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broken engine!! :(

Discussion in 'XJ Technical Chat' started by SilentRaven, May 20, 2013.

  1. Captainkirk

    Captainkirk Member

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    Josh, just about any type of solvent & brush will work to get the majority of the gunk off there. You might experiment on your broken head to see what works or not.
     
  2. jmilliken

    jmilliken Well-Known Member

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    someone on here did a nice job with eastwood's 2K ceramic paint.....
     
  3. SilentRaven

    SilentRaven Member

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    Update! valves on the new head have been lapped, valve seals have been replaced and its ready to be reinstalled.... right after i order some parts from chacal lol. all in all the process wasn't to scarey. i practiced removing and reinstalling the valves and springs on the old head yesterday, and then this morning went and bought some grinding compound and did it for real on the new head. only took me a few hours to complete.
    a shot of the valves before and after some cleaning, and this wasn't even the worst one! (this is before i lapped them, just after cleaning off the carbon)
    [​IMG]
    old and new valve seals
    [​IMG]
    i could not find anywhere that had a spring compressor to rent out and i didnt have the money to buy one, nor did i really want to, so i made my own! a 6" C-clamp and a 2" piece of pvc pipe with a notch cut out works really well! the notch allows you to get in there and place the keepers while the spring is depressed. and it didnt cost me a thing!
    [​IMG]

    everything has been tested and nothing leaks, now im waiting for the new parts so i can reinstall it, measure for shim clearances again and get it all back together so i can then go back to my original issue of it not starting....
     
  4. BruceB

    BruceB Active Member

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    by golly you're a MacGyver.... Good Job!!!!
     
  5. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    Josh: do one more thing. If the replacement head DID NOT come with cams and you're using yours, please take the additional time to "Plastigauge" the cam-to-journal clearances. It should be fine, but if it isn't you're going to build a grenade and not know it until it lets go.

    If you're unclear on the process I can send you scans from the factory manual. Or go to the Plastigauge website: http://www.plastigaugeusa.com/how.html

    A good machine shop will usually give you a 6" or 8" "hunk" which is plenty; or you can order the "retail pack" directly from Plastigauge for a whopping $8.25 http://www.jhps.com/mm5/merchant.mvc?Sc ... ry_Code=PL

    Speaking of manuals: if you're working with only the Clymer, please PM me with your email address so I can get you the relevant pages (head re-installation and cam installation/timing) from the FACTORY book to go along with the sadly weak Clymer book. Slow down long enough to get these pages in-hand before proceeding.

    By the way, the PVC-pipe valve spring compressor looks remarkably like the real kind you need for these tiny, buried valves. Good job.
     
  6. Polock

    Polock Well-Known Member

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    i still see motor oil and little chunkies in on the head. so i have to wonder how you got all the valve grinding compound out ?
    maybe there's other ways but i usually give it a real good squirt out with the garden hose before i start putting it back together
     
  7. SilentRaven

    SilentRaven Member

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    i do have a factory manual, at least i think i do (i dont look at the cover much, lol) i will investigate the plasitgauging because i am reusing my old cams.

    thanks on the compliment son the PVC compressor, it worked super awesome, and it only popped off once. but i had the PVC laying around and i borrows the clamp from a friend. the clamp cost $8 at autozone, that amount of pvc would probably be less that $1 so its a compressor for under $10. although i wouldve liked it to be wider PVC just to be able to get in there and position the keepers a bit better, but needle nose pliers worked pretty well. the only thing i had to buy was the grinding compound!
     
  8. bigfitz52

    bigfitz52 Well-Known Member Premium Member

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    READ the factory book. More than once, carefully, BEFORE you put the head back on. Starting on page 3-31, on through 3-33. VERY IMPORTANT stuff in there, if ignored spells disaster.

    Use of Plastigauge for measuring the cam clearances is on page 3-16, along with the specified clearances.

    DON'T RUSH reassembly. It will only lead to tears. Follow the (factory) book to the letter; if you have the Clymer it just helps "fill in" some things.

    ASK QUESTIONS. We don't want to see you go through all of this and have the mill frag on you the first time you wind it past 8K rpm.
     
  9. SilentRaven

    SilentRaven Member

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    ok i read over the manual (yamaha factory) pages about the cams; so if i understand it correctly the plastigauge will tell me if my cams should be replaced or not, due to clearance measurements, true or false?

    And ive read the installation pages as well and will read them over again, while i wait for my other parts to come in

    and heres an interesting question that my wife had for me wife i was lapping the valves. she asked why is it important that the valves dont leak? what damage could occur from leaky valves. i told her i dont know exactly but its never a good things when leak, lol. any one care to enlighten her... and me?
     
  10. Captainkirk

    Captainkirk Member

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    Sure. Leaking valves do the following:
    1) Lower your compression readings (duh!)
    2) Cause you to run higher EGT's (exhaust gas temps)
    3) Cook your brand-new valve seals
    4) Coke the oil on your valve stems causing stuck open valves....that means being kissin' cousins with a piston dome down the road and = grenaded motor
    5) Leakage past the valve face will erode and burn the valve and seat, making a small leak bigger.
    6) Leaking intakes will cook your carb innards and manifold rubbers, cause backfires and other assorted mayhem.
    Heard enough?
    The way to check if your valve lapping job is good is:
    1) There should be an even gray ring around both the seat and valve face
    2) Lay your head on a level table, valve heads up. Fill each combustion chamber with stoddard solvent, let sit 5 minutes. There should be no solvent leakage through either intake or exhaust port. If so, lap them again until they don't leak (I usually do this before I reassemble the springs and keepers)
    I did like you on the PVC/C-clamp on the last head I did...after doing all 16 valves I said NEVER AGAIN! and ordered a real valve spring compressor.
     
  11. greg_in_london

    greg_in_london Member

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    Leaking valves let the magic power pixies escape.
     
  12. SilentRaven

    SilentRaven Member

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    ok so update on the progress, which it indeed is, so got all the valves lapped, i relapped a few of them after i retested and noticed some leaks. new valve seals installed. plastigauged. and today i got my parts from chacal (thank you!) so it was time to install the new head which thankfully, with some help from my wife, went fairly smooth; other than the head getting stuck a few times on one of the little metal sleeves that didnt want to sit properly. but now the new head is on and secure, following the direction of the factory manual. cams are on and caps are secure. but i can not go any further because i need to rotate the cams to line up the dots with the arrows but i dont have a wrench large (or small) enough to rotate them. none of my adjustables go large enough to fit are the cam and the wrench needs to be fairly small in size because the frame is in the way, it wouldn't be an issue if the motor was off the frame like it is in the book. so it should be a bit of an interesting day tomorrow trying to position my cams.

    but i am happy to just have the new head on, im making progress and now its visible! and i can finally starting picking up all the parts laying around my garage, lol

    i now also have a nice work bench and cabinets in my garage thanks to TeddyTedTed who brought them to me instead of putting them on the curb for any joe schome to pick them up! nothing fancy but its nice to have a work space and storage space there now.
     
  13. Captainkirk

    Captainkirk Member

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    You're gettin' there!
     
  14. SilentRaven

    SilentRaven Member

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    UPDATE: cams finally installed! chain is on and everything lines up. so i filled it back up with oil (i had planned on taking the oil pan off but could not remove all the bolts) and measured shim clearances. now thankfully i was smart and made note of what shim sizes i put in before i got everything installed, so i wouldnt have to go through the hassle of pulling them out to see their sizes. there wasnt any sorta rhyme or reason for the size of shim i put where it was just kinda what i had, figured i had to measure them all anyways. so here is where i am with with shim measurements.

    Ex
    265 275 275 285
    In
    280 270 280 275

    Ex
    .152 .051 .038 .038
    In
    .051 .051 .038 .063

    so just checking with every one else here on what i believe needs to be replaced in what position...

    Ex
    260 260 260 270
    In
    270 260 270 270

    does this look right? im just using the chart from the book.
     
  15. hogfiddles

    hogfiddles XJ-Wizard, Host-Central NY Carb Clinic Moderator Premium Member

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    Which book?

    Some books have the chart incorrect.

    Dave F
     
  16. SilentRaven

    SilentRaven Member

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    im using the Yamaha factory manual, but i was actually using the chart from a print out of bigfitz shim write up.
     
  17. Ted

    Ted Member

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    Nice doood, you're getting close! I can't wait until this moves out of the "broken engine!! :(" thread and back into a "getting it running" closely followed by a "got it running.. now what?" sort of thread! :lol:

    I didn't have time to double check your shim calculations but I'll see if I can get to it a little later.

    Yeah buddy!
     
  18. SilentRaven

    SilentRaven Member

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    Im finally back to where i was before i started this thread, lol. now just waiting to order some shims, after i come back from my vacation this week and then get back to figureing out the electrical issue.

    thanks for letting me borrow the wrench!
     

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