PCV VALVE... Really?

[hanleyclifford]

How about this, appropriately cobbled? http://www.lslproducts.com/IL-DSPage.html

[Ball Racing]

Another thing that needs to be considered (I feel) is that some of the people reporting tons of blow by may also be way over proped and run the engine at the point for hull speed that alot of gases are going past the rings.

People that have their set-up spot on engine, and prop settings are probably not seeing as much as of a issue.
Go to youtube and look up some of the highly modified tractor pullers, they have hoses that just dump out of the block towards the ground.

As the pull sled gets a good bite and lugs down those big motors, the amount of vapors-steam-gases coming out of the hoses is crazy.As soon as they lift off the gas it clears right up. And yeah those engines are fresh, and tightly built.

I only argued about the reported vacuum readings because the picture and text were not in keeping, thus making any further number crunching variable depending if you went by the gauge or the text. It was only later cleared up that the picture was not the correct one, and a better one was produced.
To say that I was doing anything else is not needed..

I would like a opinion from Anyone weither or not it is possible to smell hot oil from this motor, even if there is not visible fogging from the slash tube, and you have great compression over 120lbs.

I'm done with it. I made my case and supported it with Jerry's data, willing to let it stand as-is. No need to repeat it further.

I am glad to see Mr. Dutton was not done with this as he said.
Now we have alittle more particapation, and some more ideas floating around.

[Mo]

Another thing that needs to be considered (I feel) is that some of the people reporting tons of blow by may also be way over proped and run the engine at the point for hull speed that alot of gases are going past the rings.

People that have their set-up spot on engine, and prop settings are probably not seeing as much as of a issue.

Danial,

I think you hit the nail on the head. I have no idea what my current compression numbers are but last check over a year ago had them all over 100 ... I can`t remember exactly what they were but I remember being impressed. Snow storm Nor Easter heading in tonight and tomorrow so I imagine I won`t get to it in the next few days to see what my numbers are.

I noticed I smelled some blow-by while towing a 30 foot Bristol (diesel) back to the club earlier this year. Wind was 30 kts on the nose. My temp stayed at 140, so I actually went inside and layed my hands on the engine to ensure it wasn`t hot....that`s when I noticed the smell, not much but it was there. Typically I don`t get blow-by but in that situation every horse was up and running hard.

[marthur]

So we may be at the point where we will have to agree to disagree about the PCV. I get the sense that some of us may have different opinions about this because we have made different engineering choices.

For example I have a PCV installed and I am very happy about it. I would install one again, so my take on this is slightly different. I know that my A-4 is still in good shape and had relatively few hours when I purchased the boat. As I mentioned in an earlier post, my A-4 has great compression and blow-by is not an issue. So the PCV is not there to defer maintenance.

I also have power to spare for my 27 foot boat. My direct drive turns a 12 x 7 Michigan Sailor two bladed prop. Right now, my PCV equipped A-4 can run my Catalina 27 at hull speed and beyond (I top out at about 6.7 knts). I can run as fast as I am comfortable into waves and wind. AND it averages 1/2 gallon per hour at hull speed (carb has the fixed main jet, by the way). I don't think that I can improve on that fuel economy.

However, I have a wife and kids who are very sensitive to the smell of oil and gas. And I don't like the idea of breathing hydrocarbons either. So I am willing to configure my boat to maximize cleanliness down below. Since installing the PCV the oily odor is significantly reduced. Perhaps a small performance penalty is paid, but that is not noticeable on my boat because I don't need 30 hp to power it.

So it is all good, kind of like the zen aphorism: One path is not for everyone, and not everyone is fit for the same path.

Mike

[Mo]

Hi Mike,
I think 6.2 kts is the most I`ve ever gotten out of mine under power. She sails faster than the engine can push her. The prop that`s on there is, as far as I can tell, a Michigan 12/6 3 blade. My fuel consumption is around a gallon per hour, perhaps a bit less but certainly not as good as yours. Loaded up I figure the boat is at least 12000 lbs.

If I were to be having to deal with blow-by under normal conditions you bet I'd be coming up with something to deal with it.

[marthur]

Mo, I am pretty sure that my fuel consumption is low because of a couple of things:

1. My C-27 probably weighs in around 10,000 lbs fully loaded. Lighter than a lot of boats.
2. I don't push the speed. I usually cruise between 5.5 to 5.7 kts which is just very close to the calculated hull speed (just a tad above). I can't tell you the rpms (no tach), but I rarely push the throttle down.
3. I keep the engine well tuned, the ignition system in good repair and the carb leaned right out.

And by the way, I never had a blow-by issue. Just the ordinary oily vapor that escapes from the hot crankcase.

[joe_db]

The Edelbrock engineers most likely would think differently if their engines were run INSIDE their bedrooms instead of under the hood of a car

[tony201]

Amen to that Jo.

[High Hopes]

This is a long thread and I haven't read all of it. However, my solution for the engine smells was to disconnect the slash-tube and run a heater hose from the engine crankcase port fitting to the blower duct. The hose sits about two feet inside the blower duct so there is always a negative pressure draw present at the crankcase port. The cabin engine smells are gone.

[lat 64]

One path is not for everyone, and not everyone is fit for the same path.

Mike

There's that Zen thing again,
Seems like it always comes up when messing about with boats.
I have found much to ruminate from everyone on this issue, thanks all for stirring the pot.
I did, however, run out of popcorn.

R.

[joe_db]

THAT is what I was talking about - no fumes and no mixture issues either

This is a long thread and I haven't read all of it. However, my solution for the engine smells was to disconnect the slash-tube and run a heater hose from the engine crankcase port fitting to the blower duct. The hose sits about two feet inside the blower duct so there is always a negative pressure draw present at the crankcase port. The cabin engine smells are gone.

[ndutton]

I love this forum.

That's great. Along the lines of Hanley's and Romantic Comedy's comments about coming up with a better mousetrap, up steps High Hopes with a simple and effective solution.

All other factors being equal I still maintain increased blowby and engine wear are directly correlated but this solution eliminates screwing up the fuel/air ratio as mentioned early in the thread and the huge issue I have with the PCV system in our carbureted application.

[Mo]

Not a bad idea.

I have a spare blower motor sitting in my garage. Agreed Neil...High Hopes just nailed something there. It crossed my mind to tap into the exhaust but figured the pressure would just drive it back.

Now he has me thinking as well. What about a smaller blower motor used in conjunction with a small hose such as heater hose. It couldn't help but solve that problem. Smaller hose would draw less power, and could be rigged to come on with ignition switch.

The only problem would be were to put the exhaust. If I had to do it I think I'd make another through hull in the transom for it. Currently my blower is what I consider noisy and exhausts in the cockpit... so I don't think exhausting blow-into the cockpit is a plan. Smaller motor should be quiet as well and it wouldn't need much to move air / blow-by through the hose.

[hanleyclifford]

Mo, What do you think of this? http://www.lslproducts.com/IL-DSPage.html

[Mo]

Hanley, that would do it for sure. Doesn't draw any power to speak of and continuous running capability. I'm thinking this whole thing might be a viable solution to the blow-by odor.

One drawback that I anticipate after implementing this system "might" be a build up of carbon products (gunk) in the hose. I've hauled apart a few carbs this past season and a couple of the flame arrestors were just plugged with blow-by oil and carbon. I was thinking a plastic strainer might take care of that...I'm sure there are better quality to be found...ie, brass with drain plug. Either way it could be removed and cleaned with carb cleaner once accumulation is noticed.

http://www.go2marine.com/product/44040F/jabsco-pumpgard-in-line-strainer-fresh-or-salt-water.html

So, I'm thinking a few things would be needed.
-hose
-strainer installed upside down to collect gunk.
-blower motor
-perhaps a hose size adapter or two.
-thru hull for where the new line exits the boat.

...just a guess but I figure all could be built for under $150.