8ba questions
 

Hi folks, I recently acquired a Merc 8ba, I want to install it in my 34 after rebuild. I would prefer to eliminate the oil fill and vent tube from the front of the intake. It looks like an early intake will fit but will it work? will the block still vent Ok and will I loose power by not using the merc intake? Im new to 8ba's. Ken

Re: 8ba questions
 

The intake will fit, and it will work WHEN re-vented properly, usually with some sort of a PCV system. We're working on building such a mod as we speak. It can be done with poor to terrible results if you don't understand how the 8BA originally breathed, and if you don't understand how a PCV valve is actually designed to function. It can actually be accomplished ALMOST inconspicuously if you put enough thought and planning into it. DD

Re: 8ba questions
 

On my 8BA the fuel pump stand was replaced with a homemade oil fill tube and the original oil fill tube is the breather using a small K and N filter. The OEM crankcase vent tube running down the front of the timing cover was left in place but I think than could be removed and a crank case breather (like you see on valve covers) bolted to the oil pan would suffice. I know it's important to alleviate crankcase pressure build up.

Re: 8ba questions
 

This is a hard-to-find diagram that may help you understand the direction and path of ventilation flow in an 8BA. DD


https://www.fordbarn.com/forum/attac...1&d=1593547011

Re: 8ba questions
 

That is an excellent picture. Thanks

Re: 8ba questions
 

If you put an early manifold on it, then you should think about welding up the TOP of the vent tube that pulls air from the crankcase and delivers it to the bottom of the manilfold - and out the road-draft tube on a stock 49-53. Then you can mount a PVC into the top side of the tube so you can have a vacuum system pulling the crankcase fumes and water vapor from the crankcase. This encourages the inlet air (from the back of the manifold) to be pulled down into the crankcase and pulled up the tube that you just modified. There are a few posts about this technique and the associated mods to the tube, to the bottom of the manifold, etc..

Personally, I do not like crankcase breathers bolted to the oil pan - every one I've ever done or seen (unless really tall - like a long filler tube) will cause oil to drip down the whole undercarriage of your car as well as your garage floor. The vapors coming out of the oil pan will carry oil mist - and you'll have oil on the outside of the breather . . . going places you don't like. Also, there is nothing on a pan breather to actually PULL the air out the breather --- like the original road-draft tube did . . . so you need a PVC to replace that original concept if you're not going to run it.

Best of luck!

Re: 8ba questions
 

B&S is correct on ALL counts above. The PCV valve must draw from the modified (capped-off), removable road draft tube stub at the front of the valve chamber, 8BA. That can clearly be seen on the drawing I posted above by the UP-flowing arrows toward the front of engine. The idea is for fresh air to enter the breather tube at rear on an EARLY intake manifold, which is drawn down into the lower crankcase and exiting into that forward, up-flowing tube. One more important function is to relieve internal crankcase pressure generated from blow-by. If not relieved, you WILL have oil leaks everywhere. This arrangement accomplishes the fumes/ventilation going from one end of engine to the other.....cross ventilation. Your PCV valve, and ultimately the vacuum source, will pull the vapors from that tube, hidden by the intake manifold. We're doing a system based on the same theory, but with the PCV valve mounted just inside and below the rear breather tube for future service/changing without the need to remove manifold. There will be one simple, polished copper tube exiting the side of a custom breather tube, plumbed to manifold vacuum fitting between the 2 x 2s on a Thickstun PM7. NOTE: MOST PCV valves should NOT be mounted any way other than vertically! Pictures and part numbers and details to come at a future date. Teaser picture below! DD


https://www.fordbarn.com/forum/attac...2&d=1593566310

Re: 8ba questions
 

Hey V8VCOOPMAN - good point on the angle of the PCV valve . . . every one that I've ever seen needs to be vertical as that is how the little "shaker valve gizmo" needs the orientation to be - in order to work correctly.

Maybe I'll fab up a front breather tube to show the concept. I like your idea of running a tube to the front (welded up pipe) with the PCV mounted in the back (where you can service it more easily). Maybe some mods to the original fuel pump stand are in order - will think about that a bit and maybe mount the PCV inside the stand ???

Re: 8ba questions
 

Thanks Coop and others for a better explanation of this system, especially the vertical position of the valve. learn sumpin every day, till they throw dirt on ya.

Re: 8ba questions
 

I'm tellin' ya, this is all still in the "R&D" stage, and we promise....there will be a full-blown expose with full explanation and more-importantly, part numbers that we have painfully developed into a comprehensive, finished package of sorts, so that anyone could go out to purchase a few known parts, and be able to throw this all together and have it done with. There has been a lot of trial and error here to hopefully make this a clean, functional and fully-serviceable sub system that does not require the removal of the whole intake to service or change your valve. Except for one short piece of polished copper tubing (similar to the carburetor plumbing), there should be no ugly hints of this valve's existence, and it's vertical mounting is a far better solution than many we have seen mounted horizontally UNDER the manifold. For B&S's (and everyone else) consideration, I'm posting one more 'teaser' picture of the IDEA for plumbing into the modified, front breather tube. This picture only shows a preliminary mock-up. The final hook-up at this point is quite simple, yet bullet proof. Stand-by for more! DD


https://www.fordbarn.com/forum/attac...0&d=1593582704

Re: 8ba questions
 

Wow that's some good info, DD I'm not getting any pics or diagrams in your posts to me so its a bit hard to get with just text. although from what I have read I think I know why my 59ab that's in the car now is leaking around the pan so much, Its a 59ab with a 34 pan and no vent in the pan corner. Yes/no? Thanks for all responses. Ken

Re: 8ba questions
 

That sounds like a reasonable assumption. These things must have a way to relieve blow-by pressures, or they find their own way at the most convenient, leak-prone gasket surface. I'm not sure why you're not getting the pictures, 'cuz they're 'priceless'! DD

Re: 8ba questions
 

Thanks Coopman. This looks great. I will have to do this on a build very soon.
Great work.
Cheers
Tony

Re: 8ba questions
 

I have never seen a breather system with that small of diameter tube. The gases are going to be moving pretty quick in that tube.

Re: 8ba questions
 

Zeke....I believe you've asked a valid question, but you should remember that the PCV valve-vented system has engine vacuum helping to propel the noxious gasses, through a roughly 3/8" nipple on vacuum side of PCV valve. On a stock road draft set-up, the volume of gasses is only vacated by whatever suction the road draft tube has on it produced by air speed from vehicle going down the road. It's not like that stock road draft tube is pushing-out huge volumes at high pressure. That draft tube's large diameter is necessary to aerodynamically induce a vacuum as the tube moves through the air below car. You should also realize that PCV valves allow the MOST air evacuation at a LOW vacuum (like at wide-open throttle/acceleration)….when the MOST blow-by pressure is created. Likewise, the LEAST amount of air is allowed past the shuttle at HIGH vacuum (like during idle/steady cruise)….when the LEAST blow-by pressure is produced. This is likely the REVERSE of how most folks think these valves are designed to work. Check-out below! DD


https://www.fordbarn.com/forum/attac...2&d=1593633214

Re: 8ba questions
 

When I went to school to get my California smog license in 1968 the story at that time was that crankcase fumes were 75% of the smog emitted from a car and that the positive crankcase breather system would eliminate 100% of that 75.
Crankcase fumes are bad stuff.

Re: 8ba questions
 

Back when gas was golden,exhaust and blowby smell was common and every highway had an oil stain stripe down the middle on the lane..

Re: 8ba questions
 

Back in the day, when concrete hiways had strips of tar across the road. T
I probably date myself.here was a black mark on the other side of the strip, where all the oil under the car would fall off.

Re: 8ba questions
 

Ron, I'm old too. Why do you think the old time driveways only had two strips of concrete about 18" wide leading to the garage? If they had been completely paved, there would have been a big stripe of oil right up the middle,:D

Re: 8ba questions
 

Any updates on this?