The Boxer Repair thread | FerrariChat

The Boxer Repair thread

Discussion in 'Boxers/TR/M' started by JTR, Dec 11, 2007.

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  1. JTR

    JTR Formula 3
    Owner

    Apr 26, 2005
    1,502
    in a house
    Full Name:
    John
    Hopefully this can be a permanent home for Boxer Repair Projects, that the owners have done.
    If you remember a good write-up on a particular repair that someone has done, please post a link to it here.
    Engine, clutch, suspension, tune-up tips, electrical, cosmetics, you name it, are welcome.
    And hopefully someone can post just how to post a link, as I don’t have a clue!
    John
     
  2. ferraripete

    ferraripete F1 World Champ

    it would be nice to set it up such that there are sub-threads within this sticky.

    ---clutch service

    ---major

    ---suspension rebuild/lowering

    ---brake service

    just a thought.
     
  3. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  4. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  5. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  6. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  7. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  8. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  9. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  10. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  11. JTR

    JTR Formula 3
    Owner

    Apr 26, 2005
    1,502
    in a house
    Full Name:
    John
  12. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  13. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  14. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  15. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  16. Newman

    Newman F1 World Champ
    Consultant Owner Professional Ferrari Technician

    Dec 26, 2001
    14,092
    Canada
    Full Name:
    Newman
  17. JTR

    JTR Formula 3
    Owner

    Apr 26, 2005
    1,502
    in a house
    Full Name:
    John
  18. LightGuy

    LightGuy Three Time F1 World Champ
    Silver Subscribed

    Oct 4, 2004
    39,594
    Texas
    Full Name:
    David
  19. Drew Altemara

    Drew Altemara Formula 3

    Feb 11, 2002
    1,504
    Tuscaloosa, AL
    Full Name:
    Drew Altemara
    I used this method to repair/replace the fuel sending unit on a 1979 carbed Boxer. I suspect it will work on an injected Boxer and probably on the 3X8 series Ferrari's.

    The sympton: Fuel gauge reads zero and you just filled it up.

    You need to decide if it is the gauge, the wiring or the sending unit. The easiest way to tell is to send +12V to the gauge through the wires from the sending unit to the fuel gauge. The fuel level sending unit is located on top of the passenger side tank. There are two leads coming from it plus a ground. One lead is for the level the other is for the red low reserve light.

    Disconnect the two leads. Get a 12V battery, clamp the ground to the frame and take the positive to one of the two wires. You should be able to make the red light come on and the fuel gauge should peg full if the gauge and wiring are fine. If not, I would remove the gauge and take +12V to it directly to determine if it is the wiring/fuse or a faulty gauge. In my case I concluded it was the fuel level sending unit.

    There are 6 nuts which retain the sending unit in the tank. Remove the nuts and carefully remove the sending unit. Be careful and stuff a rag in the open gas tank hole.

    Examine the sending unit. There is a rheostat that the float attaches to. There is a "door" that can be removed from the rheostat to allow you to see the internals of the unit. It is fairly straight forward. One wire is connected to an arm that rides the windings of the rheostat and the other will connect to another arm that engages the red low fuel reserve light wiring. In my case the rheostat wiring had broken after 25 years of use.

    I did not have any luck sourcing a new unit after calling the various Ferrari parts distributors. Ferrari UK does list it as available but after converting to dollars, paying VAT and shipping it was just under $400. Ugh!

    However David Feinberg suggested I use one from a Fiat. He directed me to International Auto Parts www.international-auto.com . The one that I purchased was for a 2000 Spider, 1890-on, inj (Item no. 34285); $38.95, now we're talkin. The only problem is that the arm that attaches to the float is too short.

    I spent considerable time making sure attaching the old float arm to the new sender would result in the same correct length from top to bottom. It was remarkable close, and certainly reasonable given the accuracy of the fuel gauge itself.

    There is some modification required. First remove the old rheostat from the old fuel sending unit. Now remove the arm. Unfortunately, the contacts on the old, longer arm are designed differently than the newer one. What you want to do is to put the contacts from the newer arm onto the old, longer arm.

    Get out the dermel tool. Carefully remove the contact body that is sodered to the old arm. This is hard to describe but I guarantee that once you look at the two arms you will see what has to be done. Now remove the new contact piece from the new arm; it is just press fit.

    Put the new contact piece on the old arm. Study the orientation so that the contact arms are in line with the line of the float arm. It takes a bit of trial and error to get this to aling but it's not that bad. Soder the contacts in place. Again this is easier once you see what has to be done. You will also have to cut off a few mm of the arm portion that enters the rheostat. Again, no big deal.

    The problem that I had that was that, though the bolt hole pattern was the same the new unit is rotated about 30 degerees from the old sending unit bolt hole pattern. This made the float arm hit part of the baffel on the inside of the fuel tank. By bending the arm slightly, actually to remove the existing kink in it, it can be made to clear the baffel. Again once you are there doing this in person it will become apparent what has to be done without effecting the travel length of the arm.

    There you have it. For $40 and 2 hours time you know how much fuel you have on board.

    Drew Altemara
     
  20. Drew Altemara

    Drew Altemara Formula 3

    Feb 11, 2002
    1,504
    Tuscaloosa, AL
    Full Name:
    Drew Altemara
    TUNING THE CARBURATED BOXER

    PREAMBLE

    Let me start off and say that I am a novice at this but with the help of a number of people, especially David Feinberg, I was able to get my 79 BB512 really tuned up nicely. Much of the advice I initially got assumed that I had more knowledge than I actually did. With that in mind I thought I would sit down and write, subject to their review, a how to procedure for the Boxer of my experience since it basically starts from scratch. My car is a BB512 but I believe it can be adapted to the 365GT4/BB.

    A COUPLE OF THINGS IT WOULD BE NICE TO HAVE AHEAD OF TIME:

    1) Haynes manual on Webers
    2) Pat Braden book on Webers
    3) Weber Carburetors by John Passini
    4) Weber WSM

    In truth you don’t need any of them to accomplish the procedure but I owned the first two manuals and there were very interesting and increased my understanding of what I was trying to accomplish.

    A COUPLE OF THINGS THAT ARE JUST ABOUT MUSTS:

    1) Timing light
    2) Synchrometer (type STE SK from Weber works well and available here http://www.webercarbsdirect.com/tuning_aids)
    3) Gunson Colortune (available here http://www.eastwoodco.com/email/default3.asp?SRCCODE=O1KW2342&SKW=COLORTUNE) You don’t have to have this if you have tuned Webers previously using the lean drop or sound methods but it sure made life a lot easier for me and helped trouble shoot a carb problem I encountered.

    A BIT OF “PRACTICAL” THEORY BEFORE WE GET STARTED:

    Tuning the car is a concert; everything influences everything else so you end up iterating; doing it a couple of times.

    You are basically tuning the idle circuit. The progression and full power phases are preset by the types of jets that are installed in the carb. One major assumption that is made here is that the throttle plates are positioned correctly in the carb. That is, that they are above the idle ports but just below the progression ports. If this is just a minor tune and tweak and nothing resulting from a carburetor rebuild I think you should be fine. If the carburetors are off the car then you should address this by consulting one of the manuals listed above.

    Makes notes as you work in order to establish a baseline in case something goes awry.

    There is no excuse for not reading the condition of the plugs and relating this information to the readings you are taking.

    GETTING STARTED

    Clean The Idle Jets:

    I learned the hard way. I initially tried tuning the car but ran into problems. My problem was plugged jets on one of the carburetors.

    Shown below are pictures by David Feinberg of the idle jet. It is the brass one towards the top of the carburetor. There are 12 of them, 3 per carb. Remove them, blow it out with compressed air, get 12 new o-rings and reinstall. I intend to do this once a year.




    Clean Up the Distributor Cap and Rotor:

    To do this right I feel you really need to make sure the distributor is operating properly. Very few people, and shops for that matter, have a machine capable of measuring advance. But we can make sure the cap and rotor are clean. Mine has a habit of accumulating moisture during hot, humid summers in the Southeast. I think its good practice to remove the cap, blow it and the distributor out with compressed air, lightly sand the contacts and rotor re-blow with compressed air and put everything back together. At least you know where you are starting from.




    Next Set Timing:

    The owner’s manual is a little confusing on this issue. It states that the advance is 5 deg static at 900rpm and 16 deg at 3200rpm but further states that it should be 35 deg at 5000rpm. Upon careful reading you realize that the first two readings are referencing to distributor advance and the 35 deg is referencing engine advance. As David Feinberg pointed out to me that the distributor turns half the speed of the engine. So, in terms of engine advance (what is marked on the flywheel) we are looking for:

    1) PM1-6 mark which indicates TDC
    2) AF10 mark which should line up with the pointer at 900rpm
    3) AF32 mark which should line up with the pointer at 3200rpm
    4) AF35 mark which should line up with the pointer at 5000rpm.

    First find the timing hole. It is located on the top, passenger’s side of the bell housing. There is a 2x3” plate secured by two 10mm bolts. Remove it to view the flywheel

    Here is a picture of the hole that David Feinberg took with the plate removed. (Please note David has a custom fuel delivery system for his carbs and you will not see the stainless steel hoses and fittings in the picture.)



    Now to the flywheel. I was advised to turn the flywheel using a large screwdriver until I found the PM-16 mark. This didn’t work too well. Not that the advice was bad but rather that I either didn’t have a large enough screwdriver to turn the flywheel or not enough muscle; maybe both. What I ended up doing was putting the car in 5th gear and rolling it forward until I could see the mark. Once you find it paint it red. About ¾ of an inch to its left (counterclockwise when viewed form the rear you find the AF10 mark, paint it green. Roll the car forward and about two inches further to the left you will see the AF32 and AF35 marks. Paint them white and yellow respectively.

    Warm up the car and shine the timing light down the hole. The green AF10 mark should line up with the pointer. If not, loosen the distributor and advance/retard until the green AF10 mark lines up with the pointer. Now have your assistant (wife in my case) slowly increase the rpms to 3200 and then briefly to 5000. You should observe a smooth increase in the advance and the pointer should line up with the white AF32 mark at 3200rpm yellow AF35 mark at 5000rpm. Is great, odds are you advance mechanism is working properly. If not, time to send your distributor to a shop to have it fit the advance curve.

    Time to Take and Initial Sychrometer Reading:

    The first thing I did was to record the air flow of all 12 throats. Be sure the car is warmed up and that idle is between 900 to 1000rpm. Any reading that is off by more than 1 from the others may indicate a problem.

    Balancing Carb Air Flow

    The first task here is to get all 3 throats of the carb flowing the same amount of air. This is complicated by the fact that as you later change the mixture setting the air flow will change. I started with all air bleed screws closed. The air bleed screws are identified by being locked in place by a 8mm nut. There are 3 per carb, 12 total. My readings were close enough, aside from one cylinder that had a plugged idle jet, which I elected not to do anything since I knew the readings could change later. You may want to open or close the bleed screws at this time to get all 3 throats flowing similar amounts of air. I think any variation within each carb less than ½ Kg/H seem reasonable at this stage.


    Balancing Carb to Carb:

    People attack this in different manners. I did it the way I thought was the most straight forward. First balance primary carb to primary carb across the bank. On the BB512 this is the RF and LR. These are identified by having the idle set screws and have hard linkage to the accelerator mechanism. Go slow, and 1/8 turn goes a long way. In my case since I anticipated idle increasing as my car became more in tune and my idle was a little on the high side to begin with I lowered the idle set screw on the carb that was flowing the greater amount of air. Now on to the secondary carbs. These are the ones that are attached to the primary via a linkage with a set screw mechanism. Adjust the set screw of the secondary carbs to match the primary. Now all 12 throats should be flowing the same amount of air. In my case this was about 5 Kg/H at 950rpm.

    On To Setting Idle Mixture:

    Pull out the Colortune and the instructions. The Colortune is a crystal plug that sparks and lets you see what’s happening inside the cylinder. You are basically going to richen up the cylinder, observe a white/yellow color and then slowly close it, leaning it out until a bunson blue color is detected. The are 3 idle screws per carb, one for each throat, 12 in total

    Follow the instructions, go slow, this takes a lot of time because each time you use it you have to pull the plug, insert the crystal plug, wire it up, and set idle mixture, then put the real plug back in.

    Two suggestions. First, this is a good time to “read” the plugs and make sure the reading is consistent with how you had to adjust mixture. This should be consistent with air flow observations and any problem you may have encountered. In my case cylinder no. 7 would not adjust. All I saw with Colortune was the spark and a black hole. The plug look like it was brand new, not oily or grayish. When I reved the engine slightly it would glow blue. This turned out to be a clogged idle jet. (Remember when I said to do this first. I wasn’t kidding)

    Second, as the old plug had to come out I installed new plugs after the Colortune.

    This takes a lot of time. But I was very satisfied with the results. Cylinders 1 and 12 are difficult to set idle mixture on because you have to use a very small screw driver and the cam gas recirculation system blocks the path of the screw drive to the idle set screw. I actually moved them out of the way temporarily. It’s nothing that’s all that hard just more of a nuisance.

    One More Time:

    Now that idle mixture is set you have to go back and check/rebalance the throats in each carb using the air bleed screws and then finally carb to carb as previously done. Get out the Sychrometer again. In my case everything was very close. My idle had risen as the car came in tune and I had to adjust the idle set screws of each primary carb down about 1/8 of a turn. Also go back and check your timing. In my case it was still dead on.

    If you get significantly different air flow readings you have to go back, get out the Colortune and set idle mixture again as the air flow effects idle mixture which effects air flow. Then once done with the Colortune for the second time, go back and again and check/rebalance intra carb throats and then carb to carb. Check timing.

    It Sounds Like A Lot:

    It is. It took me about a day, say eight hours to accomplish my task. This was after I had already spent the prior day tuning it but had not blown out the idle jets.

    It’s worth it. Your Boxer should run like a rocket now. You will notice very little progression stumble on take off and the car will feel much peppier.


    Drew Altemara
     

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