mdwatson Posted October 28, 2013 Share Posted October 28, 2013 Warmed my engine up this morning and everything sounded normal. Ran fine going to work and when I pulled up to go through gate I heard it knocking when I turned the radio down. I'm going to take it back to the shop that put the long block in but was wondering what y'all might think it is. It's a 86 2.5L auto. The knock gets faster with rpms while giving it gas. Used a dowel rod to pin point the sound and it's extremely loud at the distributor cap. You can grab the cap and feel the knock through it and even through the wires. Not sure if the cap is acting as a echo chamber or not but when I put the dowel rod at the base of the distributor it's not as loud. Pulled cap and rotor and it looks fine. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 29, 2013 Share Posted October 29, 2013 Make sure the bolt is tight that holds the dizzy down. Link to comment Share on other sites More sharing options...
zagscrawler Posted October 29, 2013 Share Posted October 29, 2013 Can you hold the distributer and feel it when crankin it? or just when its running? Link to comment Share on other sites More sharing options...
mdwatson Posted October 29, 2013 Author Share Posted October 29, 2013 Distributor was tight and didn't think to feel it when starting. Truck died and dizzy doesn't turn when trying to start. Hoping it's just broken and no other problems. Link to comment Share on other sites More sharing options...
zagscrawler Posted October 30, 2013 Share Posted October 30, 2013 ouch.. does it still sound like it has even compression when cranking it over or does it have an easy spot or fast turnover rate (faster then when it was before it died) when holding the key in start for a small period? I'm assuming you mean my dizzy doesn't turn you pulled the cap and the rotor doesn't spin while cranking? Link to comment Share on other sites More sharing options...
Oyaji Posted October 30, 2013 Share Posted October 30, 2013 Have you done a compression test?. Link to comment Share on other sites More sharing options...
mdwatson Posted October 30, 2013 Author Share Posted October 30, 2013 Yep pulled cap and it doesn't spin at all when trying to start. Motor does turn over but it is at a faster rate than before. It's at the shop now, I'm not looking forward to what the diagnosis is. Link to comment Share on other sites More sharing options...
zagscrawler Posted October 30, 2013 Share Posted October 30, 2013 oh man that's not good. Are these motors noninterference? ive never asked. Link to comment Share on other sites More sharing options...
Minuit Posted October 30, 2013 Share Posted October 30, 2013 Yep. 4.0s are non-interference. No danger of piston-on-valve action. I bet you probably screwed up your oil pump in some way since that's what turns the dizzy. Link to comment Share on other sites More sharing options...
zagscrawler Posted October 31, 2013 Share Posted October 31, 2013 I would like to think it was just the oil pump but isn't it driven off of the cam? The fast spinning makes me think maybe broken timing chain or missing bolts in timing gears.... good to know about the clearance though I have always wondered. Link to comment Share on other sites More sharing options...
carnuck Posted November 1, 2013 Share Posted November 1, 2013 Dist drives the oil pump If it was loose because someone forgot to tighten the bolts, it can drop down and seize the motor from no oil pressure. Dist gear can also be wiped out by a bad/loose oil pump. Link to comment Share on other sites More sharing options...
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