Why was this over looked (Hammer)

[Hockeekidd98]

has any looked at how much the ehxaust header restricts airflow?

take a look
http://home.comcast.net/~hockeekidd98/P1140046.JPG
With a little grinding I think you could see a big improvment

[dannyUAL767]

I've got that same header that I'm going to be using on a water cooled .15. I'm going to grind on it because that hole is way too small and there is plenty of metal that can be removed ;) .

RCBoatmodeler magazine had an article several issues ago with this header and they ground on it as well.

[ejp]

Yep, I ported mine out to match the exhaust port. I don't know that it made a difference but it couldn't hurt anything. So, what about the thing blocking the end of the pipe??? What is it and why is the hole only like 1/8 inch big.

[Hockeekidd98]

Why kind of bit did you used to grind it down? Don't know which one to use, yes and I have a dremel.

[ejp]

I don't know what it is called. But, it looks almost like a drill bit with about 100 more swirls and w/out a sharp end.

[Ron Olson]

Hockee, I did an article before on port matching. Seeing how you already have the Dremel, there is a quick way to do it. Take 4 of those cheap cut-off wheels (use new ones so that the diameters are all the same) and stack them on your mandrel. with the gasket on the header, mark with a Sharpie, scribe or whatever you have handy the area that needs to be removed. Be careful when cutting as you don't want to go through the joint where the header and flange meet. On some headers that area is thin. Grind from an angle a smooth transition from the flange to the header pipe. After you're done, clean it thoroughly to get rid of any metal dust.

[BoatDoc]

i think porting that header was the first mod i did to my hammer. i never thought to do it the way that Ron said...i'll have to keep that in mind next time.

[dannyUAL767]

Great idea Ron. I've got a bunch of grinding discs so I should be able to do that.

originally posted by ejp,
So, what about the thing blocking the end of the pipe??? What is it and why is the hole only like 1/8 inch big.

The outlet hole (looking into the stinger, you can see it) is only about 1/8" :eek: . Its tiny! I've been thinking about drilling this out a bit as well. What do you guys think?

[Hockeekidd98]

Hockee, I did an article before on port matching. Seeing how you already have the Dremel, there is a quick way to do it. Take 4 of those cheap cut-off wheels (use new ones so that the diameters are all the same) and stack them on your mandrel. with the gasket on the header, mark with a Sharpie, scribe or whatever you have handy the area that needs to be removed. Be careful when cutting as you don't want to go through the joint where the header and flange meet. On some headers that area is thin. Grind from an angle a smooth transition from the flange to the header pipe. After you're done, clean it thoroughly to get rid of any metal dust.


That's a great tip, thanks!

[Hockeekidd98]

all done, your tip worked great. When i was done with the cut off wheels i used a grinding bit to smooth it out. I know these pics are horrible but it gives you an idea.

http://home.comcast.net/~hockeekidd98/P1140049.JPG
http://home.comcast.net/~hockeekidd98/P1140050.JPG

[Ron Olson]

Yeah, they're a little fuzzy but I can tell that you did a nice job on it.
For the others, our Moderator did a brief article also on how to do it an issue or two ago in the Nitro Hammer hop-ups article that he did in RCBM.

[Hockeekidd98]

I'm trying to find that article with all the hop ups.. missed the magazine...and don't see it on the web any where.

[Ron Olson]

it's in the issue with the Triton on the cover, the February 2005 on page 69. Rick did his in a differently than I do, I have done it like he did before.
BTW, you can use my way of porting for another use, cutting a notch in a flex cable for the set screw.

[BurnZ]

If you run the boat for a while you'll begin to see a dark area around the port on the header. This is the actual size of the port on the engine. Use this to guide you as you remove material from the header. It is also a good idea to pick up some better quality gaskets. I use Associated gaskets and wided the cut out a little bit. be careful not to remove too much and be sure to polish the inside where you grind.

I've never seen a side exhaust that had a port matched header without being modified.

[BurnZ]

quoted from ejp
So, what about the thing blocking the end of the pipe??? What is it and why is the hole only like 1/8 inch big.

That is a baffle. Tuned pipes don't have them the stock pipe on the hammer is more like a muffler. My Nitro RS4 had one. It's muffler could be taken apart so I took the baffle out. I don't remember it doing much though.

[Ron Olson]

BurnZ, you brought up a good point. I've been using the Associated gaskets also on my .12 powered boats. They have more "life" in them, being more flexible plus the larger opening for better flow.
I've seen some boats that need trhis mod badly. The new Shockwave 36 could really benefit from port matching.
I have got to give credit to John Finch for this motor mod, I read this a long time ago in his books from Air Age. If you haven't gotten these books, get them. I still refer to them a lot for setup tips.

[BurnZ]

I never thought of using several wheels to open it up. I've always used the diamond bits, I think that is what they're called.

[Ron Olson]

I tried using other bits before but had trouble with them wandering while trying to use them. You can use them for the finishing to get the corners rounded and smooth out any transitions.

[dannyUAL767]

I should've done my header yesterday. It was nice and warm-about 70° F. Today, its in the 30's and very windy. They say it should make it into the upper 40s but I'm not too sure about that. Yeah, I know, these are mild temps for you northerners :D .

[Ron Olson]

Danny, quit whining! :D I'd gladly take that over what I have, 5 degrees right now and about a foot of snow. Yes, great boat building weather.