help cam gear sheared off

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Dec 19, 2003 | 07:31 PM

mikem78

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From: c,c tx

help cam gear sheared off

hi, i have a 1986 f250 4x4 460engine 4 manual. the engine is stock. the problem i have is that the cam gear sheared off even the broke the bolt out of the camshaft and it also crack the timing cover. anyone know why it did this? i had the engine vapor lock wensday. truck had a rough idle before the cam gear sheared. i also put and new water pump and radiator in started it today and thats when the cam gear sheaded.

i'm gonna put a stock cam,timing chain,timing cover and new gaskets back in tomorrow. i wanna know before i spend over $200 in parts and i blow another cam or something.

thanks
michael

Last edited by mikem78; Dec 19, 2003 at 07:37 PM.

Dec 19, 2003 | 11:02 PM

oxford01gt

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From: Chehalis WA

Hard to tell what the problem is without taking a look at things. If I were you I'd take a hard look at that cam shaft when it comes out. From the sound of things something stopped it from turning freely while the crank kept going. Maybe the cam seized due to a bad journal, or something binding/breaking in the valvetrain (ie lifter, valve, pushrod) . I'd definately make sure everything cranks over easily by hand before firing it up again. Once you slide the new cam in make sure it's turning freely and not binding. Also, make sure there was no other "collateral" damage when that cam gear let go. This way you do no further damage, and ensure the safety of your new parts.

Dec 20, 2003 | 08:10 AM

mikem78

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From: c,c tx

i'm gonna remove the cam shaft today and take a look. going to buy new lifters and push rods . the engine is a rebuilt i bought the truck from someone and they never started the truck. when i was puting the water pump back on i heard 2 pops from to bolts 1 was the inside bolt buy the pulley shaft and the other bolt was at the bottom dont know if i broke a piece off the timing cover and it wedge it self i the cam gear?. i was starting the engine when this happen.

Dec 21, 2003 | 05:32 PM

shazam

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From: Porterfield

Sounds to me like someone forgot to put the cam retainer plate on.. or the bolts came out of it and jammed up the timing gear .

Dec 21, 2003 | 05:56 PM

mikem78

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From: c,c tx

it has a thrust plate which is crack in half theres only one bolt for the cam and that runs in the middle of the cam. the bolt was out of the cam when i took the timing cover off and a peice of the middle of the cam broke. i talk to the person that i bought it from and he said everything is tork to specs. something happen. anyone have a diagram of the bolts for the water pump i wanna double check where the small ones go and the big ones.

thanks
michael

Last edited by mikem78; Dec 21, 2003 at 06:00 PM.

Dec 21, 2003 | 07:52 PM

mikem78

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From: c,c tx

hey, does anyone know if the water pump uses a backing plate? because mine did not have one. i was looking at a pic on the net and it showed a backing plate. was wondering if this could be my problem all along?. when i was puting the new pump in i heard 2 pops like something broke either the timing cover or cam.. also if anyone has a bolt diagram or know from the top of there head where the bolts go so i can double check them. i'm gonna buy a new cam tomorrow.

thanks
mike

Dec 21, 2003 | 08:46 PM

shazam

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From: Porterfield

yes the water pump does use a backing plate

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Jul 8, 2004 | 11:41 AM

zaug

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Hello,
I found this thread on a search and was wondering what the outcome ended up being. I have a similar situation resulting from putting the cam gear on backwards and not realizing that I had cracked the thrust plate. How long did you crank the engine ? Did you end up damaging any valves ?

Thank you,
Zaug

Jul 8, 2004 | 12:51 PM

#10

mikem78

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From: c,c tx

hi, the person that put the engine together before i bough it did not have the backing plate for the water pump installed and it pushed the timing cover on the cam gear. the truck ran for 1 sec and then it broke. it did not do any damage to the valve train

my broke on start up but check and make sure u did not do any damage the truck. my truck is running great now the oil pressure is 100psi on start up warm up is 50psi driveing is 60-70psi on a normal oil pump with 10w30. now its the ac time to get fix hehe to hot down here.

hope ya get your truck going again.

mike

Last edited by mikem78; Jul 8, 2004 at 12:56 PM.

Jul 8, 2004 | 06:07 PM

#11

zaug

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Thank you for your quick response ! How did you check out things ? Did you have to pull the heads? Also, would you say the engine rotated more than ten or twenty times in that 1 sec ? Mine fortunately never started, but I did crank it for several seconds.

Thank you again,

Zaug

Jul 8, 2004 | 06:42 PM

#12

zaug

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More specifically, how many times would you say the crank rotated after the chain broke ?

Thank you again,
Zaug

Jul 9, 2004 | 12:59 PM

#13

mikem78

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From: c,c tx

hi, the engine turned 1/3 of the way and then it broke the cam gear. i did not pull the heads. i just drop the oil pan and clean it out and clean the oil pump screen. did your engine try to start? mine started and then stoped i did a compression test after i install the new cam it was 150psi so that told me i did not put a hole in a piston. after u get the cam and timing chain install turn the engine over 2 complete full turns to make sure it turns freely. take the spart plugs out so your not fighting compression.

laterz
mike

Jul 29, 2004 | 05:04 AM

#14

zaug

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Hey just wanted to say thanks for your responses, my truck is running fine.
No, it never tried to start. After running a strong magnet over everything surface I could access, I washed (held my thumb over the end of the bottle and squeezed) everything down with engine flush several times scrubbing with as toothbrush and pulling and reinserting the magnetic drain plug between each wash. I followed that with warm atf then oil. I filled the engine with new oil and after letting it sit overnight I started the truck and let it idle for about five minutes and drained the oil and replaced the filter and refilled. I have good oil pressure and the truck runs as well as before.

Thanks again,
Zaug