Hey fellas.... I've got a head full of confusion surrounding configuring a 4-71 to a flatty. I have questions about pretty much the whole sha-bang to determine what the setup is going to be. I've already searched and found lots of good info, but still questions remain. A little background to what I'm doing; I have a '49 Merc 255 in gorgeous shape, standard bore, going into a 30 Tudor. I bought myself a real nice 4-71 blower, still setup for a diesel though. I'm only looking at 5-6 psi of boost, so for the time being at least I was just going to freshen up the motor, some new rings, bearings, resize the rods, check out the crank, and, if it doesn't need bored (it looks fairly promising that it won't), just run the cast pistons with the low boost (if I need to bore, I'll go forged and maybe consider a hair more boost, but otherwise that will wait until an engine bore is necessary). The drivetrain will be up to whatever I toss at it; I have an aluminum bell that'll let me hook a wide ratio Toploader I have laying around to it, haven't bought a rear end yet, waitin' on a deal. This will be my first supercharger car, I had a pair of pretty serous turbo cars though, so while I am supercharger ignorant I am familar with forced induction motors. I WANTED to run v-belts because of both cost and look. Here's the problem, I don't have the skill/tools/what-have-you to fabricate pullies. I was thinking about using a 4-groove French pulley (I don't think I'm gonna fart around with a mechanical fan, I'll probably use an electric pusher behind the grille). I've looked at pictures (namingly, this one: http://www.35pickup.com/PA120016.JPG) and my eyes seem to think that the back 2 grooves are wide belts, the front 2 are narrow. My current setup is a 2-groove wide belt, but I'm gonna slap some new water pumps on it so it really doesn't matter all that much at this point (and I don't figure a single v-belt would work resist slipping enough, am I wrong?). I was thinking, if that turns out to be the case, use the back grooves to drive the accessories and the front 2 to drive the blower. Since I can't use a lathe, I was thinking somewhere along the lines of adapting a lower pulley from something else to the blower snout. (BBC's seem to have diameters that would let me underdrive the thing enough, hell, for that matter I have a single groove 351 pulley that would underdrive it enough as well, so the sizes are out there) What is the story with these French pullies (where can I even GET one? I can't find jack)? Would a stamped steel double groove blower pulley be a recipe for a catastropy? I'm not against Gilmer belts, but I figure Gilmer belts are against me. It seems like there is alot more fabrication skill required for them. As far as serpentine, I would only think about using one to drive the blower, I don't want a bigass serpentine belt driving everything, this engine is gonna be the focal point of the car and I just don't like the looks of it. So, here is question one... I can't sit and stare at the front of the motor anymore, I need to get pointed in one solid direction. Coming soon, intake questions! Thanks guys -Jason
Bumpity bump for the late night crew... Someone's gotta know somethin' about the French pulley and/or anything else. I found NOTHING anywhere on the internet about the pulley itself, just a picture or two.
http://www.uncommonengineering.com/ Look here, you can call and talk to the owner about what your looking to do. I think he has done the type of set up your looking to do, but I remember someone once posted that he would only sell the whole blower kit, not do piece work. But in today's economy, he might be doing whatever it takes.
Jason, Max Sr. from H & H Flatheads, we have all the drive hubs , pulleys etc for a 471 on a flathead and we are currently making the V belt pulley system as well, since we already have the gilmer set up. The pully you saw on the crank of the pic is a 2 diff size and alignment will be real tough. We will have the 3 V Belt system like the one on the 471 Blown Ardun On the cover of R & C. Also you will need to determine snout drive etc. If you ahve any questions, feel free to give us a call and we can walk you thru this and give you some idea of what you will need etc. 1-818-248-2347 flateads-forever.com Max Sr.
Hi guys, thanks for the input! I'm so jealous of people that have access to machine tools and know how to use 'em. I also read somewhere that they won't sell parts, just whole kits. Kits are nice, but I like to have to use a little ingenuity, not to mention that, even with a "off-the-shelf" drive, intake, etc. piece-mealing it together will be at least a hair cheaper (not to mention it's alot easier to buy a $300 blower, then a couple hundred on an intake, and on and on, compared to plunking down 3 large all at once). Unfortunately, every idea I've had for a drive has had some sort of major roadblock that I can't work around, even if it starts off promising. I thought about the French pulley with the rear grooves running the accessories and the front 2 driving the blower, but even if I could get the alignment (which doesn't sound like much fun, lining up pulleys frustrates the hell out of me after a while of no luck), I don't have any really good ideas for the top pulley (as it would have to be a big feller), looks like machining your own pullies is needed. Then I thought, I got it! I'll adapt a SBC damper to the crank snout as it would make running a Gilmer pretty easy, until I realized, hey, I have waterpumps and an alternator, they'd have to be driven behind the damper most likely. Single belt, real easy to setup! But I figure it'd slip like crazy, even at 5 PSI (I'm using my stock 8CM heads, so the CR will be in the dirt, I think it's in the 6's). I really appriciate the offer Max, I might end up buying a drive if my brain continues to be mush on this particular subject. I'll look forward to seeing your tri-belt setup, now THOSE are a great looking setup! I essentially have as much room in the front of the motor as I need, I'll just mount the engine back. I figured I'd choose a snout after the intake and lower drive pulley is laid out, that way it's one less thing I have to work around (I have numerous questions on the intake too, but thats for a different thread, I thought I'd break up my questions for the search engine's sake). The blower is gettin' here tomorrow, I can't wait... UPS is gonna make me sign for it so I gave my friend 10 bucks and a 30 pack of Pabst to sit on his lazy ass all day long at my house and watch TV until it shows up.
Joe Abbin just released his latest book - talks about sizing blowers and pully ratios in one of the chapters (I just got mine last night & read it cover to cover) - using his formulas, I figured I'd need to underdrive the 4-71 about 15-20% on a 284" engine to do 6-7psi at 5000 rpm...the 3-71 would seem to be sized better, but I know 4-71s have been made to work just fine on a flatty (don't know drive ratios). I've got a brand new rebuilt 4-71 (diesel rebuild) and a very nice used 3-71 in my shed...blown engine project is on hold for right now (military moving me out for a couple years), but when I get back...one of those is going on! New book is here: http://www.roadrunnerengineering.com/Flathead V-8 Performance Handbook.html
Thanks for the heads up on the book... I have 1/2 dozen flathead books and honestly they've all been pretty disappointing (pretty much, look at the pretty picture!), I'll certainly pick it up, his site's where I ripped off the drive formulas.... My math for my motor shows a 30% underdrive to get 5.5 PSI (that's assuming the bores aren't tapered too much and I can get by with a good hone... Who knows what I'd bore it to if I have to do it). The 3-71 definitely is closer to what I need, but I found this 4-71 and it is near perfect condition... With that much of an underdrive, I figure it'll live a long and happy life up there. By my math, with that underdrive, the engine at 4500 RPM is spinning the blower 3100 RPM, give or take... I'm staying pretty tame as far as the long block's concerned; I'm TRYING to stay fairly budget-concious, which is the only reason that I'm hoping the stock shortblock can get a refreshing and be happy. Gonna use the 8CM heads that were on it to keep the compression down in the dirt, I don't remember the exact numbers but IIRC it's in the 6's:1 (man, after getting used to late model small blocks, that's hard to say!) The drive is of course the biggest hurdle for me, but I knew it would be goin' into this, low expectations means less disappointment. I've been told by a couple guys that if I'm underdriving it that much, I really don't have to worry too much about converting it from diesel. Just the same I figured I'd pick up a rebuild kit off EBay, fella selling them for around $60. My dream was to adapt some off-the-shelf crank pullies to get the drive ratio I need, but things don't seem to be shaping up that way. Good luck with your blower! Mine is coming tomorrow via UPS, I have a full evening of sitting in the garage drinking a few cold ones and staring at it and my flatty trying to figure out how to cobble 'em together planned . I really am super jealous of the guys that have access to and know how to use a metal lathe, seems like every "homemade" blower drive includes a self-fabbed blower pulley.
Get in touch with Crusty Nut. He's running a (i Think 471) on his French Flatty in a 1929 A PU. It was for sale about a month ago. Homemade manifold & drive setup. Movin/on
Thanks! Will do for sure... I'm considering giving a homemade manifold a shot, I was gonna start a new thread 'bout it (I have all sorts of blower questions from crazy/bad/stupid ideas I have, and I've done some SERIOUS searching at work when I'm supposed to be working and still have questions, so I thought I'd do several posts about the topic to help future wishful thinkers such as myself out). The only intake I have laying around is the stock iron one, I thought about setting it up in a bandsaw and hacking the top portion off, then brazing a piece of 1/4 or so steel plate to it to mount the blower, but I worry about the strength of the braze; I can only MIG weld. I have a buddy that's a boilmaker and had a formal welding education (funny thing, he hates MIG welding for some reason, so he has me do that...) so I was gonna talk to him about the joining. Now, if I have to use an aluminum intake to make a homemade blower manifold, I figure as much $$$ as that would take I could have gotten the Mitchell manifold for the 300ish I hear it costs since I'll have to buy a manifold to begin with. I really want to do this as much as possible with home-done stuff, but if I can't do it, I can't do it, in which case I'd be a customer of Mr. Max higher in the thread (see, companies that interact with customers on forums like this in a friendly and helpful manner get customers!). The intake deal is why I haven't put any thought into the snout yet... I'm hoping to be able to pull off a homemade one, which would give me some lee-way as far as snout length is concerned. I really would like to be able to adapt something stock, or at least something stock-esqe, the engine itself will look pretty much like a factory 255, heads and all, I am sort of putting it together the same way a broke guy back in hotrodding's hayday would have done it, adapt what's available as best as possible. -Jason
Well, blower got here today, it's in great shape! The rotors have no endplay, the bearings are smooth as silk, and there is not a gouge or scratch to be found anywhere on this thing. I paid $375 for it and, considering the condition, am pretty satisfied with the blower for the price. I think it'll live a long and happy life only turning 3000 RPM. Now if I could just figure out a way to drive her...
What Alchemy is saying is to "prune" the bottom plate so it takes a on rounded shaped vs. a flat base. The Navarro intake requires either the case to be pruned or a flat plate used to mate the two. To prune a case take a fair amount of work. Best if you have a mill. Can be do by hand, but labor intensive. The problem of getting chips into the rotors open case is real and best to disassmble the blower first. That being said, if you are not a blower guy, talk to someone who is. The timing of the rotors is crucial and if not right, will mess up your day real quick once it spins over on a motor. Good luck.
Ahh... Gotcha. In that case, no I don't plan on pruning it, my two intake options I'm considering are 1. The Mitchell manifold from New Zealand. It seems like quite a bargain at 300ish bucks and doesn't require the base of the blower to be modified (at least that I can tell). 2. Would be making my own manifold. I really really like this idea, but I don't have an aluminum intake (doh, sold them) laying around, only the factory cast one. I was considering at least trying to hack the top off the cast iron one and attempt to braze a steel plate to it, worst thing I could do is screw up a crappy factory iron intake (I don't figure a steel plate could be welded to cast iron, which was why I was thinking brazing would be the best way to go). I could get an aluminum intake of some sort (since I won't need a road-draft tube I'll have some more options) and weld an aluminum plate to it, but I don't have one, and I figure by the time its done, it could get expensive.
May I ask where you got that price for the Mitchell intake? I've seen them all around $700-$800. I'd be interested in one as well. One small issue with the Mitchell is the lack of a pop off valve. Easy to make, just an FYI... Also, a flat intake is best for this. A Fenton, Alquist, others. Once cut apart, leaves a nice space to graft the top onto it.
I saw that price mentioned in a couple threads around here... Sorry but I don't recall which ones (I saw it pop up more than once), I think I've read every flathead blower post in this whole damn forum. It looks like a nice intake, but he could use some better marketing, I've been able to find jack about them away from the HAMB. I see what you're saying about the flat-topped intakes. It certainly would be easier, looks like you just have to cut the top of the flat top off. I can't weld aluminum, I only have a MIG (I would love to learn how to gas weld), but I have a friend that's got all sorts of welding certificates, it should be kiddie stuff for him. Could someone tell my why there is a lack of fabricated intakes used for blowers on flatheads? it seems like it would be a nice alternative, what don't I know that makes it an unattractive proposition? I'd like to thank everyone who's posted here, alot of the questions listed weren't in any other posts, this should be a good one for the search engine to find for other beginner blower fellas.
A quick EBay search seems to have yielded some nice possibilities for a intake core; I figure since I'm farting around with it to begin with, I'll convert to a PCV system since I can't imagine trying to use a road draft tube with a blower... Anyhow, since I don't need the road draft boss, I could throw an early intake on it, looking at some stock ones, it looks like some of them were not only aluminum, but pretty flat too... That'd be good and cheap, not to mention I wouldn't have to hack up a vintage speed part (I don't feel like gettin' lynched by an angry mob of hotrodders for tearing up a vintage intake that I might not even be able to get to work in the first place) . Plus I don't really plan on using too many EXTERNAL aftermarket speed parts, I think it would be interesting to have a fairly stock LOOKING motor with the blower, something a bit different. I'm gonna weld up some basic headers and likely go with a Mallory dual point (I've had Mallorys on everything else, might as well stick with what worked in the past) with a Crane HI-6 hooked to it (that baby's gettin' hidden somewhere, no way is that gonna ugly up my engine). Gonna get a blower-friendly cam with some new valves (I got one that's burnt) and lifters, but of course you won't see that! The top plate I plan on making, just gonna use a pair of 2-barrels, stick with something proven. I'm actually enjoying the intake part of this, I'm seeing some good ideas people have come up with without breaking the bank... Now the drive is a different story, it's got me pulling my hair out! -Jason
Jason: I think the shorter SBC drives will work for a flathead. But, you'll either need to live with the toothed belt or fab up a V belt pulley set-up if you don't want to buy the one from H&H. Good luck on this. Take your time and do it right.
No need to weld/braze an adapter plate to an existing iron intake manifold, just use as many 5/16-18 (coarse thread for cast-iron) tapered head allens as you can to make a pattern. If the surface is perfect you can just use gasket sealer, or a paper gasket. If the plate is thick enough, it can also transition the shape between the blower exhaust side and the manifold.
If you run V-belts, you don't really need a pop-off valve. If you run a toothed pulley, you do. You won't have enough room to run enough v-belts to worry about non-slippage...
You'll still need to "convert" the blower to gas. Either send it away or do it yourself. There is some work involoved and you do want some endplay. Be very careful when aking it apart so as to put it together correctly. I'm currently writing a tech right now (foran upcoming) tech week but it won't be done for a bit.
I'm adapting a blower to a cadillac flathead. Finding pully's to line up was impossible. I went to my local machine shop and showed them what I needed. They fabbed me a new crank pulley flange,double keyed and the pulley's for $200. I got exactly what I needed, with the look I wanted. Might be they way to go for you.
Don't think I can help much on this one. Mine is serpentine driven and the intake is a Roadrunner Engineering model that prolly wouldn't fit the bottom end of the 4-71.
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