1zz Tear-down

[shnazzle]

@HereComesTheWife and I decided to strip down a spare engine we were donated for a very low price by @Turbotrucker. The intention was for it to be a learning project to rebuild a 1zz and then put it into whichever car needed it first. Handy fresh spare.

We started tearing it down and all we can say is that Objective #1 is still very much valid. So we wanted to share the experience for those who were interested in rebuilding a 1zz. 
Objective #2; refitting; is unfortunately a no-go for this particular block.
The reasons why is what this post is for

Pending engine stand, we stood the block up on a tire on a trolley. 

Then removed the valve cover but undoing the 10mm bolts in the middle and around the cover, with the exception of the 12mm bolt that is also used to hold the plastic cover on the top. 

Removed timing chain tensioner by removing the two 10mm bolts (there's a trend here...)

Removed exhaust sprocket, by using an adjustable wrench on the exhaust cam (on the dedicated location on the cam) and a 14mm wrench doubled up with another wrench for more torque. 
Then the 12mm bolts for the big bearing cap, and allllll of the 10mm bolts for the smaller bearings caps keeping the cams in place. 
Then removed the cams.

At this point the initial assessment started and unfortunately for us, this head is scrap. 

More to come.... Including pics.

[shnazzle]

So, this is one view of what we found on the cams. 
You cannot view this attachment.
It shows a very heavy amount of scoring. This car occur for a number of reasons but all in all it has to do with foreign matter (FM) in your block getting squeezed in between in bearing surfaces and grinding away on the cam and the bearing caps. It accelerates cam and bearing cap wear.
What you want to see is a mirror-like surface with no scratches. Perfectly smooth metal. 
This cam is a wall ornament. Don't get me wrong, this cam would run for miles and miles to come. But at the cost of noise, emissions, oil burning, performance.

[shnazzle]

Then on the inside of the valve cover and the head there was a lot of varnishing. 
Every engine will have some degree of varnishing but if yours looks like you just emptied a bottle of Betadine on it, something wasn't running right. 
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It's a by-product of lots of heat on films of oil. Same stuff that's in the inside of your oven. It's also equally sticky. And sticky resin along your valves and piston rings leads to poor sealing, poor oil control and oil burning. 
Good quality fully synth oil of the correct spec at the right intervals, can prevent.
As the cams were scored, likelihood is that lubrication was sub-optimal, meaning a lot of friction, and heat. Vicious circle.

[Ardent]

Good read.

[jvanzyl]

So, this is one view of what we found on the cams.
You cannot view this attachment.
It shows a very heavy amount of scoring. This car occur for a number of reasons but all in all it has to do with foreign matter (FM) in your block getting squeezed in between in bearing surfaces and grinding away on the cam and the bearing caps. It accelerates cam and bearing cap wear.
What you want to see is a mirror-like surface with no scratches. Perfectly smooth metal.
This cam is a wall ornament. Don't get me wrong, this cam would run for miles and miles to come. But at the cost of noise, emissions, oil burning, performance.

I'm assuming it will become the next PB award then?

[Dev]

 I like stuff like this. Good job.

  Varnishing in older engines can be tolerated to some degree but on the newer engines with VVTi it can cause all sorts of lubricating  issues when the small passages that lubricate the head and VVT system become gradually occluded with build up over time. 
 The VVT oil circuit is very important to keep clean and only a hand full of synthetic oils have the right cleaning formulations to not leave behind varnish. 

[HereComesTheWife]

And there was a Forky Tail (Earwig for the southerners) in one of the spark plugs! He didn't look too healthy

[Ardent]

 

[StuC]

And there was a Forky Tail (Earwig for the southerners) in one of the spark plugs! He didn't look too healthy

Are you sure it wasn't a lightening bug?!

[HereComesTheWife]

And there was a Forky Tail (Earwig for the southerners) in one of the spark plugs! He didn't look too healthy

Are you sure it wasn't a lightening bug?!

Boom Boom! I think the poor thing had found himself a cosy home, until he got stuck and died

[Carolyn]

Probably pissed and lost its way.  Oh - no  -  that would be the mechanics.

[shnazzle]

Probably pissed and lost its way.  Oh - no  -  that would be the mechanics.

Well that's just rude... We were not pissed when we lost our way

[shnazzle]

I forgot I had these pictures, so I thought I'd post up to show what the head should look like. Unfortunately no pictures of the camshaft journals but I'll add those soon. 
This engine has done 94k miles, at least 50k of those quite hard. Lots of visits to the limiter, quite a few "launches", prolonged 4.5k rpm runs, etc.
But it has had Fuchs Titan Pro Race 5w40 oil for almost every service (bar 2 I think), at least yearly but often twice a year. 

You cannot view this attachment.

You cannot view this attachment.

You'll notice the lack of dark red/brown sticky film. This has been kept at bay by using oil with the correct amount of cleaning agents, while maintaining a high level of lubricity.

[mikek]

Lubricity??? Good word!