Sluggish Acceleration

[macleanflood]

Worn out cam? Springs? Push rods? Rockers? Timing chain - er 2.4 so belt.

This is the gravel driveway mechanic in me asking questions...

When was the timing belt changed? Tensioner?

-Mac

 

[Duner]

Worn out cam? Springs? Push rods? Rockers? Timing chain - er 2.4 so belt.

This is the gravel driveway mechanic in me asking questions...

When was the timing belt changed? Tensioner?

-Mac

The engine was rebuilt so I’d imagine those all should be newer, but I don’t want to assume.

The belt looks like it’s in good shape too, but the fact that from TDC in exhaust to compression goes from no leak to complete leak makes me think it’s a timing issue and maybe something jumped a tooth

 

[macleanflood]

Also wondering if when it's at TDC and the valve is leaking if you can physically grab it and wiggle it up and down.

-Mac

 

[Duner]

Also wondering if when it's at TDC and the valve is leaking if you can physically grab it and wiggle it up and down.

-Mac

I’ll give it a try tomorrow

 

[Duner]

@macleanflood

Update:

I wasn’t able to grab the valve but I did do some more testing to compare cylinder leak down results.

All cylinders valves, exhaust and intake, leaked during exhaust stroke TDC. No cylinder valve leakage occurred at compression stroke TDC.

 

[Duner]

Update:

I discovered something called “valve overlap”. This occurs as the piston nears TDC as the strokes transition from exhaust to intake. This is consistent with my results as all cylinders leaked from exhaust and intake valves during this transition.

None of my valves leaked during compression stroke TDC. At most I saw 7-10% pressure loss, which is well within spec especially with a cold engine.

 

[Duner]

Update:

Removed head and intake/exhaust valves for cylinder 3. Im gonna assume the intake valves are disgusting. Should I be concerned with the carbon up the stems of the valves?

Valve seats also look a bit gunked.