78 620, L20B foreign matter in combustion chamber.

[datzenmike]

The PCV has ZERO effect on running and performance. Totally benign. It's one of those little things that does so much for engine life. Introduced about '62.

[Stoffregen Motorsports]

http://www.redlineweber.com/html/Tech/38_dgas_tunning.htm

 

 

Would this be good enough?

It's not a 38/38 DGAS carburetor, so why would you tune it using those specs?

[G-Duax]

I use the exhaust vacuum evac system.

So not only does the inside of the engine stay clean, but also my intake manifolds, ports & valves :)

 

Moroso, and others make the kits, but the only thing halfway special are the inline check valves, which are nothing more than air injection system valves.

[datzenmike]

Interesting... for home made intakes without PCV, or pressurized intakes like on a turbo. Can I borrow this idea?? :lol:

[Stoffregen Motorsports]

It's about as basic as the road draft tube design. I have never built one of those setups, but I've always wondered if they actually work.

[Stoffregen Motorsports]

Calling weld shop for a plate tomorrow and I was gonna get a bung welded on.

 

 

Multiple threads I’ve read about this and each had you mentioning the PCV, seems important lol.

 

Is it absolutely neccesary for it to get recycled into the manifold or can I put a breather valve on the hose?

I do a simple PCV cheater system where I plumb the valve cover and block breathers together with a tee, and then attach a hose to the air cleaner housing. It works, and is more simple than a true PCV system.

 

It may not be as clean as the exhaust type system, but can be built from hardware store fittings in about an hour.

 

In this pic, you can see the rubber grommet on the right hand side of the air cleaner. That's where the hose runs to.

[Crashtd420]

So is there a way to use this info for side draft webers?

I currently just have the little filters no pcv.

my thought was plumbing the block breather and/or the valve cover breather to a catch can instead of the air cleaner then use g-duax concept as the vacuum for the system....

[Crashtd420]

I do a simple PCV cheater system where I plumb the valve cover and block breathers together with a tee, and then attach a hose to the air cleaner housing. It works, and is more simple than a true PCV system.

 

It may not be as clean as the exhaust type system, but can be built from hardware store fittings in about an hour.

 

In this pic, you can see the rubber grommet on the right hand side of the air cleaner. That's where the hose runs to.

Do you even have a pcv in that setup or just hoses plumbed to the airbox?

[datzenmike]

The advantage of the stock set up is fresh filtered air is pulled in at all but full throttle. If you plumb the valve cover and the block vent together it has to have some blow by to push vapors out and no fresh air in. If using exhaust extraction I would still leave the valve cover hose open or to the air filter so there is positive scavenging.

[Crashtd420]

The advantage of the stock set up is fresh filtered air is pulled in at all but full throttle. If you plumb the valve cover and the block vent together it has to have some blow by to push vapors out and no fresh air in. If using exhaust extraction I would still leave the valve cover hose open or to the air filter so there is positive scavenging.

That's more how I was thinking about plumbing it. but I see these catch cans with air filters on them too so I really didn't know.... it's something I need to eventually deal with.. i saw these comments and figured it my be a good time to ask...

[Stoffregen Motorsports]

I've done it both ways, with a tee and with separate connections, and either way still seems to do the job. On race motors with dry sump oiling, there are no breathers and the vacuum created by the oil pump actually makes horsepower. Also, they tend not to leak oil because the vacuum is so strong that it pulls air in through the crank seals. I am not suggesting this, just pointing out that both can be teed together without any negative side effects.

 

This pic shows a catch can that I used to build for high horsepower, big cube Datsun L motors. It catches the oil but then also drains back into the crankcase any oil that has accumulated. I have also plumbed PCV systems into this catch can to help pull a vacuum. The can is baffled inside to keep splashing oil from puking out the breather.

 

 

 

Bottom line is, a PCV system is good to have, but there are a few different ways to achieve similar results.

[distributorguy]

I use the exhaust vacuum evac system.

So not only does the inside of the engine stay clean, but also my intake manifolds, ports & valves :)

 

Moroso, and others make the kits, but the only thing halfway special are the inline check valves, which are nothing more than air injection system valves.

 

This type of system is used to pull a vacuum on your crankcase - to decrease the effort to push the pistons back down the hole when drag racing.  The issue is that for a road car/truck, it will suck an enormous amount of air.  With air comes oil vapors.  You may find that you now lose a quart of oil every 500 miles.  It depends a lot on where you suck from, if the air is filtered, and what size tubes you run.  A simple PCV valve plumbed into the air cleaner base is more effective on the street with smaller side effects.  DO NOT hook a PCV valve up to an area in the carb or intake where fuel has already been metered or you will find your mixture going very lean at times.  Plumb it upstream - on the air cleaner side of the throttle plates.  Either that or add a restrictor (like a Holley carb jet) in the hose to limit how much air movement there is, so you have a fixed limit on air flow that you can adjust the carb to.  A 3/8" hose is just way too much to correct metering on.  

[wayno]

This is an interesting alternative, so is your last post showing the catch can, never seen this before.

I do a simple PCV cheater system where I plumb the valve cover and block breathers together with a tee, and then attach a hose to the air cleaner housing. It works, and is more simple than a true PCV system.

 

It may not be as clean as the exhaust type system, but can be built from hardware store fittings in about an hour.

 

In this pic, you can see the rubber grommet on the right hand side of the air cleaner. That's where the hose runs to.

[datzenmike]

Catch cans are a ridiculous add on just like the little blue filters. The stock hose from the valve cover goes to the inside base of the air filter. If blowby is excessive, the air reverses direction and just gets sucked into the carb and burned. Even the Weber air filter has a provision for this. Catch cans don't eliminate fumes unless also plumbed to the carb and then what was the point??? So you can collect oily water you now have to dispose of?... what? just toss on the ground or down the sink? recycle??? Waste of time. Catch cans are often required if racing to catch oil from a blown engine and keep off the track. Other than those that actually race their cars, who needs them? Posers do.

 

 

wayno...

You could restrict the hose size so not an excessive suck from the exhaust. I guess you could suck from the valve cover end to give the oil fog time to settle. Run the crank vent to the air filter.

[Stoffregen Motorsports]

I mentioned that the catch cans I made were plumbed to drain oil back into the block. So no, you don't have an oily mess that needs to be drained. And with the baffled system, they don't suck oil into the carb, but they do provide a space, a buffering zone, for oil that pukes out so it doesn't get sucked into the carb. The standard PCV system will allow a degree of puking oil to get sucked into the intake.

 

I also mentioned big cube L motors. For some reason the big bore engines puke oil. So do the high RPM motors. It's just a fact of life.

 

Do I like the way they look? No, but they do serve a purpose. I should also clarify that eliminating fumes is not the point here, but to eliminate or drastically reduce the amount of oil getting sucked into the engine.

[Stoffregen Motorsports]

wayno...

You could restrict the hose size so not an excessive suck from the exhaust. I guess you could suck from the valve cover end to give the oil fog time to settle. Run the crank vent to the air filter.

Some PCV valves have a removable orifice. These are easy to disassemble and replace with a small washer with any size hole you want. The smaller, the better, in my opinion.

[Stoffregen Motorsports]

Do you even have a pcv in that setup or just hoses plumbed to the airbox?

No PCV, though you could use one if you wanted to.

[wayno]

This is all interesting to me, all my engines have PCV valves Mike, I have no intention of deleting a PCV valve, but I do have Dual SUs for the E1/J13/J15 blocks, and they do not have a traditional PCV valve nor do they have a vacuum advance fitting.

[Atikin9000]

It's not a 38/38 DGAS carburetor, so why would you tune it using those specs?

Anyway to determin which one it is?

 

Only reason why I thought it was a 38 is because of two idle mix screws on the bottom.

[datzenmike]

Only way I thought it might be is because both throttles open together.

 

Will the throttle bores measure 38mm???

[Atikin9000]

Only way I thought it might be is because both throttles open together.

 

Will the throttle bores measure 38mm???

 

 

 

Am I doing it right lol?

[Stoffregen Motorsports]

Anyway to determin which one it is?

 

Only reason why I thought it was a 38 is because of two idle mix screws on the bottom.

Google 34 DGEC. See if the pics look similar to your carb. If they do, then do another google search for 34 DGEC info, diagrams, etc.

 

It should be stamped somewhere in the carb though. I bet if you cleaned all that grease off the carb, you would find the model number.

[Atikin9000]

Opened up the butterflies and inside the carb It says solex 26.

[Atikin9000]

Google 34 DGEC. See if the pics look similar to your carb. If they do, then do another google search for 34 DGEC info, diagrams, etc.

 

It should be stamped somewhere in the carb though. I bet if you cleaned all that grease off the carb, you would find the model number.

 

Can’t find any stamping on the outside.

[Stoffregen Motorsports]

I just searched for Solex 26 and the pics I found show a completely different carb.

 

Did you google 34 DGEC? Compare those pics with the carb you have. Or post more pics.