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Thread: Ok.. It's head gasket time!

  1. #31
    Senior Member
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    My VIN:    10757 1st place Concourse 1998

    If the motor was overheated you would know it. It would be using coolant, blowing coolant out, and generally running lousy. I never heard of someone preemptively surfacing a head without some evidence of a blown head gasket. And NEVER just one on a motor that has 2 heads. One obvious sign of overheating is the plastic screen in the oil filler. If it is melted or missing then you can suspect the motor has been overheated. You confirm by testing for combustion gasses in the coolant. Pieces of spark plug are concerning but I would try to get them out the spark plug hole before removing the head. If someone had to take 20 thou off the heads they were severely overheated and to try to flatten them and have to take even more off is way too much. I am suspicious of your measurements and would recheck your cylinder height in several places. Whatever you do to one you should do to the other head. If the heads really are cut that much you should not waste any time or money on them. Find a good used set and clean them up. As for honing marks, even on a well used motor you could still see honing marks so that by itself is not a good sign of previous work. More obvious would be sealant, the gaskets, wrench marks on the bolts, spots where things may have been beaten or pried on, that kind of thing.
    David Teitelbaum

  2. #32
    Administrator Ron's Avatar
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    Quote Originally Posted by SpudMurphy View Post
    I have since been contacted by an established DMC dealer that the heads would not be garbage after a 20 thou cut - he's done 100's of Delorean heads, so I would think that I could trust him?
    My guess is that he has a source for cylinder head spacer shims or over-sized gaskets that compensate for the material removed...

  3. #33
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    Location:  Cardiff

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    My VIN:    11789

    Quote Originally Posted by David T View Post
    If the motor was overheated you would know it. It would be using coolant, blowing coolant out, and generally running lousy. I never heard of someone preemptively surfacing a head without some evidence of a blown head gasket. And NEVER just one on a motor that has 2 heads. One obvious sign of overheating is the plastic screen in the oil filler. If it is melted or missing then you can suspect the motor has been overheated. You confirm by testing for combustion gasses in the coolant. Pieces of spark plug are concerning but I would try to get them out the spark plug hole before removing the head. If someone had to take 20 thou off the heads they were severely overheated and to try to flatten them and have to take even more off is way too much. I am suspicious of your measurements and would recheck your cylinder height in several places. Whatever you do to one you should do to the other head. If the heads really are cut that much you should not waste any time or money on them. Find a good used set and clean them up. As for honing marks, even on a well used motor you could still see honing marks so that by itself is not a good sign of previous work. More obvious would be sealant, the gaskets, wrench marks on the bolts, spots where things may have been beaten or pried on, that kind of thing.
    David
    I will be doing the two heads.
    This is a project car - it came to me on a trailer together with boxes of bits.
    The car went to Dubai in 82, returned to the UK in 94, and has never been used on UK roads - it's not even registered to do that.

    Having spent time in Dubai myself - the roads over there in 82 were not good and temperatures easily get to 50+ / 125 degrees - so there would be a every likelihood that it overheated - the wires from the otterstat were bridged keeping the fans on all the time

    When I got it the engine had not been fired up since the 90's.
    I've replaced all the fuel lines, pump, water coolant pipes, water pump (and a lot more)
    After establishing that a previous owner had reinstalled the distributor at TDC on the exhaust stroke, after reinstating the accumulator which had been removed and bypassed, after replacing the distributor, bleeding the air out I fired up the engine - it ran fine and started first time every time but I could only time it to TDC - (still a tooth out) and the water wasn't circulating - the engine may have overheated (again) .

    I found water in #1 using an endoscopic camera - it was water not unburnt fuel.

    There is a lot more evidence to infer that the car has had work.
    - gasket sealer, the main 36 mm bolt on the engine has quite clearly been removed.
    - The cylinder head valves had identifying marks punched into them - I can only presume to aid re assembly.
    The measurements were carried out by a guy who has done this work for 50 + years.
    He showed me the results on a micrometer - I verified this when I got home using my own digital Vernier gauge.

    So I'm not quite sure where you are going with your comments and you have me confused?
    In one instance you say that my head is trashed - now you say do the two of them the same ?

    I'm trying to resurrect this car, and pulling the heads seems the right thing to do and this has been confirmed as the correct thing to do by owners here in the UK.

    I seem to be damned if I do and damned if I don't

    I have tried to show the measurement on the attached photo and it says 4.354

    magne 02.jpg
    Last edited by SpudMurphy; 03-15-2019 at 06:25 PM.
    Currently resurrecting Vin # 11789 - One of the batch of 50 exported to the Middle East in 1982.

  4. #34
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    Quote Originally Posted by Ron View Post
    My guess is that he has a source for cylinder head spacer shims or over-sized gaskets that compensate for the material removed...
    Hi Ron.

    He didn't mention that , but I will check. Thanks.

    I was on a Swedish Volvo parts stockists and checked out head gasket dimensions - some varied by as much as 8 thou in thickness. One was 1.5 mm thick, the other 1.7 mm
    Currently resurrecting Vin # 11789 - One of the batch of 50 exported to the Middle East in 1982.

  5. #35
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    Here's an interesting thread which verifies my earlier comments

    http://dmctalk.org/showthread.php?71...from-PRV-heads
    Currently resurrecting Vin # 11789 - One of the batch of 50 exported to the Middle East in 1982.

  6. #36
    Administrator Ron's Avatar
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    Quote Originally Posted by SpudMurphy View Post
    Hi Ron.

    He didn't mention that , but I will check. Thanks.

    I was on a Swedish Volvo parts stockists and checked out head gasket dimensions - some varied by as much as 8 thou in thickness. One was 1.5 mm thick, the other 1.7 mm
    Having skimmed this thread, I didn't see mention of a compression check?
    If several cylinders had acceptable compression, chances are that the bottom half is ok (not damaged by heat...).
    Could be a reasonable option.

    ...I'm not sure if you meant the timing chain itself was installed "one tooth off". Which would throw the compression check off.

  7. #37
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    Quote Originally Posted by Ron View Post
    Having skimmed this thread, I didn't see mention of a compression check?
    If several cylinders had acceptable compression, chances are that the bottom half is ok (not damaged by heat...).
    Could be a reasonable option.

    ...I'm not sure if you meant the timing chain itself was installed "one tooth off". Which would throw the compression check off.
    The distributor (spark) was installed incorrectly . I'm guessing a PO hadn't checked that the valves were on the rock and the cam was looking like "Micky Mouse Ears"

    I reset the spark distributor but could not turn it enough to get the timing at 13 BTC. so I took it out and pushed it back in - so it was one tooth out.

    The marks on the timing chains have been checked and they line up all ok.

    I believe that the bottom half is ok - when I had the engine running - it all seemed ok - I will definitely do a compression check when it's all back together.
    Currently resurrecting Vin # 11789 - One of the batch of 50 exported to the Middle East in 1982.

  8. #38
    Administrator Ron's Avatar
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    Quote Originally Posted by SpudMurphy View Post
    I believe that the bottom half is ok - when I had the engine running - it all seemed ok - I will definitely do a compression check when it's all back together.
    I see... Sounds like you are going for it.

  9. #39
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    Quote Originally Posted by Ron View Post
    I see... Sounds like you are going for it.
    Cheers Ron.
    Yes I'm doing the best I can but having never worked on a Delorean it's a learning curve.

    It was my ambition to have a car project when I retired and I bought #11789 knowing it required a lot of work - well the doors were held tight on the delivery trailer by cling film

    it was a big moment getting the engine running but it wasn't "on song". A stuck oil light sensor left the red warning light on, on the dashboard (it has a can which slides within a chamber and the can was stuck). But the oil pressure was showing good.

    I solved that - and ended taking off the old exhaust to make solving the can problem a lot easier. I ended up putting on a nice stainless exhaust (stainless headers and no cat - mine didn't have a cat from new - as ironically Dubai didn't have unleaded fuel back in 82.

    Lets wind forward - I opened the engine core plugs and drained the block and flushed it through with a hose .
    fast forward - and now I had to take the head off as shards of ceramic had fallen into#3 - vacuum or grease on a stick wouldn't get the bits out .... but even if I did get two big pieces out would I be confident that I had got the small bits out?

    Finally, after measuring the head it showed that 20 thou was skimmed off the deck.
    I rely on information provided by other users and when somebody says its basically only good for landfill, then worries / concerns creep in.

    Don Steger has set my mind at rest saying that you can take off up to 40 thou - I'll take off as little as possible ... and will do both heads, one by one .... not together.


    P1160534.jpg
    Last edited by SpudMurphy; 03-16-2019 at 08:37 AM.
    Currently resurrecting Vin # 11789 - One of the batch of 50 exported to the Middle East in 1982.

  10. #40
    Senior Member Parzival's Avatar
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    I'm guessing that since they had the fans hot wired to run 100% of the time, that who ever did that was fighting with heat, and over heating. Sucks that you are inheriting the ghosts of these past issues with the car. Lucky for that car, you are dedicated to implementing the proper fixes, and its gonna be a great car when you're done I'm sure! Just out of curiosity, was the plastic oil fill screen on the valve cover intact?

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