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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: screamin86 on September 10, 2009, 05:23:59 pm
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Alright well i believe the silvys ol 305 is finaly on its way out!i wanted to get some others opinions beforehand though.its never been a high oil psi monster always held 45 at most and 15-20 at lowest once warm idle in gear.past few days the psi hasnt been holding very high at idle like 5-8 but still climbs like normal at 25-30 cruise. Today going to work it felt very slugish. Got to moms and picked up some parts for one of my fbodys and came back out at started it up and im getting.a offbeat rattle like a pushrod not a consistant knock and im holing 10psi or so of preasure. I drove to work and it doesnt seem to get faster or lounder with rpm but i can still hear it. Any one got any sugestions other than its gone. If so that sucks but i i was planing on a build but not this soon! I really would like to have two 4x4s come winter time.
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5-8 at idle is normal, can you pinpoint where the noise is coming from?
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Only need 10psi per 1000 RPM, but 5-8 at idle sounds pretty low. Could just be the oil pump. Check oil level also.
Get a length of hose and narrow down the location of the knock.
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Im gona do more diagnostic tonight after work and see if i can narrow it down a little better! I had thought about changing the timing chain and oilpump for awhile but was waiting. My 82 ta with a stock crank turned stock rods and 030 flat tops and a stock replacemet melling pump not hv holds at minimum 25-30 hot idle and 55-60 cruise and 60+ wot.idk just worrys me since the truck seems to have lost power also. Im gona check it over tonight and tomarrow and see whats going on i supose.ive broken/bent pushrods on my fbodys b4 and it was similar but the oil preasure never droped at idle.
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IIRC if you be careful and disconnect one plug wire at a time, if the noise goes away when you pull a particular wire off you have isolated the problem to that cylinder, and it could be a rod bearing or wrist pin as it takes the strain off of it...I could be wrong though...the fact you lost lots of oil pressure at the same time as a knock came makes me think a rod bearing could be the issue...you could put a mechanical gauge on there to verify the dash gauge, and / or drain the oil and check for metal debris.
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Im using a mechanical gauge now! That was one of the first things i added when i bought the truck! I mean i didnt loose alot of psi but 5lbs or so.
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Check your fluid levels, Pinpoint your noise and check your distributor/timing. Make sure the flexplate isn't loose or cracked.
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It needs tuned bad i know that! I put a used 1406 carb on it and the timing hasnt been quite right and been getting around 8mpg but a freind from work that has had some bad family issues lately has my vac gauge and timming light and i wouldnt feel right asking for them back right now since he has been off work!
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alright i did what i could tonight in a local foodlion parking lot with my cousins assist. lol cold startup im getting about 40psi oil psi and then goes down to around 20 but i still got that godawful racket. pulled the pass side valvecover and everything is fine which i kinda asumed.it seems to drive fine like normal. i got to thinking that i am running open ypipe at the moment and i had retarded the timing a few days ago to run regular hehe so that could be my prob with lost power....but doesnt explain my drop of oil psi. anyway on the way home it never went below 22ish doin 55-60. took a right to go towards the house and oil psi droped to 0 then bck up so im thinking it could be either the pickup fell off or just low level. i know i konw i should have checked the level first tonight but i didnt think about it till after i already had it running. so im hoping/thinking that maybe its just low oil level or the pickup fell off causing the sudden drop or low oil preasure since come to think of it most of the time it read very low was on a incline or decline. the knock well im gona check my converter bolts and flexplate tomarrow before i tear into this thing. hopefully i dont gotta rebuild yet im still building my 383 for my car!
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well i tried to inspect the flywheel and converter bolts and i dont see any cracks or have any converter to flywheel bolts and watching it idle nothing wobbles so idk im lost. seems to be holding good oil psi for the most part though. never went below 25 and climbed with revs. i didnt let it warm up to its full heat but i let it run for about 5mins. im trying to upload a video but having problems.
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So after all of this you still haven't even checked the oil level? ???
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I have and its where it should be!
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here is a video of the knock/rattle.
http://www.youtube.com/watch?v=3YbJ4j3xXao
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does this engine have a air pump on it?
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no it did at one time though. the previous owner removed all the emissions stuff and wiring. when i got it i swaped the carb to a non cc carb and had to redo the exhaust since ti wouldnt pass inspection around here with true duals and no cats.
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If I were a betting man I would wager a whole 2 weeks paycheck that the flywheel is cracked.
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idk i finished building my new crossmember on my car so i can get it out of the way so i can work on the truck a little more. gona unbolt the converter and check the flywheel little better and remove the oil pan to get a better look and check all my berrings. i checked the oil the other day and its up to level but it almost looks like ive got some metal shavings but it could be my eyes playing tricks on me also.
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Pull some belts off and see if it stops.
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busted ringland on the #7 piston! oil was thick and sparkaly when i removed heads everythign looked good until i saw no.7
thats crud from headgasket in the bore btw lol
(http://i285.photobucket.com/albums/ll55/screamin86/Mobile%20Uploads/IMG00744.jpg)