Happy Little Accident, a EUREKA! moment.

Pancho86

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Just like Bob Ross said, sometimes our great works and creations are nothing more than a "happy little accident". And this just happens to be the case with an issue I've been having with my motor.

A few weeks ago I posted a THREAD about issues I'd been having, mainly a funny noise in the high end range that was robbing me of power. I tried everything, new (and hotter) plug, different mix ratios etc. and while some things did help I was still plagued with the weird power shortage near top, although not as often.

Last week I burned through my first exhaust gasket since I built the thing and got it broke in, so i replaced it with the only other one I had. That thing turned out to be a straight piece of crap because it burnt out in 3 days. Seeing I didn't have any more around I had to just tighten it as best I could and deal with it. But as I was riding it like that I noticed I didn't have that wierd fluctuation at high end anymore, and the motor actually responded way better than it ever had and I was hitting speeds that I had never hit before either.

That's when I realized it was the exhaust the whole time, it was too restrictive. I even had to drop the idle over a full turn of the set screw.

So I bought one of those banana shaped exhausts off Amazon for like 35 dollars, it just arrived today and I bolted it on and it works like a charm. Now it even kicks over easier, sometimes in only 3 or 4 revolutions of the motor. I also bought a reed valve to experiment with, it won't be here till Tuesday.

While I waited on the exhaust I tried an experimental surgery on my stock exhaust. I thought I could take it apart and remove some of the baffling and try and recreate the flow I got with the busted gasket. Well I ended up removing too much and while it helped a little, all I really ended up with was a very loud popping and rolling contraption. Neighbors weren't pleased, I'm sure. If they weren't then, they won't be now either because its got a nice deep throaty growl to it.

For the record though, it will still make that weird sound at around mid range but only if it's not up to temp yet though. If I'm correct that tells me I might need a hotter plug, because honestly its taking a little longer than before to reach an operating temp. I'm using NGK b7hs, I tried to get b6hs but they're sold out all over around here, with no cross overs available. They had one at an Advanced auto but it was like 10 miles away. Oh and also now for exhaust gaskets, I read a post on here somewhere about the Toyota Highlander O2 sensor gaskets, and those are great. Those look like they'll last a while .

I wanted to post this because I know it could probably help someone someday who's going through what I went through.
 
I read a post on here somewhere about the Toyota Highlander O2 sensor gaskets, and those are great. Those look like they'll last a while .
Here is the current Toyota dealer parts#/stock#, for that gasket...89466-20020-83.

If you shop Autozone, Amazon, etc., its a "Dorman" brand part number ...Dorman 47021.

https://www.amazon.com/Dorman-47021-Oxygen-Sensor-Seal/dp/B000TYU1WE

When installing this gasket, you will need to slightly elongate the holes that go over the studs/bolts...I use a slightly largerbolt to do this through those holes.

You will notice that this gasket has some metal affixed to both sides of the gasket...The side that has the most metal is what goes against the exhaust pipe itself...DO NOT use any gasket sealers with this gasket.
 
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Ok here's where my inexperience with this stuff comes in, can you explain the windowed piston. And where to get a good one.
 
Here is the current Toyota dealer parts#/stock#, for that gasket...89466-20020-83.

If you shop Autozone, Amazon, etc., its a "Dorman" brand part number ...Dorman 47021.

https://www.amazon.com/Dorman-47021-Oxygen-Sensor-Seal/dp/B000TYU1WE

When installing this gasket, you will need to slightly elongate the holes that go over the studs/bolts...I use a slightly largerbolt to do this through those holes.

You will notice that this gasket has some metal affixed to both sides of the gasket...The side that has the most metal is what goes against the exhaust pipe itself...DO NOT use any gasket sealers with this gasket.
Luckily I got that one right, metal on pipe.
 
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It depends on what motor you actually have and the physical mm size of your piston.
Yeah I'm starting to read up on it, oh well something new to learn, and a project for down the road. That's why I got into all this to begin with, it's just fun and I have a blast learning new things. I didn't realize how advanced some of this stuff has gotten.
 
Here is the current Toyota dealer parts#/stock#, for that gasket...89466-20020-83.

If you shop Autozone, Amazon, etc., its a "Dorman" brand part number ...Dorman 47021.

https://www.amazon.com/Dorman-47021-Oxygen-Sensor-Seal/dp/B000TYU1WE

When installing this gasket, you will need to slightly elongate the holes that go over the studs/bolts...I use a slightly largerbolt to do this through those holes.

You will notice that this gasket has some metal affixed to both sides of the gasket...The side that has the most metal is what goes against the exhaust pipe itself...DO NOT use any gasket sealers with this gasket.

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Why can't gasket sealers be used? It usually makes the connection tighter. Or does it not help here?
 
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