Oil recovery to pressure tank 1957 evinrude 35

[jdunham]

Hello,
I want to incorporate oil recovery into my 1957 lark rebuild.
I believe that I have a handle on the normal process from reading the various threads here but I have a question that I have not seen asked or answered.

Is there any reason that I cannot simply plug the normal pressure nipple on the reed box and install the drain nipple on the crank drain cover and use that as the pressure source for my dual line tank?
Unless this would cause inadequate drainage, I see this as a rather simple way to deal with the vapor concerns. I have not pulled the reed valves in the drain apart yet to investigate, maybe they do not have good enough seals for this to work?

I had also considered keeping the existing pressure port and just Teeing into the pressure line from the drain. I think they see equal pressure and this might take care of the restricted flow from the small drain passages.

[crosbyman]

I think… if you remove the reeds on the purge valve and install a nipple you will end up wit alternating vacum and pressure pulses cancelling themselves out in you fuel tank the reeds make certain waist oil/gas only goes OUT the crankcase just like the air from your tank pressure nipple feeding air ONLY to the tank.

hope I read your right

in any event if you are worried about crankcase oil reaching the water you could use xd-100 if your consumption is not great $$$ .. xd-100 is more nature friendly

search around I recently saw an oil recovery set-up to send crankcase oil/gas sludge to a spare non pressurized holding tank

Joining AOMCI has priviledges 🙂

• This reply was modified 4 years, 5 months ago by crosbyman.

[jdunham]

Thanks Crosbyman. I think you misunderstood my question a little bit. I will try to restate it differently.
The reeds in the crank case drain in theory are there to do the same job as the little check valve in the reed box. venting the crank case out on each stroke but not letting them vent back in.
They are of different construction and may not seal as well (metal vs rubber). They were not required to resist more than the vacuum of the crank case.

My thought was to install a nipple on the drain cover and plug the drain into the exhaust tube (standard oil recovery mod). Then use the new “pressure” nipple on the drain cover as the pressure source for my dual line tank. I would cap off the original pressure nipple from the reed box.

The unknowns for me are as follows:
Will inadequate drainage, if caused by back pressure, damage anything or just make it run rich? I do not have a good sense of whether or not there will be enough “flow” to keep fluid from building up.
Do the drain reeds seal well enough to maintain tank pressure? Do they seal well enough to maintain tank pressure but leak back into crank case and mess with the fuel/air mix ratio?

If there is no risk of permanent damage I am game to try this. For now I will do the separate collection vessel with a vent line up to the air silencer.

I hope this makes my thought more clear.

[frankr]

After reading this several times, I think I understand your goal is to eliminate the crankcase drainage from being sent to the lake. I guess you deserve an A for creativity, but I don’t think it will work. But go ahead and try. You won’t damage anything, other than making a poorly running engine. Or not running at all because of insufficient tank pressure.

[crosbyman]

got you … the original bleeder reeds would stay in place & the bleeding sludge would be pushed back in the fuel tank via the new nipple to be remixed in the fuel …… presumably along with enough air to pressurize the fuel tank .

I think I’ll let the experts vote on that option .

you could always revert back if any problems come up.

Joining AOMCI has priviledges 🙂

• This reply was modified 4 years, 5 months ago by crosbyman.

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