Auto vs. Marine - SBC Vortec

[Beech2000]

What are the main differances between Auto aluminum intakes and Marine.

I am having trouble keeping the budget under control building a 5.7 liter removed from truck and entertaining the idea of using non emision aftermarket intake auto type. Any concerns?

Note boat usage is used in fresh water only.

[Frosty]

The difference is auto is better and cheaper -- exellent idea and the way to go.

I have done this myself to a chevy block mercruiser, An Edelbrock dual plane for 4 wheel drive torque. The best money I ever spent.

[Beech2000]

The difference is auto is better and cheaper -- exellent idea and the way to go.

I have done this myself to a chevy block mercruiser, An Edelbrock dual plane for 4 wheel drive torque. The best money I ever spent.

Thanks. That's exactly what I wanted to hear. What do they cost and whats the best place to purchase?

[Frosty]

No Idea how much they are today. This was in Uk years ago. Absalutely no idea where to get one in the states.

Stone breaker will no doubt be along shortly and tell you exactly what you need to get.

[jimslade]

Marine aluminum intakes are bronze lined, automotive is not. As long as you Never run in salt water you should be fine. Aluminum will not last as long as cast. Just make sure that you use a marine cam and engine gaskets.

[Frosty]

To be honest I just cant imagine any one running raw water cooling systems these days.

[Beech2000]

Jimslade,

Bronze lined. Yeah, I do remember running across a marine intake lined with bronze but remember it being almost 800 USD on some website. Ouch!
I can buy 4 auto manifolds for that price. A new one every two years and still would be ahead. I do know about the gasket needing to be stainless. Received camshaft education from stone in another thread.

Jack frost,
Are you speaking of closed cooling? I had this system in a fourwinds 170 with 470 engine. What a mess the engine was but liked the antifreeze coolant. I just don't think I need it with freshwater lakes around here though.

thanks for the help. Will look for the edlebrock performer.

[Frosty]

Yeah well if your only using it in fresh water and taking it home with you, it'le be fine.

[stonebreaker]

www.summitracing.com

[stonebreaker]

Marine cams (http://www.cranecams.com/index.php?show=browseParts&lvl=2&prt=5&Vehicle_Type=Marine&Cylinders=8&Engine_Make=CHEVROLET&Year=1998&Engine_Size=305-350%20C.I.)

For some reason, they list the p/n 109811 and 109831 cams as marine cams, but they didn't list the 109821 cam, which is probably the best cam of the three. It's right between the other two in terms of duration, and all the other numbers are the same.

[Beech2000]

Hey Stone,

You mentioned in a differant post that you liked the Ramjet cam from GM.
Is the 109821 similure.

I found out I can actually go for a little more radical of a cam than I thought. This late information was shared to me by a very good machine shop who took the time to call Crane with my boat information. i.e. length, engine size, prop size, and primary function of boat.

I don't think the 109821 was mentioned in my notes.

He did say the choices for roller marine were more limited than the previous generation SBC's.

[stonebreaker]

What did Crane recommend?

The ramjet cam is a good choice, and you can see its power curve on the ramjet, which has the same iron vortec heads as your engine, in the GMPP catalog: http://www.gmperformanceparts.com/_res/pdf/gm_performance_parts_catalog_2006.pdf on page 39.

ramjet cam: 196/206 dur at .050, 109 deg LSA 350 hp at 5200 rpm
Crane 109821: 214/222 dur, 112 LSA 400 hp at 5800 rpm
Crane 109831: 222/230 dur, 112 LSA unsure of hp with vortec iron heads

The 109821 cam gave my car about 50 more hp and 50 more ft/lbs of torque on similar heads, but somewhat less torque below 2000 rpm. It moved the horsepower peak upwards about 600 rpm, to 5800 rpm, although the torque peak stayed the same at 3500 rpm.

[Beech2000]

My appologies Stone,

I spoke to Comp Cams.
They recomended the following

Comp Cams PN 08-416-8
Link to specs. (http://www.compcams.com/Technical/Search/CamDetails.asp?PartNumber=08-416-8)

This cam seemed more radical then the RamJet Cam.

[stonebreaker]

Not really. It's very similar to the Crane 109821, just a little less exhaust duration. It looks like it will work just fine.

[Beech2000]

Just need the torque to be strong from 2000 to 5000.

Stone,

Is there a place to store pictures on the net.

The freind that gave me the engine wants to see its progress.

[stonebreaker]

Scroll to the top of the page, click on "boat design gallery" then on the right side just below where it says "Welcome Beech2000" click on "Upload Photos".

[Beech2000]

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

[Frosty]

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.

[Beech2000]

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

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

[stonebreaker]

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.

[Frosty]

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.

[stonebreaker]

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.

[Beech2000]

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

[Beech2000]

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

[Beech2000]

Forgot to link image of line.

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

[Beech2000]

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

[stonebreaker]

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.

[RMSOSF]

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

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

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.

[stonebreaker]

So you think it's a heat riser?

[Beech2000]

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.

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?

[RMSOSF]

Generally, it is not needed in cars because car engines run hotter than a marine engine. Mercruiser and Volvo Penta use the heat pipes because the engine runs cooler in a boat and the heat at the intake is not sufficient to completely atomize the fuel. Without the heat pipe, you will likely suffer some on fuel economy and performance. How much? I couldn't tell you, just keep an eye on your spark plugs.... if they run rich, lean out the carb some..... keep playing with it.

[Beech2000]

just keep an eye on your spark plugs.... if they run rich, lean out the carb some..... keep playing with it.


I hate pulling spark plugs out of my boat. Takes all day. What a pain. Still need to though as is is the best indication of whats going on in there.

Was wondering what the heck that tube was for.

Anyway now have 4 hours on engine and anxiously await 16 more hours breakin to enjoy results.

I did throttle up to 5000 for a second or two. Any problems?