[1971 240z ITB install]

On 1/16/2026 at 2:25 PM, cgsheen said:

Very interested to see. Jim's Swiss 240Z (stock internals except for a mild cam) with ITB's and a Holley ECU tuned by our local legend - Tony at UMS - made about 183 RWHP. Jim was a bit disappointed (he was thinking 200ish) but we all thought that was pretty amazing for just ITB's and a good tune!

 

It would be nice to see what all your engine work will accomplish. In ANY case it'll be a blast to drive!

I wish I would have dynoed my 2.4L with ITB, but sadly I broke my oil pressure bung mount.  I will be taking that block, stripping it down and finding an expert to weld it.  

[1971 240z ITB install]

On 1/10/2026 at 11:18 AM, MONZTER said:

Looks nice, Im guessing 260hp at 6500 to 7000k  Do you plan on dyno testing it?  Seems like it will be a super fun street car.  Realy clean but not so over the top that you cant drive it everyday and enjoy it.  Looking forward to more.

Gosh it better be more then 260hp.  

 

I will eventually dyno test, but we don't have one close to me.  I live in a tiny town in Northern Idaho.  

 

Its a very clean z, but sadly painted in the 70s- early 80s and the owner danced on the roof.  Lol

[1971 240z ITB install]

For you that have been following along. My 3.12L is finally in my car and home. Gosh it looks so good I’m just going to stare at it! Amazing work by Andrew Kazanis!

This engine was built and done prior to a shop fire. So it’s been through a lot!

I love the contrast of the stock blue block and gold zinc and black.

It features.

My 3.1L

10.2:1 compression ratio

88.5mm bore. N42 block. Sonic tested.

LD crank by marine crankshaft. Crank �Off-set grind to 84.6 stroke�Finish rod journals @ 1.8889"

Thrust Finish 1.27”�R & R plugs with threaded plugs�Dynamic Balance�Ion-Plasma nitride, straighten & micro-Micro polish all journals

E31 head. Port work by Andrew Kazanis

Dsi valves Diameter: 45/36.5mm Length: 118mm, titanium retainers. Isky springs.

Bonk cam. Roughly stock exhaust and intake port sizes. Vapor honed inside and out.

Rebello JE Eagle pistons and toyota rods

221 CFM flow at .45-.5 lift.

Mine is 88.5x88.5x.25x3.14159x 84.6x6 /1000 = 3122cc

It is showing off my intake design and Efi throttle bodies as well as a bunch of my small parts.

[New All Aluminum Body Panels of Datsun240Z manufactured in Japan]

Thanks for posting, pretty amazing sheet metal work. 

[A COMPLETE EARLY MODEL 240Z BODY may be available soon]

They make bronco bodies, and a bunch of people have complained about how crappy they actually are.  Fit, overall shape, poor paint etc.. 

 

I guess still better then a rusted out junk car.  

[1971 240z ITB install]

 

 

A fun z video I just was sent. It has my R35 coil bracket on it and has over a 1/4 million views! How cool is that.

[1971 240z ITB install]

Working on PCV again, I am going to try for the exhaust. My basic plan is, valve cover to stock pcv valve, to a catch can, then block to the catch can, catch can to the exhaust.

[3.2 Build EFI N42 / MN47]

I really think you should move to an overhead bar.  

[3.2 Build EFI N42 / MN47]

Linkage is what I am calling the small arms between throttle bodies and the shafts.  

 

You need to remove everything connecting each throttle to the overhead bar.  Then sync.  Then check again once hot.

 

Also blip each throttle, see if they stick or bind once hot.  

You should have the cable going to a cam on the overhead bar.  If that isn't what you are doing, I would highly suggest that route.  

Setting butterflys is extremely difficult to do perfectly.  I would print the 3D file I posted for syncing, then set each off the car.  Then put each in an oven to 185 and check each again.  

 

Do you have an injector company in your town? Have them checked for flow matching?  

 

[3.2 Build EFI N42 / MN47]

How close are they synced now?  Are you removing linkage to do that? Are dog bones the exact same lenght?  

[IMSA GTU vintage racer build]

man, how cool is that! 

[MSX3 - NO CAM SIGNAL - JEEP I6 Sensor]

Have you tried clocking it any? There is an area of the stroke that it won't work in.  

[Twin cam head for the L6 from Derek at Datsunworks]

I am designing a DBW actuator for this DOHC now! 

[Twin cam head for the L6 from Derek at Datsunworks]

On 5/13/2025 at 7:38 PM, zboi said:

Don't worry PAMS is already testing a real DOHC head on cars and you will actually be able to buy it. I expect prices to be better and unlike this head it will install without a headache and an engineering team.

Its now my least favorite looking DOHC, but it's pretty darn cool technology. 

[DCOE ITBS wanted]

Used ITBS seem to be very rare.  HKS, 

 

I would stay away from the full chinese DCOE ones.  KMS takes the chinese bodies and retrofits them with better butterflies and such.  

 

https://en.kms.vankronenburg.nl/products/throttle-bodies/bodies/throttlebody-twin

 

Then there are 

Jenvy

EFI Hardware (probably the best designed out) Throttle blades open the opposite way, tapered bore, better throttle blade angles

Borla 

OER(I would stay away from these)

ETC.... 

 

A common issue with ITB is when the engine is hot on a hot day, they tend to stick slightly open and having them return to idle doesn't work.  I believe the bodies expand and cause pinching, but who knows.  

[1971 240z ITB install]

I got my Datsun Z Car Series Oil Sending Unit Relocation / Remote Block done! I have only one for sale now, but more are on order. I am pretty proud of this design.

Three outlet remote oil sending unit block. Metal 3D printed out of aluminum to look stock and mimics the 240z, 260z and 280z brake proportioning block design.

Block has 3 outlets, all are 1/8 NPT. Comes with a custom length -3AN hose and one 1/8 NPT -3AN fitting and either a 1/8 BSPT or 1/8 NPT for the engine block side of the hose.

Stock sending unit on a 240z is BSPT, this will require a NPT sending unit like this. [https://zcardepot.com/products/oil-pressure-gauge-sender-240z-260z-280z-70-77?variant=32184292737137](https://zcardepot.com/products/oil-pressure-gauge-sender-240z-260z-280z-70-77?variant=32184292737137)

No sending units come with this order. Pictures of sending units are just for reference.

Link: https://www.m2racing.com/shop/p/datsun-z-car-series-oil-sending-unit-relocation-remote-block

[3.2 Build EFI N42 / MN47]

15 hours ago, madkaw said:

Reducing vacuum line size seems to have helped the MAP reading. Looks like I might even get 60kpa at idle too! 

First drive was interesting for sure. Almost stalled pulling out in traffic and rich and lean mixtures all over the table-lol. The autotune was trying to correct but some of my settings were off. I didnt stay out long because it was Little 5 in Bloomington and too many crazy kids out . Monday when everyone is at work Ill do some more tuning, 

Idle seemed to increase as the engine got hotter. No heat shield yet so that is an issue  

Idle increase while hot is the same issue most of us ITB guys are dealing with, I hope a heat shield fixes it.  

[1971 240z ITB install]

Here is something fun/ silly I have been thinking of and finally made. It’s a remote oil pressure distribution block made to look like the stock 240z brake prop valve. I previously had a steel T In the block, that broke off and then when I was using an easy out I cracked my stock block bung. I said never again!

3D metal printing is neat stuff. I had it tumbled to look even more cast.

I run stock gauges and my ecu needs its own signal. This location allows stock wiring to also work.

[1971 240z ITB install]

On 4/15/2025 at 3:42 AM, Derek said:

Man that is so cool. Not as cool as a DOHC though. 😀  I'm for sure going to do this mod at some point especially after seeing how responsive it is. Great job!

I don't have DOHC type funds:) 

[1971 240z ITB install]

 

[1971 240z ITB install]

I love it when a plan comes together!

Fully operational below dcoe throttle body actuator for DBW ITB. Mostly hidden!

[R180 pinion shims]

Gonna have to use the internet for that one then.  

[R180 pinion shims]

6 hours ago, madkaw said:

Okay - you would think they are the same . Were you able to specify sizes ?

Yep, I bought a few.  

[R180 pinion shims]

I was told the subaru shims are identical, i bought from the local dealer.  

[1971 240z ITB install]

Well I decided to pick a new header. I wanted the header to give my room on port 5-6 for my lower mounted actuator and also get out of the way of the throttle bodies a little more. I decided on the Kameari drag 45mm. Which I purchased through Binh Nguyen.

The header design gives me plenty of clearance for my actuator and throttles! Pretty darn happy with it overall. Prior I had a now moth balled Fujitsubo header. Which had a terrible runner design for a lower actuator.