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1991 Chevy S-10 valves

Tiny
PAULYWAULY
  • MEMBER
  • 1991 CHEVROLET S-10
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
When observing the valves while trying to crank the motor they do not go up and down

i took off timing chain cover and there is no belt or chain it is simply two gear type cogs that turn on each other in no way do these 2 gears seam worn

when observing the two geas when it is being cranked they are turning on each other

so why dont the lifter rise and fall?
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Thursday, April 22nd, 2010 AT 3:22 PM

7 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
The lifters are stationery. The cam rubs against what is called followers and the folowers push the valves up and down. You probably can' t see the valves moving because the cams are over it.
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Thursday, April 22nd, 2010 AT 7:04 PM
Tiny
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Should have included that the cams are not moving as well

there is no movement on the top of the engine where the springs are at
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Friday, April 23rd, 2010 AT 9:24 AM
Tiny
HMAC300
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If you don't see a chain up there where the gears are then probably the tensioners and chain wore out and broke. You will have to check for bent valves as well as this is not a free spin engine and the pistons may have hit the valves.
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Friday, April 23rd, 2010 AT 9:34 AM
Tiny
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There seeems to be under the timing area by the flywheeel no type of chain or belt it is only 2 gears that intertwine to make it work the lifters

is there a chain internally in the head
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Friday, April 23rd, 2010 AT 9:43 AM
Tiny
HMAC300
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  • 48,601 POSTS
You can't see it because it's fallen inside the motor. Once you pull the timing cover off the bottom half of the motor you'll see it probably just llying there in a pile. It shouldn't be by the flywheel anyhow it's on the other end. After re reading your post if the gears are turning and the cams aren't then there is a problem with the gears as they should be bolted tight against the cam to make the cam turn.
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Friday, April 23rd, 2010 AT 2:46 PM
Tiny
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Sorry not flywheel

the front of the engine

and this engine does not contain a chain or belt it only has two intertwining gears under the timing cover

im wondering if under the left side large gear under the timing cover in the engine something is broken and if it can be pulled off and out in some way?

Or is this like the old style nissans where there is a timing chain in the head compartment that may have broken?
After lifting the valve cover I see no apparent chain but then again this has been an abused engine and has alot of sludge built up that almost is the consistency of plastic
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Friday, April 23rd, 2010 AT 3:09 PM
Tiny
HMAC300
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Take it to a pro where he can look at it and give you aproper diagnosis.
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Friday, April 23rd, 2010 AT 8:55 PM

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