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Poly 318 Valve Adjustment Jump to page : 1 Now viewing page 1 [50 messages per page] | View previous thread :: View next thread |
Forward Look Technical Discussions -> Engine, Exhaust, Fuel and Ignition | Message format |
Rob |
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Elite Veteran Posts: 990 | I have a '58 Plymouth with a poly 318, factory four barrel. I've had the car 13 years, engine was rebuilt before I got it, engine runs well, never had a problem with it. It started clattering like a loose lifter from the passenger side, so I pulled the valve covers to do a valve adjustment... I'm finding that the exhaust valves are adjusted very tight, .005 cold. Specs call for .018 hot. The intakes seem to be close to specs. Why would someone adjust the exhaust valves so tight? Engine seems to run fine, is there any bad effect from having them so tight? | ||
BigBlockMopar |
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Expert Posts: 3575 Location: Netherlands | I would wonder more where the valve noise would have come from if everything still appears 'good'. How did you check the valve lash? Both valves at once on the same cylinder (that would be wrong btw)? | ||
ttotired |
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Expert 5K+ Posts: 8443 Location: Perth Australia | Sudden valve noise from 1 lifter in a solid lifter engine = wiped cam lobe, bent push rod, adjuster come loose (need a new rocker) ect Find the noisey one and compare valve geometry and parts with another cylinder | ||
Rob |
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Elite Veteran Posts: 990 | I checked valve lash by setting the engine to TDC, and then following that diagram given, checking one intake and one exhaust, then bumping the engine 90 degrees, repeating, etc. I have not checked all the valves as of now, but all the exhaust I've checked so far are at .005 cold, which according to the specs is wrong. Why would the rebuilder of the engine set the exhaust so tight? Are there any bad effects from setting them so tight. Agreed, there's probably one valve that's gotten way too loose or wiped cam lobe or more serious problem. | ||
ttotired |
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Expert 5K+ Posts: 8443 Location: Perth Australia | Depends on wether it was done hot or cold, If adjusted cold, the gap will tighten once it gets hot Bad thing that can happen if to tight is burnt valves, valve seat, but if that's happened, you loose compression. Start the engine without rocker covers and listen for the noise And yes, it makes a mess, but easy to do. Valve lash checking should find it though, but also look for one adjuster thread being different to the rest, may be a clue | ||
57chizler |
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Expert Posts: 3777 Location: NorCal | Rob - 2018-05-20 5:41 PM I checked valve lash by setting the engine to TDC, and then following that diagram given, checking one intake and one exhaust, then bumping the engine 90 degrees, repeating, etc. Not really a good way to do it due to overlap. The adjustment procedure below is good for any engine with the same firing order. (valvelash.jpg) Attachments ---------------- valvelash.jpg (22KB - 105 downloads) | ||
BigBlockMopar |
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Expert Posts: 3575 Location: Netherlands | I think that's the way he did it. | ||
swede59 |
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Member Posts: 11 | does anyone know where i can get tappet adjusting screws and a timing bracket that mounts on the bottom of water pump on a 318 poly | ||
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