Hi guys , lookin for some advice . Im hoping to have the engine done for my 55 this spring so until i have the money to go any further i am taking inventory of what i have , whats gonna work , what wont and what i need. So this is my first real step into the world of superchargers , one of those things ive always wanted to do and never had the scratch . Well ,a package came up for sale here awhile back from a friend of mine . he had picked it up at a swap meet as a running unit and never installed it . he priced it to me and i had the huffer itself checkout to make sure all was good and bought it. I was going through the slough of parts i got with it and was looking at other folks pictures of blown big block chevys to see what they were running. Now it looks like the drive snout on mine is alot longer than the ones i am seeing being ran on the street. I looked into the box o parts and came up with a blower hub but it doesnt look like its going to have the bottom pulley out far enough to line up with the snout pulley. So this is my question , What do i need to run to get my lower out far enough ? Should i ditch the crank hub and run a damper ? im only going to be running one vbelt for my water pump and that will be it . Sorry if this question sounds dumb but like i said , im new to this and im not sure i know all the options out there or what the best resipie is for it . Im not going to be running a super power house , we are shooting for 550-600 hp. The intake is a weiand 7151. Thanks in advance for any help This is my set up , i have replaced the holleys with a pair of afb's.
There are many different lengths of blower drives. The most common length for a Chevy that I have seen is 4.5 or 5.5 inches, but this can very. Different manifolds will mount the blower farther forward or back for various reasons. You do NOT want to space your crank pulley out any farther than you need to. A blower belt puts a lot of stress on a crankshaft, and the farther forward that the belt is the more leverage it has on the crank. I would guess that the blower was last used on an engine with a crank support which is nice for racecars but is not needed for a street engine. Personally I would not worry about buying any extra parts right now, until you can mock up everything on your engine, and then I would just swap out the blower drive with the one that you will need. Try going to www.RBSSuperchargers.com and talk to J.R., and he can set you up with what ever parts that you need. For a street engine I like to run a GOOD damper like an ATI or a Fluidampr. The blower belt will absorb alot of the vibrations, but I dont think that a damper will hurt it. Also if those old carbs are 660 center squirters, they will probably run better than the AFBs that you put on it. Brian
Hey Thanks. I didnt want to space it out for the stress reason on the crank snout. theresnot a whole lot of folks in my area with a bunch of supercharger exp. so i looked around on here and never really turned up a deffinate. I figure so far at worse case scenario is ill have to swap blower snout with a shorter one to get the lower pulley backed up closer to the damper. Thank you again!
You should not need to double key the crank, if you are sure you won't be trying to get more boost out of it later. Agreed, get the thing mocked up on the motor and see what it needs for a snout. I've been running a hub on mine for 20+ years, the motor has almost 100k miles on it, and I overhauled it recently because it dropped a valve. I had overhauled the engine previously when it had 50k miles on it. The bearings looked fine this time, as they did the first time. The engine is an old crate LS-7 with TRW pistons, a mild hydraulic roller, and the rest is pretty much stock high perf stuff from GM. What is the rest of the motor going to be like?
Changing to shorter snout is super easy and will not cost tons of money (probably can sell your snout for what another will cost).... If you're running an external balanced motor, you'll need to run a balancer. If internal balanced run a crank hub. What are you using for an Idler? Also ..... If you are running 1/2 pitch pulleys, they come in all kinds of widths. From 2" to 3.5". I am running a 2" Snout pulley, 2" Idler on a swing arm and 3" lower pulley on my crank hub....... Using a 2" belt.
I'm running a crank hub on my externally balanced 454. The double key thing is one of those things that you "should" do, but in many cases you can "get away" without. You need to know more about the specific engine to decide. If it'll never see more than about 7 psi boost, and it's a big block, and the crank snout is in good condition, and the hub is a tight press fit, you can get away without it. Otherwise, you want to double key it.
I've built 2 454's like your talking about,both total successes.6-71, 8:1 oval port open chamber 8 lbs. boost at 6% overdrive. .525" / .550" lift 280 degree on 110 centers, 2 750 edelbrocks on one Q-jets on the other. ran 10:49 1/4 in 2900lb car, 181 mph maxton in 53 stude. cross country reliable.
i was planning on doing a double keyway in whichever route i took , balancer or hub. The engine is a 396 punched 60 , the cam im running is a solid lift isky z33 grind on 110 degree lobe center instead of thier 108... Valve lift int/ex of .560 -adv .290 duration - 250 @.050 , oval port open chambers with some port work stainless valves etc , im planning on running 8:1 and maybe 6-7lbs of boost which should put me in the 11:1 range On the otherside of things i went out and pulled the front blower pulley to get a snout measurment . I noticed all the bolts in the top pulley were finger tight , then i went ahead and checked the front cover bolts........ again , all of them are just finger tight which has me worried . I will probably be money ahead to send it in and have it gone through . was suppose to be a functioning unit but that all came from the swap meet seller and its changed hands twice since then and has never been bolted on anything so now im a little uneasy. they way it sits right now is they have a 32 tooth on the upper and a 35 tooth for the lower. there is also another 32 tooth pulley but it looks like its been wallered out pretty bad in the center.The stamped steel pulley is just a stock pulley that has been drilled to somehow work on the last setup but im not sure , i wont be using it. Im not even sure if thats a bbc crank hub , i know the intake is big chevy. Thats what sucks about cornfields , not to many knowledgable folks out here on these matters ha ha.
If you buy an aluminum lower v-belt pulley for use with a blower the are usually about an 1" thick and will space your bottom pulley out without creating undo stress on your crank. They are also machined to fit the lip on your hub true/centered and have a lip on the other side to locate your blower pulley true/centered. Sending you a pm.
You can Call Dyers, they were very helpfull when I was putting my set up together, if you need a new drive or parts they will have them. The other thing I would suggest is an MSD BTM box.
ive heard alot of good things about the msd boost control and i think its going to be must . I really appreciate all of the advice . So far i think i am going to swap over to run a double keyed damper , single groove v belt and my lower pulley then ill find a snout to match that setup . now does it have to be an ati or fluidamper or will a nice aftermaket one work aswell. like this one http://www.ebay.com/itm/Summit-Harm...Parts_Accessories&vxp=mtr&hash=item5647e7bc68
I think a Steel hub would be highly recommended rather than a stock type damper or even a fluidamper, the belt will dampen it already. Call Dyers they can explain everything you will need to know.
I was in your same shoes when I built my first blown engine, I did it in Dubuque Iowa in 1989 . 2 great sources of info; Pat Ganahl's book, "Street Supercharging", and the nice conversation I had on the phone with Don Hampton. These old blower guys have seen it all and can answer any questions, but be nice and justify their time. I screwed together 3 blower systems over the years from new and used pieces gathered from everywhere. The power these things produced had me forget all about normally aspirated anything. Definitely(not Defiantly) worth the trouble.
I have had several roots blown cars and you do NOT want to run anything but a hub on the crank snout. Also the suggestions for the double key way in crank are vali. Ask me how I know! The blower drive consumes quite a bit of horsepower and that power/ torque twisting the end of the crank. I had a key gouge out the key way on blower drive until the blower pulley spun on the crank. Didn't cause engine damage but effed up the pulley. I added another key way to crank 180 degrees apart and had blower pulley rekeyed also. BDS is the company to deal with....get a blower catalog from them. If u are near Dick Landy Enterprises call them. Very knowledgable, sadly Dick has passed but the shop is top rate. By the way....stay AWAY from Speedomotive! If you don't believe just do a google search. Never used an MSD boost timing master on a roots blower, I did need it on a centrifugal unit. Be careful of your static compression combined with your boost level. BDS has charts that show all this. Read pat Ganahls book on street supercharging. Blowers need lots of fuel. Be sure your pump, regulator, supply pickup and return lines are up to the task. Weak fuel supply and lean conditions will kill a blower motor quick. Spark plug choice is important too. People get too greedy with boost without enuf octane. Your motor should make 650 easy horse and huge torque on pump gas. I have had more on the street and is just a waste. Be sure your entire driveline is up to the task! Talk to a pro about your system....the learning curve can be steep and expensive on your own. Ask a blower pro....there is too much backyard myths out there for you to listen to. Good luck! One thing...once you drive a blown car set up right it is very difficult to go back to a naturally aspirated ride! You'll be hooked on the instant tip in power and torque!
The Jalopy Journal
