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Experience:  ASE Master Technician/Advanced Automotive Diagnostic Technician
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i rebuilt a 305 v8. it misses and shudders...timing..cam

Customer Question

i rebuilt a 305 v8. it misses and shudders. i replaced rings, timing gear and chain, heads, turned crank, oil pump. i did not replace the cam and lifters. checked and replaced new plugs-sooty black but dry. no sensor problems,no crossed wires,no vacuum probs.,etc. blows light blue smoke from valve cover, low oil pressure, runs hot. i'm thinking timing 1 toth off or worn cam and lifters. can anyone help?    
Submitted: 11 years ago.
Category: Car
Expert:  Davo replied 11 years ago.
 Did you have the problem prior to the rebuild?Did you adjust the valves properly?
Customer: replied 11 years ago.
Reply to Davo/diablo666's Post: no, it didn't have the miss prior to rebuild. my son spun a rod bearing. it did have low oil pressure and used plenty of oil and smoked as 305's do, so i figured it was mains and rings. w/new crank, bearings and rings i thought that should do it. i did have some problem adjusting the valves but feel they are correct now. i even checked the rockers again and they seem about right, with just enough clearance for a minimal twist when they are not under pressure. a couple of the lifters were very dirty, but not worn so i soaked them in solvent. this may have been a mistake. when i aligned the marks on the timing gears the distributor ended up slightly left of center of the engine at about 7 o'clock which leads me to believe, after thinking about it, that i'm 1 tooth off, but the marks lined up pretty well. or could it be that i need to move the distributor back 1 tooth? i did match the firing order, beginning at the 7 o'clock position. i'm not sure if this causes misadjust-
ment of the valves or throws the timing off. i just hate to tear into it again not being sure. i'm lost. thanks for the help and i'm anxious to hear what you think...      
Expert:  Davo replied 11 years ago.
 Run the engine until it's warmed up turn th engine off.Remove one valve cover and restart the engine,loosen one rocker arm nut until it starts to make a knocking noise.Tighten the rocker arm nut slowly until it stops making noise.Continue to turn the nut for 1/2 turn tighter in small amounts about an 1/8 of a turn.Do all the rest of the rockers on that side.Replace the valve cover and then perform the process on the other side.Then we can go from there.Do not attempt to adjust the timing right now it is running and we will do 1 step at a time until it runs right.
Customer: replied 11 years ago.
Reply to Davo/diablo666's Post: ok, i'll do it again.
Customer: replied 11 years ago.
You were exactly right. The haynes manual ssaid 3/4 of a turn after the lifter stops clicking but that difference seems to have done it. The only problem is, now theres a knocking that sounds like its coming from the mains and the oil pressure is still low. i'm not going to drive it until I get a reply from you. Thanks
Expert:  Davo replied 11 years ago.
 When you say low oil pressure do you mean low or no oil pressure?Have you checked it with a gauge?It could be cam bearings causing the low oil pressure what concerns me the most is the knocking noise.Did you replace the connecting rod on the cylinder that spun the bearing?If not it may have spun again try removing plug wires 1 at a time to see if the knocking changes or goes away that will tell you what cylinder is causing the knock.Might as well start at the cylinder that spun the bearing.Did you put the pistons back inthe same location and check ring end gap?

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