Cabin fumes

[Mark S]

The PCV Kit (Positive Crankcase Ventilation) creates just what it says. It is sucking the blow by through the intake. I think you need to have a vented oil cap to let the pvc kit do its job.

Seems to me when the feds required autos to have PCV valves they also banned vented oil caps. I don't think the valve sucks fumes so much as provides a single exit point through a one way valve to the air intake of the carburetor.

Mark

[joe_db]

The A4 is NOT airtight, vented cap or no.
Try putting one with the oil still in it into your wife's Accord and let the front end get lower than the back and you too will be scrubbing oil out of the car

Seems to me when the feds required autos to have PCV valves they also banned vented oil caps. I don't think the valve sucks fumes so much as provides a single exit point through a one way valve to the air intake of the carburetor.

Mark

[ILikeRust]

joe db has it right - the Atomic 4 is NOT an airtight engine, period.

The fed standards for automotive engines do not apply to our old friend, the A4. So whether or not the feds banned vented oil caps doesn't matter.

First, as has been pointed out above, the front end of the crankcase is not sealed. If you tip the engine forward a few degrees, with a crankcase full of oil, you will find oil dribbling out from behind the flywheel and running all over your shoes. Second, the stock oil cap on the filler tube on the front of the engine (on the newer-style engines) does not make an air-tight seal on the filler tube.

The reason the PCV valve kit works better than the stock arrangement is because it takes advantage of the point of high vacuum within the intake plenum. The spacer plate allows you to take advantage of the Venturi effect right behind the carb. This creates a stronger "suction" effect than just pointing the little stock rubber hose towards the flame arrester. This direct connection causes the crankcase fumes to get sucked through the PCV valve and into the intake plenum and re-breathed, rather than getting pumped out the front of the crankcase, or the oil fill cap, or out the vent tube on the side, where they might or might not actually get sucked back into the carb.

[ILikeRust]

I recently installed the kit on my 1979 Atomic 4 in my C&C 30.

Are you referring to the MMI kit, or the Indigo kit?

I installed the Indigo kit, and it did not come with any new fuel fittings, so I'm curious as to the differences.

[joe_db]

BTW - if you have an old Indigo kit with a horizontal PCV valve it will not work. You need the new fitting with a vertical valve.

[Mark S]

I only meant that the vented cap isn't necessary. Poorly expressed, no doubt.

Mark

[dvd]

I installed the Indigo PCV kit and completely eliminated the blow by smell. I think it is for any engine, new or old.

DVD

[ndutton]

Just One Sailor's Opinion (JOSO, remember?) but I view the PCV kit a stopgap measure, albeit a potentially long term one, to mitigate a specific symptom of internal engine wear.

I do not mean to suggest it should not be used. Who wants a stinky boat? Maybe those diesel guys can get used to it but not us, right? But recognize the presence of blowby is for a reason and the more blowby you have, the more serious the reason.

[Marty Levenson]

installing Indigo PCV question

Hey All,

I will be installing the Indigo PCV to my recently purchased rebuilt A4 soon.

My old A4 has a short copper pipe coming out of the block just behind the flywheel cover. The Indigo clamps onto that nicely. My new A4 has no such pipe: just a smooth hole. The PCV slips into the block pretty snugly, but can't be clamped in any way. Wondering if I should attach a pipe (how? JB Weld? tap?) or is there a way to glue that hose in so that it is still removable for replacement? Or is a fairly snug pressure fit enough?

Thanks!
Marty

[keelcooler]

Marty, Looks like you have an early model plate. Copper pipe section works best, drill out to match your plate and secure with a long cotter pin.

[Dave Neptune]

Venting a must!

Keelcooler, you are lucky that the A-4 is still vented. It is not a good idea to plug or seal the crankcase as explosive gasses can accumilate. I have seen the pans of Hi-performance and duty engines literally blow the pan off of the engine when ventilation was eliminated.
In the case of the A-4 even by plugging the oil fill it is vented to the carb through the side plate vent and any extra fumes will still go out through the open crank on the flywheel end.
The PVC still requires that fresh air be allowed into the engine so it mixes and is extracted by the PCV system.

Just an FYI.

Dave Neptune

[Marty Levenson]

confusion?

Hey Neptune,

I thought Keel meant for me to insert a copper pipe snugly into the vent hole, pin it with a cotter pin, and hose clamp the PCV valve to the other end of the pipe. Does that seem like a good plan to you? Totally agree with your warning: I would never plug the vent hole.

If the pipe insertion plan is a viable way to go, wondering if I should put a sealant around the pipe....and what type?

Just noticed your handle is "Neptune". Our Tartan 27 is "Poseidon"....(Neptune was the Roman version of the Greek god Poseidon, as you probably know...).

Thanks,
Marty

[Jkeevy]

Cabin fumes

I installed the indigo system and fixed some gas related leak issues and lo and behold no smells of any kind at least from the engine.

[keelcooler]

Marty, That's right you should find a cotter pin hole at 12 o'clock. The early vent hoses were metal flex and attached in this manner.

[Dave Neptune]

Hmmm

Marty, I'm not exactly sure what the pin is for unless to hold in position. I too have the Indigo and I just attached a bit of hose to both ends of the copper elbow one to the block and the other to the valve and clamped them, so far they have held fine. I don't want any vacuum getting by the valve not sucking on the crankcase itself. I think he is referng to the early type and I would fasten it with the pin if you have access or you could clean it well and put together with some JB Weld or even orange RTV.
Yeh it's Neptune and I have gotten a bit of milage and a few dinners from people betting it wasn't really my name.

Jim, my point was that unless you have air coming in you won't displace enough to get the accumilating gasses out and that can be explosive. I have seen pans and valve cover blown clear off an engine. Ever see the straps on a blower motor at a track? I was part af a blown alchohol car crew a few times and once at the old Irwindale raceway the car we were going against had a cranckase explosion and fake straps. Te blower went clear over the stands and landed abot 200 feet away, that was a 8-71 with most of the manifold attached. They were in deep doo doo and were suspended from competition for a while. When it went it scared the ~~~~out of me for sure. The track officials went nuts, and thanked their lucky stars it didn't land in the stands or on someone in the parking lot, however it did do a number on a cars trunk and rear window.

Dave Neptune