1.4L Teardown/Modification

[theenico]

RS Rod Ratio~ 1.6:1 relatively close to the "ideal" 1.75? Or is that way off?

Is this the "diamond coating" that's already worn through at 14k miles?

Yep, it's that black stuff on the skirt.

Being that the ratio is lower than 1.75:1, does that classify the rods as "short"?

Aggressive angle causing piston side loading..... Bad.

Longer stop at TDC for better AFM burning.... Good.

1.6 is just fine. There are a lot of high-revving Honda motors that stay together plenty well with ratios closer to 1.5:1.

 

[Preloader]

But did those Hondas have zero-friction diamond-coating.

I still laugh when I think about the discussion about diamond coating that took place here when I first joined. Some were eating it up with a spoon, and even posted the brochure from Chevy as "proof" that it was some high-tech advancement in engine design.

At 16k, half of my diamond coat has left my engine via the tailpipe.

Anyspray, it's great to hear that the dimensions of the block, bore, and stroke are a more than decent foundation to build up into, hopefully, twice the factory power.

 

[theenico]

The coating works. Is it the end-all be-all in the friction fight? No

Being scuffed is okay. It transfers over to the cylinder wall as the piston and wall get happy with each other.

 

[Preloader]

I looked hard, and was unable to find sarcasm...... I'm speechless.

How hard will Wiseco laugh at me if I tell them I want my new pistons diamond sparkled?

 

[theenico]

Trust me. They won't laugh. If you want to take it a step further, send those pistons to Swain Tech and get the crowns and skirts done. The crowns would get a thermal barrier coating and the skirts get an anti-friction coating.

Link to pricing:

Automotive Coatings Price Sheet | Swain Tech Coatings | Industrial Coatings | High Performance Racing Coatings

 

[Preloader]

I had been considering getting the pistons coated, but I think for the first initial motor swap, I just want to git'r'done. Maybe on the 2nd Teardown and build, I'll go for the expensive confections.

I'll be spending enough to get the turbo plumbed in that I'll have to settle for a rudimentary short block build the first time around.

 

[theenico]

I'm just dangling the carrot. Your plan for round 1 is solid.

 

[AJH]

In all the over square vs. under square banter, no one mentioned rod ratio. It's the rod's length with respect to the crankshaft's stroke that determines the acceleration characteristics of the piston. Bore vs stroke has NOTHING to do with piston speed. The over under debate is one that drives me nuts.

Bigger bore just makes room for larger valves and makes the flame front have to go further.

So Pre, did you measure the center to center length of the rod?

Found a decent write up on rod ratio:

Rod Stroke Ratio Fully Explained

If you guys actually take the time to read it, you'll notice that bore is missing from all the calculations used to determine piston speed. Oh yeah, that's because it is unrelated. I think I may have already mentioned that earlier. [/end rant]

I don't claim to be an expert on this stuff so I went out and looked it up. ALL the piston speed calculators I found used STROKE and rpm to calculate piston speed.

Piston Speed Calculator - Universal Entry
Mean piston speed - Wikipedia, the free encyclopedia

Then I found this and it mentions both stroke and rod length!

index

"OK, so what does this calculus mean?

It means BOTH stroke and rod length affect velocity and acceleration of the piston.

If you increase stroke, you increase piston velocity and acceleration.
If you reduce rod length, you increase piston velocity and acceleration.

Rod stroke ratio (RS) is often used to describe an engine's piston motion. RS is just the Rod Length/Stroke. Rod stroke ratio is important because it determines wear, velocity, and acceleration of the pistons. From figure 1 we can see that RS ratio directly affects rod angularity (a) along with Rod length and Stroke (definition of RS)."

So it looks like we were both right :banana:

 

[AJH]

I knew rod length was important in the thrust effect, I know I read about this stuff but thanks for getting me to rattle the old grey matter around.

 

[theenico]

My pleasure. Knowledge is power (sometimes even horse-power ).

 

[ChrisJ]

I might be sorry I asked this but why are there no scotch-yoke style gasoline engines?

It eliminates the connecting rod all together and at least in compressors makes for a super smooth running pump.


EDIT : actually apparently there is! http://youtu.be/otFMjX377Ss

Although that one has a conn rod of sorts, the compressors I've seen do not. The bottom cylinder that rides on the crank is part of the bottom of the piston.

 

[theenico]

Wikipedia has a better explanation than what I was going to say:

The Scotch Yoke is not used in most internal combustion engines because of the rapid wear of the slot in the yoke caused by sliding friction and high contact pressures[citation needed]. This is mitigated by a sliding block between the crank and the slot in the piston rod. Also, increased heat loss during combustion due to extended dwell at top dead center offsets any constant volume combustion improvements in real engines.[2] In an engine application, less percent of the time is spent at bottom dead center when compared to a conventional piston and crankshaft mechanism, which reduces blowdown time for two stroke engines. Experiments have shown that extended dwell time does not work well with constant volume combustion Otto Cycle Engines.[2] Gains might be more apparent in Otto Cycle Engines using a stratified direct injection (diesel or similar) cycle to reduce heat losses

 

[AxelRipper]

Random note on the piston coating (though I might be a bit late to the game) think about it this way: If it didn't work, would an OEM be using it? Think about all of the small stuff they leave off to cut cost. Don't you think they'd have left this off if it didn't do anything? Not many people will look at the tech specs of an engine before buying a car.

Also, this is the same think I say with regards to any fuel or oil additives that are supposed to increase fuel mileage, engine life, emission ratings, and the gender of your third born child: If it worked so good, why wouldn't an OEM be using it?

And your wear on that piston is minor. Still working fine. Also can tell you that the engine is pretty clean. Get debris in there and the first place it will show up is scratches in the piston coating.

(I interned for GM in college, including a term in engine post-teardown inspection. I've seen more than a few of these in fully disassembled states)

 

[Preloader]

Found a great way to use the 1.4T timing chain :

 

[rdss]

Gangster!

 

[sx sonic]

Gangster!

Wouldn't the Misfit wallet and unique wallet chain make him a hipster .

 

[rdss]

Good call!

 

[Preloader]

My affinity for getting up at 4am and busting my ass for a living, contributing to society and my lack of descent for my country exclude me from the cancerous hipster genre.

 

[sx sonic]

My affinity for getting up at 4am and busting my ass for a living, contributing to society and my lack of descent for my country exclude me from the cancerous hipster genre.

How bout derpster? Yo can have you're own genre, set to permanent trend set .

 

[thebook92]

Forgive me if I missed the discussion on this(or for asking a dumb question, as my camshaft knowledge is somewhat limited), but at 7k+ RPM, will the OEM cams be able to support that much airflow without becoming a restriction themselves? Keep up the awesome work; I'm keeping an eye on this.