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94 512TR 66,000 mile major

Discussion in 'Boxers/TR/M' started by JIMBO, Sep 9, 2019.

  1. JIMBO

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    At this point all cam timing marks should be aligned perfectly and it's best to mark the cam sprockets in relation to each other as well (pretty much mark everything you can so there are visual clues if anything is out of whack).
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  2. JIMBO

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    On to the valve adjustment.
    First make some sort of chart so that you can't make a mistake (or at least it will be harder to screw up). Here is mine:
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  3. JIMBO

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    You will need a set of metric feeler gauges. Rotate the crank until the lobes on the intake (upper) cam for cylinder one (or whichever cylinder you want to start with) point straight out. This means the valve is closed, sitting on the base of the cam lobe. Take your feeler gauges and measure the gap between the base of the cam and the valve shim. You want the intake gap to be between .20 and .25 mm and the exhaust .35 to .40 mm. Keep the cam well oiled. Repeat 47 more times and record each clearance value.
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  4. JIMBO

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    Now we've gotta get into some theory and calculations. Circle on your paper any valves that are out of tolerance. They will most likely be exhaust valves and they will most likely be too tight. We then need to remove the valve shim, measure its thickness and replace it with a thinner (or thicker) shim that will give us the right clearance.
    For example, in my chart above, exhaust valve for cylinder #5 shows .33 clearance. We want .35 - .40, so picking a new shim that is .05 mm thinner than the one now in place would give us .38 clearance, right on spec. Thinner shim, more space between shim and cam. Easy peazy.
    As always, check and recheck before taking action.
     
  5. JIMBO

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    That's theory. In practice, removing the old shim is a pain in the rear. Expletives are allowed.
    The shims sit tightly in a bucket. To remove a shim you first have to compress the shim and bucket together, then wedge a tool on the very edge of the bucket only, leaving space for the shim to be removed. Also, try not to damage the cam (duh).
    There are special (read expensive) Ferrari tools made expressly for this purpose. Some can be borrowed from other F-Chat fellows.
    I used a common curved pick which has the leverage to do the job. I then crafted a nifty tool to wedge between the bucket and the cam to hold the bucket down. I don't know what this piece of metal was used for. Search the forums and you will find tools made out of wrenches that are ground down.
    Keep everything well oiled.
    You will also need a shim kit with various thicknesses.
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  6. JIMBO

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    I bought the shim kit. 112 shims. $400. I used 6. Oh well, I'll just keep it around for the next major at 106,000 miles.
    Also, always measure your new shims. Mine were all spot on, but you never know.
    You will need a caliper with metric capabilities. Mine is a cheap one from Northern Tools I bought many years ago. Today I'd check Amazon and it would be here tomorrow.
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  7. JIMBO

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    Here is the Amazon listing for the pick set that contains the "Ferrari Valve Shim Depressor" tool.
    GearWrench 84000D Hook and Pick Set
    by GearWrench
    302 ratings



    Amazon'sChoicefor "gearwrench tools"


    List Price: $49.35
    Price: $22.38 FREE Same-Day & FREE Returns
     
  8. JIMBO

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    So, you depress the shim and bucket with the curved pick, then insert the other tool on the edge of the bucket so it all stays depressed. Then remove pick.
    Theoretically the shim should pop out, but it is held pretty tight in that bucket and needs coaxing. Some say compressed air at the edge. That didn't work.
    I took a tiny screwdriver and put it on the edge of the shim and gently tapped. Eventually the shim came out. Expletives were heard. Adult beverages were consumed.
    Then measure the old shim (in this example it was 3.79 mm) and then pick a new shim that is smaller (3.75) and will give the correct clearance. 3.75 is .04 mm smaller than 3.79. Our old gap was too tight (0.33), so the thinner shim increases the gap to 0.37, right in our 0.35 -0.40 range.
    Oil the new shim, slip it back in the bucket, remove the tool and everything snaps in place. I then rotate the crank through one revolution to fully seat the shim and re-measure just to be sure. Boom. Done. On to the next valve.
    Be sure to write all this down on your valve chart and save this info for the next major.
     
  9. JIMBO

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    FYI the shims are 29 mm diameter.
    You can purchase a kit of 112 shims for $399 from Newco products in Chatsworth CA.
    Info@NewcoProducts.com
    818-341-9216

    FER-SHIMKIT29M-112
    METELLI VALVE SHIM KIT QV 29 MM,
    112 PIECES WITH TOOL, (03-1064) ITALY
     
  10. turbo-joe

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    why you not just take the cams out after meassuring and have a look at all the shim sizes, write all down. so next time then you just know what shim size is for what valve. also it is much easier to take the shims out. even you have the special tool to do this without removing cams and there have been more than 12 valves each bank to be adjusted you may be faster removing the cams. if only 2 or 3 shims have to be replaced then it makes no sense.
     
  11. JIMBO

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    It was only 6 shims total.
    Clyde Romano has a 100,000+ mile car and he says the valves don't really start to move until about 75,000 miles, but I imagine every car is different. The valves I adjusted now at 66,000 are not the same valves I adjusted at 30K.
    If a lot of valves are out of spec, than maybe your way makes more sense, but it's also more complicated. I do one at a time and them move on. I'm less likely to make mistakes and time is not an issue.
     
  12. JIMBO

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    Now the good stuff, changing the belts.
    The first thing to do is loosen the cam sprocket bolts (19 mm socket and impact gun). In doing this we want to maintain the crank/cam relationship. Leave all belts on and tight. Put a vice grip somewhere on the cam and try to keep it from turning while you give the impact gun one quick blast. It is even better if you leave the plugs in, so in retrospect I would do this after removing the belt covers and before checking the valves. Do not remove the bolts, only loosen slightly. Repeat for all 4 cams.
    If you contemplate changing the front seal, also loosen the big crank bolt.
    In loosening these bolts you may have moved everything in a counterclockwise direction slightly. Theoretically there could be some slack in the cam belts from moving it the wrong way. Now remove the plugs and rotate the engine two full turns clockwise to take up any slack and return everything to top dead center. All marks should again align.
     
  13. JIMBO

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    Mark your sprockets R/L and upper/lower. I do one at a time.
    Loosed the 19 mm bolt on the tensioner and then push the bearing down so the belt is loose and tighten 19 mm bolt to hold tensioner in this position. Remove belt.
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  14. JIMBO

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    Remove sprocket bolt (19 mm). The large washer has a cut out that corresponds to the pin that locks the sprocket to the cam-shaft. There is also a small O-ring that needs to be replaced. Image Unavailable, Please Login
     
  15. JIMBO

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  16. JIMBO

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  17. JIMBO

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  18. JIMBO

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    Once clean, install the new seal. Apply a thin layer of oil to housing and either press in seal or gently tap in with a rubber mallet. I got mine started by hand and then used an arbor press. Go slow. Do not mess up the new seal. Install the new o-ring.
    After cleaning the area around the cam, oil the cam surface and re-install. Clean nuts and torque to 10 nm. (I could not find this torque setting in the service manual but it seems right. If anyone has better info please let me know before I close everything up).
    Mark bolts after final torque.
    Repeat with other cam. Image Unavailable, Please Login Image Unavailable, Please Login
     
  19. JIMBO

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    Remove, clean and replace rear plastic cover while sprockets are off. Note shiny clean front of engine block and bolts. Brass brush and Brake-Klean. Image Unavailable, Please Login
     
  20. JIMBO

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    Reinstall cleaned sprockets and bolts, making sure sprocket pin is in the correct hole in the sprocket and also in the correct hole in the cam. All marks should line up. Hand tighten bolts, making sure cut out in washer is over the pin head.
    Repeat above process for opposite side, then have an adult beverage. Image Unavailable, Please Login
     
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  21. JIMBO

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    Oops, I got one thing out of order. While the cam sprockets are off, it's a good idea to remove the tensioners and change the bearings. On my car the edge of the tensioner hit the sprocket when trying to take it out.
    First, remove the two 13 mm locknuts and washers, then remove tensioner unit. The tensioner spring should be already fully compressed for belt removal. Wedge a screwdriver so that the spring will not release when the 19 mm bolt is removed. I learned this doing the second tensioner. Much easier.
    Remove 19 mm bolt, large washer and bearing centering washer. Pull bearing with a puller or tap off with a hammer. Clean all parts. Replace with new bearing (use a press or tap on with a socket that fits the bearing hub area. Don't whack on the bearing itself). A little oil on the shaft makes it slide on easier.
    Reinstall bolt, washer and centering ring in proper relationship. Clean area on block around tensioner, clean bolts and washers and reinstall. I don't know the torque setting for these 13 mm lock washers. Any educated guesses?
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  22. JIMBO

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    I opted to go with the Hill Engineering tensioner bearings. They look just slightly better machined than the ones from Ferrari in the service kit, but really I have no idea if they are better. After 36,000 miles, the old bearings were smooth as silk.
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  23. JIMBO

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    For what it's worth, the old belts looked fine except for slightly frayed edges. Does this affect the structural integrity of the belts? I don't know, I'm not an engineer. I do feel that changing belts every 5000 or 10,000 miles is nonsense. Next belt change in 40,000 miles!
    New belt on right, old on left. Image Unavailable, Please Login
     
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  24. JIMBO

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  25. JIMBO

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    S, we have the tensioners installed with springs fully compressed, the back plastic covers in place, all 4 cams seals and sprockets in proper alignment. Recheck all cam timing marks, and it's time for belts. This requires a little muscle. It was 9 at night and I had no one to take photos. Put your cam locks in place. I made some from a hockey puck, a threaded carriage bolt and a wing nut (total cost $4.63). I also had vice grips on cam.
    Start with the LH (rearmost) belt, start with crank sprocket. Hook belt onto crank sprocket and then pull tightly to seat in bottom sprocket, then loop over top sprocket, seat belt again and now try to work belt over edge of tensioner bearing. Another person would be helpful to keep belt from slipping off crank sprocket, but I did it after 2 or 3 tries. Same with RH belt. Boom, done.
    Check TDC (PM) mark, all sprocket relationships to marks and 4 cam timing marks. Loosen the 19 mm bolts on the tensioner bearings and let the spring expand to put full proper tension on the belts. Tighten bolts (we will torque later).
    Now remove all cam locking apparatus. Check all marks again. Rotate crank two revolutions clockwise to fully seat belts and to distribute tension. Check marks again. If all line up, the belt change is a success.
    The belt should be tight. You should only be able to twist it 30 degrees or so by hand. Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
     

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