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Discussion Starter · #1 · (Edited)
Hey guys, I just hit 40,000 miles and decided to check my spark plug gaps, and while I was in there, I was curious to see what the combustion chambers looked like so I picked up a cheap scope off of ebay. The car is running great, I'm currently not having any issues and I've been really impressed with how it's held up, being 400whp for half of those miles.

When I pulled the plugs, I didn't notice anything abnormal, color seems perfect. They have about 20,000 miles on them and are 2 steps colder:


40kPlug1.jpg




Then I got the scope out and noticed a lot of shiny silver on the tops of the pistons. Here they are in order:

Cylinder 1

Snap_003.jpg


Cylinder 2

Snap_004.jpg


Cylinder 3

Snap_009.jpg
Note that in this picture, at the 4 o'clock position you can see a small mark on the edge of the piston reflecting off of the cylinder wall. Could this be a cracked ringland?



Snap_010.jpg
Snap_011.jpg

Note that this angle shows a larger, gold colored blemish reflecting off of the cylinder walls. Ringland?



Cylinder 4

Snap_012.jpg
Snap_013.jpg

Notice the same gold colored spec reflecting off of the cylinder wall








I always monitor Knock Count 1-4, Boost Pressure and I keep an eye on STFT at least once when I mix a tank of E40. I very very rarely see knock counts go over 3, and the max I've ever seen is 5. Typically they stay between 0-2.

I will say this though. These marks look like they are very fresh. One tank ago, I ran an E40 blend from a pump I don't normally use that said E85 (contains a minimum 70% ethanol), meaning the pump could have actually been as low as E70 that I mixed with 93. I kept an eye on STFT/LTFT to ensure they stayed below 20% (although they were a bit higher at 17,18,19%, and that the AFR stayed at 14.70 on cruise and 11.5:1 on WOT, which it usually hits. I did not notice any abnormal knocking. As luck would have it, I even did a datalog but hadn't really analyzed it until just now because what I monitor on the AP (knock, AFR, etc) didn't look abnormal. Upon further investigation, I noticed something abnormal:

datazap-chart (2).png


The purple line is the Fuel Rail Pressure PSI. Normally that climbs into the upper 2,000's, but in this graph it dips bad on two occasions. That being said, knock counts only hit 2-3 and AFR only went as high as mid 12's. Then again, this correlates with the Electronic traction control (stratified) and maybe it's timing and fuel being pulled to reduce wheel slip?

Link to log is here to play around with: https://datazap.me/u/clarkru/log-1513638392?log=1&data=3-6-10-11&solo=3-6-17-26


I'm going to run out now and do a WOT pull on a tank of gas I KNOW is good and will see what the results are and will post later in this thread.

What are your thoughts?
 

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nice build,

not very good with engine internals, but interested to see what the experts say.
 

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Discussion Starter · #3 · (Edited)
New Log with a good tank of E40. Similar correlations between fuel rail pressure, air fuel ratio and electronic traction control angle but not nearly as bad of a dip in fuel pressure from the original post on bad gas.

datazap-chart (3).png


Paging @[email protected] - on the custom tunes, do you guys pull fuel rail pressure at all for the new traction control settings, or could this be a sign of something bad like a fuel pump failure, fuel injector failure, or issue with Aux System?
 

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Discussion Starter · #4 ·
nice build,

not very good with engine internals, but interested to see what the experts say.
I definitely understand I'm pushing the limits with the stock internals, and knew going in it would probably be a matter of time before I got a bad batch of gas causing something like this.
 

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2017 Ford Fusion Sport
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You might be better off emailing stratified for this question if you're concerned about it and want to get a quicker response
 

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Straified will appreciate the detailed write up with photo's. Like Brian said I'd send it in. I've been looking at intakes and combustion chambers a ton on these cars the last couple years and can tell you it looks fine to me.

If you have extra money and another car you can drive for a few weeks - Grab that 2.3l Speed Stage2 block. I think that thing is good for around 700hp.
 

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Discussion Starter · #10 ·
Straified will appreciate the detailed write up with photo's. Like Brian said I'd send it in. I've been looking at intakes and combustion chambers a ton on these cars the last couple years and can tell you it looks fine to me.

If you have extra money and another car you can drive for a few weeks - Grab that 2.3l Speed Stage2 block. I think that thing is good for around 700hp.
You’ve seen this before? Does this look more like the reflection of oil/carbon and not gouges taken off the top of the piston? I know the quality of the pictures isn’t the best.
 

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Something about this really bugs me.



your afr is mid 12 to 13 until 18 psi (don't see wheel spin, based on mph/rpm at 2,200->3000, or significant ignition retard aka cobb traction control), but your frp is okay and the stft is clearly adding 10%. Not a fan of the FRP dips, I worked those out on my own car by adding in more port injection and lowering the demand from the cars side by messing with VE. Another thing that bothers me is the boost curve, the throttle is closing which means the vehicle is hitting a tq limit somewhere or tip ceiling, but it starts to close at 22 psi, but re opened at 26 psi up top, so maybe it's the TIP 3D ceiling table, but why not just run 26-27 psi across the board and have a nice flat curve?
 
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