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[patsmx5]

Just a little write-up on how I modified my manifold from a T2 flange to a T3 flange. I've posted some pics here, but figured I do a little write-up anyways. I'll be doing a longer one on repairing broken fasteners soon…

When I bought my manifold, it was T2 based and the threads where stripped. I had a T3 based turbo though. I looked into T2-T3 adapters, but with the lack of clearance I already had, adding a spacer wasn't an option. Plus adding a spacer/adapter means more failure points. But I got a deal on the manifold and didn't want to sell it and pay more money to get a shittier T3 manifold. Well, I measured and there was plenty of surface area for the manifold to have a T3 bolt pattern.

Before I did this, I searched and searched for this to find several people talk about it, but few said it would work, and I never found any pics of where someone actually did this or reported they did it and it held up. So I tried it and it works.

First, I needed to fill the old holes up. Since they were stripped, I first drilled them out and retaped them 3/8-16. This was easy as the stock holes were tiny anyways. Then I cleaned the threads and bolts up with brake parts cleaner applied some high strength lock-tite to the grade 5 bolts, and torqued them down into the manifold. After sitting for a day the lock-tite anchored the bolts into the manifold.

Then I just cut them off with a hacksaw. I used a file to surface the manifold to get the bolts back to flat and to take any warp out of the manifold. Now we're back to all metal.

Now I C-clamped a T3 flange I had to the manifold and used a 3/8 drill bit to mark my four holes (using a transfer punch would have been better, but this worked). Then drilled a pilot hole with a 1/8 bit, then drilled them tap size for 3/8-16, which is 5/16". I used a 1/20 HP drill press from Lowes so it was slow but it kept everything square, which is important.

I actually drilled into part of the bolt when retaping. That's why I lock-tite'd them into the manifold so they wouldn't try to spin out when the drill bit hit them. Worked. Then I tapped the manifold 3/8-16. The threads actually go into the manifold over 1" deep. This helps keep the fasteners from vibrating out. So does drilling and wiring them together though.

And that's pretty much it. I used grade 5 bolts and it wasn't hard to drill into surprisingly. Could have used a lower grade bolt and been fine probably though. Been running for almost 3 months so far and it's worked perfect. Cost me $1.20 for the bolts. Cheaper than a new manifold.


Pics..

Manifold as purchased for 118 shipped.


I retaped it for 3/8-16 and lock-tite'd new grade 5 bolts in it.


Then cut them off with a hacksaw


And surfaced it with a bastard file.




Then retaped the manifold to T3






Test fit






Works great. $120 T3 Cast FM manifold converted to T3.

[ryan89crx]

how does the inlet/outlet hole line up? porting needed?

[patsmx5]

They're lined up, but the turbo's inlet is slightly larger than the manifolds T2 opening (which is really bigger than T2, but slightly smaller than T3). I never did port it to match, but I probably should have. Guess I'll do that next time it's off. 

[92CXyD]

Nice 

may have to bookmark this :yes:

[TTC]

Why are their holes in the bolt ends?

[MTZ]

Why are their holes in the bolt ends?

its for safety wire, really used in motorcycle (mandatory in some most motorcycle tracks) and airplanes
look it up in google just a piece of wire interwined together from 1 bolt to another with a tendency to tighten 1 given bolt at any time.

in simple words if 1 bolt gets loose the wire will hold it in place

[Foowee]

       :yes:   

[patsmx5]

Why are their holes in the bolt ends?

its for safety wire, really used in motorcycle (mandatory in some most motorcycle tracks) and airplanes
look it up in google just a piece of wire interwined together from 1 bolt to another with a tendency to tighten 1 given bolt at any time.

in simple words if 1 bolt gets loose the wire will hold it in place

Yeap. You can wire all the bolts together so if one tries to loosen, it pulls and tries to tighten the two it's tied to. Since they're all tight when you wire them, none of them can back out. I still haven't acutally wired them yet though.  :somb: Need to order the wire one day.

[MTZ]

we use .032 gauge at work everyday by hand :| not cool

[TTC]

OOO for wirelock patterns.. Ya I remember now.

[j.h.christ]

you are one cheap son of a bitch. jesus approves of your frugality.  :yes:

[Logan76]

I do lacing at work sometimes, on my old 240 I had some trouble with my turbo loosening up on the manifold, so I just used studs and tacked the nuts to the stud when it was tight. I was wondering where you bought the bolts with holes in the heads? My work buys everything from McMaster Carr and I was hoping to find them somewhere local.

[patsmx5]

I do lacing at work sometimes, on my old 240 I had some trouble with my turbo loosening up on the manifold, so I just used studs and tacked the nuts to the stud when it was tight. I was wondering where you bought the bolts with holes in the heads? My work buys everything from McMaster Carr and I was hoping to find them somewhere local.

I C-clamped a 3/8-16 nut onto my drill press table, screwed the bolt in it with the head hanging off the table, and drilled a 1/8 hole in the head. Only took like 30 seconds to drill through the head. Cheap and easy.

Still, you tack the nut to the stud, then the entire stud can still come out. Better than nothing though, but wiring the fasteners to one another is the fool-proof way.

[HiProfile]

Nice write up along with a great idea. Too bad 99.8% of Honda manifolds are t3 already. I'm sure it will help the people who's cars come with T25's, and have un-innovative aftermarket companies. I also like the safety wire idea. I'll be trying that this year, or just bent-up tabs like they do with GM cam bolts (and some Garrett CHRA's).

Only thing I might change is welding the stub in vs locktight. It could possibly evaporate at the temps it will see, and would make removal a bitch if the stubs turned a fraction. Even if it was a weak weld, it will booger things up enough to lock it in.

[patsmx5]

The lock tite was just to hold the studs while drilling it. Once the manifold was heat cycled the lock-tite has surely been defeated. That said, I removed the turbo after running it a few days and there was no problem. I taped the holes in the manifold such that the bolts binded up when torqued and lock-tite'd, so even when the lock-tite is gone, they're still stuck to the tune of ~40 ft*lbs. Perhaps they could have been welded, but I'm not sure that would have been any better. Plus the manifold's cast iron, and I can't weld to cast with a stick welder.

And yeah, this probably won't help many honda folks. For some reason miata folks are scared to death of T3 stuff, so 99.8% of their manifolds are T2.

[Logan76]

Thanks, I think im also going to do that route, did you use lacing pliers on yours or just needlenose? Not too many guys have lacing pliers unless you formerly worked on airplanes, but we lace bolts on blowers that come into my work.

[MTZ]

Thanks, I think im also going to do that route, did you use lacing pliers on yours or just needlenose? Not too many guys have lacing pliers unless you formerly worked on airplanes, but we lace bolts on blowers that come into my work.

by hand u will get a much better lace than needle nose so either use the safety wire tool or hand trust me