Timing Chain Inspection and Replacement

[Tynan918]

Is the fan, water pump, and harmonic balancer the only things I remove to get to the timing chain cover ?

 

[scoti]

Crank gear looks original. Chain and cam gear look new. I don't think there is any thing to be gained replacing any of it.

Keep in mind the original cam gear is nylon on steel, the nylon teeth wear out fairly quick so the gear has to be changed.

This is subjective. We didn't swap the nylon gear out from the motor out of my '79 El Camino until 1996.

I agree the gear & chain look relatively new.

 

[Tynan918]

Melling S390 36 Tooth Timing Cam Sprocket...

Says "EXC. ROLLER CAM"...

While while this far and so close, should I go ahead and pull this cam sprocket and see exactly what camshaft is behind it in this engine ?

 

[Tynan918]

What a loose chain looks like, versus how tight the chain should be..

 

[scoti]

What a loose chain looks like, versus how tight the chain should be..

Yep. That one in the video was loose.

 

[Tynan918]

Yep. That one in the video was loose.

The video of mine ?

 

[Tynan918]

Decided I'm going to go ahead and replace the timing chain set, for peace of mind...

Ok, so before I can remove the camshaft gear, the camshaft sprocket and crankshaft sprocket timing dots need to be lined up on the compression stroke of cylinder 1 of the engine.

I used a cylinder stop/TDC finder tool.

Rotated the engine clockwise and this was the result...

Turned it counter clockwise, and this was the result...

Not quite lined up. When I went to remove the cylinder stop tool it was stuck, so I rotated the engine clockwise to remove the cylinder stop tool...

Once I had it removed, I turned the engine over back until the dots lined up vertically, removed the drivers side valve cover, and attempted to put the cylinder stop tool in the cylinder 1 spark plug hole but it would not go...dots are lined up... Here are those results...

Cylinder 1 intake and exhaust valves and valve springs are up open, indicating TDC ?...

 

[Scoot-71]

on a chevy, when the dot on cam is at the top the engine is at #1cyl tdc on compression stroke, dot to dot is #6 at tdc on compression stroke. if it was me I would give 2 sh*ts about the tdc tool, line the dots up and put new chain in, its a tight fit so its gonna take effort to get new stuff on, tell me, is #1 spark plug wire at the correct spot on distributor??

 

[Tynan918]

on a chevy, when the dot on cam is at the top the engine is at #1cyl tdc on compression stroke, dot to dot is #6 at tdc on compression stroke. if it was me I would give 2 sh*ts about the tdc tool, line the dots up and put new chain in, its a tight fit so its gonna take effort to get new stuff on, tell me, is #1 spark plug wire at the correct spot on distributor??

Distributor rotor is 180° out with the dots lined up...points to firewall towards the passenger seat/door.

Just took out the TDC tool and had my brother put his finger in cylinder 1 spark plug hole and felt for air blowing and I turned the crankshaft clockwise and lined the dots up...cylinder 1 valves are closed and rocker arms are up, and I can't install the TDC tool anymore, thus meaning the cylinder is in the way and up at TDC ...

That's TDC on compression stroke...

Got to order parts and they more than likely won't be here until Saturday or Monday.

 

[Tynan918]

Would like to know what camshaft is in this engine...helps to know these kind of things, that way I know if this is truly a stock engine or not, and to buy and put on the correct parts if I decide to add or upgrade anything...

The front of the camshaft has no logos or ID numbers imprinted on it... How can I identify this camshaft ?

 

[DRIVEN]