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Thread: TD5 blow-by remains

  1. #1
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    TD5 blow-by remains

    Good day all

    Following up on these 2 threads :
    TD5 cylinder glazing
    TD5 "Blow Back"

    We rehoned the bores and fitted new bearings and rings. Closed everything up and chucked some cheapo 10w40 oil in.

    The disco starts fine and runs fine - although very down on power cause we decided to run an old ecu on it to keep things standard.

    The oil test results came back with no diesel present, so no over feuling.
    Very high lead, calcium, phosphorous and zinc contents though.

    EGT's, coolant and head temps seems fine.

    BUT I still have considerable blow-by from the crankcase.

    Could this at all be caused by the cylinder head we originally purchased brand new or valve stem seals ?

    Nobody here in CT seems to have an answer any more....

    Any ideas.

  2. #2
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    Quote Originally Posted by DiscoJakes View Post
    Good day all

    Following up on these 2 threads :
    TD5 cylinder glazing
    TD5 "Blow Back"

    We rehoned the bores and fitted new bearings and rings. Closed everything up and chucked some cheapo 10w40 oil in.

    The disco starts fine and runs fine - although very down on power cause we decided to run an old ecu on it to keep things standard.

    The oil test results came back with no diesel present, so no over feuling.
    Very high lead, calcium, phosphorous and zinc contents though.

    EGT's, coolant and head temps seems fine.

    BUT I still have considerable blow-by from the crankcase.

    Could this at all be caused by the cylinder head we originally purchased brand new or valve stem seals ?

    Nobody here in CT seems to have an answer any more....

    Any ideas.
    its a possibility? what were the piston clearance measurements?
    if it were the head is there the same ammount of blow by out of the oil filler cap??
    if its coming out of the dipstick and not the oil cap then one can assume its going past the rings.
    can you chuck up a video of the blow by for viewing??

    cheers phil

  3. #3
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    Can you post up the UOA please ?
    What is the labs limit on fuel ?
    If Wear Check, their limit may only be 1% and therefore fuel can still be present yet not show.
    Calcium is an oil additive, and often varies between 2500 up to and over 3000ppm on Japanese specific diesel oil blends.
    Zinc is an oil additive and the basis of assembly lube.
    Phosphorous is an oil additive, particularly in diesel oils.
    Lead is obviously bearings, although oils such as Neo use lead in the additive package and can make interpretation difficult. Redline have started using a Lead Napthalate add base too FWIW.
    I'd be more interested in Silicon and sodium. These will be you indicators of contamination.

    Can you do a leak down test ?
    This will tell you what % the rings are leaking.
    On race engines it was rebuild time anything over 5% ie, 100psi in the cylinder, and if the gauge read 94psi (=6% leakdown) it was re-ring/hone time. This was to maintain max. hp/torque.

    <edit> Was the block honed in situ or stripped ?
    What stones/grit were used and by what method ?
    Have the bores been checked for taper/straightness, and as Phil asked, what is your piston/bore measurement ?

  4. #4
    mike 90 RR Guest
    Quote Originally Posted by DiscoJakes View Post
    Good day all

    Nobody here in CT seems to have an answer any more....

    Any ideas.
    Yes ...


    Rebuilding a motor isn't rocket science ... for someone who does it for a living

    I think you have just found the "limitations of knowledge" of the folks at the engine shop that you have been dealing with
    How does that saying go ... floggin a dead horse

    I would either ....
    Put up with it
    Find another shop
    Post the motor to Dave ... (How will you fit it in the mailbox?)
    Replace the motor

  5. #5
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    As i have said before,i am not a mech,but cheepo oil doesnt sound good.....


    The other thing is how much blowback is too much?The TD5 always seem to blow a bit more than say a petrol motor,i think they are designed this way.
    Paul

    D2,D2,D2a,D4,'09 Defender 110(sons), all moved on.

    '56 S1,been in the family since...'56
    Comes out of hibernation every few months for a run

  6. #6
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    cheepo oil is definetley the way froward for a newly built engine for the intial bit.... alllows everything to bed in more quickly.

    I used to use the cheapest 20/50 mineral oil I could find for the first say 4 hours in my integrale race engines... Then swap to Motul 300v competition ester based fully synthetic

  7. #7
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    Quote Originally Posted by Psimpson7 View Post
    cheepo oil is definetley the way froward for a newly built engine for the intial bit.... alllows everything to bed in more quickly.

    I used to use the cheapest 20/50 mineral oil I could find for the first say 4 hours in my integrale race engines... Then swap to Motul 300v competition ester based fully synthetic
    x2, the cheapes mineral oil for the run in then change to your regular choice.

    cheers phil

  8. #8
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    On the run...

    Thanks guys as the Q's come in I'm compiling all the data.

    I did take some video Phil but still need to convert them to mp3's - can't get mp4's to download.

    Honing was done insito.

  9. #9
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    Crack in the head pressurizing the sump???
    Goodluck
    Andrew
    DISCOVERY IS TO BE DISOWNED
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  10. #10
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    Still waiting for the measurements but at least I've got the oil test back.

    Videos of oil filler cap, dip stick and general running with a plastic lemon on the rocker cover. Very scientific !!
    Attached Images Attached Images
    Attached Files Attached Files

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