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ENGINE GUYS.....rebuild or Run it?

Discussion in 'The Hokey Ass Message Board' started by MarkX, Jun 2, 2006.

  1. MarkX
    Joined: Apr 8, 2003
    Posts: 1,232

    MarkX
    Member
    from ...TX

    I have a older "running" small block chevy engine that I think could be used as-is for driving and crusing NOT RACING. but i'd like to freshen it up. My question is.... If I go and change the timing chain and gaskets..... can I change the rings and bearings without having to go and get machine work done on the block and crank? or just run it till it NEEDS to be rebuilt? its a little tired but runs ok........ Im workin with a budget so I cant just run out and buy a crate motor or get a premium rebuild. what do you think?
     
  2. hsheartaches
    Joined: Jul 3, 2005
    Posts: 460

    hsheartaches
    Member

    Check your journal sizes on your crank, matched w/ the bearing sizes...also check the cylinder wear w/ an inside mic and see what it looks like. If the journals haven't worn down, I wouldn't mess w/ bearings. There will be a ring lip at the top of each cylinder. You can just hone most of that out...I'd at least invest in a new set of cylinder rings.
    I'd tear the heads down and check the valve guide clearances to make sure they're not worn too much. Also, lap the valve to reseat them properly. With the head loaded and off the block, you shouldn't be able to get a feeler gauge in between the valve and the cylinder head. Put new valve stem seals in as well.
    Also, check your camshaft bushings in relation to the wear on the cam. As long as everything looks good, I'd put a new set of gaskets on her, along w/ new rings, lap the valves, and give her a fresh paint job, and slap 'er all back together. Helpful?
     
  3. burndup
    Joined: Mar 11, 2002
    Posts: 1,938

    burndup
    Member
    from Norco, CA

    Get the heads rebuilt, and it'll be like a new engine.
     
  4. HEATHEN
    Joined: Nov 22, 2005
    Posts: 7,591

    HEATHEN
    Member
    from SIDNEY, NY

    Were it mine, I'd give it rings, bearings, gaskets, and new chain and gears. It's out right now--are you really that anxious to yank it out of your car a week/month/year from now? Also, a sbc is still the cheapest engine in this part of the world to freshen up. It's not like the parts would cost much. Besides, I've known guys that tore an engine down under the same circumstances, just to "freshen up an already good running engine", and upon teardown found something like a piston with broken ring lands that would have been a real pain in the ass down the road.
     

  5. plan9
    Joined: Jun 3, 2003
    Posts: 4,062

    plan9
    Member

    freshening an old motor is a pretty broad subject.
    there are a few things you can check with the right tools... a feeler guage, plastiguage and a Haynes SBC rebuild book

    if the motor is covered in gunk, you can pretty much write the motor off as a core (just my opinion). if the motor is relatively clean and spins w/o ANY binding throughout its 360 deg rotation, the bearings/rings are probably OK.. although, in regards to the rings.. it is no way to check for excessive wear.

    how was the motor stored? how long was it stored? did the previous owner claim it was a low mile motor? did he look shifty? how do the spark plugs look? (excess oil on any of them?) did you see/hear it run?

    i rolled a 307 chevy with bad rings... it'd smoke like a motherfucker coming off the freeway, it was like that for at least another 1000miles until i sold it... the new owner drove it home, no problems aside from smoking.. ;)
     
  6. chiefbobber
    Joined: May 2, 2006
    Posts: 114

    chiefbobber
    Member
    from NH

    If your'e looking to do it on the cheap, I'm with hsheartaches. I would use a ridgereamer and go 10+ on the rings filing the end gap to spec. Good luck..........
     
  7. MarkX
    Joined: Apr 8, 2003
    Posts: 1,232

    MarkX
    Member
    from ...TX

    rebuilt heads i think i can do.....
     
  8. burndup
    Joined: Mar 11, 2002
    Posts: 1,938

    burndup
    Member
    from Norco, CA

    Lemme make an addendum... if its a 305 or a 350, just get it running nice and beat the shit out of it. If its a 327, sink a bunch of time and paychecks into it!
     
  9. Find a friend with a leakdown tester and leak it. If it's been sitting, fog the cyls with WD40 and spin her over by hand a couple of times. If you have no cyls higher than 30%, change the oil pump, pop it in and go.

    If you are going to tear it apart, there's about a 98% chance you're going to do a full machined rebuild. Most lo buckers don't like to admit it, but that's normally how it works...
     
  10. Yeah if you're planning on re ringing it hell man, machine it and instead of being half assed and runnable it'll be a new fresh engine.
     
  11. hotrodsnguns
    Joined: Apr 3, 2004
    Posts: 545

    hotrodsnguns
    Member
    from Fresno, CA

    What ever you do clean the pan and install a new oil pump.
     
  12. SwitchBlade327
    Joined: Dec 15, 2002
    Posts: 2,911

    SwitchBlade327
    Member

    If you tear it down, might as well go all the way....expecially seeing how cheap SBC engine kits are.
     
  13. MarkX
    Joined: Apr 8, 2003
    Posts: 1,232

    MarkX
    Member
    from ...TX

    thanks guys ... all your advice is helpful
     
  14. MarkX
    Joined: Apr 8, 2003
    Posts: 1,232

    MarkX
    Member
    from ...TX

    I didnt want to just BUY a rebuild..... I dont know much about engines but I'd like to Do-It myself as much as possible
     
  15. blackrat40
    Joined: Apr 19, 2006
    Posts: 1,167

    blackrat40
    Member Emeritus

    What kind of oil pressure is it showing,when up to
    operating temperature,at idle and at 45mph ?
    Compare it to what the manuals say it should be.
    If it's very low (50% below normal) it probably needs
    bearings.
     
  16. Check compression, if everything looks good I can help you go through the heads. I have the spring compressor tool.

    I just did this exact thing on the replacement motor I put in the Commander.
    clean and paint everything
    Go through heads
    checked ridge
    new water pump and fuel pump
    Gaskets
    etc...
    It runs like a champ.

    So I guess the budget comment means you don't want to buy the 383/5sp??
     

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