Charper's Boosted F24c build diary
 

I'll start off by saying I never intended to build a F24. As I see good deals on parts i'll buy them just to resell. It just so happen the stars aligned and I ended up all the major components I needed for a full build...so here we are

I'm shooting for mid to high 700s...or whatever maxing out a gen II gtx3582r will get me on a divied 1.06ar housing

This is mainly going to document just the build of the motor.. Its' going to include a LOT of pictures, so be prepared.


Notable items in this build:
Inline Pro F24c rods
K24 crankshaft
CP pistons @ 11.3:1 comp - Swaintech coated Ceramic tops and PC-9 skirts
Darton mid sleeves
Supertech springs/retainers
BC2 cams

Carbonetic Triple disc clutch

Xperformance ford 8.8 kit

The donor block came from a friend with supposedly only 30ish k miles. He got it from his uncle?, who hydrolocked cylinder #3...no idea how. It had been taken apart and sitting for a few years and the outside def showed and all the cylinders were trash, but the main journal bores were MINT and that's all that mattered.

https://cimg1.ibsrv.net/gimg/www.s2k...79d2928793.jpg





Before cleaning the block the cylinders needed to be notched for the rods. A considerable amount of material must be removed.

https://cimg7.ibsrv.net/gimg/www.s2k...1015722e24.jpg

stock



Crank and rod installed to mark the locations for clearance.

https://cimg3.ibsrv.net/gimg/www.s2k...77be012840.jpg




Not pretty but when you're doing it by hand and not with solid machinery it's a bit difficult.


https://cimg8.ibsrv.net/gimg/www.s2k...485ed780a9.jpg



All cylinder notched and the block is ready to be cleaned.

https://cimg8.ibsrv.net/gimg/www.s2k...8b050a1af1.jpg


After several hot soapy baths, its time to get the cylinder spotless. This step is EXTREMELY important for break-in and ring seal. The hone left on the cylinder does a very good job at trapping debris. We get this out with lint free rags and ATF. This process can take quite a bit of time and I had to do each cylinder 5-6 times before the rags showed no more signs of dirt.

https://cimg8.ibsrv.net/gimg/www.s2k...15c56e8900.jpg

https://cimg2.ibsrv.net/gimg/www.s2k...28994c1133.jpg



Next we move onto the crankshaft. It's not often talked about, but cleaning the oil passages of the crank is a must. Most people are shocked at how much crap will come out just by spraying brake cleaner through the passages. A lot of american stuff has caps that can be drilled and removed making this process much easier. Unfortunately, most metric stuff does not have this feature. To do this, we bend the tip of the straw at 90 degree angle or something close to it. stick it down each rod journal and watch the crap come out the mains.
I think I went through 3 cans of brake clean on this.

https://cimg9.ibsrv.net/gimg/www.s2k...f3c465b8f4.jpg


Yes, that rag use to be blue...and that is the 3rd set of rags.

https://cimg4.ibsrv.net/gimg/www.s2k...298180390e.jpg

I'm not going to post the cleaning of every part, but the same must be done with everything. Even new parts. Spray some brake clean on a rag and wipe that brand new set of rings...shit everywhere. Just because parts are new does not mean they are clean.

Next we'll move on to some measuring...I'm not a fan of plastigauge, but it does work when tolerances do not need to be precise. I forgot to get pics of mic'ing the mains on the block...just use your imagination. Im was shooting for anywhere between .002 and .0025..ended up with .0022-.0023

https://cimg9.ibsrv.net/gimg/www.s2k...d1d8f6e080.jpg


Rod bolts are next. The F24 rods I picked up were used. I do not know the history of the bolts which means I don't know what the free length was new..so I don't know if they are stretched. I chose to purchase new.
I took a measurement of the free length before installation so I can compare how much they stretch the next time I pull this motor apart. ARP states no more than .001 variance should be present in a set.

https://cimg4.ibsrv.net/gimg/www.s2k...7607b5ea89.jpg


Here came one of the first dilemmas that I really didnt expect. I talked to 3 different people at Inline pro and got 3 different answers on rod bolt torque/stretch. This is very unnerving. Rod bolts and piston pins are what I consider to be the 2 most important parts of the short block. I'm waiting on their main engine builder to get back so I can get advice from him. One of the engine builders sugggests 47ft lbs. which should give .002-.004" stretch, not to exceed .005".
The problem with this was even at 50ft lbs and using ARP lube I was only getting .0016" stretch.

https://cimg7.ibsrv.net/gimg/www.s2k...50ca9132b5.jpg


I went ahead and measured bearing clearance, but I will end up revisiting this if the torque spec changes.

https://cimg2.ibsrv.net/gimg/www.s2k...a0d31c8b9c.jpg


Next up was rod small end, piston pin, piston, and cylinder bore measurements...all of which I forgot to get pictures of. I was shooting for .0012" clearance on the wrist pin to rod and wrist pin to piston. All of the piston to pin clearances are fine. Rod to pin came between .0012 -.0016" Not worth rebushing the small end imo so im gonna let it ride. Cylinder bores are all with in.0003" of each other. Piston to wall clearance is at .0035". The PTW clearance may be a bit tight for this power level, but the PL-9 coating on the skirts is quite thick and adds .0016". I took this into consideration when I chose the PTW clearance as a buffer incase things want to touch...hopefully they won't though.

https://cimg6.ibsrv.net/gimg/www.s2k...5617f61c36.jpg


Next up is pin fitting.. Sharp edges are no bueno. Looking at the first picture you'll see the pin is just sitting on top of the hole. If you try to put a pin into a fresh piston, you'll more than likely notice that it doesn't just slide right in...that resistance is a problem. It's usually caused by a bur on a sharp edge We take some sand paper and put a radius on all the edges and WALA,...smooth as butter.

https://cimg6.ibsrv.net/gimg/www.s2k...94c38b146d.jpg


Radius vs non radius edges

https://cimg0.ibsrv.net/gimg/www.s2k...99308ec3b2.jpg


Now we move on to piston rings. This ended up being dilemma #2. Standard CP ring sizing for boosted application goes bore x .0055 for the top ring and add .004-.008" for the second ring. That would mean .019" top and .023" minimum. After speaking to CP and stating the HP level somewhere close to 200hp per cylinder I was told to use .021" for the top and .027" for the 2nd ring. This is where experience really comes into play, which tbh, I don't have in this particular circumstance. Not to throw shade at CP, but the techs seem like they are more or less just reading from the computer screen when asking for advice...not a whole lot of substance there. This car will be run exclusively on E85, which generally speaking you can run a bit tighter ring gap as it burns cooler...adding to that is the fact the tops of my pistons are ceramic coated which additionally helps keep heat off the rings. This isn't the problem though. The problem comes at how loose the rings are out of the box...more on that in a minute.

Remember those sharp edges? Yeah, we can't have those.

https://cimg4.ibsrv.net/gimg/www.s2k...44b62a07bc.jpg


We need to get the sharp edges off the ends of the rings so we can keep from scratching up the cylinders. For this I use a small Jewelers file.
Mmmm smooth.

https://cimg8.ibsrv.net/gimg/www.s2k...8a3a998b84.jpg



Now that all the rings have their edges cleaned up we can put them into the cylinders and get to measuring. Ideally you wan't a tool that can perfectly square up the ring. Some will just use a piston to square them up, but that really isn't the best practice and its pretty much impossible to get the ring perpendicular to the bore. If you don't have a square tool the next best thing is just using a pair of verniers measured to 1" and tap it down evenly. Repeat this on the same ring ~3 times to make sure your measurements are accurate.

https://cimg5.ibsrv.net/gimg/www.s2k...702af76c95.jpg


Now we come back to that dillema. The ring gap unfiled and straight out of the box...is large to say the least on he 2nd rings. The two rings marked .031 were actually .034" ..had to put two feelers together to make one large enough. I know its better to be loose than tight, but im not trying to burn a quart of oil every 500 miles here...this is a street car. The manufacture tolerance on this ring set is a bit out there. I called CP on this and they were very helpful. The rep I spoke to thought it was odd the tolerance was .007" from one to the next so they are sending me a new set of rings on the house. Had the pistons not been coated and the bore be slightly smaller I probably could have worked around this, but it is what is now. I'm going to wait til the new set of rings come in next week and take it from there.

https://cimg7.ibsrv.net/gimg/www.s2k...2e970c75be.jpg

Hell of an undertaking good luck

Good luck brother. These types of builds (stroking, rebuilding, etc) intimidate the crap out of me to do on my own. You sir are one brave man!

Are you having any issues marking the bearings with the bore gauge? I'm currently going through the process of replacing bearings and my bore gauge (mitutoyo) has a small contact point which marks the bearings a little bit...possibly digging a ten thousandth or two. My main bore is consistently measuring .0001-.0002 smaller when doing the math vs bore gauging the bearings.

Thanks for taking the time and effort taking pics and documenting this. Looks good so far.

I'm not, but I know what you're talking about. It depends on how stiff the bore gauge is. If you have that issue do not use the bore gauge. Instead, use a set of T gauges and then use a micrometer on those to get your measurement.

And just a little teaser for later... Carbonetic triple disc


https://cimg9.ibsrv.net/gimg/www.s2k...0785369ba2.jpg


https://cimg1.ibsrv.net/gimg/www.s2k...04997680df.jpg

Questions;

1) Why the high compression ratio? In the Supra world, 10:1 is considered high. On their webpage, all of 4Piston's K20 turbo pistons have compression ratios in the 9:1 to 10:1 range.

2) What bore did you use? Did you go full 2.5: with an 89.5mm bore?

3) Did you consider using a gapless top ring to reduce blowby?

4) What timing are you installing the cams at? EO/EC/IO/IC.

5) Did you do anything special in the head to deal with exhaust valve temp? In K20a.org 4Pistons had a writeup on a 1300hp K24 and talked about the problem: "One of the biggest problems in these big power turbo engines is dealing with the exhaust heat and exhaust valve distortion. There is no bulletproof fix to make them last forever at Pro Mod like power levels, but you can drastically extend the life between service intervals if you can manage that heat. It is common to throw 6m and 6.5m valve stems at it, but it does interrupt some exhaust flow. We have found ways to make them last without resorting to that...but honestly some guys are harder on them than others and still need that https://www.k20a.org/forum/images/smilies/smile.gif We use a special high temp allow for the valve that can handle another 800 degrees on top of a standard Comp Plus or Inconel valve, and they are stronger and lighter than an Inconel valve. The A3 beryllium seats and our special exhaust guide helps to pull heat away from the valve as quickly as possible. The cheaper guides can become brittle with the heat and break off...shooting through your $3500 turbo https://www.k20a.org/forum/images/smilies/bs.gif It actually provides pretty good life with a standard Comp Plus valve as well."

1. This is a street car and needs to have good street manners. Off idle and transient throttle response is much better with high compression. I will only be running E85 and I ceramic coated the piston tops to further reduce the chance of preignition. As with everything else, its all in the tune. A competent tuner that can dial in the ignition timing is a must.

2. While going 90mm would have been nice to have a square motor, I went with 87mm as thats what the CP pistons I picked up on the cheap were. Plus, going straight to max over bore leaves no room for servicing.

3. Gapless top ring? I'm not trying to window my block.

4. I don't currently have aftermarket cam gears, nor do I have the incredible about of time/money it would take to dial them in on the dyno. For now I will just be using stock cam gears. If I come across some adjustable ones on the cheap i would pick them up and just degree them to make sure they are on stock/BC recommended timings.

5. Their write-up is dealing with a motor at almost double the HP..so that doesn't pertain to me. While C630 seats and guides do transfer heat MUCH better than stock, they are also not as reliable and can show wear much faster. I've never witnessed a guide breaking off...i've seen seats drop though. This is not an all out race motor. If it was, I would have just sent it with the wide open ring gaps that I currently have and also would have gone for a wider PTW clearance.
I had debated sending the head to 4piston just for porting and radius cut on the seats, but I really don't have the time, nor do I want to shell out another $1500 for it. I'll clean up the ports where it meets the seats and send it.

I had a couple people message me about the cost of parts for this. I already had a spreadsheet so Im just going to list it here. Nothing in this build was purpose bought except for the springs/retainers and the coatings on the pistons. Just stuff I bought because it was a good deal. Some stuff is used which is noted, going to list what I paid vs what retail is on it.

The used block I got from a buddy for $400. The crank in it was mint and sold that for $550...So not listing it but up $150 on that
I have a few arp headstud sets laying around so those will go in but not included in cost.
Machine work consisted of decking block, sleeving the block, then decking block again for .003" step, dynamic balancing of the entire rotating assembly and hot tanking
--------------------------Cost --------Retail
K24 kit(used) ---------$600 ------$1200
CP pistons -------------$380 ------$650
Swaintech coating----$260 ------$260
BC cams(used)--------$350 ------$650
Springs/retainers------$200 ------$400
Darton mid sleeves---$500 ------$700
ACL bearings-----------$100 ------$100
Machine work-----------$1100 -----$1100
OEM oil pump----------$299 -------$386
gaskets/main bolts/timing chain ect $324

Cost ----Retail
$4113 ---$5770