Auto vs. Marine - SBC Vortec

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Strange water cooling from intake water jacket to starboard exhaust manifold

I notice this strange cooling line to starboard exhaust. What the heck.

It looks like a 3/8" stainless line that is adapted from 3/4"NPT at intake manifold in cooling crossover between the intake runners for cylinders 4 and 6. It runs over to the starboard exhaust manifold.

Edlebrock intake does not have this feature or at least one I could use thats in same location. Anyone know what options I have for reconnecting to edlebrock performer?

I wish I could post a picture of it.

Any help would be appreciated

 

Are you sure its water. I would have though that it should have gone to both sides if it was.

3/8 is also a bit small to do anything.

I personally dont know what that is, unless its some wierd EGR. I would discard it and try it with out.

 

Here is a picture of the line. I hope that is.

http://www.boatdesign.net/gallery/showphoto.php?photo=7857

 

That looks more like an EGR line than a water line. It's not in the right place to tap into water, for one thing. Unless someone can tell you for sure, the best way to find out is to unscrew it and see what's on the inside. Do you have an EGR valve on the motor? Maybe at the back of the manifold?

I can also see what looks like an identical fitting on the other side of the throttle body.

 

Well I dont know what that is. It does look like an exhaust gas recirculator but why. An EGR is for a catalitic converter.

You gotta see whats inside. Ille bet Gonzo would know.

 

EGR has a couple of benefits. It's primarily for emissions, but doesn't have anything to do directly with the cats. By introducing a measured amount of burnt exhaust gasses into the mix, you can lower combustion temps and reduce the formation of NOx (smog). It also has the property of reducing detonation, again through lowering of combustion temps. It's normally shut off at wide open throttle, so there's no power lost.

A bad EGR valve can cause a rough idle.

 

Why just one manifold?

I question what port in the SBC head is in the middle which is where this taps into intake.

I will scope it out this weekend.

Wonder if mercurypartsexpress.com would help?

Gonzo?

Your services are needed here so feel free to step in at any time.. LOL

Thanks all

Kevin

 

OK Looks like line has exhaust on both ends.

Also looks like line is flexable steel.

I used chrome plated steel 3/4" Pipe thread plugs to plug holes.

No EGR valve found. Again I say, what the heck, when did they start
putting emisions in boats?

Strange

 

Forgot to link image of line.

http://www.boatdesign.net/gallery/showphoto.php/photo/7863/cat/500/ppuser/15445

 

Just completed the engine swap. and she purrs like a kitten.
The engine was a 5.7 litter pulled from a 1999 C-3500 work truck with 106,438 miles and tired. Wow have I learned a lot. I believe 1999 is the last year the 350 is available but they sure have perfected this little mouse motor.

Stock - Vortec heads.
Stock - 1 piece crankshaft seals
Stock - Inconel exhaust valves
Stock - Roller hydraulic tappets
Stock - Brass freeze plugs
Stock - 4 bolt mains

Any way I chose the Competition Cams Extreme marine XM270. with its recommended springs. I had to have the heads machined to accommodate the larger diameter inner and outer springs. I replace the roller lifters with new factory type.

Pistons. .030" over stock flat top cast. 9.7:1 calculated compression. *Weight delta less than 2 grams each
Rods - .010" over Weight delta less 2 grams
Mains - .010" over

Crank, Pistons, rods and harmonic balancer spin balanced.

Heads stripped, smoothed the casting roughness from ports and matched intake the same. Intake manifold is Summits cheap $119.00 Vortec type manifold but port matched to heads and high polished in accessible areas. *Both Edlebrock RPM and Performer as well as summits own manifold are not ready out of the box. A lot of time and material had to be removed to even get is close to the size / shape of vortec head ports.

I used an old carter AFB 600CFM marine (Weber) I won off of E-Bay for dirt cheap. I believe they are call edlebrocks now.

I met my 2K budget and estimate about 340 ponies. Not bad for all stock and best of all she started immediately with very little timing adjustment.

Question: What is the recommended procedure for high performance marine engine break in.

I am used to flat tappet camshafts and am told rollers do not care if engine falls below 1500rpm during break in.
So I assume my first start and run time was correct by running at 1000rpm for about 15 minuets and shutting down for the night. I saw another post where they baby it for for first 1 hour and then change the oil. Isn't this a little much? why not wait until the 20 hours are up?

Would love to hear response

Thanks

 

It's true, rollers don't need the same break-in period as flat tappets. The only break-in my engine builder recommended after I had my block machined for the forged pistons was to keep the revs below 3000 rpm for a few heat cycles to break in the springs and to change the oil after 500 miles.

 

That line heats the intake manifold for better fuel voporization, the pre-vortec heads have the crossover through the castings. Vortecs do not have that crossover, so they use that pipe to feed the heat over.

 

So you think it's a heat riser?

 

Thanks for the information. I was wondering what it was for. Any problems not using this feature? I now have an aluminum intake with no port to plumb in heat tube.

Engine runs fine without it. Thoughts?