Homebuilt ohv manifold interior cleanup or fun with grinder W/picture now.

[Jeff T.]

I've been cutting and grinding excessive tube flash out of the plenum of my homebuilt twin carb manifold for my ohv six before I cap the ends of the plenum tube.

Before I drive myself batty grinding everything to a mirror finish, how smooth does this thing need to be?

I've been tinkering with this down in the basement on our recent batch of 100 degree heat index days

Jeff T.

[r1lark]

Pictures Jeff, we need pictures.........!!

[Alan]

Leave it rough. Put gas on a piece of sandpaper then hit it with an air hose. Do the same with a piece of glass. You will see why.

[wolfie]

I've been cutting and grinding excessive tube flash out of the plenum of my homebuilt twin carb manifold for my ohv six before I cap the ends of the plenum tube.

Before I drive myself batty grinding everything to a mirror finish, how smooth does this thing need to be?

I've been tinkering with this down in the basement on our recent batch of 100 degree heat index days

Jeff T.

A very knowledgable machinist told me to polish the exhaust as smooth as possible but leave the intake rougher. I will say it as you want a basically clean flow but still rough enough to "tumble" the fuel mixture however you do want that "tumble" for a good air/fuel mix. The exhaust would want no restriction. Others here may disagree but thats what I was taught. Steve

[sweetolbob]

Jeff

My poor old mind is trying to recall laminar flow in a tube from my physics days. If I recall correctly, the flow at the wall is essentially zero so a mirror finish is pretty but not required. It should be relatively smooth but the a larger problem is any kind of restriction or roughness. These can form eddys an reduce flow in that area and ruining the laminar flow over a section. I'd also be Leary of any restriction that opens to a larger area as that will also reduce laminar flow.

With all due respect to the gas on glass vs sandpaper, that is more a demonstration of surface tension and wetting than flow in a tube. The flow we are discussing is a gas in air flow not liquid movement.

So I'd smooth it to a reasonable finish but be more aware of restrictions and sharp edges if it were mine.

Now I'm sure the boys from Racing Studebakers will eat my lunch but it was fun to recall some physics.

Bob

[whacker]

32 RMS is what I heard.

[Ron Dame]

Pictures Jeff, we need pictures.........!!

As PAul sez.. PICTURES!

If and when I ever put the 185 OHV in the truck, my next step ( It'll only take 10 years) is to graft two intakes and two exhausts into a dual carb intake and dual exhaust.. I'd like to see what you've created, Jeff.

[Jim B PEI]

Jeff, as several people have said, pictures PLEASE! Those who have done a 185 conversion, and those (like me and some others) who would like to do a 185 OHV conversion in the future, would like to see what you have done, and how you got there. Help all these poor souls who keep on re-inventing the wheel....

[sals54]

Here are a couple of pix of my 4 bbl intake for a flat 6. Very easy to make. 1/2 inch bar stock, exhaust tubing and rectangular tube for the plenum.


This is the one I used on my Turbo flat 6 that some of you have seen. This could easily be made to use a couple of 1 bbl carbs or a single WW 2 bbl carb. Nothing fancy. But for a stock engine, nothing fancy is needed.

[DEEPNHOCK]

Yikes!
That plenum has enough volume for a V-12!
Ought to look cool on there!

[Jim B PEI]

Saved sals54 picture and explanation in the flathead turbo file. With Jeff T's pictures and explanations, or Ron D's, or Ted J's, that would fill up the OHV file pretty nicely! I have someone who can do this all up for me quickly with a welder and do it well, better than I ever could, but pictures help.

V12, eh? That's just two 170 blocks welded together...with a few modifications.<g>

[Jeff T.]

I took some pictures and I got them in my laptop... now how do I get them on the forum????

Oh, I think that I need to reduce them too???

I may have got them onto my profile, I'm not sure.

Jeff T.

[Jeff T.]

There A few exhaust flanges about $15.00 of tubing and some effort

[sals54]

Jeff, The manifold looks great. As a note of caution, though, don't forget to get your 5 degree slant on the carb bases. It makes up for the slope of the engine toward the rear of the car. Carbs work best when level to the ground, not level to the engine. Keep up the good work.

[Ron Dame]

That does look nice! Isn't this for your OHV though? How does it transition to the rectangular head ports?