[T3] First Steps Engine Reassembly

Fri Jul 6 10:47:21 PDT 2018

 I recall many cars in America having draft tubes into 64 with an oil filler 
cap that was vented through holes in the bottom and a wire mesh filling the 
inside and that was the entire vent system until they changed to  PCV which 
in it's early form still had the same valve cover vent cap on V8's on one 
valve cover and the PCV on the other . Then they had a closed system where 
instead of a vented filler cap they added a small filter in the air filter. 
When I moved to Calif in 81 I was amazed they had smog pumps on 1965 cars 
and EGR valves.

 From what I've seem on the few T-3's I've seen the 72 and 73 had the PCV 
system . The main issue now with this is since the PCV is plastic and the 
same valve was used on Porsche and VW T-4 is long gone so if it brakes or 
fails then what? I've read about using a fixed orfice in the line yet must 
be sized proper .

 Due to this I thought of replacing the late two cap breather with an 
earlier one with one large cap yet from what I've seen the actual connection 
at the oil bath is on the air intake of the oil bath . I don't know if a 
later PCV oil bath can be used with that older breather i think you would 
need the oil filler with the extra hose connection for it to work. . Also 
I'm not sure what's inside the breather meaning are they simply an open box 
where they hang over to the rear of the engine rear of the caps or is it 
filled with some sort of mesh. I have one spare from a 72 that is all gunked 
up yet didn't cut it open in case I might need it. With the PCV system and 
venting from the cylinder heads it's a closed system . I have read it keeps 
the heads where the rocker shafts exist cleaner or is it just basically an 
emissions device . I have not seen how the early one cap breather with one 
hose to the oil bath on the air intake side works . In my mind the hose on 
the oil bath air intake or the one from the later oil as my 73 has it's 
still air intake just the oil bath has two ports which is basically to allow 
only filtered air through the heads and push rod tubes into the crankcase 
where you really don't want dust or dirt to enter.

  The Bentley does a poor job . on page 38 engine section it shows two 
gaskets on either side of the oil deflector plate . I recall on the last 
gasket set I got for my car the deflector plate had no ridge it was flat and 
needed the gaskets to seal.
----- Original Message ----- 
From: "Jim Adney" <jadney at vwtype3.org>
To: <type3 at vwtype3.org>
Sent: Friday, July 06, 2018 8:50 AM
Subject: Re: [T3] First Steps Engine Reassembly

> On 6 Jul 2018 at 1:20, Dave Hall wrote:
>
>>  The 36HP just put any oil mist down onto the road through a slit rubber
>> cap, rather than taking it into the aircleaner as on later Type 3s.I 
>> think
>> there's a tube alongside the dynamo stand - which is part of the 
>> crankcase,
>> as you say.
>
> The goal of the breather system is to let blowby gases out while keeping 
> oil
> in. It's evident that achieving this goal was a challenge since VW made so
> many changes along the way.
>
> Type 3s had the same tube and slit rubber cap up thru '66 or 67. In fact, 
> I
> think ALL cars had a similar tube until it was outlawed, at least in the 
> US. It's
> called a Draft Tube and that was how the engine got rid of the blowby that
> got past the piston rings and into the crankcase. The hope was that the 
> oil
> mist could be captured and returned to the crankcase. That was the 
> function
> of various things VW put along that path.
>
> One of my Beetle shop manuals shows a contraption that VW suggested to
> help separate the mist from the blowby. It's quite complicated, consisting 
> of a
> formed plate, a tube, and a cap, all presumably brazed together. It 
> installed
> between the case and breater stand and stuck up into the breather. I'm
> amazed that VW suggested that it be locally made, to prevent excess oil 
> loss
> due to oil mist loss. No shop would have the facilities to make something 
> like
> that one at a time.
>
> Up thru '69 or '70 there was a sort of knitted plastic ball that looked 
> like a
> blue nylon kitchen scrubber that sat in the breather box. It was there in 
> the
> hope that tiny oil droplets that were entrained with the blowby would 
> stick to
> the plastic filaments and coalese into larger drops which would eventually
> drip back down into the engine. It worked, but it also collected water 
> droplets
> and froze up in very cold weather. Almost all of those were removed and
> thrown away at some point.
>
> Type 3s got the larger square breather box around '68. The purpose of that
> was to allow the blowby to slow down and give the oil mist time to settle 
> out
> and drain back into the crankcase. By '68 the draft tube and slit rubber 
> cap
> were gone and replaced by a very similar drain tube that returned liquid 
> to
> the filler pipe and sent blowby gasses to the air cleaner.
>
> There are a number of things that appear to be wrong in the parts book. 
> The
> lovered plate is called out starting about Jan 1, 1969, but I'm sure my 
> '68
> came with it. The early teardrop breather box doesn't show up at all, but 
> the
> slit cap does. I guess that means the square box superceeded the
> teardrop one so I can't confirm when the square box was introduced.
>
> The parts book also shows the slit cap up thru '71, which I KNOW isn't 
> true,
> since my '68 didn't have it. I don't think ANY FI engines ever had it. I 
> think
> the last year for the slit cap was '67 or '66. Anyone out there know 
> which?
>
> And we were wrong about the gasket under the breather stand. Both the
> Bentley and the parts book call out just 1 gasket, and, oddly, they place 
> it on
> the underside of the louvered plate. My guess is that one gasket was used
> when there was no louvered plate, but I think no gasket was used once the
> louvered plate was introduced. Otherwise, why ripple the edge of that 
> plate if
> you're going to put a paper gasket there?
>
> Sorry for the long response....
>
> -- 
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
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