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Compression

Discussion in '80-Series Tech' started by concretejungle, Feb 17, 2004.

  1. concretejungle

    concretejungle SILVER Star

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    I know if it aint broke fix it until it is. ::)

    I'm going to take the cruiser to get the compression checked. Wondered what it should be? I'm not a :banana: :banana: :banana: :banana: mechanic so i'm assuming all the cylindars should be nearly the same, right?

    Also, i have never checked the valve clearance. Thinking about doing that, but i'm a bit worried with the whole shim thingy. What would be my best attack route? Or in other words, is there a standard clearance that each valve should have, or a specific #ed shim that should be at each valve?

    I did try the search junk! :D

    I've got a 95 with 143,000 miles on her.
     
  2. cruiserman

    cruiserman

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    Get a factory service manual before you start tearing into it. The specs are there as well as the procedures. It's no big deal at all to check clearances or even to change the shims, but it helps to have the manual.
     
  3. robbie

    robbie Guest

    intake valves are between .006 and .010 in, exhaust is between .010 and .014. If you know for sure that they have never been check you will need the 6 spark plug seals (these get hard and can not be reused) and a new valve cover rubber. The spark plug seals are expensive, about 8 bucks a piece.
    For a compression check you must have a screw in type compression guage, a warm engine. Disconnect the coil power (real important), Good is around 171 psi or more ( new is around 175 psi), Mininum from the book is 128 no more than 14 psi between each cylinder. later Robbie
     
  4. concretejungle

    concretejungle SILVER Star

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    Thanks Robbie. That's what i was looking for. I really need to invest in a FSM, waiting on some tax $$ and i'll get one from Mr. CDan. I hate being broke.
     
  5. DMX84

    DMX84

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    I always us a cylinder leak down tester also known as a differential cylinder pressure tester (MAC Tools pn# cld200m @ $100 bucks) With this system you can check everything, head gaskets, valves & piston rings. If you have a military base near by and know someone that can get you in, try going to the auto hobby shop. They have tons of tools, lifts etc. They usually help with knowledge and will give some assistance if needed.
    I think that the standard compression test is a thing of the past. It does not tell you any thing other than that you have compression or the lack there of. Check it out and you will see.
     
  6. cruiserman

    cruiserman

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    The standard test will tell you pistons/rings versus valves.
     
  7. concretejungle

    concretejungle SILVER Star

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    all this madness started after i went through a big frickin' mud hole which splashed water on the top of the motor. The furthest back spark plug leaked a drop of water down and got between the plug and the plug wire. She started to shake while running (missing). Took the plug wire out and shot some compressed air down there to dry it out. Now it runs o.k. but my paranoid ass thinks it's not running 100%. I figure since i've never checked the compression or the valve's maybe now's a good time to start screwing things up.
     
  8. Pitbull

    Pitbull

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    Let it sit over night before you check the valves. They need to be checked cold. I think the manual says to check them at 100K mile intervals. Mine were dead in the middle of the spec at 100K miles. They will get tighter as they wear in. On a FZJ80 it is a bad thing to have it sound real quiet, means it might be adjusted to tight and you could burn a valve. Good luck. PS- never heard of one that was not within spec. at any mileage.
     
  9. landtoy80

    landtoy80

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    New spark plug seals and new OEM spark plug wires,cap and rotor from cdan will solve the water/motor problem. I can hose my motor off now and it runs fine. Before it would shake rattle and die.
    I put a little sealent around the cap too.
    New NGK Iridium plugs and you are as good as new.
     
  10. robbie

    robbie Guest

    a couple of thoughts on the cylinder leak down tester. One it will not catch the slight compression leaks that lead to the overheating of the 1FZ. I have done several head gaskets that show only slight drop in compression of 15 psi(leaving compression at or about 160psi) but has some of the other signs bubbles in the coolant, lots of crap on the radiator and found the head gasket having signs in the cylinder that I think it has. The cylinder leak tester works on the 80- 100 psi shop air and would not catch this type of head gasket leak. It does come in handy when I see the compression low or my guage jumping to confirm a leaking valve or even worse the rings messed up or cylinder walls screwed. I do think the compression guage still has a place in the tool box, it does also take more skill to set up the cylinder leak down test, and is easier to screw up. later Robbie
     
  11. DMX84

    DMX84

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    Cruiserman said
    How?
    Lets say it shows one cylinder with less compression, how do you tell if it’s the rings or valves?
    I know what you are going to say, put oil in the spark plug hole and if it increases than its rings. But what if it does not go up? Not necessarily the valves either. So it does not tell you anything other than it has good / fair compression in my opinion.

    Robbie
    True, I see your point, the high compression of 160+; your cars compression is out-doing the shop air going in. And if someone is using a supercharger or turbo then that will increase even more. Perhaps a bottle of compressed gas is needed for the higher compression & supercharged / turbo applications. I still believe that the leak down tester can find most problems faster than a compression test. In your case it was a little harder to find, as you know, it was a small leak that was causing overheating and you had other indications to what it might be & where to look. I still believe that the leak down tester is easier, because you turn on the air, compare the differential readings & if need be look & listen for the air escaping. Just because the car has 160+ compression doesn’t mean that a leak down tester will not work.
    A standard compression test takes more skill than it seems. I’ll bet most people don’t know how do a proper compression test anyway. People think you screw it in and turn the engine over. That couldn’t be the furthest from the truth!
    Either test will tell you if you are having compression problems. It’s when determining what is causing the problem is where skill is involved. When the leak down tester is used by the normal do-it your-selfer this tool will do a better job in pinpointing the cause with much more ease. The hard to find problems are certainly out there, and like your situation it was not an easy one to find, as it sounds like your head gasket was only leaking a small amount @ over 150psi. That’s a far cry from water on a spark plug wire & just wanting to see how everything is looking! :D
     
  12. robbie

    robbie Guest

    I do use the cylinder leak down tester but not as often as I use the compression guage, the compression guage is my first choice. If I see a problem with the mechanical then I will get the CLDT and find the problem, valves rings etc. But for finding head gasket leaks the leak has to be faily good and by that time (at least with the 1fz), you will already blowing white smoke or overheating when pulling hills. Just my experence in the last 3 years working on the 80 series cruiser.
    I do agree with you most people do not know how to use either tool very well. It does take experence to determine the cuase of any problem.
    My experence not limited to a one case experence with the 1FZ, but with over 24 head gasket experences in the last couple of years, the problems are easier to find using the most expensive tool I have, the gray matter between the ears. tools can only do so much. Have a great day. robbie
     
  13. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator

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    robbie,

    In the cases where the only indication of a problem was running hot when pulling a hill, where did you find gasket failure in the teardown? And, was there any indication on the exterior of the engine?

    Thanks, D-

    (the guy has me wondering....) :-\
     
  14. Beowulf

    Beowulf

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    C-Dan,
    You're the hall monitor; my job is to obsess over the HG.
    -B-
     
  15. Eduardo96FZJ80

    Eduardo96FZJ80

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    :eek: OH NO!!!! and I had almost forgot about the "Head Gasket"
    Not you to0 Dan!!
     
  16. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator

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    I don't think so... :D

    at least not yet anyway.
     
  17. Tank

    Tank

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    Not again...I was starting to sleep again at night...............
     
  18. DMX84

    DMX84

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    Is there a concern for the 80 series blowing head gaskets? ??? As you all know, I am looking for a Land Cruiser. I am leaning towards the 80 series but would like more info on what tends to go wrong with these vehicles 80 vs. 100. If you guys can point me in the right direction it would be greatly appreciated.
    I have a guy calling me to look at a 1998 TLC fully loaded w/ rear diff lock with 60k miles. I know the 100 is better on the road, and I do like to drive fast. But the 80 series seems to be fine for the most part. I had also compared it with the Land Rover Discovery and found that the TLC 80 series out performed it. I went to the same hill as I did with the Disco, & the TLC was able to go up & over forward & backwards in high range. My wife is also impressed. The Disco just got halfway and started digging in with the traction control. :flipoff2: I do know that the traction control is not as good, but this hill was relatively small. Hell I even did it in my Toyota Tacoma Double Cab full of people! We then found a steeper hill and had to use the F&R locks in low range and it made it. My Taco did the same steep hill, full of people, but not as smooth as the LC. I also like all the modifications that can be done with the 80 series. A supercharger on the I6 ROCKS! :cheers:I also like the size of it, just right, the 100 just a bit big, but not too bad though.
     
  19. robbie

    robbie Guest

    to answer your question dan, on several that I have had with overheat on a hill and the fan clutch was not the issue and I saw little bubbles in the overflow tank, the compression was never below 150psi in the offending cylinders, i did not see any external signs. One truck I recently did had 175 in one cylinder and #6 cylinder was at 160psi the other cylinder with 175 had carbon between the head gasket and head, indicating squeeking to the coolant. Just did a Pre purchase for a customer and there was good compression (160 low, 175 high), but 5 0f the 6 cylinders has fresh external leaks to the head gasket (dark red area between the head and gasket). Hope this answers your question.
    One thing I learned the hard way this last week end was that I need a better oil pressure guage, I had not got around to putting in a better more relaiable guage and I was doing a trail run with high revs and did not notice the my oil pressue go way low, slight over heat ( all due to the fan clutch being bad). I also have had this condition of where my oil pressure guage would fall off to the first mark from the second mark when my RPM's would go over 4k rpm. I had hooked up a pressure guage (manual) and check my oil pressure and it held steady. so I ingorned it. well I lost more than one bearing and will be pulling my engine this week end to pull it down. lesson do things right, spend the money to replace the things that are goofy. bummer for me. soon to have a good water temp guage and oil pressure guage. later robbie
     
  20. cruiserdan

    cruiserdan SupportingVendor Emeritus Moderator

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    CRAP robbie,

    I'm VERY sorry to hear about your engine failure. I truly feel your pain. I know how much time you have invested in it.

    To recap, hill over-heating that is head gasket related is usually accompanied by bubbles in the overflow if the engine is run-up to around 3 grand and held there for a minute or so?
    And, #6 tends to be the cylinder with lower compression?

    Symptoms not chiseled in stone, but known to be present?

    Thanks, D-