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1986 chevy k 10 350 engine rattle

 
86chevyguy
I love my Chevy Chevette!
Posts: 2
Joined: 02/11
Posted: 02/26/11 12:34 PM

i have a 1986 k 10 chevy shortbox. bought it from a guy about 6months ago, said he rebuilt the engine he out a 1970 350 block its a 3970010 with 10 percent more nickle. anyways i recenty just gave it a tune up and now the engine is starting to knock maybe even more of a rattle. it only does it when the rmps are low and does not do it all the time when i rev up the motor the chatter goes away. if anyone could help it would be great.  

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idrivejunk
I mow my lawn and find Chevys
Posts: 5119
Joined: 12/09
Posted: 02/26/11 12:37 PM

Hello and welcome.

How is the oil pressure?  
idrivejunk

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86chevyguy
I love my Chevy Chevette!
Posts: 2
Joined: 02/11
Posted: 02/26/11 12:41 PM

oil pressure has ben a little higher then has been almost to 60 when warming up but goes back to about 30 when warm  

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redneckjoe69
I mow my lawn and find Chevys
Posts: 2337
Joined: 03/10
Posted: 02/26/11 02:25 PM

did this problem start after the tune-up?  maybe you got the timing off?    try some thick oil like straight 50 weight & see if your oil pressure goes back up.   Wink    sounds like the bearings may be gettin loose.    when the guy "rebuilt" the engine did he have the crank cut?  

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tuffnuff
Moderator
Posts: 7841
Joined: 12/09
Posted: 02/26/11 03:40 PM

+1
Sure sounds like a bottom end problem that's about to get worse.,. bummer.
IF it gets more noticeable, stop driving and tear into it before a rod comes out the side of your engine.

Grin  
When The Flag Drops.,.

tuffnuff

The Bull ***t Stops.,.
tuffnuff

P. Engineer, Engine Builder

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waynep7122
I mow my lawn and find Chevys
Posts: 1130
Joined: 08/09
Posted: 02/26/11 11:43 PM

some 86 models have electronic spark control...

its has a 5 PIN HEI module in the distributer.. 3 pins on one end..  2 on the other..

there will be a KNOCK sensor in the bottom side of the motor... a computer looking thing under the dash or front seat...


i would also pull the distributer cap....   grab the ignition rotor... turn it against the spring tension.. then release .. does it snap back fully???  all the way to the stop.. or is it binding...  the second layer rotates on the shaft.. the grease inside gets hard and sometimes rusty... causing the stiff if any movement..

if this is happening..  the timing will stay to advanced... will ping like crazy.. sometimes be really hard to crank... sometimes start right up..

pull the rotor.. are the weight bushings all torn up...  are the pins grooved..

one more thing.. does your distributer have a vacuum advance???    with a single wiring harness to the cap.. or with a vacuum advance and 2 wiring harnesses...  one to the cap.. the other to the firewall....    or NO vacuum advance and 2 wiring harnesses...

how about posting the 8th digit of the vin.. and if it is california or US federal emissions..  

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waynep7122
I mow my lawn and find Chevys
Posts: 1130
Joined: 08/09
Posted: 02/26/11 11:53 PM

and additional thing....

pull the distributer cap... bump the engine around until the rotor is pointing towards the number one spark plug wire position in the cap...    then pull the rotor...

carefully bring the motor forward until the tips of the reluctor line up with the tips of the pick up coil  ><   note the position of the crank damper timing marks.. this should be exactly where your base timing is....  so you can double check your base timing.. with the motor off...


the timing marks will line up with the damper.. in the #1 and #6 cylinder firing position...  

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