i am planning to run a graham centrifugal supercharger on my model-B motor but i want to turn it on its side the grahams orignally had an angle drive unit to let them sit flat my thinking is that i can bore it out and put sealed bearings in it then just mount it sideways and make a 90 degree intake on the side to sit 1 or 2 stromburg carbs does anyone see any problems in this set-up? i dont totally know how these graham things work...im assuming you pump oil through them and i dont want to do that...but also looks like it might have had coolant flowing through.. in any case...does anyone have any thoughts? thanks alot zach
Zach - It's been a while since I've seen a graham unit up close, but I'm pretty sure they were oil lubed with no coolant circing thru them. I'm also pretty sure you have to run oil to the bearings, as the rotational speeds of the blower will exceed the rated speed of a sealed bearing. Without constant lubrication, the bearing will overheat and fail - evenutally. any good bearing house will be able to give you the tech specs for the rated speed of the bearing, BTW. If you look at any of the 'modern' blower designs (Paxton, procharger, vortec, et al) you'll see they all rely on oil for both lubrication and cooling of the rotating element bearings. You'll need that - even if you sit it on its side. A common method of oiling this case would be to pick up a pressure lube line off the cam galley, and then direct the oil back to the tappet galley - assuming you've converted the B to full pressure lube. Really cool project, BTW - I'm envious! Go kick some V8 butt with it!
thank you very much its just in the planning stages right now really...as i have a few other things to get going first...its up in the air wether its going in a roadster or a belly tank...we'll see...but either way the plan is to do atleast 100MPH thanks zach
Somewhere, I have a really good article on how to do this; it's possible to turn 100, but I'm pretty shure you'll need an OHV conversion, too.
Let's talk a few things here Zach... Not to "poop" on your idea (because it is worthy and may have some cool-factor merit) but let me understand what your motives are. Are you doing this to gain a "WOW" factor from your buddies, --or to really gain horsepower? I think you are going to find about 3 or 4 major issues that will cause this to be a less than ideal scenario. a) The McCulloch blower is a less than efficient design that has a limited amount of boost available in stock form. By the way, the McCulloch was named after Robert P. McCulloch ... his full name was Robert Paxton McCulloch --hence where the Paxton name came from later on. He learned that his first design was more of a "blender" of fuel and air due to it's driven speed and design. The Paxton brand actually turns at about twice the speed of his McCulloch brand unit. The McC design was lacking in many areas including reliability and was scorned by many who saw the unit as a copy of the Switzer (sp??) built units that were found on Duesenburgs, Stutzs, and aftermarket racing applications. Enuf boring trivia. b) The 2nd issue you are going to experience is that a banger engine likes compression to build torque on the bottom end. Adding boost to a "middle of the road" compression ratio (i.e.: 6:1) will likely see 7.5:1 - 8:1 with the blower. This is not a real problem because you can do THAT with combustion chamber size decrease and without a horsepower robbing blower to spin. Now the CR goes up on the square as static CR is raised, so when you apply 3 or 4 lbs of boost off of the blower into a 7:1 chamber, you quickly run into head gasket reliability issues. This is why someone suggested running an overhead (the head does not distort or flex). The issue is two or three-fold but the simplest explanation is that detonation is extremely hard to control on an F-head design under high combustion pressures, and detonation causes head gasket issues when there are not enough studs to hold the head onto the block. c) The other big problem you are going to have is lag time with the blower --& throttle shut-off time. There is not a good way to mount the blower close to the intake without getting fuel puddeling. This issue is compounded by the stupid firing order of the Model A/B with the siamesed ports (Too much port reversion). Also, when you snap the throttle closed (like to make gear shifts and etc.) due to the fuel/air having been "packed into the intake and the cross-over pipe, the fuel must be "used-up" before the engine will de-accelerate. How annoying will that be? If you HAD to run a McC blower, I might suggest trying to run a Corvair blow-through carb (or something similarly designed) mounted on a manifold in the normal position ...and force your air through the carb. The Corvairs were about 25% smaller in cubic inches so that may not be the ideal carb set-up but it makes a good starting point. d) The final thing that I think that hinders the blown banger idea is the difference of RPMs the set-up was intended for. Bangers are not high RPM engines. They instead are long stroke, big-inch (3.3 litre) engines that made power down low --as compared to small stroke engines (Bentleys, "flattie V-8's", Grahams and etc. Remember that the smaller Graham engine was 6 cylinders but only 300cc'es larger than a stock Model A/B. Also understand that the McC blower had met it max rating at 25,000 RPMs and was overdriven at approximately 5X of the engine speed. In other words, it was maxed out at 2500 RPMs of the engine. How much RPM is that on a normal banger engine? You are wanting to run 100 mph with a likely gearing of mid to high 3's (3:50??) That will equate to about 4000 RPM. Again, suffice it to say that with the parasitic drag of the belts and gearing, plus the back-pressure of the compressor, and add in the poor fuel distribution, AND the lack of enough head bolts to keep the head and it's gasket intact, Zach I think you are in for a bunch of work for little rewards. Heavy on the cool factor but I think a built flat-banger will do just as good if not better. Just my 2 cents and what do I know?? If forced induction was a definite, I think I would be looking towards a Buick 231ci waste-gated turbo in my racer.
thanks brent thats alot to think about i guess i have to weigh all my options and whatnot before i go about it i hadnt thought about that off throttle lag for one luckily this is a bit of a "down the road" project so i have time to get everything thoguht out thanks alot zach
Brent didn't you get half way through a McCullough setup for a Banger? I'm sure you mentioned it on Ahooga once.
Well now ....I appreciate you poking at healing wounds!! Actually, I got a little further than that. About the only good thing that came out of the experience is being able to write a credible story on H.A.M.B. about what to do ...and NOT to do. The thing I have come to believe is that a "built" flathead can produce reliable horsepower in the 100+/- range. A good OHV on the same block can produce numbers in the 200+/- range when it is naturally aspirated ...and when forced induction is added, maybe another 100 horse can be added but it takes modern technology to be able to do it.
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