Projects Building a Blower Manifold.... that's the plan anyhow.

I have a 401 Buick Nailhead sitting around with a 671 blower and the keys to a machine shop. I'm really at the "bench racing" stage and wondering what advice or suggestions you guys can offer as I begin to design and build a manifold to mate the motor and blower. My goal is to have a "street" motor that won't be angry about highway miles, not so much a "race" motor.

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They don't seem to be too picky....a plenum, maybe raised in the center. Ports on the nailhead have to be at about a 45 degree angle, eh? although the mounting surface is flat.

this is a BBC Blower Drive Service intake from 1990.

 

just find a 2x4 manifold and make alum plate for the top, that was how the dyers set up came

 

32v hit the nail on the head

 

Just buy one Imperial Speed sells them for $500 or so. (6-71) even on evil pay they are cheap,

 

that's a lot of money to spend, when a guy could be making one, and learning a whole lot in the process

 

Yup..... Easy for some people to spend other people's hard earned.

Make the plenum equal to the height of the intake ports. That should work fine.

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I definitely don't want to modify a 2x4 intake and I really need to sharpen my heliarc skills on something. I also have a bunch of cool parts laying around doing nada. It seems like a fairly straight forward thing to make, and I figured if anybody had some good advice it would be here. I guess I'll have to drag that motor over by my bench and get to work.

 

Check out the intake manifold spacers Dashmans sells for Buicks. Something like those could be a good start and with machine shop availability those can be pretty easy for you to make. Add some aluminum square tube runners and a fabricated plenum and you're good to go.
Think about rigidity, a pop-off and at least a 1/2" thick plate to mount the blower.
I make it sound easy, but with the Buick horizontal intake port layout and valley cover it really is easier than many other engines.

 

When building an aluminum manifold the trick is to build it oversize and machine it down to fit, not doing that and welding machined parts, the manifold shrinks and the holes will not line up anymore

 

Will need a bit of shape to it with the blower being wider than the valve cover rails. Also some sort of a pop off valve. At least the intake runners are straight up and down and no water ports. Can probably center the blower front to back as long as there is no interference with distributor, etc. Maybe a two piece billet or welded box.

A few examples to study.

https://www.jalopyjournal.com/forum...-falcon-futura-with-a-nailhead.427930/page-18


https://www.jalopyjournal.com/forum...64-nailhead-1932-studebaker-cabriolet.979288/


http://www.hellsgatehotrods.com/int...uick-nailhead-401-425-blower-intake-manifold/

 

Matt, I'm going to call you when I bring the motor in. You need to come down to the shop anyhow.

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make sure you use a good sized pop off valve, instead of one of those little modern ones.

 

Will do.

 

"Good sized".... that's my kind of measuring!

 

the old Weiand intake on my chevy II has a nice big one on it.

 

I'll have to make one like that except with Nicky on it...

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Hi there I saw a 671 blower adaptor plateon Ebay recently that bolts to a 315/325 Dodge Hemi twin four barrel Offenhauser manifold, I think it was originally made by Bob Walker @ Power Play, which I think became Hot Heads , you might be able, to use/modify this adaptor? Or make cast your own adaptor? other wise fabricate a sheet alloy blower manifold, up to you which route you go, all the best

 

Hello,

For something as critical as a cast blower manifold that is going to be under a ton of pressure and power, would you want to make your own without proper testing facilities and preparations? We all have seen manifolds for sale by speed shops and it seems very simple. But, those manufacturers have done their homework in the design, testing and rebuilding until they get a great product that won’t cause any problems.

Your machining skills, your machine shop set up, your casting process, building products, all need to be hospital clean and safe. Bubbles that you cannot see in a final casting, create interior holes that cause problems later. Those big manufacturers have techniques to spot check those errors.

Unless you have the million dollar facilities like Edlebrock or Weiand to make these, it may not be worth it to say…”Hey, I created my own blower manifold.” There are too many variables to consider to make a great trouble free product.

Normal, molten metal, casting of small projects usually requires a lot of prep and finish techniques, but they are not subject to tons of pressure created by the 671 and injectors/carbs. So, a bubble or two will not be a total defect that makes the product useless, unless of course, it is a surface blemish. Then the whole process has to be completed over again to have a great, retail product for sale.

Jnaki

Why is there a pop off valve inserted in those big manufacturer’s products? That must tell you something. The tech inspection requirements for blower blankets and cover straps also should give one a clue as to how much power these things are going to create.

But, one thing a 671 will do to a motor is make it sing with so much more power than just a carb set up. Check out the Hampton, Littlefield, or places like BDS, set ups for your Buick. They have been in the business for years with tons of research and build experience.

If we were rebuilding today, gathering the safe, proven products would be the first step for a 671 motor build. Safety first…

 

Street engine....

Check out this 471 intake Ross Racing Engine built

See post 49 and 50
https://www.jalopyjournal.com/forum...stored-or-custom-engine-builder.628121/page-2

 

I do this sort of stuff for a living. The manifold won't be cast. It won't be for sale either, it'll be a one off just for me. We have the tools and technology to make a 1936 Buick with a straight 8 go over 160 mph at Bonneville, I reckon we can figure out a fabricated blower manifold.

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Not saying a thing about you capabilitys, but another thing that must be done with a fabbed manifold (for the people reading this) is that after building oversize the weldment must be heat treated back to T-6 condition as all the welding brings it to O (soft) condition. Belt tension and/or lean bacfire, torqueing bolts will warp the flanges. There are reasons fabbed Hogans Manifolds are $2500/$3000

 

Wow. ^^^^ Ross Racing Engines' intake. Sheez'. Try finding one of those for an aluminum Buick 215/Rover engine. Missed a Cragar and an M/T because $$$$$$$$$$ (!!!!!) .

Good luck Nick, in whatever you do. Love your adventures here, thus far. Awesome stuff.

 

You got that right. I have given up on using a blower. To match any of the blowers that I have, to any of the engines that I have would require a manifold that would cost more that the entire car that the engine would go in.

 

So... build it like a tank and have it heat treated? Seems easy enough. This is the sort of stuff I don't think about.

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Some of the issues Ive had to fight with building one off manifolds, the shrinkage and warping is a big issue, and had a racer friend who had built his own manifold, bend the blower flange after 3 passes. I had to take a tall deck intake and split it to shrink it down for a short deck. big problem was that it was already finished machined. welded it without 065 gaskets, shrunk so much that I had to slot the holes and use 125 gaskets

 

Bruce,

When you say your friend bent his blower flange, which flange to you mean? Also how much boost was he running?

 

I like the bit about having a million dollar facilities and test equipment just to build something, You think they had all that stuff when they started out? Back when everyone was starting out, you made what you could in your own garage, if it worked, great, if it didn't, you had information you didn't have before starting.

Joe

 

The main flange with the eight studs holding the blower. There is a lot of pressure the belt puts on the drive hub, boost could be as high as 22# for the class, and add a backfire, and the blower lifted from the back side