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Thread: Out of power at 5600 RPM.

  1. #41

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    Open headers are just to test with a few pulls. I disabled Closed Loop, so WBO2 sensor missing shouldn't be a problem

    I was losing power much earlier in RPM due to having bad head gaskets.

    My last datalog has two pulls through three gears. Both pulls die at same RPM in each gear.

  2. #42

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    I do have a datalog of a broken valve spring during acceleration. (I don't really feel like looking through several hundred right now to find it and I don't remember if I named it.) The AFR goes bananas when one spring breaks. You could imagine how horribly the intake charge gets corrupted when the valves don't shut & stay closed when they should.

  3. #43

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    Spoke with Comp Cams and the guy said it's sounding like valve float. He needs my installed height and spring pressure. I found a $100 spring tester that you can test while installed, but cannot find it locally and neither O'Reilly, nor AutoZone knew what I was even talking about. Ugh... I'll try NAPA and then maybe just order one.

  4. #44
    Join Date
    May 2019
    Location
    Ct
    Posts
    262

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    They have an adapter so you can plug an air line into the spark plug hole and pressurize the cylinder so the valve doesn't fall down. They sell shims, but I would order the recommended springs if you find they aren't strong enough.

  5. #45
    Join Date
    Dec 2009
    Location
    Connecticut
    Posts
    25,659

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    Quote Originally Posted by Leon82 View Post
    They have an adapter so you can plug an air line into the spark plug hole and pressurize the cylinder so the valve doesn't fall down.
    Yep, it works well. However, I'd also put a ratcheting breaker bar on the damper bolt because the air pressure can push the piston down on some engines.

    They sell shims, but I would order the recommended springs if you find they aren't strong enough.
    Yes, ensure the valve spring pressure is correct and installed at the correct height. Purchase new valve springs if not. If it's valve float, I'd put that $100 (valve spring tester) towards a new set of valve springs.
    May God's grace bless you in the Lord Jesus Christ.
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  6. #46

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    I'm scouring my neighborhood via Facebook to see if anyone has the tool. There are a few gearheads around me. I'm fairly certain I'll be in for a new set of springs, but Comp Cams wants to know what I have currently to ensure they guide me to the right set if I need to move up the scale.

    I hate throwing away $100, but if it's for a tool, now that makes it tougher to say no. I have a whole bin full of "used once" tools. Never know. Hoping I find someone like me in the neighborhood. ;-)

    https://www.dropbox.com/s/xlcjge97bv..._4128.MOV?dl=0
    The first gear I pull in is 2nd, listen to the top of that RPM before I let off. Right at seconds 6 & 7 in the video.

  7. #47

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    Sounds like progress. A clean length of rope down the spark plug hole will also keep the valves from dropping if you don't have access to compressed air. You only need 10 psi or so if you do. Post the info on the springs when you come up with some numbers. Should pull nicely to 6000 with the right springs.

  8. #48

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    Quick update. I pulled a spring today and all signs point to Comp Cam 942-16. The OD of outer is 1.437", which is same as specs. The install height of this spring is 1.7". I did buy a spring height micrometer and my valve height is...(drum roll)... 1.850". So I'll take valve float for $1000 Alex. Plano Machine Shop may not be as good as I was told.

    I will again call Comp Cams to see what they might have, but I've zeroed in on a set of Trick Flow TFS-16972-16. Similar specs to the springs I have, but at a 1.85" install height.

    I may take my current springs over to another local machine shop to see what the actual seated pounds are at 1.850". From looking through Summit Racing and filtering for specific sizing that will fit without machining (install height 1.850" and min ID of .987/max OD of 1.460"), the Trick Flows are the only option I see. These are 109 lbs. @ 1.850 & 293lbs. @ 1.250. I only have .480" lift, so I'm under the 300 lbs. suggested for hydraulic flat tappet lifters.

  9. #49
    Join Date
    May 2019
    Location
    Ct
    Posts
    262

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    You might want to price out a different retainer that'll give you that height as long as you don't get coil bind and at 1.7" give you proper pressure.

  10. #50

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    Glad you found the issue.

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