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Technical FRUSTRATED AND MAD!!!!

Discussion in 'The Hokey Ass Message Board' started by kscarguy, Jul 14, 2014.

  1. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,574

    kscarguy
    Member

    B I N G O !!! Blown head gasket

    I pulled plug #2, with air connected to #4 and I can feel air coming out of the adjoining cylinder. I tried it with #6 and didn't feel anything. So I will put air in #6 and feel #4 next.

    Update - WRONG
     
    Last edited: Jul 17, 2014
  2. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,574

    kscarguy
    Member

    My engine builder would fix it, but he is four hours away. If I need to he will try to do repairs in one day, while I wait, but it is a long drive both ways, double if he can't do it in one day. The head gasket problem was probably due to the timing getting severely retarded by a cheap broken distributor clamp. I supplied the clamp, so it was my fault. I don't blame him and he has been talking to me about it over the phone.
     
  3. Well at least you found the problem. Now take the heads off and make sure that there is no other damage, which there probably isn't since the cause is the head gasket failure not mechanical, so we think til you pull the heads off :D

    good work keep the updates comin, I like reading lol
     
  4. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,574

    kscarguy
    Member

    Darn, I have to stop jumping to conclusions.

    It turns out that cyl #2 has the exhaust valve wide open when cyl #4 is TDC. Air was just feeding back into #2 through the exhaust system (I loosened header, blocked header pipe on #2 and no air out of #2 plug hole)

    I loosened both the intake and exhaust rockers on #4 and quite a bit of air is leaking out of the exhaust.

    Is it time to pull the head? :eek:
     
  5. ok well then its not the head gasket... yet lol
     
  6. See post 118 and 120 -
    Been there done that and now so have you. You'll tell the next guy
     
  7. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,574

    kscarguy
    Member

    I pulled the rocker completely off the exhaust valve and rotated it. It feels smooth. Same leakage in different rotated locations. Spring looks fine.

    Could the head be cracked? I have a set of 400 heads that came off the engine originally. I could use them if this one is cracked. This is an 882 casting, the originals are 1879493 castings.

    Again...is it time to remove the head?
     
  8. where is the air escaping from now? where do you hear it?
     
  9. How are you rotating the valve ?
     
  10. i thought he meant rotating the crank while testing with both rockers off?
    how are you rotating the valve?
     
  11. Torana68
    Joined: Jan 28, 2008
    Posts: 1,189

    Torana68
    ALLIANCE MEMBER
    from Australia

    I think you need to do the 4 hour drive, we're going in circles and getting different results. At least it will get sorted.....
     
  12. goneflyin
    Joined: May 23, 2012
    Posts: 14

    goneflyin
    Member
    from ontario

    I think you need to try a substitute carb.
    Make sure the plugs are clean after that.
     
  13. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,574

    kscarguy
    Member

    What I meant by rotated is: I rotated (spun) the valve in the guide to "feel" how it rubs on the valve seat inside the head.

    First I put that piston at TDC with an air hose connected into the spark plug hole. I double checked it to be at TDC firing position.

    I then loosened both rocker arms and I still heard the leak into the exhaust. That cylinder is clearly and loudly leaking and into the exhaust. I then removed the rocker arm and valve spring off the exhaust valve.

    With no air pressure on the hose and the spring removed, I could spin the valve in the guide. To me, it feels like it touches all the way around. I then tried airing up the cylinder with the valve at different points in the spin to see if it made any difference, it did not. With 80-100 psi of air pressure on the cylinder, It was really difficult to unseat the valve.

    Some notes: The exhaust valve moves up and down freely. At TDC, there is about 3/8" travel before the valve touches the dished piston. It seems a little loose in the guide. The seals are just an O-ring type over the valve stem.

    The adjoining cylinders had wear leak down numbers too, but I cannot air up them up without removing the header entirely. My hose adapter won't clear the header pipes and I no longer have the rubber hose from the leak down tool I had borrowed. However, I would like to check them so tomorrow I will remove the header and check them.

    I wonder if the head is cracked from excessive cylinder pressure created from the time the distributor slipped and ran very retarded.

    I think I just need to pull the head off and see what is going on.
     
  14. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,679

    dirty old man
    ALLIANCE MEMBER

    This has turned into one gigantic "Chinese Fire Drill" as my Drill Instructor used to say when I was in boot camp @ PI back in '57.I not only don't know who's on first, I don't even know what ballpark we're in, LOL!!
    Never yet read that OP actually used that positive stop to determine actuial TDC, 2 pages of bullshit about vacuum advance that should have been disconnected in the beginning till all else was straightened out, and on and on. Quite revealing about the knowledge level of many who have posted.
    Start over, verify TDC and set spark advance to total (Without the vacuum advance, plug it up and forget it till this is over) at 34-36 degrees, all in by about 2500. You need weights, stops and springs adjusted for this and an idle figure around 18-20* if your compression is really down around 9.5:1 or so.
    Something is going on with those leakdown tester figures and that needs to be resolved. Compression testers are notorious for inaccurate pressure readings, and what matters is consistency from cylinder.to cylinder.
    Take the push rods out and try rolling them on a piece of plate glass or other truly flat surface and you can spot bent ones easily, and yes, they should spin, and fairly evenly at that, in a running engine with properly adjusted valve lash.
    If you continue to get uneven compression tests and leakdown tests, then it's head pulling time. When thay go back on, don't use any sort of thick head gaskets to lower compression, as you need that quench action else wise the detonation will get worse, even with power robbing ratio decrease.
    But you need to do this in order, and back to the basics ot proper timing, measured from a timing mark checked for accuracy, and clear and accurate comp. test or leakdown tests.
    If you do have to pull heads, pat particular attention to intke gasket sealing with your mixed up assortment of block, decking, heads and intake manifold, and use RTV instead of the rubber seals at each end. Put some good gas in it also.
    Good luck and keep uis informed.
     
  15. BobMcD
    Joined: Jan 25, 2013
    Posts: 322

    BobMcD
    Member

    For now, I would close the hood and walk away for a few days. Dont take anything apart or replace any more parts. Come back with a fresh eye and don't assume anything. Reassemble and run compression again,. Check all 8 cylinders one at a time using the same technique on each cylinder, and post the numbers. Dont take anything apart until you report back.. Need to take things one step at a time. With a systematic approach you will get this figured out without replacing parts that aren't needed
     
  16. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,574

    kscarguy
    Member

    Actually I have made a lot of progress on a series of odd and frustrating issues that started with oil leaking from the timing cover seal. The next issue was a broken valve spring on a long highway trip, followed by a loose distributor causing retarded timing, then a poorly running engine with pre-detonation and now smoke and popping in the exhaust. I almost forgot that weird (high) set of compression numbers from a rarely used compression tester.

    I have tacked each issue to the best of my abilities. Most are now solved.

    I solved the leaking timing cover issue - replaced cheap chrome cover with a factory cover (done)
    I replaced all the valve springs and it seemed to run "ok" , but never great. (work in progress)
    I discovered and replaced a faulty/broken distributor clamp that allowed the distributor to rotate (done)
    I replaced the valve covers with baffled covers and cleaned /replaced the oil fouled spark plugs to correct pre-detonation issue (done)
    I replaced a worn HEI with a new one, engine sounds strong again (done)
    I ran a compression test (again) and got numbers that make sense (done)

    I am now trying to solve for popping in the exhaust and smoky exhaust. Timing was the tool that led me to discover that it was popping in the exhaust. As for the smoke, it could be leftovers from the PCV issue, or bad rings, or? I'm still investigating that.

    Since the leak down shows something is wrong with cylinder #4, I will deal with that. I might have bent a valve with the broke spring or cracked a head/valve with the heat from the loose distributor and subsequent severely retarded timing that occurred.

    So although I feel like a chicken with it's head cut off...I am getting there.
     
  17. F-ONE
    Joined: Mar 27, 2008
    Posts: 2,273

    F-ONE
    Member
    from Alabama

    The more you fart around with this engine, the less likely the builder will cover it. His baby becomes, your baby.

    If you are not sending it back, do the basics. Time, Fuel and Fire. Cams can go south quick. Have you checked the oil for metal? Is the distributor in correctly and has it been confirmed to be on the right tooth? They can run a tooth off . Are the valves adjusted properly and do the rockers have the right ratio for the cam used? Are the rocker studs pulling out? If a high lift cam was used with stock heads, this can be a problem.

    My advice take it back if you can.
     
  18. You never can tell how a group of random Internet contributors will lead a thread.

    Starting at the bottom and going up is the most efficient way to do just about anything. Personally I wouldn't do anything but a compression test first. If that's off it needs correction or everysinglemotherfuckingthing you might do is for absolutely for nothing. That's a fact it will be always.
     
    BORRACHO13 likes this.
  19. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,679

    dirty old man
    ALLIANCE MEMBER

    I agree 31 Vicky, but I also INSIST that TDC on pointer be verified. With all the parts that will bolt on but not necessasarily be compatible in this area of a sbc, there are God only knows how many out there with false readingson this basic requirement.
    The OP has stated he bought a positive stop, but if he stated he had actually used it in this thread, I missed it mixed in with all the rest.
     
  20. You might notice that I often tout the benefits of a piston stop test for TDC mark verification. Funny that Guys will argue till the cows come home over 2 degrees, and sometimes very passionately without ever knowing if TDC marks and timing notches are even correct. Balancer rings slip all the time too and that means your timing light is telling you stories.
     
  21. jamesgr81
    Joined: Feb 3, 2008
    Posts: 265

    jamesgr81
    Member

    Just my 2 cents.

    You have already verified that piston is at TDC when timing mark is at zero.

    Forget about engine break in, oil, piston ring seating. If you did not have ring seal you would see major blowby and burning oil out the exhaust big time.

    Timing cover fixed oil leak. One down.

    Forget about valves, lifters, pistons, heads, leak down tests, compression tests. I suspect there is nothing wrong with engine mechanically. 10 psi difference is nothing. Wasting time and effort there. If cam was running flat it would loose valve adjustment on that cylinder right away and you could see that lifter was not spinning. Readjust all your valves and call it a day with the mechanicals.

    Go back to basics. First install one PVC valve only to baffled valve cover. Second, beg, borrow, steal a known good distributor. Install distributor. Vacuum advance to manifold will give better idle and part throttle but none at full throttle is the best way. Disconnect vacuum advance. Set initial timing to 8 degrees. Don't worry about total advance. Reconnect vacuum advance. Get the carburetor idle mixture and speed right.

    OK, now work on drivability. Flat spot? Accelerator pump probably. Maybe carb has a clogged passage. If carb came off the same engine that ran fine before no way jetting is way off.

    Mech advance. Stiff spings delay point at which advance tips in. Weak springs fine for drag racing but mean engine could knock if too much too soon. But this is just the small stuff.

    Popping in the exhaust? Like a random misfire? Plugs and plug wires, clean terminals in distributor, bad rotor. Like I said try a known good distributor.

    Don't change too much stuff. One thing at a time. Get timing and carb dialed in first. Work from there. It's an easy fix - just don't get discouraged.
     
  22. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,574

    kscarguy
    Member

    I checked leak down on all the cylinders of the weak head. Of the four cylinders, the one with the .9 leak down number leaked through the rings. The other three all leaked into the exhaust.

    I pulled the head and discovered a 1/16" thick, gooey tar substance inside the cylinder heads and on the pistons. The head gasket did not appear blown. It was a three layer metal gasket.

    I cleaned off the pistons by scraping, light thinner wiping and "soft" wire brushing. No marks from valves. Good

    I then pulled all the exhaust valve springs...damn! The guides are all shot. I know the engine builder said he went through and checked them all, but no way he missed this. I can rock the valves and see them move. Just to check, I pulled down one original 400 head, dang that moves much worse!

    I took the head the local hotrod shop and the mechanic there looked it over and said 'Scrap them. They will cost too much and probably need new valves too'. The only thing these have going for them is screw in studs and light intake port matching. We figured out that they were off a remanufactured engine. 75cc chambers.

    Unfortunately, I have not won the lottery and money IS an object to me and I can't afford $1200 aluminum heads. So the question is, do I get these rebuilt or find different cast heads.
     
  23. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,574

    kscarguy
    Member

    Just talked to engine builder and he will stand behind the heads...I am going to road trip to his shop and he will do a one day turn-around for me.
     
  24. F-ONE
    Joined: Mar 27, 2008
    Posts: 2,273

    F-ONE
    Member
    from Alabama

    Lets see, worn dizzy, broken springs, shot guides, carbonized cylinders, Pro builder....Somethings not adding up. Sounds like a junkyard engine.
    [​IMG]
     
  25. vtmopar
    Joined: Jun 5, 2013
    Posts: 47

    vtmopar
    Member
    from Vermont

    I'm not a chevy guy (used to be) but if I was I would not mess with anything but a new crate motor from GM.
    For just a hot rod motor.
    You can buy a 260 hp 350 long block
    With a 3 year 100,000 mile warranty for $1600!!!!
    Hard to beat.
     
  26. vtmopar
    Joined: Jun 5, 2013
    Posts: 47

    vtmopar
    Member
    from Vermont

  27. kscarguy
    Joined: Aug 22, 2007
    Posts: 1,574

    kscarguy
    Member

    Weird day. It started by slicing my thumb wide open on a sharp edge (burr) off a fuel line, then my fortune cookie had no fortune in it...now this. If it weren't for bad luck, I'd have no luck at all.

    I just hope they do the guides correctly and that they are not loose again.

    It is not carbon in cylinders. This is way too "tar like". I think it was a residue from the gobs of engine oil being sucked in from the PCV valve. Local hotrod shop said it looked like something caused by a fuel additive, or maybe there is some residue/reaction from the aluminum fuel tanks causing it to gum up. What surprises me is that it did not burn off after running in the garage for over an hour, and with frequent revving to set the timing.
     
  28. wingman9
    Joined: Dec 30, 2009
    Posts: 804

    wingman9
    Member
    from left coast

    I still don't see that op ever used the positive stop to check tdc. I've had the mismatch problem between timing mark and pointer on several occasions and now I check this as a matter of course before I mess with timing issues.
     
  29. Unrelated to the performance issue, but about the exhaust smoke:
    I once broke a rocker arm on a SBC and had to drive the car a ways on 7 cylinders. Since the valve was not opening, it was sucking air from wherever it could and got a lot of oil in the dead cylinder. After fixing the rocker, the engine smoked for half an hour at freeway speed before it finally stopped.
    Your problem could be similar (or not).
     
  30. stimpy
    Joined: Apr 16, 2006
    Posts: 3,547

    stimpy

    sounds like cold oil on top of the pistons , diesels get this when they are idled for long periods and the water is under 180* we call it Detroit dribble or diesel snot or slobber , gas engines can get it too .

    as for heads you can also look into world products they make a replacement iron head that is assembled and drops right on ( in your case you you have to drill the steam holes ) that were cheap , we used them for replacements on older cars and trucks because it was cheaper than doing guides and seats . and these are not junk heads either ( made in Detroit USA )
     

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