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Lloyd Elliott

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  1. #1
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    Default Lt1 top end overhaul

    I recently completed a top end overhaul on my Camaro and thought I would share the build up through a series of photos and comments. There were many setback aggravations but it's nearly complete. Perhaps what I learned may help others in the future.
    Nolan
    '94 Z28 Bone stock,4l60e
    '97 SS SLP,T56,385 stroker,AFR210,XFI292,NO traction til top of 3rd gear.
    '57 Chevy 3100 p/u LT1/T56

  2. #2
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    Alex Rauld
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    1994 Trans Am GT
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    Default

    That's awesome can't wait to see pics
    1994 Trans Am GT - HPS Ported Heads/Intake, LE Cam, FTI 3600, TP Built 4L60e, Moser 9" w/ 3.90's, BMR Suspension, Formato Tuned

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  4. #3
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    Default

    The engine build was a comedy of errors from the get go. The previous owner knew what he wanted but was paying folks to work on it. This is a 385" stroker(.040 over), all forged bottom end,AFR 210 heads, comp xfi292 cam and other assorted goodies. When I bought it the valvetrain sounded bad, it stunk bad at idle and sometimes smoked a bit ot of the tailpipes. But at WOT it was a beast. I played around with it for awhile and figured out some of the random misfire issues and got it running better but it had more issues.
    '94 Z28 Bone stock,4l60e
    '97 SS SLP,T56,385 stroker,AFR210,XFI292,NO traction til top of 3rd gear.
    '57 Chevy 3100 p/u LT1/T56

  5. #4
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    Default Continued

    The misfire issues were caused by his mechanic putting stock LT1 spark plugs in the AFR heads and also a couple of bad plug wires that sometimes fired and sometimes not. I had run into the spark plug issue once before on a different engine. Stock heads use a tapered seat spark plug, AFR heads use a gasketed seat spark plug. I put a set of gasketed seat plugs in along with a set of wires I custom built to go over the valve covers. Ran alot better but it still stunk and smoked some times. I was actually losing compression from the plugs leaking because the tapered seat plugs were tightened against a flat seat.
    '94 Z28 Bone stock,4l60e
    '97 SS SLP,T56,385 stroker,AFR210,XFI292,NO traction til top of 3rd gear.
    '57 Chevy 3100 p/u LT1/T56

  6. #5
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    Default

    I finally decided that the engine seemed to run like it had an internal vacuum leak and made plans to pull the intake and investigate. While I was at it I planned to check out the valve train noise as well.
    '94 Z28 Bone stock,4l60e
    '97 SS SLP,T56,385 stroker,AFR210,XFI292,NO traction til top of 3rd gear.
    '57 Chevy 3100 p/u LT1/T56

  7. #6
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    '94 Z28 Bone stock,4l60e
    '97 SS SLP,T56,385 stroker,AFR210,XFI292,NO traction til top of 3rd gear.
    '57 Chevy 3100 p/u LT1/T56

  8. #7
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    Default

    Yep, It was what I thought. The rear four ports (5-7 and 6-8) were leaking internally. Ports were very oily. The 5-7 reminded me of another issue I discovered while doing the plugs and wires. By chance I happened to notice that the #5 and #7 fuel injector plugs were hooked up reversed. It actually ran like this, LOL.
    '94 Z28 Bone stock,4l60e
    '97 SS SLP,T56,385 stroker,AFR210,XFI292,NO traction til top of 3rd gear.
    '57 Chevy 3100 p/u LT1/T56

  9. #8
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    Default

    The heads on this engine are AFR 1057's. AFR says DO NOT use GM LT4 intake gaskets, they will leak. Use AFR 6860 with a little bit of silicone sealant on the port bottoms. Guess what was installed on it? I think all the ports leaked slightly but the rear four were the worst because the engine slants back and the oil drainback really flooded the rear four ports.
    '94 Z28 Bone stock,4l60e
    '97 SS SLP,T56,385 stroker,AFR210,XFI292,NO traction til top of 3rd gear.
    '57 Chevy 3100 p/u LT1/T56

  10. #9
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    Default Valvetrain

    The more I looked the more I found. The rocker arms were running all over the valve spring retainers. At this point I started looking closer at the valve spring setup and discovered several valve guides on both banks that appeared to be worn badly. I could push on the springs and make the valves move side to side in the guides. Well hell, its time to pull the heads to have them freshened up.IMG_0178.JPGIMG_0177.JPG
    The clay was a good way to check clearances that are hard to see.
    These are Crane Gold rockers.
    '94 Z28 Bone stock,4l60e
    '97 SS SLP,T56,385 stroker,AFR210,XFI292,NO traction til top of 3rd gear.
    '57 Chevy 3100 p/u LT1/T56

  11. #10
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    Default

    The heads were a real pain in the ass to pull. I got some help after I had cut myself all up trying to get to all the hardware and bolts. Finally out;IMG_1127.JPG
    '94 Z28 Bone stock,4l60e
    '97 SS SLP,T56,385 stroker,AFR210,XFI292,NO traction til top of 3rd gear.
    '57 Chevy 3100 p/u LT1/T56

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