Exhaust Compatibility: Swapping 91' Wagon LX (F22a1) Block With 91' EX (F22a4) Block

[Mishakol129]

Hello everyone. I have some important questions which I think only some here may know. I have a 91' Accord Wagon LX with 334,000 miles and very bad blow-by. I need a swap or a rebuild asap. For this, I have ordered a 1991 EX short block from ebay which I am planning on rebuilding. I did not know at the time of purchase, but I now understand that these two engines are actually different, the exhaust manifolds are different (the EX having a better, duel exhaust-flow). I understand that the engine I have is an F22a1 and the EX is a F22a4.

So, all that I need to do is buy a 1991 EX exhaust manifold and it will bolt right up to the remaining 1991 LX wagon exhaust?

Here is something I found on ebay that looks like it will work and it seems also to come with a flex pipe which I really need because mine has a hole in it.
http://www.ebay.com/itm/STAINLESS-ST...ht_4073wt_1272

So these are my questions:

1. Will this work with my 91' LX Wagon? The price is extremely good, and I am not looking to spend the regular price of 100's of dollars for this.

2. I want to know also if this comes with a flex pipe like the pic shows.



Thank you very much.

[F20A CB7]

1. any 9093 header for a f22a wll work with any yr cb. All u have to worry about is putting the o2 sensor in the rite bung. Most aftermartket headers out there come with 2 spots. On top and on bottom.


2. I didn't click ur link.

[deevergote]

The best person to ask about the header is the seller... but most of them do come with flex pipes. I'd suggest getting better gaskets than the ones they give you, as the gaskets with those cheap-o headers often leak.


All F22A head and block castings are exactly the same, so you will have no problems bolting everything to the new one. Actually, the ONLY difference between the F22A1 and F22A4 is the exhaust manifold. The rest is identical between the two.

[Mishakol129]

1. any 9093 header for a f22a wll work with any yr cb. All u have to worry about is putting the o2 sensor in the rite bung. Most aftermartket headers out there come with 2 spots. On top and on bottom.


2. I didn't click ur link.

1. Are you sure, because the pics of the 2 exhausts look totally incompatible:

This is mine for my LX wagon F22a1:



And this is the 91' EX (F22a4):




Totally different, do you not see it?

[deevergote]

The F22A1 stock manifold is a 4-1 design. The F22A4 manifold is a 4-2-1 design. That is the difference you are seeing. You'll be replacing both the upper and lower portions with that 4-2-1 header. It will fit just fine (aside from imperfect manufacturing of the cheapie part... but it'll fit well enough.)

[F20A CB7]

Ok you have 4-1 header design, pic to with the header will be a 4-2-1 design. The mid pipe takes either design. Its a triangle inlet/outlet.

Doesn't matter wat f22a u have. A 4-1 and or 4-2-1 will bolt up.

[F20A CB7]

Ah hell bossman beat me 2 it.

[Mishakol129]

The best person to ask about the header is the seller... but most of them do come with flex pipes. I'd suggest getting better gaskets than the ones they give you, as the gaskets with those cheap-o headers often leak.


All F22A head and block castings are exactly the same, so you will have no problems bolting everything to the new one. Actually, the ONLY difference between the F22A1 and F22A4 is the exhaust manifold. The rest is identical between the two.

Okay, I got the answer i was looking for here: http://www.cb7tuner.com/vbb/showthread.php?t=129555

That much needed flex pipe seems to come with them, and at a great price too (even better than 1aauto).

[F20A CB7]

Just so you know, 4-1 are more for top end, 4-2-1 is for low and mid range power...Where u from man?

[deevergote]

Just keep in mind that cheap headers aren't known for their incredible build quality. That may crack in a short time, and it may not fit perfectly snug (hence my suggestion for better gaskets.) Some people have great luck. Others have terrible luck. For the price, and since you need a replacement, it's well worth a shot... but be prepared.

[Mishakol129]

1. any 9093 header for a f22a wll work with any yr cb. All u have to worry about is putting the o2 sensor in the rite bung. Most aftermartket headers out there come with 2 spots. On top and on bottom.


2. I didn't click ur link.

So is their like a plug or a cap for the o2 sensor hole that you don't use?

I think that is what I see in this pic, there is what appears to be a cap over the holes for the two different sensors:

[deevergote]

Yes, there is a bung plug.