilling and tapping the head/intake now, and putting pipe plugs in them. Then next summer if I want to try it, it's easy...

Drilling and tapping with the motor in the car doesn't sound like fun...

[This message has been edited by istock59 (edited January 06, 2004).]

posted January 06, 2004 09:38 AM
Actually, I kinda forgot about the stuff on top, obviously I run a hilborn injection which does away with the t/stat housing and all that. but, yes the sides are my only inlets, the fronts are completely blocked off. I talked to several "name" builders and the fronts actually do a poor job of circulating water to the cylinders properly and evenly, thats the whole purpose of going to the sides. I am also using a standard KSE water pump and the capacity is quite a bit more than any stock style would have. I do however believe in the keep it as simple as possible theory, if its simple its always easier to locate problems, and makes repairs or whatever easier as well.
There is another thread about watter wetter, etc... I HAVE used them all, w/ the exception of tranny fluid or fabric, but for ACTUAL cooling additives, water wetter is a joke, the only thing I found that really does work and work well is " 40 BELOW " I found it at schucks/checker/kragen... or parts america stores. Its made by pro blend. I was using this stuff about 4 years ago after trying everything else w/ no real luck. I highly recommend it for any heating/overheating issues if all else is functioning correctly.


posted January 13, 2004 08:22 PM
On the mopar site Sanborn has an excellent article on plumbing. What my question is what all applies to a SBC. I am pretty sure the reasoning behind all this is to allow the heads a chance to cool before sending the coolant straight to the block. I think he blocked off the main cooling holes between the heads and the block in the front, and left a small hole in the rear deck holes. Especially if you do this I think your required to run external cooling lines. Except I thought the best method was coming off the back of the heads not in the middle? He also has an excellent article on drilling the oil holes. Surely there has to be a reference somewhere on all this for the SBC.

posted January 13, 2004 09:42 PM           
I would go ask sanborn, hes gave me some great engine building advice, as far as cams etc, and I tell him Im a chevy guy...

posted January 16, 2004 02:02 PM
We have -8 lines running fron the back of our power plus manifold to the front of the manifold. That transfers a lot of rear heat to the radiator that may not make it as quick. Where you can make the most difference on heat transfer is to restrict the deck surface [front & rear] holes and open the middle holes of the head gasket to increase flow between th two middle cylinders. Mr gasket offers a gasket already done this way, but costs a lot more. We had a friend with a pure stock and we installed -6 fittings and lines to his stock manifold and lowered his engine temp aprox. 10 deg.

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