Cylinder wall pics (2 Viewers)

[GCCFZJ]

I posted earlier about my dyno results and ultimately finding low compression on cylinder #1 (30) & #4 (60). I have not been able to do a leak down test but took some not so happy pics with a borescope tool. It seems there is a nick on the cylinder wall....any experts want to weigh in if it needs to be honed or bored? It also seems I'm missing a piece of the intake valve.

 

[JoeW]

Chipped valve definitely will lose compression. I've never seen a low number as opposed to just a big fat 0. Either way your head has to come off to get that valve fixed.

 

[Kernal]

Was something sucked into the engine to chip the valve, broken spark plug, or??

 

[GCCFZJ]

Was something sucked into the engine to chip the valve, broken spark plug, or??

Negative….valves burn and chip for different reasons/conditions. Anyone care to comment on if this block will need work or potentially just the head?

Also I was looking for the thread but has anyone successfully modified the second gen head, having a machine shop bore the hole for the distributor, and fit it to the first gen block?

 

[ozarkmud]

I would be surprised if you could get away with just a hone on that. Ouch.

I'm also curious what caused the valve to chip. Maybe there's many different causes but sounds like a very serious issue.

Might have other damage you don't know about yet.

 

[GCCFZJ]

I would be surprised if you could get away with just a hone on that. Ouch.

I'm also curious what caused the valve to chip. Maybe there's many different causes but sounds like a very serious issue.

Might have other damage you don't know about yet.

I believe when my ECU was damaged and unable to control my IACV this created lean and or rich issues. I clearly remember a time when one tube of my header was glowing red at idle.

I knew at some point with almost 290k miles a rebuild would be inevitable...as bullet proof and well made as the 1fzfe is ....things wear out eventually.

Any input on upgrading to the next gen head vs modifying the current head?

 

[ozarkmud]

I believe when my ECU was damaged and unable to control my IACV this created lean and or rich issues. I clearly remember a time when one tube of my header was glowing red at idle.

I knew at some point with almost 290k miles a rebuild would be inevitable...as bullet proof and well made as the 1fzfe is ....things wear out eventually.

Any input on upgrading to the next gen head vs modifying the current head?

Ah, wow. I know nothing about next gen vs current heads. I didn't know the 1fz had different heads, other than maybe a coil on plug head that's super rare.

I don't see how the idle air control valve could change the mixture, though. At least not by much.

 

[GCCFZJ]

Ah, wow. I know nothing about next gen vs current heads. I didn't know the 1fz had different heads, other than maybe a coil on plug head that's super rare.

I don't see how the idle air control valve could change the mixture, though. At least not by much.

The GCC version only runs open loop so the IACV plays a role. There are no O2 sensors or catalytic converters to provide any ECU feedback.

 

[GCCFZJ]

I would also note there’s potential that valve lashing went out of spec and contributed. I’ll confirm this soon enough.