Building/ freshening up my 175 big bore crossflow

[keefallan]

Here's the rest in random order..........there are the water covers, bubble back cover, t-stat covers and stacks mixed in.


I want to powder coat the idle passage cover on the carbs too. I wanted to do the starter case, but aren't there magnets epoxied to it? I think the heat will ruin the epoxy. That's all the bling stuff..............or is it.

[keefallan]

I got the hone just a few minutes ago. I am excited..........first rigid hone for me and I have heard great things about this one. I am also excited to have the 500 grit stones as a final pass. The hone came with 80 and 180 stone. I bought extra the 280 and 500 stones for it. Metal starts to take on a different sheen after 320...........

Anyways, after talking with my friend. I am gonna hone the cylinders(hopefully tomorrow) and then make my decision about things. I do plan on working on the ports tomorrow and the clean up of the intake tracts and intake manifold...........oh yeah powder coat? yep. Its gonna look good. its functional and looks good too.

I wish my baking soda had showed up by today...................oh well. It would've been nicer porting a clean block versus a sticky greasy one.

[keefallan]

I got some help today from my two sons and my wife. I worked on showing them what to do.......so I could get working on the ports and porting and blending. Here's the b4 and after of the intake.

[keefallan]

I didn't have all my supplies with me at the shop to hone. I will do that Monday......Lord willing. I did port the lower area where a crossflow would normally get a scalloped treatment. I ground down the large lip there instead. It is a blockage of the incoming air from the reeds. What happened in the process was that the lower edge of the cylinder was raised about an 1/8 inch. No big deal......if an engine runs fine with the scalloped ports. I blended the whole area around that to be smooth and not hinder airflow. Many thanks to my friend CC about explaining the whole scalloped area and its purpose. I still will blend the areas a little more. But its 95 percent done. The pics don't show the taper in there.....the factory slope

As you can see in the pics, the huge ridge. there is a taper in the intake area at the bottom. I followed that to the bottom of the cylinder lip and ended up raising the lip about 1/8 inch.

[keefallan]

I said in a previous post that I would only port the middle port and leave the others stock............minus removing that fang in the middle. So I will post pre porting and after porting.



The intake ports look huge now. But they really aren't. I blended the aluminum for a smooth entry. The sleeve side is smaller than what you see here. The bridges haven't been changed. I do perceive that through the removal of the fang in the center, the ports did get larger overall by about 3-5% because of the sanding roll.

I will straighten the edges a little more when I go back and port the other side of the motor.

[keefallan]

here's the exhaust before and after. I only have completed half of the engine at this point. I show a port pic of the exhaust , by looking thru the intake port as well.

As you can see, by just moving left and right with a smaller radius, the port gets significantly larger. That radius is between 3/8 to 1/2 inch.....more towards the 1/2 side. The cartridge roll was 1/2 diameter. So, it may have worn down and been less than 1/2".....that is why I said between 3/8 and 1/2 inch. It probably would be, in reality, 7/16 to 1/2.

Here's what I learned on this go round with porting: this is my 4th time porting a crossflow by hand. I used air tools(burr and sanding rolls) and a rat tail file at the end on the exhaust(2 of the 3). The file is easier and faster. It doesn't chatter or dig too much. There's no whoops! And when you are done........chuck in a sanding roll and make it all blend. I will port the other side this way. I will however, use air tools for the blending at the bottom of the cylinder in the inspection cover area.

Remember now, I still have to hone(maybe bore) and chamfer the ports. I am already aware of certain things. I just haven't mentioned them to save me writing bout them.

The only prob with a rat tail file (for me)...........my hands ache..............oh well

[keefallan]

For what its worth, the piston never goes past the lower edge of the intake port during its travels.....actually the piston is about 1/8 inch above the lower edge of the port. I checked on this before I tore the motor down. So, I don't really see the need to port the lower corners. I did it however, because it made it easier to "see" what I was doing when I was porting. The symmetry help my eyes focus on lines............

[FMP]

Just going by eye, you've raised duration on the transfers as well as area. Do you have a specific number of degrees in mind?

[keefallan]

No. My intent wasn't to raise anything......except the area at the bottom of the cylinder on the intake side(which you cant see from the photos). I do believe that things got raised by me smoothing out the hump with a cartridge roll. But if you are looking at it from the outside of the piston looking in, it may not be as raised as it looks. I intentionally chamfered the intake ports to make smooth airflow into the piston......instead of a straight 90 degree turn into the cylinder. But I do believe that the sleeve holes themselves are slightly larger from blending with a cartridge roll......unintentional. I will go back and further tweak things. But the general porting is done......for 1/2 of the motor anyways. I will check the ports with a caliper to make sure that the heights are the same b4 I am done.

[FMP]

I see, the area increase should help some.

If you can for interest, after assembly take a degree wheel measurement of the opening, transfer and exhaust.

[keefallan]

Just going by eye, you've raised duration on the transfers as well as area. Do you have a specific number of degrees in mind?

I am trying not to alter things too radically.....just to blend and smooth everything..........everywhere. I will also make sure that the transfer edges(bottom of cylinder) are the same height across the board.

This is the first engine that I have taken the time to go through it and smooth everything. Raising the transfer area is a new one too.

[FMP]

Bottom area? I'm only referring to the transfer"roof", the top of the port for duration degrees open. When it opens as the piston clears and closes on the compression upstroke.
The area is the area of the passage, which increases with the squaring.
Specific angle degrees is a figure worked from area and duration taking into account the piston blocking at BDC of the passage. But for the stock ex duration you can bet OMC made low rpm grunt a must.

[keefallan]

I finished the porting today and the blending etc on that half of the block. Before I ported the other half of cylinders I decided to take some readings with a caliper. FMP had me a little nervous about raising port heights. I thought I was careful when doing it, but I am human, and often miss things. I measured the height of a stock port in its highest opening towards the top, I came up with ..........pooey! I cant remember the exacts. It was 2.02" I think. I went and measured the ones I did previously and had .01.....the difference being 1/64" higher. And that was only one of them. The others were spot on. I was quite relieved. I also measured how much material was removed off the bottom area of the cylinders(where the scalloping usually goes) to blend down the ridge. I measured the stock lip and then the new. The difference was .102" higher. I used that measurement to repeat the results today for cylinder 2,4, and 6. I then blended the ports and chamfered the ports on the inside to not catch a ring.

I went to find my 1/2 drill motor for the honing, and couldn't. So, that will wait till tomorrow. I have to do it tomorrow..........regardless.......time is wasting and I need to get pistons ordered........and I need to know what size......after honing.

Back to the porting for a sec. I actually used my friends drill press/mill to port the motor today. Its a really nice 3000 dollar drill press. it enables me to verify my measurements with the port heights and let me know my eye is still pretty good. I also did verify that my radius' were actually 1/2" in the corners......which I felt good about. I used a 1/2" end mill today in the machine. The bad part is that it took me LONGER to port this half of the engine than doing it by hand with a file , carbide burrs and cartridge rolls. It did verify things for me though.............it was worth it.

No pics today..........no camera to take em.

[FMP]

Nothing to worry about, raising the ex 0.010" on all wouldn't be a bad thing.

[keefallan]

been busy the last few days. I have been working on the cowling, getting it ready for paint. I need to cut in the louvers in the front. I am using the xp louvers. What I amtrying to figure out is what I what to do with colors. I am gonna just paint it and the belly pan plain white just to get it all the same color and cleared...........using basecoat/clearcoat from SPI. I can add any color or stripes or accents after that...........even if I go a dark blue.

Anyone have any pics or thoughts on colors?