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  • #16
    alot of the "sloppy mechanics" (the guys who by a 4.8/5.3/6.0 and a big ebay turbo, and, well,, send it) say not to even look at cab bearings, ever. but you're also building an engine that you hope to run all our for 24 hrs. I will say, that short of roller cam bearings, there is no reason to get fancy ones. just make sure you get a quality brand.
    Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.

    I get bummed out every time I type "titties" in the search bar and nothing pops up....

    Built not bought, because bolt-ons don't...

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    • #17
      I was going to do that but I learned how to use a new toy at work and the bearing spacers aren't going to be very rebuild friendly. Also, I redid the math and I'll be at 0.533" lift with a lot to too much valve spring. So I shaved 0.055" off of one side of Teflon coated SBC bearings and will sink those in the spacers tomorrow. Then I can check piston to valve clearance and get the crank off to be balanced. I was hoping the piston weights were or could be made close but the LZ pistons are 100g heavier than the LX9 pistons. I have the Federal Mogul version with the thinner ring package. The Mahle pistons are different.

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      • #18
        Got all the cam bearings/spacers in and the cam spins nice and free like it should.

        Piston to valve clearance is more than adequate for 0.533". Someone on that Fiero forum said these engines were safe up to 0.545" valve lift and that seems to be in right ballpark. I should have gotten an exact number for clearance but I was more than safe and moved on.

        I did a little playing with push-rod length and it looks like I need an extra 0.075" on the intake and 0.085" on the exhaust. Anyone else find that the exhaust push-rod needed more length than the intake? I wouldn't have expected this but maybe this is to compensate for extra heat.

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        • #19
          I've never measured them, the new 3500 I'm about to be working on will be carefully measured though. that being said, if you took careful measurements, and more than one came up longer, I wouldn't worry about it. I am worried about piston to valve clearance in mine, my cam runs about .576" lift, so I need to be careful for sure...
          Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.

          I get bummed out every time I type "titties" in the search bar and nothing pops up....

          Built not bought, because bolt-ons don't...

          Comment


          • #20
            My low mileage LX9 with stock timing chain, mild springs, and 0.504" lift had slight valve impressions on the pistons so more than that and you are very likely to have clearance problems on an LX9. I think guys with high mileage stock motors were having the same witness marks too. Hate to be the bearer of bad news but it's easier on the schedule to know you might have to cut valve pockets early that be surprised in my mind.

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            • #21
              My 1615 grind supposedly had .565 on the intake valve and left no impressions in the pistons. Lx9 bottom end with gen 2 heads

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              • #22
                Interesting... I won't deny that my motor experienced a coolant failure which might of contributed but I had stock LX9 heads- not Gen 2 heads. I also re-used the 60k mile timing chain if that makes a difference. If you measure it you'll know otherwise I guess it's just internet hearsay.

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                • #23
                  Originally posted by neophile_17 View Post
                  My low mileage LX9 with stock timing chain, mild springs, and 0.504" lift had slight valve impressions on the pistons so more than that and you are very likely to have clearance problems on an LX9. I think guys with high mileage stock motors were having the same witness marks too. Hate to be the bearer of bad news but it's easier on the schedule to know you might have to cut valve pockets early that be surprised in my mind.
                  What where you spinning it to? And what springs did you use?
                  1999 Olds Alero 2.4 to 3500 swap (running). totaled by a honda
                  1992 lumina 4 door 3500 3spd auto 15.020 @93.5 mph
                  1984 Cavalier type 10 hatch 3100 5spd!!!
                  14.96@91.47 in the 1/4
                  9.63@74.36 in the 1/8th
                  14.30 on slicks! scrapped due to rust!

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                  • #24
                    Originally posted by 1QUICKHATCH View Post
                    What where you spinning it to? And what springs did you use?
                    Maybe 6500, I try to keep it in the power band not just make noise. I can't remember exactly but they're probably Comp 26986s.

                    Something to note. If you use the LZ timing chain tensioner with a pre-99 timing chain you'll have to message the tensioner a little. Otherwise the back of the timing chain pins rub on the tensioner backing plate. A couple of light taps should do it.

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                    • #25
                      I measured the stock pushrods in the LZ and then the LA1 pushrods I had just as a second data point. The LZ pushrods are longer than all the spec sheets that I have seen for the LZ. The spec sheet states 5.750" and 6.000"

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                      • #26
                        Originally posted by neophile_17 View Post

                        Something to note. If you use the LZ timing chain tensioner with a pre-99 timing chain you'll have to message the tensioner a little. Otherwise the back of the timing chain pins rub on the tensioner backing plate. A couple of light taps should do it.

                        This is good to know, thank you!
                        Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.

                        I get bummed out every time I type "titties" in the search bar and nothing pops up....

                        Built not bought, because bolt-ons don't...

                        Comment

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