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Re: Vacuum
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That sounds low to me for an engine idling in neutral. Is the gauge known to be accurate? Does the engine idle well and run well? Is the gauge connected to true manifold vacuum, and not a port on the carburetor? I'd expect a Packard 8 to run on the high side of the normal vacuum range, 20" plus or minus, at low idle of 300-400 RPM. Timing can affect vacuum, as can any engine loading, or extreme wear. An extremely worn engine would be an obvious oil burner. A stretched or slipped timing chain might cause low vacuum.
Posted on: 2023/4/16 10:35
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Those are all good questions. I have been thinking it should be 3-4 higher as well. Gauge, possible it's not accurate. Yes, connected to manifold vacuum. Car is idling nicely, has a bit of a miss which I believe is being caused by a sticky lifter. Timing when I got the car was whacked, sitting about about 15 degrees, rolled it back to 6 as per the manual and have since adjusted it to 7 as it seems to run just a bit better. Car is new to me, but no indication that it's burning oil and oil stays super clean. Checking my gauge may be a good place to start.
Posted on: 2023/4/16 13:45
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I'd try setting the initial timing at 10 or 12 BTDC. If you have a worn timing chain and distributor drive gear or out of place timing marks, that may get it closer to correct. If it kicks against the starter when warm, back off just a little. I've had very good results using Marvel Mystery Oil in older engines with gummy lifters. A good 10W30 detergent oil is beneficial, also.
Posted on: 2023/4/16 14:05
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Good thoughts, thank you! I added Marvel last night, so hopefully that gets things freed up. I'll try playing with the timing a bit more and see what happens, might be a reason it was sitting at 15 BTDC before, although that seems excessive, but it may run better closer to 10. It's not "terrible" right now, but some more playing and I should be able to make it better.
Posted on: 2023/4/16 14:47
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Considering the mileage and unknown condition, I think you're over reacting.
It's stable and doesn't appear to cause issues. Maybe a bit of fine tune might help but if it's working, accelerates, I wouldn't mess with it. It's a stroked low compression engine, so may not match the "published" levels of more modern ones and wear is a factor. ie, close enough if no issues. UR using a compound gauge so zeroing is crucial to accuracy. I'd check with a different gauge, if suspect.
Posted on: 2023/4/18 9:43
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Thanks Fish'n Jim, I don't think it's way out, just looking to see what's "normal" for other 327's. I have some lifter issues, which are probably affecting the vacuum some as well. I'm waiting to see if the lifter issue is from sitting, that is sticky, or if they are worn and maybe the car was parked years ago with lifter issues.
Posted on: 2023/4/18 10:03
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If you are located well above sea level, vacuum and compression test readings will be a little lower than specs. At higher elevations, initial timing settings can be set earlier than spec.
Ignition point gap affects both timing and overall system performance. If your car has a dual point distributor, special procedures may be needed to set the points correctly.
Posted on: 2023/4/18 10:08
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"Vacuum is nice and steady, that is, needle does not flutter."
That's good news. That indicates that your valves are sealing and holding compression, at least at idle. Valve noise is normally a clearance issue or a lifter issue, and may not affect valve sealing. Valves can somtimes work well at low speeds, even if some noise is present, but fail work well at higher speeds due to sticking issues or weak springs or both. Driving the car at moderate speeds for a few hundred miles can resolve sticking issues. Weak springs need replaced. Rust pitted springs need repalced. If an old engine has one or more weak springs, it's usually best to replace all of them.
Posted on: 2023/4/18 10:21
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Thanks again! I too think the valves are sealing okay. I think I may have valves not fully opening causing a "small" misses sometimes when idling, which is a more pronounced when under load. A couple of videos for your viewing pleasure. In the slow mo video you can see that some of the lifters are not spinning like the rest....I wonder if those are the ones the problem ones? I do think the sounds is coming from cylinder 4 or 5. https://drive.google.com/file/d/1GZf0ACXKUmaV-AuCDse2kVwpmRDqPYTF/view?usp=share_link https://drive.google.com/file/d/1GP24x44QBN-ww6j8Tll6vkgHY_nT-PsD/view?usp=share_link
Posted on: 2023/4/18 10:29
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