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High Compression 3.2L Engine Build

30 October 2016
Austin, TX
For those of you who have been following my build thread, you've already seen some of my plans for this engine, as well as all the past plans that were either interrupted or I changed my mind about. I'll spare you the gritty details and sad backstory here.

At the time of this writing I'm waiting on the pistons to come back from having coatings applied, waiting on wrist pins to get DLC coated, then I'll send the block off to have it honed out another 0.0006" to hit target clearance with the pistons, then finally have the rotating assembly balanced.

(Build revised 3/24/2023)


The plan is a 3.2L engine based on a 3.0L block with wet sleeves bored to 93mm. I chose 93mm since pistons are widely available from a variety of manufacturers and it gives me a lot of room for rebuilds in the future at 93.5, 94, or 95. Sleeves - especially MID sleeves - are extremely expensive to have installed in a C30 so I don't want to have to do it again anytime soon. The pistons I've selected are actually 20g lighter than the factory pistons so combined with the OEM titanium connecting rods the rotating assembly will be lighter than a 3.0L rotating assembly. Throw a lightweight flywheel on top of that, and this should be a very rev happy engine.

  • 3.0L core block that once lived in @docjohns car.
  • Billet Speedworks (SoS) billet main caps, line bored by Mountune
  • 3.0L crankshaft (from the original engine in my car)
  • Benson sleeves bored to 93mm
  • Timeserts for head studs
  • ARP head studs
  • ARP main studs
  • ARP rod bolts
  • Factory titanium connecting rods, weight matched and balanced end to end, resized with ARP bolts
  • Toda 12.1:1cr 4032 alloy forged pistons, weight matched, tops smoothed, ceramic thermal barrier coating
  • Total Seal gas port top rings, napier 2nd ring
  • Toda wrist pins DLC coated, press fitted into factory rods.
  • Toda oil pump gear
  • Toda (Daido) main bearings, WPC treated
  • OEM rod bearings (Taiho), WPC treated
  • OEM thrust bearings (Daido), WPC treated
  • ATI super damper
  • Factory oil pan with CRF baffle and temp sensor
  • Eventually: Dry sump system custom built by @Mark911 (post break in and assuming engine is running well)

Endyn ported cylinder heads. These heads were done over by Endyn 10-15 years ago, then I bought them used and had a trusted local cylinder head machinist go through them to make sure they were good to go. He honed the valve guides a bit since they were tighter than he likes to run and touched up the valves and seats since they were in very good condition already.

  • Toda Spec A camshafts
  • Toda adjustable cam gears
  • Toda timing belt
  • Toda single valve springs
  • New OEM seats, retainers, keepers, and seals
  • Supertech bronze valve guides
  • Supertech 36mm +1mm intake valves
  • Supertech 30mm STD inconel exhaust valves
  • CRF locking timing belt tensioner
  • RFY billet cam plugs
  • New OEM finger follower assemblies to guarantee proper run in with the cams.
  • Deburred, vapor blasted
  • Cam tunnels lightly honed for oil retention (little to no dimensional change)


The transmission build is a more recent development, it was going to be a future project but with the favorable USD/JPY conversion rate I decided to go for it now. This is going to be a custom built 6 speed transmission made from mostly new OEM parts and reusing some parts from my 5 speed such as the bell housing and differential. The 6 speed went through a few changes from 97 to 05 so this is the ideal spec in my eyes for a high revving N/A NSX. The big hangup now is that the 5/6 shift fork is currently discontinued due to production defects and it's unclear if it will be coming back or not. I have all the other parts but if I can't find this then I might have to fabricate one.
  • Dual cone synchronizers on all 6 gears (early models only had dual cones on 1-4)
  • 4.23 NSX-R final drive ratio
  • NSX-R spec differential (early style diff with the R preload springs)
  • NSX-R twin disk input shaft
  • Deburred and WPC treated shafts and gears for longevity and theoretical friction reduction
  • Cases vapor blasted for bling

@A.S. Motorsport billet ITB system with 50mm throttles, trumpet length TBD.


To be revealed...

Engine Management

Chipped factory ECU running a hybrid MAP/TPS based load calculation algorithm based on Megasquirt "ITB mode", as discussed in my build thread.


I have a buddy who does vapor blasting on the side so I've had him do pretty much everything that will easily fit in his cabinet. I'm only having stuff done that can be thoroughly cleaned of abrasive media afterwards. Here's a few examples.



One of the more time consuming projects here has been deburring the block both inside AND outside. There's lots of ridges and sharp spots and I wanted to knock them all down and maybe vapor blast the block too.



After (not blasted yet)


In addition, I took some ideas from @Mac Attack and smoothed out the sharp edges of all the main caps especially around the oil holes.


I fabricated these 2 tapered delrin rods on my lathe and cut M11x1.5 threads onto them to help align the cylinder heads during installation and prevent gouging the delicate aluminum surface on the sharp edges of the dowel pins


The Endyn heads were pretty dirty when they showed up. They had also been installed on their previous engine with MLS gaskets and copper spray which is a bit of a no no so needed a good cleaning before going for vapor blasting then to the machine shop.


Fair amount of grinding in the bowls underneath the oversize 36mm valves. You can also see quite a bit of smoothing in the chambers and the area around the outside of the valves has been smoothed a lot. The cylinder heads were also surfaced on an old belt sander type resurfacing machine which is kind of an archaic method. The heads are at a local shop now (the guy who rebuilt the heads that are in my car now and did a beautiful job) getting worked over and checked for any issues and will be properly surfaced on a fly cutter and come back looking like a mirror. The valve job still looks great, the story was these heads were only run for a few hundred miles before the motor spun a rod bearing. They'll be pressure tested to see how well they actually seal though and then recut if needed.



After vapor blasting the outside looks incredible.




Sharp edges on the cam caps cleaned up as well. Once I get the heads back I'm going to do break them down fully and do a few quick passes with an 800 grit flex hone in the cam tunnels to add a nice crosshatch pattern for oil retention. C30s aren't particularly friendly to their cam caps so this is just a bit of extra insurance for turning north of 8000rpm, this method has helped on other engines with similar issues and shouldn't change cam clearance by any meaningful amount, but I'll measure with a dial bore gauge before and after to be sure.


12 brand new OEM rocker arm sets, given the price of NSX cams, I don't want to take any chances with wiped lobes or rocker pads so brand new rocker assemblies to get the best possible results with the Toda cams. I spent a long time trying to figure out possible ways to refinish rocker pads but since they are ground together as a set and to a specific radius curve (and that curve is different on the middle rocker) I decided OEM was the only solution. If your rocker pads look perfect this is unnecessary but mine had a bit more wear than I was comfortable running.


Port work on the Bad Guys heads, he cut the valve guides off which I don't particularly like but says he's never had any issues with doing this even on street motors.



Prepping the Toda pistons for ceramic thermal barrier top coat. I wanted to have them fully ceramic anodized then have top coat and skirt coats applied but the guy who was applying the coatings said he didn't want to try to remove the Toda skirt coating since it's adhered very well and would feel a lot better just doing the top coat. There was lots of very sharp edges from machining the valve pockets so I used a small file, 600 grit sandpaper, and very fine steel wool to knock the edges down and clean everything up. This isn't just for looks, sharp edges don't shed heat well and can create hot spots on the piston and cause detonation. Doing this can actually let you get away with a few extra degrees of timing in knock limited motors and just provides more safety margin in engines that reach MBT before then, and since I'm running a fairly high compression ratio I think is worth the time investment.


Check out the domes on these 12.1:1 pistons.


Toda Spec A cams. I would have liked to do B or even C cams for the extra duration on the middle lobe but those have a crazy amount of lift (11mm) on the primary and secondary (non-vtec) lobes so would really hammer on the valvetrain even in regular driving.


That's all for now, will post more photos as this progresses. Next thing is to finalize the main clearances after I had to order more bearings due to a problematic batch that had inconsistent thicknesses, I have the bearings but still need to go through the process of torquing up the bottom end and double checking everything.
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Wow. Cant wait to hear this thing and see some vids after it's all done. I remember Endyn (The old guy) making crazy power with B series stuff back in the day, but didn't know he did any NSX heads. Will be interesting to see his work compared to Bad Guys stuff as he always puts out great head work too.
What’s your target HP/torque numbers?
And do you plan on using pumped 91 octane fuel?
What’s your target HP/torque numbers?
And do you plan on using pumped 91 octane fuel?
I think John just wants a smooth, reliable running engine LOL. :)

Seriously though, the C30A has some limitations inherent in the design. 3.0L engines max out around 400 peak HP with a full ITB/VTEC-Killer Cams race engine setup. That was the spec for the LeMans GT2 engines. The 3.5L engines used in JGTC GT500 class racing ran around 500 peak hp. In both cases, the engine was spinning close to 9,000 rpm.

Once he gets it dialed in with tuning, my sense is we'll see 340-370 out of it, but a lot of that depends on the dyno, atmospheric conditions that day, etc. Regardless of the number, that NSX will be a fearsome car to drive. Night and day difference from stock, that's for sure. I'm excited to see where it goes!
I'm trying not to get too invested in a number since frankly C30 builds always end up a bit underwhelming. Mid 300s would be nice, but my local dyno shop is a rather notorious heartbreaker so I'll be ecstatic if I can even break 300 on it. I'm more concerned with trying to stretch the usable torque curve out to 8500-9000rpm than I am with peak HP.

Texas has 93 everywhere so 12:1 should be perfectly safe to run, and once the head gasket thickness is selected for proper piston to head clearance at the quench pads I'm hoping to be around 11.8-11.9 for a bit more safety margin. I'll probably do some logging with 91 to see if any changes need to be made to the tune before I inevitably end up at a gas station 900 miles from home that doesn't have 93.
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Mid 300’s sounds like a safe goal. Agreed, should be amazing. Back in the days I modified our Polaris 650 PWCs. First mod was increased compression as well as crazy set of expansion exhausts. It took an increase head gaskets as well to stop creating holes in the top of a piston. I’m all about reliability. What’s the equation? Pick two between performance, cost and reliability the third gets exponentially worse!
Reliability is part of the reason I chose the Toda pistons, as far as aftermarket suppliers go they have an excellent reputation. I believe they are a 4032 alloy so allow for tighter clearances and less wear on the bores than the more widely available 2618 options. I'm planning on running them at around 0.0027" clearance, compared to the 0.0035+ the Wiseco option calls for, for example. They are also very light, 378g each compared to 398g for factory 90mm cast pistons and 411g for the Wiseco 93mm pistons, since boost is out of the question with a compression ratio this high the pistons can be lightened considerably.E

Edit: I heard back from the machinist whos going through the heads and apparently he's almost done. He found the valve guide clearance to actually be tighter than he likes to run which is excellent, he was just able to hone them a bit to desired clearance. I was worried that the guides would be too loose and have to be knocked out which is an expensive and slightly risky process. He also timeserted a few exhaust stud holes that had stripped. I'm not sure if he recut the valves or not, I suppose I'll find out when I get the bill.
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I've spent the better part of a month trying to track down a good set of titanium connecting rods for this build and I think I finally got them. I'm still waiting on the last one to arrive but I made the unpleasant discovery that oftentimes the rods in a C30 are not at all close in weight.

After pushing the wrist pins out and weighing the rods I found them to be 484.1g, 484.9g, 482.9g, 484.1g, 483.9g, 516.5g. That's nearly a 33g split from heaviest to lightest! In one engine! According to @Kaz-kzukNA1 this is a known issue, and given how long C30s last it seems to be benign, but the plan for these rods is to grind them to perfectly weight match and balance them end to end, and that simply can't be done with that much of a weight imbalance. I was fortunately able to find a 6th rod close enough to make everything work out, huge thanks to @acuhon.

Pushing the wrist pins out was easier than I expected, I just used my Harbor freight vice and some sockets. The wrist pins are a fairly standard 22x57mm (0.866x2.245") and have a 0.0011" interference fit in the small ends of the rods with 0.0009" clearance in the pistons, in case anyone was wondering.


The rods themselves have a lot of sharp machined edges especially around the bolt holes where the material is thin, so I smoothed and chamfered the edges a bit to help resist cracking. Lots more of this to come.



I can't decide how I want to handle the small ends though. There's 3 ways to do this: interference fit wrist pins as the engine came from the factory, bronze bushings as most do with C30 rebuilds, or no bushings with DLC wrist pins.

I'm going with DLC coated wrist pins regardless since it's just cheap insurance to have when shooting for 9k. Bushings are okay but it weakens the small end of the rod and is another sensitive machining operation to potentially be done incorrectly. No bushings with a DLC pin is done in race motors fairly often but is pretty rare in street motors so there's little to no information about how this holds up over high mileage, and I'd love to get 50,000 miles out of this engine.

I'm exploring the possibility of running the rods as Honda originally intended with an interference fit wrist pin. This method has worked for hundreds of thousands of miles hitting 8200rpm all the time so I think Honda was on to something here. In theory I could just have the pistons honed to match the factory clearance of 0.0009", heat the end of the rod to 250C or so, and slip the pin in. The DLC coating should take care of any issues that could arise from the extra 800rpm but I've never heard of anyone doing this before so I need to do a lot of research as well as call Calico Coatings (company applying the DLC) and ask if they can think of any reason this might not work.

Update: I called Calico Coatings this morning and they said they have a lot of customers that press DLC pins into the rods, and just to make sure the small end bore is very smooth so the pressing process doesn't hurt the coating on the pin. I think this is what I'm going to do.

Update 2: I came across this service bulletin for S2000 connecting rods on the SoS website. If the S2K steel rods can be run just fine with no bushing and DLC pins then there is an OEM precedent for running a DLC pin in an unbushed steel rod for high RPM applications. (added as an attachment in case the link goes bad in the future)

Update 3: I called CP Carrillo today and asked if a DLC pin could be floated in an unbushed titanium rod and they said absolutely not.


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Interesting development, I was tired of getting OEM main bearings where the thicknesses were all over the place so I rolled the dice on Toda main bearings. (Fun fact: the only engine bearings Toda sells across their entire product line is C30/C32 main bearings.) They are also exorbitantly expensive at about $50/shell but ultimately that only amounts to an extra $250 compared to using OEM bearing shells and if you can buy less of them setting up your clearances since the tolerances are spot on then I don't think the cost difference is meaningful in the scheme of things. I bought them from greenline.jp and they arrived in 6 days. I tried to order 2 Toda timing belts from them too but was told they were out of stock with no production scheduled yet, so I paid a lot more than that for one from an Ebay seller.

A bit of background information: Honda typically uses 2 bearing suppliers, Taiho and Daido. Daido bearings tend to be in the high performance engines and Taiho bearings typically show up in the lower performing commuter engines but this isn't a hard rule, but it does sort of indicate that Daido are the "high end" bearings and Taiho are the "low end" bearings. In the NSX however we see a lot of Taiho bearings, then Honda switched to Daido for the C32 rod bearings.

C30/C32 main bearings: Taiho
C30 rod bearings: Taiho
C32 rod bearings: Daido
C30/C32 thrust washers: Daido

Toda sells the main bearings in the same color codes (thicknesses) as Honda does which is nice, and I assumed they would just be Honda Taiho bearings with maybe some magic JDM coating applied. Nominal thickness is 2.500mm with each color bracket being 0.004mm.


If measuring with a micrometer that reads in inches like most of us do here in the USA you can expect to find pink~0.09820", yellow~0.09835", green~0.09850", brown~0.09865", and black~0.09880".

Toda bearing on the left, OEM bearing on the right.


I was pleasantly surprised to find that the Toda bearings have a Daido stamp on the back. (Toda/Daido on the left, OEM/Taiho on the right)


If you zoom in, you can see that the surface finish is a lot smoother with finer machining marks, and based on my measurements, the Toda bearings also have ~10% more load bearing surface area due the less aggressive chamfering so these bearings should have a slightly higher load bearing capacity than the OEM Honda bearings for a given clearance. You can even see a faint marking in the middle of the bearing from the bearing thickness being measured with a tube end micrometer, so nice to know that Toda is actually measuring the parts before sending them out the door.

As far as hardness goes, I don't have an empirical way to measure, but these feel pretty soft like OEM just based on scratching at a corner with my fingernail. They are not hard like what you'd expect from an ACL or Clevite race bearing. I ordered 13 bearings instead of 8 so I'd have room to adjust clearances a bit so I'll have a couple left over to sacrifice to science, I wonder if any shops around here have equipment to measure hardness.


Based on my measurements with a Mitutoyo ball end mic, out of the 13 Toda/Daido bearings I purchased, 11 of them are nearly perfectly within their color band with 2 being off by 1. Compare that to my last order from Honda a few months ago, where out of 10 bearings, only 2 were correctly labeled/colored.

The Toda "egg shape" (beehive?) valve springs showed up too, at $500 for the set and reusing the OEM seats and retainers it's a cheaper option than Supertech for running high lift cams, and a single spring saves weight in the valvetrain. I didn't mean to turn into a Toda fanboy but at this point I have almost their entire NSX parts catalog in this engine.
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Before setting up my final main clearance I decided to go ahead and check the engine block main tunnel alignment. It should have been perfect since this block was line honed, but I found that one saddle was off by about 0.0010-0.0015" which is completely unacceptable. In addition to this, the main bores are too wide at the parting lines by 0.0030" and the main tunnel has about 0.0010" taper from end to end.

If it was only taper and OOR I would probably just run it but that combined with the misalignment pushes me over the edge of "this needs to be fixed". I suspect all of these issues were present in the block before any machining even took place since the block itself has over 200k miles on it. I had figured that asking the shop to line hone the block would have taken care of these problems, but from the looks of things they didn't trim the main caps at all and just ran the hone right in after installing the ARP main studs. Just line boring again would correct the taper and misalignment but not the out of round, and it would move the crankshaft up in the block and risk throwing off the alignment of the oil pump and transmission input shaft.

This has created quite the can of worms. I think the ideal fix here is to have a few thousandths of an inch of copper electroplated onto the main saddles in the block, install new billet main caps (thanks @foundry3 for supplying the new billet caps), then have the main tunnel line bored back to the factory spec of 69.00mm. This should restore the perfectly round and straight main tunnel in a hopefully permanent way without introducing any new residual stresses into the block.

Plating onto aluminum can be tricky but is often done in aviation applications where a bearing housing bore has gone out of spec and I was able to find a shop that thinks they can do it and quoted $1200 for the service, which is pricey but seems far better than the alternatives.
I'm glad you enjoy it! Hopefully some of this info is useful for someone else.

The block is on its way to NB Finishing Co. in Illinois, a shop that specializes in plating repairs of machinery including brush plating and they are confident that they can repair the main bearing saddles via copper electroplating. (but still mentioned that there's a chance it won't work out) From the various shops I called (one of which referred me here) I suspect it's one of the relatively few shops outfitted for this sort of thing in the USA so I'm hoping it is successful. Once I have a block with the mains plated (hopefully) I'll fit the new @ScienceofSpeed billet main caps and have the block line bored, honed for the Toda pistons, then probably decked again to chop down the step deck sleeves which I don't want.

I should get a set of heads back soon so I'll start prepping those by lightly honing the cam tunnels to add some crosshatching for improved oil retention then sending them off for thermal barrier coating in the chambers. Pistons have been thermal barrier coated on top and pin fitted to 0.0010". The factory press fit rods were at about 0.0009" but I'm making a lot more power so will run a little more clearance for safety.

In the meantime, I'm still working on rods. I spent some time this weekend building a rod balancing fixture so I can precisely measure the rod balance and match them all up.


The small end holder I had to machine on my lathe since the bearings I got were just barely too big to fit in the small ends. It has a bearing pressed into the back and just has a few thou clearance with the small end so it centers as well as possible.


I machined off the knurled section of a set of oem rod bolts so they slip into the rods easily, this is nice so I can just swap them between rods rather than worry about rod bolt weight variations.


After measuring out the 7 rods I have this is what I got. The first 6 can be easily matched but I don't know if I'll attempt #7 or not, 9g is a decent amount of material to remove. Ideally I'd blueprint 1 or 2 extra rods in case something goes terribly wrong but if not I'll survive. I'm pretty happy with the fixture, it provides results at least as consistent as the "real" fixtures I've seen people use on Youtube.

I measured each big end 4 times and averaged the results. Then subtracted that from the total weight to get the small end weight. From there I found the lightest big end and lightest small end and figured out how much material to remove from each rod big and small end.


I'll probably buy a belt sander to do most of the material removal but I'm going to try with my dremel first I think. Once the balancing is all done the rods will go the machine shop to be resized with new ARP bolts, which I already measured and determined will not affect balance or weight.
The rod weight difference is pretty bizarre, especially since the letters on the side of the rod caps seem to indicate weight! (unconfirmed, but this is something I've found after measuring a bunch of rods people have very graciously sent me to try) Is it really that hard to just pick rods with the same letter?? Rods 1-5 are "Q" code, 6, is "P", and 7 is "N". Every rod I've measured has had lower letters be heavier and higher letters be lighter.

I had the wrist pins DLC coated. I'm looking into having the rocker contact pads DLC coated as well, or maybe just the VTEC rockers since those handle the high RPM/high stress conditions. I need to call Calico coatings again and discuss options here.

I'm also planning on shot peening the rods in the areas where I have to grind/polish them for balancing but maybe having them all WPC treated would be a better option.

I'd like to have the crankshaft WPC treated too but shipping it across the country seems a bit sketchy, it would suck for a shipper to drop it and it come back bent. Valves would be nice to treat as well to try to maximize the lifespan of the bronze guides.

I discovered an issue in my big end balancing technique last night after posting. Removing the knurling on the rod bolts allowed the caps to be misaligned by 0.001" or so which resulted in the slight variation in measurements when flipping the rods over. So I'm going to do all the measurements again using the knurled bolts. I did this on one last night and the measurements tightened up to +/- 0.1g which is excellent. It'll take a little longer to tap the bolts in and out with an aluminum hammer but should provide better results.
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To prepare the rod small ends for press fitted DLC wrist pins I decided to lightly hone them with an 800 and 1000 grit flex hone to deburr and polish the bore. The factory wrist pins typically have a small amount of material transfer from the rod as they are pushed out so this cleans up any scratches or burrs that might be left in the bore without changing the dimensions by any notable amount. I measured maybe 0.0001" change from before and after honing and by matching the rods to the pin which fit them best I was able to get 0.0011"-0.0012" interference on each pin which is about perfect.

Before honing.


After honing. You can still see evidence of the scratches but the surface is extremely slick and all burrs are gone.


After spending what felt like an insane amount of time measuring and grinding and polishing and measuring some more and grinding some more I think the rods are as "done" as they'll ever be as far as weight goes.

Total Weight / Big end / Small end / Weight code

Starting Weights (numbers are different since I didn't have the bolt washers on in the sheet above)

1) 483.7g / 375.5g / 108.2g / Q
2) 484.8g / 375.3g / 109.5g / Q
3) 484.0g / 374.6g / 109.4g / Q
4) 482.8g / 375.2g / 107.6g / Q
5) 484.0g / 376.5g / 107.5g / Q
6) 486.5g / 374.1g / 112.5g / P

Variation: 3.7g / 1.4g / 5.0g

Final Weights

1) 481.4g / 374.1g / 107.3g
2) 481.4g / 374.1g / 107.3g
3) 481.1g / 374.1g / 107.0g
4) 481.2g / 374.1g / 107.2g
5) 481.2g / 373.9g / 107.3g
6) 481.1g / 374.0g / 107.1g

Variation: 0.3g / 0.2g / 0.3g

I could probably spend a few more hours chasing perfectly but realistically my Made In China 0.1g resolution scale from Amazon probably isn't accurate enough to get any better than this, so I'll just save myself the frustration. At this point getting it any closer isn't going to change the way the engine runs in the least.

Rod #6 had to have a little over 5 grams removed from the small end. Since I'm not running small end bushings there's still plenty of material there but if you were planning on using bushings I don't think I'd take more than 2-2.5g off the small end. On the big ends I'd say about the limit for material removal is about the same, after about 2.5g you start to run out of material to hack off. After removing most of the material with a 120 grit belt sander I used 320 and 600 grit flap wheels to polish out the deeper scratches as well as smooth over the sharp edges.. Need to send these off for WPC treatment now, then off again for ARP rod bolts.

This pictures shows where I removed material on the big ends. The best place is generally around the rod bolts here.


When I removed all I was comfortable with from the rod bolt area and still needed to remove another gram I sanded off the forging ridge from the cap evenly to spread out the material loss as much as possible. This is the old school place to grind rods but generally best to be avoided if possible. I don't think I'd be willing to remove more than just the little ridge like I did here.


This shows the ends of rod 5 and rod 6, 5 only needed a little bit removed but 6 had 5g removed.


Pistons came back from top coating as well.

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Those pistons look great.

Solid work on the rods. Lots of effort for a few grams, but having built a few "blueprinted" engines before the payoff is worth it.

I recently found this channel and they have some cool stuff they do for their builds. I particularly liked the idea of measuring out each piston diameter and then having each cylinder wall bored to the exact size of the new pistons. I have normally bored with a torque plate, but haven't ever measured pistons before. Just assumed the size was the size the mfg said it was.

I don't have a set right now but I'd be curious on my next build to check that to see if it was worth it.

I doubt the few grams of adjustment will make a noticeable difference but it's satisfying to do and hopefully going the extra mile in as many places as possible will add up to a smooth running and long lasting engine. Since I've got plenty of time waiting for stuff I'll probably go ahead and try to get the matching a little tighter.

Very interesting video thanks for sharing! I'm surprised there's enough of a difference to warrant that with JE pistons as most of the reputable piston manufacturers seem to get the diameter variation to within like 0.0002".

I was hoping for the full ceramic anodize/top coat/skirt coating treatment on the pistons but apparently the Toda skirt coating is pretty good so the guy didn't want to remove it, so I just went with the thermal barrier top coating to hopefully reduce hot spots and detonation as well as keep more heat in the combustion chambers, along with having the pin bores honed out to 0.0010" clearance for the wrist pins. I was also advised to ditch the Hastings rings supplied with the Toda pistons in favor of a set of Total Seal gas ported top rings (they have small grooves to allow combustion pressure to get behind the rings and force them outward against the cylinder walls without requiring holes drilled in the piston tops) and napier-profile 2nd rings so I've got those coming as well. The Toda-supplied rings supposedly will work with both FRM and iron cylinder bores so rather than worry about whether any compromises were made there I'm just going for the total seal gas port rings which I know for certain will work with the ductile iron sleeves perfectly.

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I'm glad it tickles you just right LOL.

The Total Seal gas ported top and napier 2nd rings showed up and specify 0.0015-0.0030" clearance in the ring groove. I was a little worried about this measurement since the Toda pistons call for a 1.20mm top and 2nd ring and the TS rings were like 1.19mm but it ended up being between 0.0015 and 0.0020" according to my feeler gauges so pretty dang near perfect.

Finding this particular ring set was a little more difficult than I expected. I got the dimensions from the Toda website (1.2mm top and 1.2mm 2nd ring, 93mm bore) and tried to find something compatible in the TS catalog and nothing. So I called TS and gave them the numbers and they gave me part numbers for the top and 2nd ring and told me it would be like $120 PER CYLINDER and didn't tell me where to buy them. I couldn't find any mention of the part numbers anywhere so I called the guy who did the piston coatings and who had originally recommended the TS rings and he was able to get the rings with his dealer pricing for $75/cylinder, which is very good for a high end ring pack.

Things might be getting a little out of hand with the connecting rods.

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Looks great!

Don't worry about removing much material on the rod cap.

From my modelling of the OEM rod when I decided to take it up to 9k RPM, the interface between the rod and cap at the rod bolts is the limiting concern. Insufficient clamping force can lead to the big end deforming and then obviously bearing/crank damage. The best rods are fracture split these days when manufactured, but your using the ARP rod bolts will help. Just purchase a rod stretch gauge when you go to install as that will be the most accurate. I took mine to the upper range of the ARP recommendation.