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6-71 help

Discussion in 'The Hokey Ass Message Board' started by bigalow1, Dec 12, 2010.

  1. bigalow1
    Joined: Feb 17, 2008
    Posts: 105

    bigalow1
    Member
    from 496 C.I.

    [BI updated my profile with some pics. Dnt now how to get them to Avatar[/B]
    i should probally give up on the blower Huh/
     
  2. bigalow1
    Joined: Feb 17, 2008
    Posts: 105

    bigalow1
    Member
    from 496 C.I.

    I read i have to pull my motor out to dyno it for mixture adjustments.(air/fuel) They install headers on your motor with sensors on the individual header tubes. Its not really possible on a chassis dyno to measure your mixture adjustments???
    If this is true I,m not sure I am preppared to pull my motor??
     
  3. 32fivewindow
    Joined: Mar 22, 2008
    Posts: 226

    32fivewindow
    Member
    from USA!

    Another crutial part of a blower motor is a having a good fuel delivery system. Make sure the pump you use will support the pressure that 2 eledbrocks need.
     
  4. Mike6969
    Joined: Sep 21, 2009
    Posts: 7

    Mike6969
    Member
    from Sweden

    Hello there Bigalow, i have built a number of blown engines from street chevy sb to 572 hemi mopars..
    If you want to make your life easy, fix double keys on the crank at a good maschine shop, cause if the key dont line with the hub... if un linement is more then .004 the double keys wont make any difference if one isnt beefy a hxxx.
    Get a steel hub and sell the damper or get double keys and a adapter to the damper.
    Get a cam with 114 in lobe separation and with your compression you can run the engine with at least 10-12psi boost, get a new aluminum radiator and top of with a pair of blower carbs from lyle stahle, hes cheap and has the knowledge..thats the easy way..i would recommend 750:s if you dont rev to much..
     
  5. bigalow1
    Joined: Feb 17, 2008
    Posts: 105

    bigalow1
    Member
    from 496 C.I.

    Thanks Mike6969.
    I can just run the steel hub for the blower belt on my crank with no dampener???.
    [/B]The steel hub and a pulley for my alternator thats it right?????
     
  6. flamedabone
    Joined: Aug 3, 2001
    Posts: 5,440

    flamedabone
    ALLIANCE MEMBER



    A chassis dyno can do all the tuneing you need. A chassis dyno will have an air/fuel sensor that goes into your exhaust pipe to read your air/fuel ratio and a print out graph that shows your readings throught the rpm range. (also power and torque).

    If you are going with the Edelbrock/Carters, you can change metering rods and springs without disturbing the rest of teh carb in about two minutes. If you have to change the jets, you will have to take the top of the carb off, but that is also very minor.

    Good luck, -Abone.
     
  7. flamedabone
    Joined: Aug 3, 2001
    Posts: 5,440

    flamedabone
    ALLIANCE MEMBER




    Yes. It took me a long time to get used to the idea of no balancer, but after about 50 thousand miles, I quit worring about it.

    -Abone.
     
  8. Good thread! I'm supposed to take a drive to Vegas next weekend and pick up a complete blower setup for a BBC. Since I haven't played with blowers in over 20 yrs, this info here is welcomed. BTW, last one I did was a 6-71 on a 482 with 2 Holleys, probly 800 DP's, and didn't do any power valve work and it ran fine.
     
  9. flamedabone
    Joined: Aug 3, 2001
    Posts: 5,440

    flamedabone
    ALLIANCE MEMBER

    One more thing about the chassis dyno....It is a very simple thing to do. Don't be intimidated if you have never done it. They back you onto the rollers, strap you down, wire you up and go. My guy charges 75 bucks for three pulls or 100 an hour.

    PAY VERY CLOSE ATTENTION TO YOU AIR/FUEL RATIO!!!!!!!!!!! They will print a graph that gives you your a/f for the entire run. Get it safe, then try to find your maximum power. Timing and fuel will change your a/f and your power #s.

    If you are new to this, listen to the dyno guy for tuneing suggestions and verify the changes on your next pull. You will find some power and it will be fun, I promise.

    I found about 100 more horse on mine....

    [​IMG]

    -Abone.
     
  10. bigalow1
    Joined: Feb 17, 2008
    Posts: 105

    bigalow1
    Member
    from 496 C.I.

    What plug wire suggestions are there. My headers will get hot. What can I do to prevent the boots from burning. On a RB 440 2,6,3,7 plug boots are 1/4 inch away from the headers

    What is: Re-clearance a supercharger mean????
    Extreme Backfire:: This has me worried what is it and how do I avoid it???
    (run 10% under 5psi )
    i have to avoid the OOOPS! or I will be roddin the turbo beetle with flower all suumer:mad:

    Cool pic" Flamdabone" What car did you win the title in?
     
    Last edited: Dec 18, 2010
  11. bentwings
    Joined: Jul 1, 2007
    Posts: 132

    bentwings
    Member

    Lots of good info here. I've been around big blowers for a very long time too. I just put 12,000 miles on my ride and drove it the day before our big snow storm in 10 deg temp so you can drive them just like any other car. I get good mileage too and it is very fast. Enough of that

    Run a hub only, 1 key 1/4 inch tool bit. 2 for good measure. 86 the damper.

    3 in 8 m metric belt. tough and kool. By the way the motor will run with no belt. not very fast but it will get you home.

    under/od drive to get about 4-5 psi boost to start with. It's easy to change pulleys and cheap. I'd go with hard anodized pulleys if you plan on lots of miles. The road dust will kill the standard polished ones. Not as kool looking but more durable. My std ones are about 1/3 worn in 1 year. My mistake.

    Buy your whole kit from Dyer or other. He is close so I'd go with him. He will probably want you to go with AVS/Edelbrocks. I've used his stuff before and it worked ok...however

    I use 750 Holley DP boost ref carbs....Summit. Buy new save yourself some heartaches. Hook up the manifold ref. easy. They will probably run right out of the box.

    Get a BDS scoop...extra kool and with K&N aircleaners. I clean mine about every 2-3 weeks and right after any significant rain driving.

    You need a good dist. MSD with a vac advance. It will give 1-3 mpg instantly. Smooths out the idle and runs cooler. Blowers like lots of initial advance and not too much total. All of your advance needs to be in at 2200 no more. You can just use the springs, bushings and weights that come with the dist or have it curved at a hotrod shop.

    Good wires and insulating boots. About $6-8 each Well worth it.

    Either buy Jet Hot coated headers or get yours coated. Headers can get bright cherry red in sunlight... and in a hurry if the misture and timing are off..like at startup. You will probably need some good header wrap and big hose clamps. Get 3 inch collectors and run 3 inch all the way back. What ever mufflers you like.

    Good fuel system. min 1/2 (#8) line from the tank to the pump then to a good fuel filter then regulator and #6 to each carb.

    I'd really suggest getting a permant AFR gage. Innovate Motorsports is what I use. You can hook it to your laptop and log tunning sessions. It makes it very easy to tune. Get the Holley tuning and Mod book. $25 or so....memorize it.

    As for the cam, it will work just fine as noted the blower tames down the cam a lot. It gives much better fuel atomization and better fuel distribution at idle so everything smooths out. I would not get too concerned about all the fine points untill you really want to go very fast and spend a lot of $$,$$$...notice the comma. haha:eek: Good rockerarms and pushrods. Use break in oil and zinc additive every change.

    If you can I'd try to get some alum heads. I like Edelbrock RPM heads for relatively cheap heads that really do work for this app and on the street. They will be much more forgiving as far as compression and running available gas as opposed to cast iron. We like to say the equavalent of 1 point in compression. I think it is because of their ability to run cooler in the combustion chamber. I run 87 occasionally as sometimes out in the country back roads there are only 4 pumps...3 diesel and 1 gas...87 :eek: so if you want to drive anywhere be prepared.

    You will need a gas line kit. Several are available or make your own. Use AN stuff it is easy.

    And you will need a throttle linkage kit. This is standard stuff everyone uses the same stuff except the outlaw guys that cobble things together. If you have time and tallent go and make your own otherwise buy it. They are good.

    this is enough for this session. I don't think I said anything new just put it all in one place.:rolleyes:

    Good luck

    Come to Back to the 50's Look for the Willys guys I'll be there.:D
     
  12. bigalow1
    Joined: Feb 17, 2008
    Posts: 105

    bigalow1
    Member
    from 496 C.I.

    (The Rocket Plan)
    I am already running an Aeromotive 150GPH elec fuel pump set-up, Duall Filters ect..
    The new 6-71 will tap me so I am going to try and use my Edy 800CFM Performer carbs?
    I am going to underdrive it 10% and follow the suggestions from this thread, timing ect...
    Once everything is installed I will make sure it starts then tow it over to a chassis Dyno shop by the house. I talked to the shop and they said they would be glad to help me tune it to eliminate any lean condition problems.

    Everybody has been so helpfull on this site!!! Thank you and I am going for it!!!
    I will post pics of my progress as I go along
    I am going to go with the single keyed crank motor that I presently have running. I will try to take it easy.
    Over the summer i will collect a double keyed crank and other parts for a 440 block I have waiting for some Luvin -Heck with that beetle
     
  13. Jingles
    Joined: May 6, 2009
    Posts: 100

    Jingles
    Member

    Bigalow1,
    I will make suggestions based upon what Gene Mooneyham (Mooneyham Blowers), Mert Littlefield (Littlefield Blowers) and others have told me in regards to running 6-71
    blowers on SBC engines. Use GOOD forged rods, GOOD forged cranks with a double keyway and preferably a big block snout-- I like Callies and Crower, about a 7-7.5:1 compression ratio, a cam with about a 14 degree lobe separation. Less separation will let the blower simply blow fuel right through your engine without burning it. Use a cam and springs that have enough valve spring pressure that the valves are not blown off their seats by the blower; this means a solid lifter spring, hydraulic roller spring or stiffer. I like a hydraulic roller if your budget allows it--- the springs are stiff enough and you don't have to adjust the valves very often like you do with a solid cam. I also recommend an MSD boost/timing retard; MSD has a nice one based on their MSD 6 series ignition amplifiers. And I recommend running an aftermarket balancer.
    Before you make any permanent decisions I recommend that you talk to Mert Littlefield and Gene Mooneyham. Tell them that you are trying to gather all of the essential engines parts together to build a blower engine and you want their suggestions on crank, rods, etc. And it is a good idea to ask them about their blowers and all of the related parts that they sell.
    When you are deciding on a cam, call your favorite cam manufacturer. Have all of your information handy: car weight, gear ratio, etc. If the salesman suggests a cam with a 110 (or less) lobe separation it means that he is only a salesman and does not know what he is doing. Call back later and ask for a tech who can help design a special cam for you. If you get another amateur type computer reader, ask your local racing engine machine shop to recommend a specific tech who works for the cam manufacturer.
     
  14. bigalow1
    Joined: Feb 17, 2008
    Posts: 105

    bigalow1
    Member
    from 496 C.I.

    Thanks Jingles
     
  15. Great thread. Especially since I just got back from Vegas with all this.
    454 block/heads/crank included
    [​IMG]
     
    Last edited: Dec 25, 2010
  16. Merry Christmas to YOU!!
     
  17. Damn Groucho,,,Looks like you made out like a bandit.
    A lot of good parts there,,keep us up on your progress.

    Tommy
     
  18. bigalow1
    Joined: Feb 17, 2008
    Posts: 105

    bigalow1
    Member
    from 496 C.I.

    Merry Christmas to you. Whats it going in?
     
  19. abone1930
    Joined: Jan 16, 2006
    Posts: 1,325

    abone1930
    Member

    So can I use non boost referenced holleys? I used his carbs on tunnel rammed 521 ford.Bought them from lyle stahle on ebay. Matter fact about to send him a pair of 750 dps for my blower to rebuild for me. For me to run about 6lbs of boost, how many teeth are on the top pulley, then the bottom? Getting mine together :D
     

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  20. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,263

    gimpyshotrods
    ALLIANCE MEMBER

    A quick note of clarification: Volume not pressure. You never want to run an Edelbrock carburetor over 5.5 psi., regardless of what it is on.
     
  21. ditto
     
  22. Running a couple of Edelbrock 600's on my Hampton 671 SBC. Tuned them using Edelbrock kits and their recommendations as starting point. 7.5:1 CR, 36 degrees locked down timing, Headers will glow cherry red if timing is too retarded in addition to hard starting and popping and farting. Ask me how I know. Accel high temp wires, Mallory dual point triggering an MSD box (cause it fits) and 18% UD. Can't remember the cam specs but it's an old B&M blower cam (shows how long this things been in service). 140 GPH Mallory pump, 1/2" line, 2" belt, steel crank, Pink rods, roller 1:6 rockers. Pretty tame setup but I was only after noise and looks and I can still pump 5 pounds when I get serious. I read the how to supercharge book from front to back a few times before I tackled this.
     
  23. 1939STREETROD
    Joined: Mar 5, 2006
    Posts: 256

    1939STREETROD
    Member

    i've been collecting for a couple of years now AND AM ABOUT READY TO BUILD my 392 hemi...biggest porblem for me is $$$....i have heads with 3 angle grind , stainless valves all done, stock rods w/ MT flat top pistons - forged, stock hyd cam with new lifters, crank 10/10 done....weiand intake and 6-71 blower, 2 predator matched carbs 370cfm-780cfm...question - since i am dealing with an approx 10-1 cr, can i run thick copper gaskets to lower my CR and underdrive to help compensate....also, thinking of running E85 to keep it kool...any suggestions?.....btw, not real sure how the choice of upper/lower pulley cogs works - is there a table that has suggestions for drives?....had a blower book, but a 'friend' kept it.......1st blower on this engine....ran an 8-71 on a 355 sm blk chevy for a while, but i did not choose the parts - they came with the setup.....appreciate any help...do they make a hub for this engine?....fluid dampers are what many are using - costly tho......john
     
  24. bentwings
    Joined: Jul 1, 2007
    Posts: 132

    bentwings
    Member

    Hi,
    Your CR is going to be a problem. I'd suggest you recalculate it. It been 40 years since I ran top gas but I think flat tops are less than 10:1. We ran down the hole some amount. You are going to need somewhere in the 8:1 range. Unless...you run a water/alcohol injection system. These work great for higher compression. Also the motor will drive easier with the high compression. You will have to run premium gas however. The E85 is a reasonable idea however it is not available everywhere.

    I don't known anything about Predator carbs. You had best understand exactly how these work. Blowers don't like lean condition and lots of throttle, plus you need lots of accelerator pump action very quickly or " boom" you will have blower damage. It is too easy to purchase a pair of boost referenced Holley blower carbs. They will run very well out of the box every time. I've got about 25k on my hotrod in weather from -5 to 105 deg.

    You could probably run .100 coper gaskets but I think you will have endless water leaks. I don't know if they would gain you one point CR or not without doing the math. I'd guess not. Additionally you would probably have to run thicker intake gaskets too. Hot Hemi heads could probably tell you your CR based on what you have. They most likely will have the right gaskets as early Hemi is all they do.

    As for drive ratio charts BDS and Dyer would have them. They also will have belt lengths. Good vibrations will also have this as well as other parts.
     
    Last edited: Jul 8, 2014
  25. Good stuff on here. I read most of it. I saw nothing on manifold prep. I torque my manifold down like torqing down a head. Then i use lay


    out dye over the top surface. I fill the opening with rags. I have a 3/4" plate 18inch by 18inch with sand paper glued to it. I sand until flat. You would be surprised to see how much distortion there can be. When the blower is tightened down with out doing this the case will twist. A lot of blower problems are due to over looking this step. twisted cases equals touching rotors. Next is the air fuel gauge. This is the way to tune the engine. There is no guess work. its so simple to dial in your car. Another thing is a boost gauge. How do you know what you have without a gauge. There are so many variables from valve and port sizes to cams and super chargers etc. don't fall into the pulley size game. its not a reliable way to figure out whats going on inside the engine it only tells you the speed of the blower. the last thing is a ignition system with boost retard. as boost goes up the need to remove timing becomes important to reduce the dreaded detonation. i have used a single keyway on my car for years with no problem. running a max at times of 15 lb. studs and o-rings are a good investment. i also run copper gaskets with a light silicone film on them. i set the o-ring off the deck at .007. my engine is a 392 on gas
     
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  26. squirrel
    Joined: Sep 23, 2004
    Posts: 55,934

    squirrel
    Member

    in addition to the intake being flat, you might also want to take extra care when torquing the blower case to the intake manifold. Use an inch pound torque wrench, follow a staggered tightening pattern, and run them up a couple inch pounds at a time, up to about 8 in lb. Turn the blower as you go, to make sure it's not binding
     
  27. 1939STREETROD
    Joined: Mar 5, 2006
    Posts: 256

    1939STREETROD
    Member

    ....i understand the idea of running them down the hole a bit, but is this only accomplished by shorter rods or crank regrind?...am i missing something else?.....
     
  28. 1939STREETROD
    Joined: Mar 5, 2006
    Posts: 256

    1939STREETROD
    Member

    i will call hotheads at some point - maybe soon!....i guess i need more engineering befroe i build!....just trying to keep the cost down, but i may have to bite the bullet now rather than later....thx for all the suggestions - they have reaffirmed my thoughts....johnnyB
     
  29. bentwings
    Joined: Jul 1, 2007
    Posts: 132

    bentwings
    Member

    Rod length and compression height are what we used to adjust CR. often we ran different CR in different holes to tune the motor. It's still done today on the race cars.

    I surely would do the calculation before you build. Pistons are not cheap.

    One thing that has not been noted is converters with auto trans. You need a decent trans as it is not fun redoing one after the car is complete. It is expensive especially when you are already way over budget. You really need a 3000 or so converter to unload the motor at idle. It makes tuning idle speed so much easier. I had a 2000 conv. At first on this car and it was difficult to get rid of the Detroit Roll. Once I got the higher stall conv. It was easy to adjust the idle mix. Don't forget a trans temp gage.

    As I noted earlier an AFR gage is a huge plus for tuning. Along with a vac/boost gage. I also have portable vac/boost that I use under the hood.

    Also when tuning these or any motor be aware that it takes a good half hour to get everything up to a stable operating temp. The AFR needs some time to come up to temp especially.
     
  30. squirrel
    Joined: Sep 23, 2004
    Posts: 55,934

    squirrel
    Member

    huh....takes about five minutes around here.
     

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