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meltie posted:Some MB engines of the era needed chain guides replacing, and yeah, chains were known for stretching. Not sure about MB, but many many engines where it's said that "the chain has stretched", it really hasn't but it's all down to worn out guides, malfunctioning tensioners, or just some wear on chain and sprockets, all of which will make the chain seem "too long" despite it not being a single millimeter longer than a new one. Some people then cheap out and only replace the chain and nothing else, which typically solves exactly fuckall. tl;dr: don't cheap out. if you replace the chain, replace everything it touches. Also gently caress plastic chain guides forever.
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Jul 26, 2018 07:00
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STR posted:Nissan's KA24E - have them as more of a regular maintenance item. Ignore the rattling too long, and they chew through the timing cover (which, helpfully, has coolant passages). Hello.  When I took this engine apart (junkyard mid-90's KA24E, allegedly about 170000km on it), I found most of the chain guide in pieces at the bottom of the oil pan, and the chain was just under halfway through in mining it's way into the water passage. The original chain guide was plastic, the replacement one was metal with a plastic surface molded onto it. The source of the problem is the tensioner that pushes the guide rail against the chain. It's hydraulically driven by engine oil pressure and typically works fine, but it has a spring in it to provide tension at startup before there is oil pressure. That spring breaks, causing the chain to rattle and flop about for a second or two every time you start the engine, and that rattling will break the plastic chain guide. I have no idea how long this thing was driven with a broken chain guide or how long it would have had left before water and oil had met. In all, a properly built timing chain system truly should be a part that never needs replacing for the life of the engine, but so many engines have some little engineering defect making them a replacement item with a lot of hassle involved compared to a regular old timing belt.
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Jul 26, 2018 08:06
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Pursesnatcher posted:I think the distributor itself is solid, since the rotor has no lateral wiggle in it, although it does have some rotational slack in it. I don't like that, instinctively, but I don't know if it's actually that bad either. It shouldn't matter at all, and many distributors do that. As long as the rotor is in contact with the right post when the ignition fires, it doesn't affect the ignition (and that would be a whole lot of slack). At least not if the slack is between the rotor and the distributor shaft. If there is lots of slop is between the distributor shaft and whatever shaft drives it I guess it could cause timing issues (depending on type of ignition, and any sensors that might be in the distributor), but that seems rather unlikely to be the problem. Edit: Pursesnatcher posted:Huh. A new rotor and cap is about $250, while a full set of Bosch cables (which I'll get eventually, can't stand the fact that the ones in place now aren't OEM) would be another $700 or so. Sounds expensive to replace all of it? I get the feeling people do once a year, but maybe that's overkill? What the hell? Are they norwegian hand-made gold-plated parts or something? There has to be a cheaper but still good alternative. The rotor and cap might be pretty Merc-specific, but there is no reason the cables should have to be anything but the right length to work. Also the rotor and cap didn't look too bad from your pics (at least not $250 bad), but if there's rust and crap inside the ignition cable connectors (if they're anything like the old plugs, that is) those deserve replacement. ionn fucked around with this message at 17:10 on Sep 8, 2018 |
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Sep 8, 2018 17:03
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