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

  1. #41
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    Another point to ponder would be to get your hands on a set of well used AMG heads and give them a really good going over to see wasssssup.

    I have a feeling that the best solution is to grab a set of new brand X heads, bolt them on and just run them..


    The flawed GM heads would generally go 200K miles give or take.

    Some cracked early, some ran far longer.

    The type of usage the rig was subjected to certainly could change the life expectancy, but overall the 200K mark is a common jumping off spot for the gaskets to fail.

    I had 2 used Burbs and the Dahoooley and these numbers were pretty close.

    One Burb went 237 K ...The other went 267 K and the Dahoooley was a crap shoot as the engine had been changed to a Goodwrench and the bottom end failed (Main web cracked into the water jacket)


    Gawd only knows what the real lowdown is on these after market heads, but the various brands seem to be staying around.

    Clearwater has been in the game a long time now.

    I spoke with AMG about the various parts (blocks/heads) that are on the market, and they told me that they have looked the stuff over well.

    The only issues they had were that the consistency of quality was all over the map... being ...some good ..some bad and some ugly...


    I wish I had more info for ya..

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

  2. #42
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    Quote Originally Posted by Robyn View Post
    and have not been overheated or run at 20 PSI boost or ???? whatever other form of torture some clown can dish out.
    Gee, I wondered why my nose was big and red...

  3. #43
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    I dropped $2100 last fall for a set of P400 heads.

  4. #44
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    Quote Originally Posted by ronniejoe View Post
    I dropped $2100 last fall for a set of P400 heads.
    If nothing else had gone wrong with this, then I might be able to do that. Right now that isn't in the budget.
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  5. #45
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    I hate to brag...but the heads I got for Dahooooley were the normal pickup arranged P400 heads that were installed on a P400 that was ordered for a civvy H1 by mistake..

    AMG sent the fella a fresh set of the proper angled bolt heads with gaskets and bolts and told him to keep the pickup style heads.

    Got them suckers with zero hrs for $600 for the pair..
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  6. #46
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    Another set of "guaranteed" good used heads with cracks in all 8 chambers, with many cracks going through the intake and exhaust valve seats.

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


  7. #47
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    Seems like you just can't catch a break! A world I'm all too familiar with.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  8. #48
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    Quote Originally Posted by JeepSJ View Post
    Another set of "guaranteed" good used heads with cracks in all 8 chambers, with many cracks going through the intake and exhaust valve seats.

    Tough break... I too have a set of heads that I bought with the assurance that they were crack-free. I found at least one crack between the valves so far. They'll need to be thoroughly checked out by the engine shop.

    With what it costs to ship these heavy items anywhere, I have begun recommending people ask that the heavy part they're considering be QC checked by an engine shop before dropping any bills on it. That'll be cheaper than dealing with all the shipping costs.

  9. #49
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    Quote Originally Posted by More Power View Post
    Tough break... I too have a set of heads that I bought with the assurance that they were crack-free. I found at least one crack between the valves so far. They'll need to be thoroughly checked out by the engine shop.

    With what it costs to ship these heavy items anywhere, I have begun recommending people ask that the heavy part they're considering be QC checked by an engine shop before dropping any bills on it. That'll be cheaper than dealing with all the shipping costs.
    So far the shippers have been eating the costs. I would think that they would test them before selling them. I'm sure they are betting on someone receiving the head and bolting it on and running it, and not actually crack checking them.
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  10. #50
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    JUST AN FYI

    Get a set of the Clearwater heads, bolt them on and enjoy...

    I went through several sets of heads back in the days of the Dahooooley and the used stuff was just junk.

    Out of 4 sets of heads I got ZERO good ones.

    The last trip through, that rig got an AMG BLOCK and AMG heads.

    The CW heads went on the Burb...
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  11. #51
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    Someone recommended the heads from SS Diesel because they are supposedly USA castings. However SS couldn't tell me if they had hardened seats or inserts. I'm just leery of the steel pre-cups in the Chinese heads. SS also said his had steel cups, which are superior to the factory stainless steel cups and people should quit reading what people write on the internet about the steel cups.
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  12. #52
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    The Heads I bought were ordered right from Clearwater.

    I stayed away from all the second and third party sellers.

    I tried sorting through all the hype on who's heads have what casting, made in what third world country, shipped to the US for machining, and using which original GM parts, that were remanufactured in what dumpy shop in Chicago ????


    The stories are so convoluted and embellished with BS that's laid on with a trowel it's impossible to ever find the real truth.

    I spent over an hour on the phone with a fella at AMG after I scored the AMG block with the mainline that was .0025 too small, and we covered the entire story on the after market parts that are out there.

    The folks at AMG certainly have the ability to separate the fly chit from the pepper and they are even at a loss as to who has what, made by who and with what parts...


    As I mentioned before, the Clearwater heads served me well...

    I have no doubt that they are not as good as the AMG parts, buttttttttttt, when $$$$$$ are a big factor the CW heads are not a bad choice.



    Trying to make a well educated choice on this subject will drive ya crazy...


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

  13. #53
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    Quote Originally Posted by Robyn View Post
    Trying to make a well educated choice on this subject will drive ya crazy...
    Amen. I have spent too many hours researching this. Latest seller finally agreed this morning to refund all of my money and doesn't want them back. So now I have 3 set of heads lying around.

    Interesting that I had a chat with Odessa regarding their rebuilt GM heads and asked them what they did about the cracks. He came right back and said they pin them all. Maybe when this is all said and done and I have some extra time, I'll call up the folks at Lock-N-Stitch and have a go at repairing a set of these and see how they turn out.
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  14. #54
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    FWIW

    I personally would not waste one thin dime on a set of well used GM 6.5 heads

    Besides cracking they have coolant flow issues internally (likely causes the cracks) and once you have a crack, getting it to stay pressure tight is going to be a crap shoot.

    Even a pinhole leak into the coolant passage will/can cause overheating, coolant loss.

    The lower end cracks can be arrested and stabilized as they do not allow and real issues, unless the breach the oil passage and allow pressure loss, or travel up into the lower cylinder area and into the water jacket..


    The best use for an old set of 6.5 heads is using them as door stops...or maybe a boat anchor...

    Back in the dark ages I fooled with the 5.7 Olds diesels...
    The cars could be purchased CHEAP once the Diesel started giving issues.

    I had a 79 Calais that was a sweet heart... but would over heat and blow the water out....sound familiar

    I got real good at getting the heads off these rigs fast.

    I finally found the issue on that rig... One cylinder had a tiny pinhole that was leaking, and the shops only mag'd the heads (no pressure test)

    I built caps for the coolant passages and aired the heads up.

    found the pin hole....

    Decided to drill it out and thread the hole for a pipe plug.

    Plugged it and then peened the hole well to prevent the plug coming out

    The spot was on the fire deck so was easy to deal with.

    That thing ran for many years that way..

    Glad you got your $$$$ back...
    (1) 1995 Suburban 2500 4x4
    (1) 1997 Astro
    (1) 2005 Suburban (Papa Smurf)
    THIS IS BOW TIE COUNTRY

  15. #55
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    Based solely on my own personal experience with crack-repaired OE cyl heads, I don't have a problem with them. I have extensive experience with "crack between the valves" repaired cyl heads (>300K miles). A cracked block on the other hand scares me too much to consider investing any money in one - considering how much quality machining costs these days.

  16. #56
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    Those repair kits from K-Line to sleeve the drilled passage between the valves that you wrote an article about years ago are not available any more -- I checked last fall.

    The concern I have with the cracks between the valves is progression through the seat. There is no way that it won't eventually leak compression.

    I've had some good luck with repaired heads that were furnace welded to repair cracks. The problem is, the source that I used has quit doing the repair. They've gotten into marketing their own aftermarket race heads and don't want to do repair work anymore. I can't find anyone else who will do it.

  17. #57
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    I have one of the K-Line kits with enough liners left to do 3 more heads.

    Seeing as how every head I have checked so far has been cracked across a seat, the repair would be...

    - Pin the crack from one end to the other using Lock-n-stitch pins. That would potentially start in the intake port, up through the valve seat, across the chamber, through the exhaust valve seat and into the exhaust port. Not all were that bad, but of the 6 heads that were crack-checked by my machine shop, every head had at least one crack that went through a valve seat.

    - Install hardened seats on the intake and exhaust

    - Install the Kline liners

    I'm hoping that a head that has hardened inserts installed in the exhaust and has not been induction hardened will not have a cracking issue.

    So far I have found 2 suppliers (SS Diesel being one of them) that claim their castings are US and that have hardened inserts. SS is more expensive, but the other supplier doesn't appear to have rotators installed on the exhaust valves. That is an easy fix though.
    1987 Jeep Grand Wagoneer...new 6.5 in process...diamond block, 18:1's, other goodies...


  18. #58
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    The sleeves are standard size valve guide liners. So, any decent head shop will already have the reamers and liners. Don't need the kit. The engine shop here in Montana that has done these for me in the past didn't use a kit.

    Cracks of any kind - found in either a head or block - always come with a fear of progression. I have enough miles of trouble-free experience with crack repaired heads to know that there are more important things to worry about.

    The repaired cracks I've seen in heads that had been torn down for other reason were filled with compacted carbon in the seat. Compared to piston ring leakage? Anything with a crack is not perfect. Myself included. Perfection remains a goal.


    Quote Originally Posted by ronniejoe View Post
    Those repair kits from K-Line to sleeve the drilled passage between the valves that you wrote an article about years ago are not available any more -- I checked last fall.

    The concern I have with the cracks between the valves is progression through the seat. There is no way that it won't eventually leak compression.

    I've had some good luck with repaired heads that were furnace welded to repair cracks. The problem is, the source that I used has quit doing the repair. They've gotten into marketing their own aftermarket race heads and don't want to do repair work anymore. I can't find anyone else who will do it.
    Last edited by More Power; 05-29-2018 at 12:14.

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