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[jayb]

All right!  Physics jokes! 

[TomP]

That is pretty cool. Compact. And if the air cleaner can't hold the boost it just acts as a blowoff valve. No big deal.
 There was a stud rocker conversion that was sold by John Haskell in the 80's . He was in Tacoma.

[Hemi Joel]

".........center carb studs to hold all that boost pressure! and confirmed at 5-6psi"... Been there done that - decades ago the steel 18" dia lid of a very low pressure (measured in inches water column)  filter housing deflected and leaked on an industrial blow through housing decades ago but it sure taught me..  I suck at math but think there's over a square foot of surface area on that filter housing lid exposed to pressure. Correct me if I'm wrong but the base* I presume is also subject to seeing boost pressure that could nearly double the effective surface area subjected to boost.   *(Note: This is the physics realm I get confused comprehending)

 For simplification lets just run the figures on one (1) square foot of lid: 144x5psi= 720 pounds of force working on separating the lid --- that's being ultra conservative..  Carb studs?.................


 
Re: "With that air cleaner not welded, or bolted together, that only leaves the center carb studs to hold all that boost pressure! Yikes! I'd imagine he can't be running for than just a few pounds of boost, max. Still a really cool looking combo, and looks very nicely done."

 I was thinking the same thing. But I'm just a lowly former Trunk Monkey, and I didn't take physics or phy-ed. Can somebody explain why the above mentioned formula isn't so?

[jayb]

That formula is actually correct.  If the pressure inside the air cleaner is 5 psi, it will apply 720 pounds of force to a one square foot surface.

[Qikbbstang]

I witnessed two epic screw up's from what most consider surprisingly mild pressures or vacuums. A truck driver failed to "vent" the Stainless Steel dairy tanker trailer's tank, started pumping out the milk/cream. The tanker imploded in the parking lot like an aluminum can. What's can a measly 14.7PSI @ sea level do under vacuum.

  Another classic an engineer on a boiler's conversion to a dual fuel project for a steam turbine power plant started screwing around  in the Control Room with the speed controls of the three enormous fans that force air into the boilers, pull it out and send it through the scrubbers and out the smoke stacks. The alarms sounded, the regular plants operators said: Hey what are you doing?..... I know what I'm doing, was the reply... I witnessed the well over 100ft long x 15-20 ft tall steel walls of the boiler bowed in 3-5 feet. The repairs to the boiler exceeded the contractor's bid "for the entire conversion job" ... Last I heard that engineers new job has him saying: Do you want fries with that?..............

 

[Drew Pojedinec]

That formula is actually correct.  If the pressure inside the air cleaner is 5 psi, it will apply 720 pounds of force to a one square foot surface.

Technically correct.....
In this case tho practically irrelevant for a few reasons.
He has two blow off valves being the big one.

[Joe-JDC]

Don't forget the suction of the engine drawing air into the carburetor is actually creating a low pressure area, and the boost is only theoretically 5 psi above atmospheric pressure.  The engine is drawing/ingesting all its air through that bonnet.  Joe-JDC

[cjshaker]

The blowoff valve only opens at a set point, and if that set point is 5 psi, then you still have that full pressure on the area. The boost readings aren't theoretical, they are actual pressure readings from sensors. But there's only one way to see if it's going to work....yeehaw!

[Drew Pojedinec]

You guys crack me up.
You'll lift a 850lb engine with four carb studs.
But containing 5psi of air pressure with two carb air cleaner studs and everyone loses their minds :-)

Worst case scenario is he hears a squeek at WOT and says "ohh geez, I have a minor boost leak, guess I gotta make this part stronger."
I'm fairly confident that the kinda guy that can fab up those manifolds and air cleaner and can figure out how to adjust as needed.  That's hotrodding.

(btw, Detroit diesels have been containing far larger amounts of boost pressure with 16 gauge sheet metal and a 5/16ths bolt for 50 years in service)

[Qikbbstang]

Crack you up or not I believe those  5/16ths bolts and 16 gauge sheet metal plates go on an air-box of a Detroit diesel or is that EMD"s?

[Drew Pojedinec]

Detroit use sheet metal on the air box.  so?

[Cruisin63]

Proof load on a single 1/4-20 grade 2 all thread is 1750#, and there's 2 of them. If anything, I could see the bottom lid flexing near the ends and leaking boost. As Drew said, if it leaks, I'll change it.

[nhsohc]

Just to be clear; Detroit Diesels don't really use the "blower" to pressurize the air boxes rather the Rootes type pump is used to scavenge the exhaust out of the cylinder through the open exhaust valves, w/ fresh air which is introduced through the cylinder ports which are uncovered by the piston at the bottom of its stroke.  The original manual for the 53 Series (don't have a 71 series) shows that the air box pressure w/ maximum exhaust back pressure should be in the range of 4-4.5psi for a non-turboed engine.  So on startup, there is little to no pressure in the air box.  If the exhaust back pressure is lowered, the air box pressure lowers too.  Turbo engines can see 18psi+ in the air box, but they have stronger parts associated with the addition of the turbo.  Just another piece of useless info, sorry. 

[Drew Pojedinec]

Yes, and they have airbox drains too that vent excess pressurized air, oil and debris..... (that are normally clogged)
But there is a massive difference between what happens in a paper manual and what happens in reality when you hook a pressure gauge up to something.  (which is much of what this thread is about). 

Oh and the turbo 71's and 149's all use the same air box covers as the naturals.  Might be different for 53's, I don't get to play with those as much.

[jayb]

Proof load on a single 1/4-20 grade 2 all thread is 1750#, and there's 2 of them. If anything, I could see the bottom lid flexing near the ends and leaking boost. As Drew said, if it leaks, I'll change it.

What you mentioned there is the only thing I'd be concerned about; certainly not the fasteners.  Its a good idea to have a plan in place to address that, because even at only 5 psi I think there's a good chance you will deform that flange and leak some boost.  Of course, you might be able to get away with a leak there as long as its not a big one.

On my supercharged FE, running between 10 and 17 pounds of boost, I've blown some aluminum tubing out of the rubber connecting hoses with rather spectacular results...    Found out the hard way that you need a lip on every piece of tube, to make sure that the rubber can't slip off under boost.  I ended up welding a lip on some pieces of aluminum tubing to solve the problem.

Really cool project, by the way...