The prior F24 engine I built 3 years ago finally caught a rod knock 37,000 miles later after being overreved at 8600 sustained in 3rd gear for about 1 month or so.

https://www.s2ki.com/forums/s2000-un...-build-1195919

That engine made 259whp/187tq on a Dyno Dynamics on 93 fuel.

So now, I will put together a replacement engine.

GOALS:
I want to see how far I can get with the build with stock bore (87mm) and stock ports on the head. I will retain 93 fuel. It is truly a waste of research to see a nice engine build only to have the data ruined by an E85 setup. Some of us love to not have our fuel system ruined by that poison.

THE SETUP:

• K24 crank from an Accord
• InlinePro rods for OEM pistons
• PZX OEM pistons (-1.4cc) PCX OEM pistons (2.3cc)
• Abradable powder coating from Line2Line on the pistons
• Factory block with 30k miles and completely undisturbed FRM. The crosshatch is still visible.
• Cylinder head has stock ports but has been milled 0.5mm (0.020). Stock head with Toda valve springs to save time and to keep CR with the AP1 pistons.
• 12.8:1 13.2 target CR with stock head gasket
• Urge camshafts ** No longer using on this setup. Using BC Stage 2 Cams
• Toda camshaft gears ** Obtained Skunk2 gears

MODS CARRYING OVER FROM PRIOR ENGINE:

• Urge Unicorn header
• Toda tapered test pipe
• EVS single exhaust
• TODA TCT
• SOS throttle body
• Subaru Blue 565CC injectors
• Toda lightweight pulleys
• AEM EMS v2

NEW SUPPORTING MODS:

• Oil pressure and temp gauges
• EVS oil pan baffle
• AEM wideband
• Toda oil control orifice

 

Power is made in the head, unless you can run a lot of compression. Restricting yourself to 93oct will make you knock limited. 258hp is decent numbers. I wouldnt expect much more. Hope you have a good tuner.

 

My personal target is 270whp and as close to 200tq as it can be. I chose to mill the head to raise the compression while keeping the flat PZX pistons in order to much better deal with knock risk. As we know, domed pistons are more knock prone.

Also, I have another OE spec rebuilt head available on the shelf so I have the option of swapping heads and/or gasket thicknesses to adjust the CR should knock become an issue.

 

With the head milled 0.020 and OE gasket the timing was retarded about 2.5 degrees. Currently I have the Ballade timing gear fully advanced to the stopper and timing is just perfect except for perhaps less than 0.5 deg advance. At this setting, with the Urge cams, I have over 0.080 intake valve-to-piston clearance at 8deg TDC and ABDC.

I will stop here until I get a degreeing kit to measure the remaining values.

Confirmed the Urge cams have 13.6mm lift in VTEC.


Now I await the "head is trash" comments haha.

 

No 93 in Socal . E85 is half the price of 91 and pretty readily available in Socal area.

 

Unfortunately Socal is not representative of most people's situations (availability, winter considerations, european residents). I drive this car cross country and in winter so E85 will never be a goal for me. I have no interest in a flex fuel setup either.

For research purposes, it is more realistic to focus this build on 93 or 91.

 

Some updates to the build above; please see stricken items.

 

Why no urge cams? You've still got some good options on the 4P and Toda side there though

 

Surprised you ditched the Urge cams. My F22C put down great numbers with them. Did you have the standard cams or the stroker set?

 

I had the standard set.

I wanted a bigger cam for the stroker. The Urge cams are solid but for my engine I want other options.