jdmboyef9

It is no secret that the stock D16A6 is a slug compared to the Japanese ZC or any B or K series for that matter. Hell even the D16Z6 and Y8 VTEC's are in a league of their own compared to this seemingly similar yet sad excuse for an "Si" engine. I have struggled with the idea of swapping out the stock motor since I first bought this car. My initial intentions with the project (prior to finding the car) were to eventually do a B16B or B18C swap. But before I get ahead of myself, I made a promise the first time I laid eyes on this car. The condition was so pristine that it would be a blasphemy to take out the era correct engine.

Naturally in my free time I would do some reading here and there on possible engine setups using the stock D16A6. That is when I first came across the concept of the SUPER-D. Basically it is a 1.7L stroker engine that uses the D16 block and the crank and rods from a D17 (01-05 Civic). The idea was appealing but there was not much info for professional builds, just a few budget builds for the most part.

D-Series Tech - High Compression Stroker - Honda Tuning Magazine

Flash forward a few months...Over the past 10+ years I have been a huge fan of ENDYN's work out of Fortworth, TX. Those of you who are not familar with who Larry Widmer aka T.O.O. (The Old One) is, please click and read...
The Old One - Energy Dynamics

For those who are also "In the Know", you will find out that Larry was not only the original owner of 2 1997 Integra Type R's (only went into storage new from Acura), but he was originally the Owner of one 1989 Honda Civic Si.
Shortly after finishing the installation of the 2

Larry was very well known for his Honda engines including his old Supercharged D16A6 that made a feature in HotRod magazine in the late 1990's.

By pure chance I sparked up a conversation one day with Larry about the original purchase of his 89' Si, and how it had evolved over the years. Although Larry is a busy man these days both with being under a contract with Nissan's racing team, and trying to keep up with other race team heads, I ran the idea past him of the new stroker crank idea in an old D16A6. He said he would never do another D motor but after about an hour or so he agreed to take on the project for ***** and giggles. The price tag on this project is in the range of "More than you can afford PAL... Ferrari!!!" but with time ticking by he figured it might be his last chance to ever build one.

Onto the build and goals for the build. Since the D17 crank is a less than ideal Crank/Rod ratio, high rpm's are going to be a bad idea. The primary focus is to increase midrange torque. This being said the RPM goal was in the 7,000-7,500 range max.

I originally sourced a donor head from an 89' CRX Si with only 88k miles on it. Don't fool yourself, a lot of work still had to go into straightening it up.



His first step was to focus on the rate of the burn. He used a special combustion chamber design that he perfected on his road race F20C engines. This both helps with flow and burn.



He tested several configurations with the use of epoxy, he would CnC each one to determine which design best suited my need.








After the right combo was determined, he cold-welded the head and let the CnC set the final design in Metal. He then went on to do his world famous port work. To further increase torque, the initial port entry's are only slightly bigger than stock, however, the ports are reshaped to optimal design. Since he could not locate an aftermarket company with the correct oversized valves he wanted, he hand machined each valve to his specification (destroying two ceramic bits in the process).










This head would work great on a Stock crank D16A6, The Pistons however are a bit of a problem...
The D16 and D17 blocks share the same deck height and rod lengths (rods not direct interchange but I will get to that), the Crankshafts and pistons are different.
D16 crank is 90mm
D17 crank is 94.4mm
That means that using a set of D16 Pistons with the D17 crank and rods would make the pistons stick 4.4mm out of the block...not good. To correct this Larry contracted Wiseco to build a custom one off set of his Rollerwave pistons with the wristpin relocated 4.4mm higher. The special dome boost the compression to 12.3:1 and is configured to the shape of the combustion chambers.







One thing to notice with this Piston design is the exhaust ports side. Not many people are aware that on D16's the location of the exhaust ports are different depending on Vtec and Non-Vtec heads. Simply slapping some D16A6 pistons in a sohc Vtec motor or a Vtec head on an A6 might be a recipe for disaster since the valve reliefs don't match up... The custom ENDYN Rollerwaves take care of that problem so these pistons are compatible with a SOHC Vtec head if I chose to do that route in the future.


Larry also had a special Camshaft built to his specifications by WEB Camshaft. This is not a simple regrind but a hardweld cam. Even after talking with Delta Cams they confirmed that WEB is the best company to do it properly. It was very pricey but the end results should be fun. No specs on the Cam sorry.









Now onto the Connecting rods. As I mentioned the D16 and D17 rods are the same length, the D17 rods however have a slightly narrower bearing. You can use any D16 rod but you have to have them machined to fit the D17 crank. I decided to just buy D17 aftermarket K1 Rods. They are built to withstand a lot of power and they are very good quality.




I sourced a donor D16A6 block along with a D17A2 block for the rest of the build. As of right now the bottom end is at the machine shop to be assembled. There are still a lot of parts to get but I'm happy about this progress.

jdmboyef9

Why oh why would I waste my time on a stupid little D16A6 that is not even VTEC? Why wouldn't I opt for another High Compression B20 Vtec or a K20/K24? Here it the reason...

The donor car is my 1989 Honda Civic Si. The car started out as a factory restoration using discontinued brand new in box Honda parts and accessories. The car is unique in the USA because it is a one year only car for the Civic as it received a facelift and different interior in 90-91. After a 4 year restoration I changed directions while keeping it ERA CORRECT. The car currently features a handful of rare and unique MUGEN goodies offered specifically for this car.
BNIB Mugen sport Suspension
Mugen EF3 Sports Exhaust System
Mugen EF3 Header
Mugen SW3 Steering Wheel
Mugen CF-48 wheels with Aero Covers
Mugen EF3 XE5 N1 ECU (sourced from New Zealand Racing Team)
Mugen ROM Chip

Car was featured on King Motorsports Blog a while back.

my 1989 Civic Si

turbo1.5

Awesome build so far! Keep the updates coming.

Dark_Teg

Damn bro.....Very cool, I cant wait to see what kind of power that motor puts out. Props to you for being different. I love seeing high end builds with baller budgets. It wont make sense to some but I get it.

Tegra206

iTrader: (2)

Clean!!!!

turbohatch96y7

iTrader: (15)

******* nice

acmoc

moogen ugly doe

Tokyosmash!

Bringing a nuke to a gunfight with all that work by Larry Widmer, amazing stuff so far.

Bently_Coop

Will follow.

213374U

In

sr20paisa

sub'd for sure

hondatuner020

iTrader: (1)

Impressive work so far!

Todd00

Glad to see some thinking outside of the box. I didn't know Endyn was still around and even more surprised you were able to talk him into doing this project (although it should be old-hat for him--at least the head work).

However, I don't agree with you that the a6 is a "slug". It was choked by Honda in factory form, but it was easy to open up 20hp or so (which was about what the ZC would give you, minus the superior midrange torque the a6 had over the ZC).

PyroProblem

Nice build. I can appreciate the time and effort going into any build whether it's a single cam or double. Larry is a smart guy although he receives a lot of hate sometimes here on the boards. I've had the chance to meet him and he gave me a tour of his shop. I was impressed to say the least. After talking with him I realized this guy really knows his stuff. Good luck on the build!

underrated

iTrader: (3)

I'm subd.

Did Larry ever say why he'd never do another d?

jdmboyef9

It is actually really funny you mention it, he was so frustrated working on this small head he said he would never do one again. Knowing Larry I'm sure he has said that everytime he has done one in the past. He is a very knowledgeable guy who not only thinks outside of the box, but he comes from a family of geniuses. His late father was actually the designer of the F-16 Falcon fighter jet. He also created a top secret design to complete with the SR-71 Blackbird. The funny thing is the military contractors purchased the rights to the secret plane and after all of these years the details still remain classified (even though the Blackbird has been public for 40+ years). I figured that having a piece Larry touched under my hood would be a piece of history.

jdmboyef9

I hope you are right, my stock D16A6 is very slow. Granted it currently has stock everything on it minus the Mugen catback but I have been told the stock exhaust manifold is a real choke point. I have the Mugen header but I plan on restoring it before installing it.

underrated

iTrader: (3)

I'm super jelly.

v4lu3s

Will be watching to see what happens. looks like an interesting build I realyl am curious to see final power numbers. I did not realize that Endyn still touched Hondas at all to be honest. Pretty cool you dragged him into it.

I also disagree that the a6 is a slug, i think it is the best of the D series. I currently daily drive a 12:1 a6 with a cam and bolt ons and it pulls very well to 8k rpm, still gets 30+ mpg while driving like a teenage douchebag. even prior to rebuild with bolt ons alone it was as good as any z6 i had come across.

redzcstandardhatch

in for results.... very cool project. d16a6=my favorite Honda engine. and I have no reason for that except a rabid love for EFs.

underrated

iTrader: (3)

Any updates??

jdmboyef9

Finally some updates!!! Sorry she still has a ways to go before running but I'm in no hurry.

I got the short block back from my friend Frank Lyion from Lyions Technical Machining. He did a great job as always. Not only does he do all of the race engines for the local bike shops, but he has also assembled a few Endyn prepped engines in the past and is a huge fan of Larry. Anyways here are some pics



Here you can see the girdle was notched on the D16A6 bottom end to clear the rods





Next was the block had to be machined for rod clearance

jdmboyef9

Factory oil cooler to my knowledge only offered on a Wagon RTi Automatic D16A6



Some of the random parts for the build.





Money Shot







New D17 Main Seal



New D16 ARP head studs



We clayed the chambers to make sure there was no valve to piston interference






Web Camshaft Hardweld cam to Endyn specs

jdmboyef9

Also of coarse brand new water pump, timing belt, tensioner, Ported D17 oil pump, New D17 timing belt gear, all new bolts and seals and gaskets. I ordered brand new timing covers also so you won"t see the cam gear...sorry fellas.


Next we move onto more clearance issues. I originally was gonna use the cast oil pan from the D17A2. I read somewhere that you must use the D17 pan to fit the D17 oil pump. I do not know if this is fact or not so someone can feel free to correct me.
Back to the headers...



I plan on using either my Skunk2 Alpha header or my URBER rare Mugen header (after it is professionally restored) Obviously the Skunk2 might yield more power but after it is tuned who knows, I might stick with my full Mugen sports exhaust. The problem is neither clear the D17 pan. They hit by at least a 1/4 inch or more in one spot. Being that the pan was cast there was not much I could do shy of cutting and welding. So i opted for a brand new D17 steel pan offered on the base model Civic. a little massaging with the air hammer and they fit like a glove.

This is the pan after the mod. Still looks brand new



Skunk2 clearance (after mod)






Mugen clearance (after mod)

v4lu3s

Impressive. I am curious about how much lift and duration the cam has. I am running the Crane 0012 right now, and sort of want more, and my compression is comparable to yours, though I do not have the extra displacement or the baddass endyne head...