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post #1 of (permalink) Old 05-12-2004, 08:26 PM
DCann
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Custom Intake Question

Beatings and salivations all! Yeah, another new-b to the group starting off by posting a q.

In the works is an 86 GMC LB 1/2t ... it was born with a diesel that the PO replaced with a SB350. After he spun the mains he sold it to me.

I'm building the next SB350 for it but wanna design an external air intake for when the lake gets a bit high. The idea is to come through the firewall midpoint then up to the ceiling and back.

What I am wondering is what I should use to make the actual connection to the carb. I'm thinking of using black PVC for the remainder ... just not sure about the connection itself.

Any assistance would be appreciated!

Keep the rubber side down ... if not, have fun with it!

Don [img]images/graemlins/scs.gif[/img]
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post #2 of (permalink) Old 05-12-2004, 08:41 PM
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Re: Custom Intake Question

Maybe you could find an air intake off of a newer truck, one with TBI perhaps. I don't know, but it may fit right onto your carb.
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post #3 of (permalink) Old 05-13-2004, 12:03 PM
DCann
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Re: Custom Intake Question

Huh ... I was probably trying to get too McGyver with it and missing the obvious eh? [img]images/graemlins/smile.gif[/img] Thanx for the suggestion ... I'll try to hit up a boneyard out here and see what they have to offer.

I was also kinda thinkin on one of those solid rubber boots you can get in Lowes or Home Depot for hookin' up sewage lines at strange angles. Just dunno how the heat will effect them.

If anyone's interested in the outcome, lemme know and I'll post the end result.


Don [img]images/graemlins/beach.gif[/img]
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post #4 of (permalink) Old 05-13-2004, 01:55 PM
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Re: Custom Intake Question

I used 4" rubber PVC clamps/connector things on the home made intake of my 92 Blazer with a 350. Worked great. Like $5 at Home Depot.

How deep are we talking with the water here? Unless it's like upper headlight or hood deep and you aren't stopping in it, you should be okay with just a GM style fender cold air intake. That's what was stock on most TBI trucks and worked great. I went through ponds and puddles (heh, not really puddles but dunno what else to call them) that were 1-2' feet deep in my Blazer and never had a problem with the air intake. Shorted out the distributor once though. [img]images/graemlins/tongue.gif[/img]

Beware that running the intake into the cab will make for some interesting noises. Proven effective though.
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post #5 of (permalink) Old 05-13-2004, 03:07 PM
DCann
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Re: Custom Intake Question

Sounds to me like you ran with the idea that I was thinkin' of with the Home Depot goodies. [img]images/graemlins/smile.gif[/img] I figured it might be less expensive to do it that way.

As far as water height, here's the scenario from our last trip to Sheeps Bridge:

2 hours offroad - cross the Agua Fria river 3x enroute - vehicle was a 78 RamCharger w/a 4" lift and 36's - the water was so high in 2 of the crossings that it flowed through the open windows (after filling the interior) and the hood was not visible. This is a distinct possibility again for the next trip but that vehicle is no longer around. (It had exhaust extensions that ran to the roof-rack in the rear and one for the intake through the hood to the roof-rack as well.)

It kept on keepin on the rest of the trip except for the last 3 miles coming back out ... the fuel pump went out. (We were towed by others in our party to the main road.)

Unfortunately I didn't get much data from under the hood except when I replaced the pump, cleaned it all out and checked everything. (It was a borrowed truck)

Far as the distributor goes I am working on getting a 'Wire Wizard' that should help in sealing it up. I'm tryin to water/muck proof this whole unit as best I can. [img]images/graemlins/smile.gif[/img]

Don [img]images/graemlins/crazy.gif[/img]
post #6 of (permalink) Old 05-13-2004, 03:11 PM
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Re: Custom Intake Question

In that case your best bet is either an ARB type snorkel or something inside the cab like you are thinking.

Yeah, amazing how you can make stuff from Home Depot parts for $20 that people try to sell you for $100. [img]images/graemlins/tongue.gif[/img]
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post #7 of (permalink) Old 05-13-2004, 05:39 PM
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Re: Custom Intake Question

There is a ton of waterproofing that must be done if you plan on running water deeper than the waterpump.

We're talking:
front axle vent
rear axle vent
transfer case vent
transmission vent
PCV system
vapor reclamation system
AIR system
all electrical connections must be filled with dielectric grease
distributor must be waterproofed

Since you'll be running deep water for long periods of time...
transmission dipstick tube
engine oil dipstick tube
power steering pump overflow
oil fill
all connections to the motor must be sealed like PCV valve and breather
interior electrical



It's the main reason I won't run water deeper than my waterpump. My next vehicle might be a different story though. This one is my daily driver.
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post #8 of (permalink) Old 05-13-2004, 07:11 PM
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Re: Custom Intake Question

Thanks for your post and input!

The water that I may encounter might be pretty deep but the crossings aren't very wide (maybe 30 to 60 yards) so the time period in the water wont be extended.

I've been figuring in extensions for all of the vents as well as for the crankcase ventilation system, etc. Some are getting rather tricky, but do-able with the right amount of time, beer and duct tape. [img]images/graemlins/wink.gif[/img]

The dipsticks are actually the easiest as they can be temporarily removed and the tubes capped. The trickiest one that I've been working on is figuring out how to waterproof the alternator.

Of course, there is something to be said about a spray can of white lithium grease, WD40 and silicone. [img]images/graemlins/smile.gif[/img]

Don [img]images/graemlins/crazy.gif[/img]

Oh wait, white lithium remains flammable. [img]images/graemlins/cool.gif[/img]
post #9 of (permalink) Old 05-13-2004, 10:38 PM
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Re: Custom Intake Question

I ran bodyline deep water once and it made me nervous. If I got stopped up I'd have been stranded because of my cab electrical. The truck started to float at that depth too.

My truck is waterproofed up to the waterpump. Some other stuff is waterproofed higher but I still have crankcase vent problems, air intake problems, and a distributor that is splash-waterproofed but not submersable waterproofed.

The vapor system is often one thing that people always forget about. It runs off your PCV system and cleans out your air cleaner and your gas tank. You have to have a vent for your gas tank to get air as you pump out and if you're running deep water you're going to want a positive-locking gas cap to keep water out.

I wouldn't worry about the alternator too much. Just keep a spare with you. You're going to be burning up front bearings and rear bushings all the time. I go through an alternator about every 4 months.

As far as dipstick tubes go, I was talking about down at the rubber seal on the transmission and the press-fit into the block. I'd RTV both of those. If you've got a good rubber seal on the dipsticks themselves I wouldn't worry about them.

I'd consider setting up a system so you can turn off crankcase vacuum when approaching the water as to avoid the potential for sucking water into the crankcase through leaky gaskets. You'll still have the breather problem though.

I don't know, these are all things I've been considering as I've been thinking about building Fugly 2.0 which is my intended trail rig.
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