I guess this would probably apply more to guys running alcohol fuels, since they put so much more moisture into crankcase gasses.
I run a pan-evac system, and while I think they are fairly effective at venting crankcase pressures, and even producing a vacuum, which helps with ring seal and seating, they obviously are not as good as a vacuum pump. I have been considering adding a pump, because whenever I pull my valve covers to inspect and adjust the valve train, there is a LOT of water condensed on the "ceiling" of the covers. This even occurs when I lean it out, and get the coolant temp up before shutdown. I believe part of the problem is the Pan Evac system, there is just no way for most of that water to evaporate, travel down those long hoses, through the check valves, and out the header collectors. The breathers on my cast valve covers are bolted on from the inside, so no easy way to remove them and vent the engine after a night of racing. Not really inclined to pull the covers after each race, (although it does make me want to see if I can find a set of throw-back T-Handle V.C. bolts like we used to use 30-40 years ago)
So I wanted to ask you guys that run vacuum pumps, on tightly sealed engines, especially those running alky - Do you still find any drops of water inside your valve covers when you run your valves? And even for those who burn gas, same Q. And since combustion gasses (blowby) can form acidic moisture that does damage to bores, etc. - Thinking maybe adding a "purge valve", (like an alky lean-out valve setup), to the back of the valve cover opposite from your vacuum fitting on the other side, and opening that valve up for a few seconds before you shut things down for good after loading it up, might be a good idea? Just to pull fresh air into the engine, and suck all the moisture and nasty stuff out? Or am I getting too far out there...

I installed a Star vacuum pump on my SBC last year. Most of the time, there is no condensation when I run thru the valves. If it sits, there will be a tiny bit of moisture because my garage is always damp inside.

I used to pull the breathers when I had a header evac system when I got done each race day. I would leave them out all week and start it the next, warm it up to 200 (like normal.) It would burn off all the moisture. When I ran thru the valves, it was a sopping mess with puddles of water sitting in the heads and the inside of the valve cover was always soaked.

One should bear in mind that engines make heat and valve covers are convection ovens.

Gas or alky is always going to have at least a little h2o upstairs.

The next step will be discussing all the different ways to boil it off or air it out.

quote:

Originally posted by Dave Koehler:
The next step will be discussing all the different ways to boil it off or air it out.

I am all ears. Looking for advice, because my best efforts still aren't working with what I've got right now.
Before I added the evac system, I just had breathers on each V.C. And after loading up at the end of race day, I would pull one of them, and pop in a PCV valve, kept the hose for it plugged but would hook it up and run it that way at idle for a minute, to purge the blowby. Seemed to help keep the oil really clean, and free of moisture. That is what got me thinking about the idea of using a vac pump setup with a purge valve at the rear of the opposite V.C. (as far away as possible from the pump fitting, to clear out both V.C.'s and the crankcase).

I knew some guys that raced a lot back in the 90’s that ran a stack injected sbc who showed me what they do to battle this problem. I passed this on to another friend a few years ago who did this after every race the next day (sbf with terminator) with really surprising results. They would take 1 of the valve cover breathers off and they hooked up an air pump (something like a pump off of a hot tub) that just pumped a lot of volume of air that could run for a few hours. They rotated the motor a few times during that time. The air circulation would dry all the moisture in the engine. I spoke with the engine builder who tore his motor apart after a few seasons and he said it was remarkable how good his cylinders looked and took almost nothing to clean up like a gas motor. I believe the original guy who showed me this used a cheap hair dryer and just didn’t run with heat on. They made a pvc adapter and it stuck right in to the vc grommet. I don’t run alcohol anymore but I though I would pass it along in case it may help you

Before we added our vac pump we used these. Spin the tops off at end of day, it'll let the engine "breath" quite a bit of the moisture out...


https://www.jegs.com/i/Moroso/...oEAQYASABEgLC2_D_BwE



Dan

A few years back I saw an Alky Funny Car team use a shop vac (hose to fitting on VC) between rounds to evacuate moisture...


Dan

I just ran my valves about an hour ago. SBC with a APD 1000 cfm alky carb. No water or snot under the valve covers at all. I never crank the car unless i can run it long enough to put heat in the motor. The first warm up of the day it goes to 190 and let it heat soak before racing for the day. Always take it to 200ish when putting back in the trailer. Its rare if i cool it between rds. Moroso vacuum pump with the bypass at the pump.

I've ran both evac and vacuum pump. I get the best results when I run the car up to 180-200° when I put it away after each race. The heat helps evaporate the alky. I have the gas primer system now and that was probably the best investment I've made. If you run injection, the primer system is a must have. It saves a ton on fuel and helps keep the alky out of the oil.

Fwiw. My experience on my car on gas with pan evacs got the same moisture even though it was no problem to warm it up. Turned out I had a bad check valve on one side that would back feed into the valve cover just enough to get stuff wet.

quote:

I have been considering adding a pump, because whenever I pull my valve covers to inspect and adjust the valve train, there is a LOT of water condensed on the "ceiling" of the covers. This even occurs when I lean it out, and get the coolant temp up before shutdown. I believe part of the problem is the Pan Evac system

No, you have an internal water leak in your engine.

Read that again strange, slowly.

For what it's worth my favorite air blower deal is a leaf blower.
Put a fine wire screen over the inlet and rig up the outlet to one valve cover.
Remove the other valve cover and let it rip.

Moroso 4 vane, enhanced design pump, with the breather like Mad Dog listed gave me best performance. Zero water and or moisture under covers in between races when i set the valves. It will not hurt to get the temp up before parking the car at the end of the night vacuum pump or not.

Setup was BBC, injected on methanol, low tension ring package 565 cubic inches.

quote:

Originally posted by Triple Nickel:
Moroso 4 vane, enhanced design pump, with the breather like Mad Dog listed gave me best performance. Zero water and or moisture under covers in between races when i set the valves.

Triple Nickel, I am curious about your setup. So do you have the vac pump plumbed to one of those valve cover breathers? And what about the other side, is it vented, filtered, or capped off? Maybe I need a setup like that, I could uncap the other side after racing, and run it like that for a minute to clear the moisture out before loading up the car at the end of the day/night.
I honestly think the biggest cause of my residual moisture problem, is the non-removable breathers on my valve covers. Even if I got the water temp up to 220+, I just don't think much of that evaporated water is going to travel out the breathers, down the hoses, through the check valve, and out of the collectors. There is nothing I know of that will cause that to happen, unless I were to remove both of the evac hoses from the breathers after the race, and connect some kind of air pump, blower, or shop vac like some of the suggestions above, to one side, and suck or blow some air through the engine to purge the water vapors out of it. Heat will evaporate the water out of the oil, but unless that moist air is removed, it will just condense back into liquid inside the engine, no matter how hot I get things. (Which is what I believe is happening). You can boil it all you want, but the water won't disappear, it just changes from liquid to gas, then back again. At least that is the way I see it.
(There are no water leaks going on, internal or external).

This message has been edited. Last edited by: FootbrakeJim,