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Need Help Rebuilding 350 TBI

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by xdelirious45x, May 9, 2004.

  1. xdelirious45x

    xdelirious45x Registered Member

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    Ok I am in the process of rebuilding my 350 TBI. I took off the TBI and rebuilt it already. Next I took off all the sensors and drained the antifreeze to take off the intake manifold. Now I am in the process of replacing the cylinder heads with rebuilt ones. The passenger side I need to take off about 5 more bolts under the exhaust manifold, I have a lot of trouble because I unbolted the exhaust manifold bolts that bolt to the heads and they can not get far enough away to get to the rest of the cylinder head bolts. I was thinking about taking the entire exhaust manifold off but the spring loaded bolts that bolt to the y pipe are all striped. This is agrivating me because I sold my other car and now I'm stuck with a half rebuilt 88 k5 blazer.
    Any solutions?

    Also, I took out the distributor, however, I turned the crank until what I thought was TDC, but I am not absolutely sure that it is at TDC of the #1 cylinder. I did not replace the other heads yet, and I know that you need to set each cylinder at TDC when you replace the heads. I know about the trick of putting the screwdriver into the sparkplug hole, but how do I know when it is at TDC??
    I need to know how to set the #1 cylinder to TDC. I noticed the slit in the vibration dampener. I tried setting it to the bracket that looks like this

    /\/\/\----

    I am not sure I NEED HELP!!!

    Thank you /forums/images/graemlins/k5.gif
     
  2. speedyvision917

    speedyvision917 1/2 ton status

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    /forums/images/graemlins/thinking.gif well...try this it usually works for me, if its broken, kick it, haha i have no idea sry
     
  3. xdelirious45x

    xdelirious45x Registered Member

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    Well, its not broken, I did kick it before when I could not get the manifold out of the way, it didnt really work.

    Thanks anyway
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, here are some tidbits that MIGHT help.

    On the exhaust, if you have, or can get, access to an acetylene torch, cut or grind the bolt heads off of those studs. If you break them off flush in the manifold, you have a lot more work. Anyways, get the manifolds off with enough bolt sticking out to grab with a pair of vise grips. Heat the metal AROUND the bolts with the torch until it is glowing red. Clamp the vise grips on them (as tight as you can) and turn. If they won't budge, the manifold isn't hot enough. This has NEVER failed me, and I've done quite a few now.

    As to #1TDC. Install the heads, don't install any of the plugs, and have someone rotate the engine with your finger over the plug hole. When you feel pressure building up/leaking past your finger, the piston is coming up, and at the top of that stroke you are at TDC on that cylinder. Piston obviously comes up twice in a 4 stroke cycle, however, both valves are closed only on the compression stroke, which is the one leading to TDC. You only need TDC #1 to install the distributor. No reason to deal with TDC on any other cylinder.

    You do however, need the valves shut on each respective cylinder to adjust the rockers of course.
     
  5. fjleiter

    fjleiter 1/2 ton status

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    Easiest method if you are removing the heads is to rotate the engine (crank) until the #1 piston is all the way up and the lifters for the #1 cylinder are both all the way down in their bores (tops of the lifters will be almost even with the tops of the lifter bores).

    If one or the other is sticking up, rotate the engine 180 degrees until they are both down. Also easier to adjust the valves with the same process, just rotate the engine and adjust each of the valves when their respective lifter is at it's lowest position.

    Don't remember the exact sequence numerically but you can adjust half the valves (rockers) at TDC, rotate 180 degrees and do the remainder. I also just did it by watching the lifters and adjusted when they were seated...

    [ QUOTE ]

    As to #1TDC. Install the heads, don't install any of the plugs, and have someone rotate the engine with your finger over the plug hole. When you feel pressure building up/leaking past your finger, the piston is coming up, and at the top of that stroke you are at TDC on that cylinder. Piston obviously comes up twice in a 4 stroke cycle, however, both valves are closed only on the compression stroke, which is the one leading to TDC. You only need TDC #1 to install the distributor. No reason to deal with TDC on any other cylinder.

    You do however, need the valves shut on each respective cylinder to adjust the rockers of course.

    [/ QUOTE ]
     
  6. 1-ton

    1-ton 1/2 ton status Premium Member

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    To install a distributor correctly...

    1. Remove the number 1 cylinder spark plug.

    2. Place your thumb over the spark plug hole.

    3. Crank the engine until the compression stroke blows on your thumb.

    4. Place a socket on the harmonic damper bolt, and line up the timing mark on the harmonic damper with the timing chain cover timing tab '0' mark.

    4. Install distributor with the Rotor cap pointing at the number one spark plug wire.

    5. Install distributor cap.

    6. Connect spark plug wires 1-8-4-3-6-5-7-2 clockwise on the distributor cap.

    The way you are going about doing a top end job is the hard way. Life would be much easier if you just pull the whole engine out, and rebuild the bottom end to go with those new heads, if it has a lot of miles on it.

    Back when I first started as a mechanic I worked at a couple of "hack" shops, which had sales representatives sell customers top-end jobs for their vehicles, only because the customer had a friend, relative, or in-law convince them that all they needed was a top-end job for their blown engine, and our sales rep's where not scrupulous enough to tell them otherwise. Before doing the job I would Cover My A$$ (CMA) by noting on the work order that a complete engine R&R was recommended, but declined by the customer.

    Almost everyone of those jobs turned out bad because the either the block had a crack in it, or the pistons and rings where wasted, and the customer was screwed because I noted the "engine R&R recommendation" on the work order invoice, and had the customer initial and date the comment to CMA.
     
  7. xdelirious45x

    xdelirious45x Registered Member

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    Well I had an oil leak problem where the truck was blowing out blue smoke, originally i was gonna replace entire upper end of the motor wit new exhaust manifolds, intake manifold, new throttlebody, however, money being limited as with most projects I was only able to rebuild the throttle body, polish the intake manifold, keep the old rusted exhaust manifolds, and rebuild a pair of old heads. I know its an old truck but I can't go that deep into the motor yet because I want to buy a 6" lift for the truck and I really want the motor to run good because it will be a daily driver also.
    ****Tell me if this is a good idea that i just thought of.
    If i buy a cylinder compression tester, plug it into the cylinder #1 spark plug hole, and turn the crank over one complete turn and while writing down the highest PSI for cylinder #1, would that be the TDC of cylinder #1?

    This way I would crank the vibration dampener just enough until it hits that certain PSI again and that would be the TDC of cylinder #1?

    Good idea or Bad idea?
     
  8. 1-ton

    1-ton 1/2 ton status Premium Member

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    Using a compression tester to find "Top Dead Center" on the #1 cylinder compression stroke would be a little unorthodox. While in theory, you may be correct, but in practice it would probably not work out for you. You should do the old tried and true method of just getting a friend, wife, or whoever to turn the ignition key for only one second, and then stop, until on one of those turns you feel or hear the compression stroke coming from the #1 cylinder (with the spark plug removed), then line up the timing mark, on the Harmonic Damper, with the "0" (i.e. zero) mark on the timing tab of the chain cover. Although this will not be true top dead center to the "Nth" degree, it is close enough to set your distributor in correctly.
     

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