Hitachi Carburetor Conversion

[Meck]

Many thanks to Darrin Moore for making the pictures possible.

A lot has happened since I first asked for help in making an adapter plate for an Hitachi carburetor. Given my experience so far, it’s a change I would recommend. I will describe the process, keeping it as brief as possible.

Background: The stock carb in my ’85 needed work. I had never been real happy with its performance even when it was much newer. I had no extra dollars for a Weber conversion, but I did have a rebuilt Hitachi carb from a ’70 Datsun 510 (1600cc). Why not try it?

The adapter plate was made from three-eights thick aluminum. The original studs from the Tercel were left and holes drilled accordingly in the plate. The Hitachi is smaller at the base and sat inside the Tercel studs. Holes in the adapter were drilled, tapped, and 5/16th studs inserted. The Hitachi was bolted down with gaskets and a 1/8th spacer that I had and that I thought might help a little with heat diffusion come summer. When the rig is set in place, ½ in collars are used on the Toyota studs to raise the level of the hold-down nuts. The only tricky part in making the plate is that, when mounted as I did it, the manifold opening and the carb barrels are offset slightly. I matched them up by slanting the cut through the adapter plate.

The carb I started with was an Hitachi DAF 328, as simple as a two barrel can get. The car ran great with it, but I discovered that I could not get it to run like I wanted with a primary jet of less than 115 in size. This also gave a too rich mixture for normal/easy running and gas mileage plummeted. I then came across a tremendous resource that I recommend to everyone, whether changing to an Hitachi or considering a Weber. It is a detailed article, entitled “Carburetor Tuning Guide,â€

[Mickey_D]

If you need help with hosting pictures, e-mail them to me at darrin.moore(at)gmail.com and I'll host them for you and will e-mail you back links and instructions on how to edit them into your post.

Just please be sure to put something about Tercel 4WD in the message subject.

[Typrus]

Looks like your primary is partially covered there.

[Meck]

No, it's not covered. The carb primary is offset slightly from the intake manifold opening. I corrected for this by slanting the cut through the adapter plate. The picture doesn't show the slant.

[GTSSportCoupe]

Hey Meck, thanks for doing this writeup. Now people have even more options for carb improvements. Nice work.