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Thread: 3T rebuild questions.

  1. #1
    Forum Member 1st year Apprentice
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    Default 3T rebuild questions.

    I have a '74 TA22 with a 3T engine. I recently bought it (without seeing it, which was a stupid thing to do) and it blows a bit of smoke and the bearings were rattling so Dad and I pulled the engine out this morning.
    The history of the car is that it was taken off the road about 5 years ago and the engine was rebuilt (I don't know how thoroughly) about a year before that. It apparently has a shaved head and has been bored 40 thou oversize.
    We're planning to put new rings and bearings in and probably get the crankshaft checked to see if it's been damaged.

    So my questions are:
    1. Any other suggestions of stuff to do while the motor is in pieces? It needs a bit of a tune but the engine seems to be running pretty well overall. Keep in mind that I only have about $600 and it will cost about $220 for the rings, bearings and gaskets to put the motor back together.
    2. There's a carbon build up on the exhaust valves but not the inlet valves. I should know what that means but I don't. Can someone enlighten me?
    3. Also there's a carbon build up on the #4 piston, the one near the body of the car, but not the others. Would this be because its rings were more worn than the others?
    4. It looks like when it was last honed it was scratched deeper than necessary. You can't feel it but you can still see it after however long it's been run. It looks like it might have been done with sandpaper. Would this have made the rings die early? We've got one of those hones you put on the end of a drill. Should that be fine to re-hone it when we put the new rings in?

    Thanks for any help.
    Last edited by flamingheads; 11-08-2009 at 05:20 PM.

  2. #2
    Toymods Net Nazi Too Much Toyota river's Avatar
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    Default Re: I just pulled my engine out and have some Q's

    Hi,

    First, please rename your thread to something useful, such as "3T blowing smoke" or similar. The current title means nothing when someone is searching for relevant information. If it's not changed this thread will be deleted.

    Secondly... your engine.. it sounds like it's has a bit of a hack job in the rebuild. If it were me, I'd get the whole engine checked and parts replaced, as it is too late to fix something internal once you put the motor back in the car. It will cost more in time and money if you do a half job on replacing/fixing things - only to pull the motor out a second time to fix things that should of been fixed the first time.

    If it was my engine I would get the bores honed and the head checked for no warpage. Get the block acid dipped and then buy some pistons and rings to suit the newly honed block. Replace all bearing and get the crank balanced.

    Get the valves checked for clearance and replace if required.

    seeyuzz
    river
    The thinking man's clown and the drinking woman's sex symbol
    RA25GT - There is no substitute | 18R-G - Toyota's Dependable Masterpiece
    Toymods Car Club Treasurer, assistant Historic Plate Registrar & Forums Admin

  3. #3
    Forum Member 1st year Apprentice
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    Default Re: 3T rebuild questions.

    Title changed.
    I will be honing the bores like I said and the head was shaved last time it was rebuilt so I would assume it hasn't been significantly damaged since then.
    The pistons are apparently higher compression pistons so I'd rather not replace them. Also they look fine and I don't know why they'd be damaged.
    What does getting the block acid dipped do for it other than making it pretty?
    I will get the crank checked and replace the piston bearings.
    I will check the valve clearances.

    It only took like half an hour to get the head off and about 4 hours to get the whole motor out and into pieces and that the only costs of taking it apart are 2/3 gaskets so I don't think there's too much time or money to be wasted if something goes wrong.

    If anyone could answer my other questions that would be cool.
    Thanks.

  4. #4
    1941cc 2T-G Domestic Engineer w810sc's Avatar
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    Default Re: 3T rebuild questions.

    1. I'd press the gudgeon pins/wrist pins out and weigh all four pistons and connecting rods and balance them. I would also check what compression your motor is running - cylinder volume, head gasket volume, combustion chamber volume, piston dome volume etc. then do a couple of calculations to work out the compression ration so you know what your working with because the last thing you'd hate to get is detonation - broken ring lands, and compression rings (been there, done that).
    I'd also port match the intake and exhaust ports and intake manifold to the gasket - radius the short turn also.
    leak test the valves, one way of doing this is turning the head upside down and pouring petrol in all four combustion chambers. Another way is to pour it in the ports. You could also take the valves out and put them on a drill and spin them to see if they are bent.
    Get the crankshaft balanced with your clutch and flywheel, it makes a very noticeable difference.
    Clean up inside the block, grind away the over cast. Chances are they might not break off but if they do it will cause damage to moving parts, so prevent it by removing it.
    2. Leaky valve seals?
    3. should have done a compression test before you pulled it apart so you have something to work off.
    4. Get a machine shop to do it the right way with their machine. Let them know what pistons you have and what rings you will be using just in case it needs more clearance.

    A 2T/3T complete top to bottom gasket kit is about $140.
    If your water pump looks sus replace it.
    Get a new thermostat.
    Clean out your radiator.

    good luck.
    deepdishfactory
    2T-G - Half the valves but twice the fun.

  5. #5
    Forum Member 1st year Apprentice
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    Default Re: 3T rebuild questions.

    Thanks for the advice. I'll have a look into it.

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