head problems
uummm
02-24-2005, 01:07 AM
i have a 90 olds cutlass supreme, my bro did a burn out and let it ping off the rev limiter when it was 7000 miles overdue for an oil change, it devoloped a knocking sound in the top end that sounded like a belt hitting something metal and he had a total loss of power. the motor is a high output quad 4 with about 80000 miles, i think the head gasket may be bad, ive got the cams and lifters off, but i think some of the lifters may be sticking as well. i would appreciate any input that may help me pinpoint the problem so when i get it back together the problem isnt still there. thanks for any input.
computerdude14
03-02-2005, 07:28 AM
i have a 90 olds cutlass supreme, my bro did a burn out and let it ping off the rev limiter when it was 7000 miles overdue for an oil change, it devoloped a knocking sound in the top end that sounded like a belt hitting something metal and he had a total loss of power. the motor is a high output quad 4 with about 80000 miles, i think the head gasket may be bad, ive got the cams and lifters off, but i think some of the lifters may be sticking as well. i would appreciate any input that may help me pinpoint the problem so when i get it back together the problem isnt still there. thanks for any input.
are you sure that the knocking sound is in the top end, and not in the bottem end? ive talked to a friend of mine and he said that usually an actual "knocking" sound is due to a connecting rod knocking against a rod bearing. I also unfortunately have had a bad experience with a rod knocking, but it was in my 91 honda prelude si. heh, in fact i figured it'd blow up due to it throwing the rod eventually, but instead it managed to blow its rear main seal but i was lucky enuf to be turning into my driveway be4 it actually started spitting out tons of oil so i dont think she is damaged too badly. however, if your sure that the "knocking sound" is comming from the top end, then it might be a rocker arm or pushrod or something like that. when you say its a knocking sound, do you mean that it sorta sounds like a little hammer inside the motor, or more like a "tapping" or "ticking" sound? maybe id be able to help you a little better if you could possibly describe the sound a little more specificly? heh, at any rate i wish you the best of luck!
mike
are you sure that the knocking sound is in the top end, and not in the bottem end? ive talked to a friend of mine and he said that usually an actual "knocking" sound is due to a connecting rod knocking against a rod bearing. I also unfortunately have had a bad experience with a rod knocking, but it was in my 91 honda prelude si. heh, in fact i figured it'd blow up due to it throwing the rod eventually, but instead it managed to blow its rear main seal but i was lucky enuf to be turning into my driveway be4 it actually started spitting out tons of oil so i dont think she is damaged too badly. however, if your sure that the "knocking sound" is comming from the top end, then it might be a rocker arm or pushrod or something like that. when you say its a knocking sound, do you mean that it sorta sounds like a little hammer inside the motor, or more like a "tapping" or "ticking" sound? maybe id be able to help you a little better if you could possibly describe the sound a little more specificly? heh, at any rate i wish you the best of luck!
mike
uummm
03-02-2005, 02:10 PM
well, the tapping kinda sounds like a belt hitting sheet metal, and it is coming from the top end, i thought it may be a bent valve, but none look bent, possibly sticking though, i havent had the head off yet to check them. but the knocking is definately not coming from the bottom end, sounds like the cam area. i just wanted to know what i should replace to prevent it tapping when we put it back together. thanks for the info though.
Ryan
Ryan
computerdude14
03-02-2005, 09:13 PM
well, the tapping kinda sounds like a belt hitting sheet metal, and it is coming from the top end, i thought it may be a bent valve, but none look bent, possibly sticking though, i havent had the head off yet to check them. but the knocking is definately not coming from the bottom end, sounds like the cam area. i just wanted to know what i should replace to prevent it tapping when we put it back together. thanks for the info though.
Ryan
well when you put it back together, make sure you set the valve clearance properly, i dont know exactly what the numbers are for that stuff off the top of my head but a handy hanes manual should tell you all that good stuff. also make sure all the bolts/nuts that hold the rocker arms down are tightened according to specifications. from what you told me, i think it might be just a case of a valve or two having too much clearance between the rocker arm and the valve stem. that would also create a similar noise that would sound like what u described. if you are also removing the valves and springs and whatnot, it wouldnt be such a bad idea to put sum valve lube on em, but remember, dont try to glob it on the valve stems, just barely a thin coat enuf to see that its on there, cuz any excess that it scrapes off while moving up and down will just pile up. good luck and if u have nemore ?'s just ask.
mike
Ryan
well when you put it back together, make sure you set the valve clearance properly, i dont know exactly what the numbers are for that stuff off the top of my head but a handy hanes manual should tell you all that good stuff. also make sure all the bolts/nuts that hold the rocker arms down are tightened according to specifications. from what you told me, i think it might be just a case of a valve or two having too much clearance between the rocker arm and the valve stem. that would also create a similar noise that would sound like what u described. if you are also removing the valves and springs and whatnot, it wouldnt be such a bad idea to put sum valve lube on em, but remember, dont try to glob it on the valve stems, just barely a thin coat enuf to see that its on there, cuz any excess that it scrapes off while moving up and down will just pile up. good luck and if u have nemore ?'s just ask.
mike
uummm
03-02-2005, 10:22 PM
i dont mean to be a dick, but its a dual overhead cam, its a quad four. therefore it has no rocker arms, just cams to lifters to valves. any suggestions from that info would be greately appreciated.
computerdude14
03-03-2005, 06:33 AM
i dont mean to be a dick, but its a dual overhead cam, its a quad four. therefore it has no rocker arms, just cams to lifters to valves. any suggestions from that info would be greately appreciated.
oh i apologize... i completely forgot that they are OHC or DOHC whatever u wanna call it lol. i guess the noise would have been from the lifters... possibly anyway. again, make sure u set the valve lash/clearance according to specifications... cuz an excessive gap would cause that ticking noise. hope this helps,and if u want more info lemme know and ill see if i cant dig up sumthin 4 ya.
mike
oh i apologize... i completely forgot that they are OHC or DOHC whatever u wanna call it lol. i guess the noise would have been from the lifters... possibly anyway. again, make sure u set the valve lash/clearance according to specifications... cuz an excessive gap would cause that ticking noise. hope this helps,and if u want more info lemme know and ill see if i cant dig up sumthin 4 ya.
mike
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