The 230 Headerfold project

[monkeymissile]

[QUOTE=maineSS;52292]MM- You may want to look into "thermal transfer cement" as an aid to making a hotspot. It's used industrially in pipe & tank heating- carries heat from a steam line to whatever needs heating. Lot's cheaper than double jacketing, and works just as well. It comes in hardening & non-hardening varieties, and can be gotten in caulking gun cartridges. Just run a waterline next to the bootom of the intake, fillet the cement on either side- you're done. Some info at: http://www.insulation.org/articles/a...fm?id=IO021203


mSS,
what funky stuff! Thanks for the link. Still leaning towards some sort of coolant-heated carb spacer though.

[maineSS]

Marius- looks like I'll have to keep looking for a lighter piston. Cutting reciprocating weight pays big dividends in rod stress reduction- the major problem is tensile forces at the top of the intake/exhaust stroke, not on the compression stroke. 1 lb of recip weight reduction is also worth about 10 lbs of chassis weight in acceleration ability- although acceleration is low on the list of most PW owners. Anyone know any sites that cross-reference piston measurements?

[maineSS]

I found some interesting info about cooling problems on a V8 repower that might shed some light on the curious heating of the flathead oil/engine surfaces in tractor pull duty. Dan O'Day noticed that his V8 overheated during break in with the stock fan, so he fitted a waterpump riser that allowed use of a bigger fan in the stock location. This time water temps on the gauge and in the rad stayed normal- but he could hear afterboil in the engine (snapping/popping caused by steam pockets). He pressurized the cooling system, and the noises went away. When steam pockets start forming, you've lost control of your cooling- cracks or a seized piston are not far off. Wonder if this was happening in the tractor pull engine? See www.dodgepowerwagon.com/glovebox/oday.html .
MM- I don't think a heated carb spacer will help with fuel dropout as it makes the turn into the manifold passages- this is the place where you have to re-vaporize, otherwise it enters the cylinders in liquid form and never burns effectively. That 90 deg turn under the carb is where you lose most of the fuel out of the airflow- it has to be 10 microns or less particle size to make that turn, carbs produce droplet sizes between 10-400 microns.

[monkeymissile]

single-barrel side drafts

filter and ducting. Hmmm, maybe a set of three side draft Mikunis off of a Japanese motorcycle would fill the bill? 32mm would be about 1 1/4" . Or would that look too high tech on that old iron? On the '41 I ran a 2bbl from a '70's 318 van- Stromberg? The GM Monojet one bbl is good, the Duo-jet two bbl Okay also. The small Holley/Weber progressive two bbl (5200?) might get the best milage. Like on Pintos. Holleys have always done a good job of atomizing fuel.

Chris,
I've been thinking more about a better intake system to match the headerfold. Due to limited hood height in the M-series, I thought maybe a clever set-up with (3) single barrel sidedrafts could create more room for the headers and perform better than the old Carter. I checked out Weber and a few others, but honestly know little about such a carbs. Any ideas? Thanks.

[chriscase]

Chris,
I've been thinking more about a better intake system to match the headerfold. Due to limited hood height in the M-series, I thought maybe a clever set-up with (3) single barrel sidedrafts could create more room for the headers and perform better than the old Carter. I checked out Weber and a few others, but honestly know little about such a carbs. Any ideas? Thanks.

Side draft Mikunis. My neighbor was running quad Mikunis on his Pinto 2300 in a dune buggy. He liked them, and he is a hot rodder/restorer/mechanic. A set of 3-4 off of a Japanese bike could be had cheaply. Simple carbs.

Looks to me like that flat log intake gets in the way of the exhaust too- necessitating hard downward bends near the block. Perhaps a design more like the slant 6, with sweeping curves on the intake would allow space for exhaust headers, plus better flow for the intake, and allow a downdraft carb at the same elevation as stock?

My pics are toast, I took the discs to an expert, everything on them is gone. Back to square one.

[maineSS]

Bike carbs often have a rigid linkage tying the throttle shafts together end to end- difficult to make that work in our application. Snowmobile carbs use individual cables to each carb that are linked together at a block- easier to adapt. You definitely want to get a set of triples or quadruples- that insures all the carb internals are identical. When multiple carbs are set up correctly, they work very well. It's not easy to do, and lots of people end up with huge fuel consumption. If you put the effort in, you'll like the results- but it's a couple steps above tuning a Holley. You may want to design your header so you can do either single or multiple carbs. A better intake shouldn't be too hard to fab- only 3 runners- and would make a noticeable difference in intake flow over the stock one.

[MoparNorm]

Fuel consumption can be moderate if the carb linkage is progressive. The more throttle you apply, the more carb you get.
Seems though we are running far afield from the original header topic, even though this is part of the whole overall philosophy of intake/exhaust.

[maineSS]

Some interesting info on multiple carburetion for flatheads... Hudsonator's stuff is pretty good- http://forum.olskoolrodz.com/showthr...6&page=1&pp=10 .

[monkeymissile]

new thread?

should we start a new thread then? How would I figure out what size carbs to get? If intake ports are 1.25" (<32mm) do I just look for that diameter?
I see that a better intake manifold would be cake to make compared to the headerfold. Maybe my project is starting backwards, maybe I should tackle the intake side first?

[monkeymissile]

best place for the heat?

MM- I don't think a heated carb spacer will help with fuel dropout as it makes the turn into the manifold passages- this is the place where you have to re-vaporize, otherwise it enters the cylinders in liquid form and never burns effectively. That 90 deg turn under the carb is where you lose most of the fuel out of the airflow- it has to be 10 microns or less particle size to make that turn, carbs produce droplet sizes between 10-400 microns.

mSS,
so where'd be the optimum place to add some heat to the mix?

[monkeymissile]

interesting links

looky what I done dug up online...... quite a thread!

http://www.jalopyjournal.com/forum/s...d.php?t=189987

and some cool pics too!

[chriscase]

A small balnce tube is a good idead to add.

A small tube, say 3/8" to 1/2", between each intake runner will make it easier to get a smooth idle. Weld or braze some nipples on, and use rubber fuel line between them. Or maybe rubber connectors with longer pieces of steel line, for the sake of the heat from the headers?

Three separate filters, or another welded manifold for a single? to the stock filter?

You may want to look at throttle linkage from a flat head car- the kind that uses a vertical stud in the head for the pivot point. That could be a good spot to transition from rods to cable(s). Keeps the cables away from header heat? Plus more room to work?

[maineSS]

MM-For individual carbs no hotspot is needed. You'd have to get some sort of accelerator pump- Mikuni does make a an auxiliary pump, but it's hard to find a supplier that stocks it. The Esslinger setup at http://www.jalopyjournal.com/forum/a...8&d=1182398346 is a good place to start- they're using the 38mm Mikuni. You can get 38 triple sets at snowmobile/ATV salvage yards pretty reasonably- I paid $130 for a Polaris triple set. For a single carb, you want to heat the intake directly under the carb- that's where the fuel drops out and puddles. If it isn't re-atomized, it runs into the cylinder as a river- not good. Hudsonater's posts on multiple carburetion are a very good intro to some of the problems you'll encounter- it can be a tuning nightmare if you mix 'n match carbs, use carbs originally intended as singles, or don't have good troubleshooting skills and persistence. Once everything is dialed in, you can have a glass-smooth idle, amazing low end, and good fuel economy- but it's a lot of work to get there.

[monkeymissile]

new thread for multi-carb/intake project

Gents,
I bit the bullet and nabbed (3) 38mm Mikunis from eBay and I'm going to start a new thread for this project. Thanks for the input so far...

justin

[chriscase]

I think a single down draft would fit on top of an intake that that is extended laterally. Isn't there a lot of space towards the fender on an M37? And is there a governor that could be eliminated too, to gain height for more sweeping curves upwards in the runners? Plus a different/ lower carb, probably a small two bbl.