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Thread: Things were just a little too cozy...

  1. #21
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    Jeep

    There are a lot of cracked blocks out there.

    With the inserts in the holes the block should be good to go.

    Are these the LOCK N STITCH ????

    THEY WILL hold things together.

    As long as the crack is not past the end of the web area you should be OK.
    When the crack gets into the area beyond the bolt holes its getting real sketchy..

    Beyond the bolt holes and they can start into the cylinder wall, and this is a no no...
    (1) 1995 Suburban 2500 4x4
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  2. #22
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    The shadowed imprint of "both" valves on the piston crown tell me that piston protrusion exceeds the allowable high limit. I doubt it's a valve timing issue. With a valve timing problem, I'd be inclined to think that one valve or the other could have an interference problem, but not likely both.

    Incidentally, I wrote an article covering 6.5 piston protrusion a while back...

    https://www.thedieselpage.com/member...rotrusionc.htm

  3. #23
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    Well if anyone wants an early squirter block, .040 over, 007 taken off the decks and has a cracked main web, please come get it. Otherwise it is heading for the scrap heap.
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  4. #24
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    Block with inserts visible -

    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  5. #25
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    Pulled my heads apart and found aftermarket seals on both intake and exhaust. No o-rings on the stems.

    Machinist recommended going to a modern viton seal instead of the rubber that were on there.

    Would I still need o-rings? Since mine did not have o-rings (and definite oil control problems) I have no reference as to where they would be installed (over or under the seal).

    Thanks!!
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  6. #26
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    The o-ring goes in the lower top grove on the stem not down where the seal is... and yes I would say you need it..
    1993 Chevy K3500

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  7. #27
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    The o ring helps keep a lot of oil from pouring down from the spring retainer past the keeper and down the valve stem.

    Yes you do want the o rings in there.


    Good luck
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  8. #28
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    Well that explains why there was so much oil residue in my intake ports...
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  9. #29
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    Quote Originally Posted by JeepSJ View Post
    Well that explains why there was so much oil residue in my intake ports...
    There is so much oil vapor/residue allowed by the CDR, I doubt you could really tell how much would be allowed by the valve stems. The O-rings are necessary, but hardly negligible compared to other sources.
    1985 Blazer 6.2
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  10. #30
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    Quote Originally Posted by DmaxMaverick View Post
    There is so much oil vapor/residue allowed by the CDR, I doubt you could really tell how much would be allowed by the valve stems. The O-rings are necessary, but hardly negligible compared to other sources.
    That would be true if my CDR had been routed to my intake, which it was not. And all of the residue was in the pocket behind the valves, not upstream of the guides.
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  11. #31
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    Then your guides were wore out...
    1993 Chevy K3500

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  12. #32
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    Ordinarily.... There is a positive pressure inside the valve runners in the cylinder heads for both the intake and exhaust. The turbocharger is pressurizing the intake and exhaust back-pressure is usually positive because of the restrictions to flow (catalytic converters/mufflers/pipe/etc).

    So... Oil doesn't want to seep past the valve stem seals all that much. Some does, but not much. A 6.5 that uses too much oil usually has more problems than just bad stem seals.

  13. #33
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    Where is your CDR routed to ????

    The CDR when things are correctly working is supposed to pull a slight negative pressure in the crankcase.

    This keeps the main seals from leaking as well as keeps oil from drizzling down the valve guides (At least in large quantity)

    Is this engine turbo'd ???

    A leaking turbo bearing that's allowing oil into the air stream will sure cause issues.

    If there is no connection to the slight negative pressure in the intake airflow then the crankcase is running a positive pressure...not good.
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
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  14. #34
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    This engine had all kinds of issues... LOL. That is one of the reasons I decided to pull it. It always used a lot of oil and had a lot of blow-by. The seals I pulled off were hard - not pliable at all. I know the guides were out of spec just by how much wiggle the valves had when I disassembled the heads.

    Yes, engine was turbo'd. There are zero signs that the turbo was leaking any oil.

    CDR was simply routed down under the frame with a filter on it. There was way too much blow-by so I never had it on the intake.
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  15. #35
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    Got a call from the machine shop. Both heads had been welded around center head bolt holes. That much I could probably live with, but when they measured them they found both had already been machined past minimum thickness, one of them being .028 under.

    No wonder this engine had issues.

    Set of Promaxx replacements on the way. $255 ea with free shipping from Jegs for a set of bare heads.
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  16. #36
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    These sort of engine jobs are out there, and the 6.5 is critical on the head dims and other things too.

    I am not familiar with the heads you mentioned... CHINA castings ????

    I have used the Clearwater "NEW" heads and the ones I had worked fine.

    The ones from AMG are the best choice... if the budget can stand it.


    Welding on these heads is a disaster waiting to unfold.

    Good luck
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  17. #37
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    Well after reading some real world experience with the Promaxx stuff, I cancelled the order. I ended up grabbing a couple used heads with a 6 month warranty off Ebay and will have my guy work those instead. The Promaxx are China. Issues with casting shift and they use a steel (magnetic) pre-cup and the holes are too big for factory pre-cups. I wish I had an extra $1800 in the budget for a set of new AMG, but...
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  18. #38
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    So...Robyn...how are you liking those Clearwater heads? Heads I got were cracked and seller could not come up with another set that weren't cracked, even after pulling off of "running" engines, so I got a full refund from him.

    Did the Clearwater have good pre-cups? One issue with the Promaxx was that their cups were magnetic and they were slightly larger than a stock cup so stock cups wouldn't stay in place.
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  19. #39
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    The Clearwater heads worked fine.

    The cups were magnetic...
    The fact that they magnetic is a moot point me thinks...could be stainless steel (some grades are magnetic)

    I have no clue, but it was not a deal breaker..

    I checked them over for anything unusual and then dropped them on. (Make sure the cups are slightly above the head surface .0005" to .002"

    The engine ran good and we put over 50K miles on the rig after the O'Haul

    I sold the Burb and I saw it a year or so later and the fella said it was running great.

    They are not as good s a set of AMG heads, but far less $$$$.

    I good part is that they are ZERO hour parts with zero duty cycles and have not been overheated or run at 20 PSI boost or ???? whatever other form of torture some clown can dish out.
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  20. #40
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    Thank you for the feedback. Seeing as how uncracked GM heads seem to be like hens teeth, I'm looking at alternatives. Feedback on the CW heads seems to be good so far from what I have found on google. I would like to find someone that ran a set for a while then pulled them to find out if they cracked between the seats also. I could interpret the fact that no one has pulled off a set as a good sign.
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


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