Going to bore my own TB to 67mm. Any suggestions?

[fowljesse]

...Besides "Leave it to a professional"

I have 2 extra K8 TBs to practice on, and I feel confident that I can do it well.
Here's what my plan is; I took the butterfly out, and have access to a drill press, so I figured a tool store would have some kind of bit that I can put into the drill press, and drill it out. I have a boring kit from Harbor Freight that's made for wood that is 65mm. I think I can make it work with the drill press (If I can't find a boring tool). I started with a battery powered drill, and it started to cut, but a drill press would work much better, of course. If it doesn't turn out perfect, I can wrap sandpaper around something the same diameter, and sand it smooth. Then I'd cut the slot in the shaft wider that the butterfly goes into, and make a 68mm round piece for the butterfly, and shave the sides to 67mm so it's ovalised, and sits correctly in the bore. Then, I'd mark, and drill the holes to connect it to the shaft. Then I'd hourglass the shaft.

What do you think?

[Daninski]

Getting the bore uniform is your biggest issue. The butterfly needs to fit perfectly and as such I'm not sure how your going to accomplish that doing it by hand. Lets face it Jesse, this isn't sex you know.

[fowljesse]

Yeah.
I figure a drill press is a vertical lathe I'd clamp the TB down to the drill press table, and get a boring bar head, and carbide tip set, and start slow, making the hole slowly bigger.
There's a volley for you, or whatever you call it when a Hockey player sets up a goal shot for someone else
Also, I'm going to look into Pizza cutter sizes for my butterfly, that way, it is already knife edged, thin, and very strong.
If/ WHEN this works out, I'll do this whole service for others

[Daninski]

That would be called an 'assist' in hockey. And I don't think it's as much 'boring' as 'reaming' So on that note over to you Jess.

Isn't there a guy you can buy a bored TB from, you then send him your TB and he refunds you a credit?

[Ryan]

Jesse, I had the cluster ring group buy a year (or two?) ago, and I know first hand how impossible it is to make perfect handmade circles. Unless its on such a massive scale where small imperfections can be hidden, doing something TB or cluter ring sized is way too easy to mess up. You won't even see the mistake until you turn it around a bit and look at it out of the corner of your eye for a few days. Its not really a good idea to try this. If your butterfly doesn't fit perfectly, you'll have mor problems then you'll make up in ponies, and don't forget you need to modify the I/M so its useful.

[mitmaks]

T/B is so precise, if you're off a 1/1000th it's scrap.

[Daninski]

So now you need to find something else to do next week Jess.

[fowljesse]

Okay, I'll see how much local machine shops will charge to ream me.
There are places to send them, but I couldn't find one for less than $120.

[Daninski]

If I can remember the site I'll let you know. Like I said there's someone experienced who does this. I'd be leary to bring it into anyone with out references.

[MugenReplica]

Okay, I'll see how much local machine shops will charge to ream me.
There are places to send them, but I couldn't find one for less than $120.

http://www.maxbore.com" onclick="window.open(this.href);return false;

You could always email them and ask if they'd do a Mazda TB.

[wytbishop]

I don’t want to discourage you Jesse, but it is absolutely impossible to do this yourself with any accuracy. If you do this and it works and shows a measureable improvement I will paypal you $100USD. Call it an R&D investment. If it works I'll pay for it.

[Daninski]

OK so what kind of gains are expected by doing this?

[fowljesse]

You're on Wyt!
All the OEM TBs I've looked at with light behind them looked like a solar eclipse. I'm going away for 3 weeks, so I won't get to it until after that, but now it's a challenge I discovered another ZE TB in my stuff. It would be alot easier to bore.

The advantage to this mod comes after many other mods. The TB is restrictive, after I opened the intake and exhaust alot. I think that on a ZE with headers, it may be worth it to bore it out, I know Mooneggs loves his.