Stock exhaust vs Hedman header - 22R?

[IdahoDoug]

I am thinking of buying a Hedman "shorty" header for more power since I have a leaky exhaust gasket.  However, my exhaust (likely original at 32k miles) is dual exhausts from the factory cast iron exhaust manifold, which I did not expect until I crawled under this morning.  It connects to a larger single pipe about 6" behind the cab door hinge.

 

Two questions for you:

Is that stock?

Has anyone else any experience with the shorty header (less added power than the full header which is some 4 feet long)?

 

Also, I was surprised to find my carb 22R has an oxygen sensor in its factory manifold, which I'd have to have installed in the Hedman.  Any comments about that? Eliminate it (Idaho has no classic car exhaust requirements)? Input welcome - good, bad and ugly.  Thanks. 

[extech]

your exhaust is factory.   unless you do other mods to the engine(cam, intake, carb)  i don't think it'll get you much. the o2s is a part of the system, as such removing it can cause some complications.

  i have a weber 32/36 carb, and i think it's the most bang for the buck

[IdahoDoug]

Yeah, OK.  I'm going to pass on it.  For anyone interested, it's near San Diego and the guy says it's never been mounted.  Still available for $286 new including shipping and he's selling it for $100 obviously with no shipping.  I know someone down there and get to SoCal regularly so shipping would have been "free".  PM me for details if you are interested.

 

I will just install a new gasket (it's actually the flange gasket leaking, not the block gasket), and as Extech says, avoid having any issues with the O2 sensor.  Plus the original manifold heat shield is in great shape, and that also has the original heated air tube that helps warmup, both of which will not fit the header.  Plus I won't need expensive exhaust work to mate to the header.   All that for a few HP doesn't have the bang for the buck. I've been trying to talk myself out of it and Extech helped me!!

 

Curious how the Weber conversion went, Extech?  My Sunrader has super low miles at 32k, and it runs well.  My understanding is the original Toyota carbs eventually have wear issues, but otherwise are reliable.  There's a guy on YouTube with a stone grey Sunrader that really likes his Weber conversion.  Did you do yours yourself, or..?

[extech]

my dolphin came to me with the weber.    i have used this carb many times on datsun 510's and 620 pick ups.

 easy to install.   the air filter adapter is a must if you need it to smog, but the standard oblong k&n type works better

   look on ebay as they come up occasionally

[fred heath]

Toyota 20R engines are famous for cracked exhaust manifold ( usually between #2 and #3 exhaust ports).

 

I realize yours is a 22R, but the same issues occurred with that block too.

 

Turns out the heat shield is the culprit. The excess heat generated by the hot exhaust gets trapped underneath the shield. With no way to dissipate, it ends up cracking the cast iron header.

 

Unless you feel you absolutely need that heat shield, I’d delete it completely.

 

Not to be a doomsayer, but the cracked manifold is often mistaken for a leaky exhaust gasket.

[extech]

back in the day, toyota knew about the problem and would replace the manifold for free. in the 22r they redesigned the shield and the cracking stopped

[IdahoDoug]

Interesting - thanks for the input.  Mines definitely the flange gasket.  Funny how a pedestrian part like that can be an issue even with a world class company. I had an 89 Mitsubishi Van Wagon, which was a 4 cylinder built for the world market in huge volumes by a world class engine builder. It cracked exhaust manifolds to the point I'd yank them at the U Pull even when there for another vehicle.  Felt bad that after I sold it a couple years ago, I later found a small pile of manifolds I had forgotten about.