VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 Oil return tube on the oil separator early 1929

Hello all. The workshop manuals show an oil return tube protruding from the middle of the oil separator. It looks like maybe 4" long and maybe 5/16" diameter. My separator has a little clamp sticking out of the centre pipe where this tube must have been, but the return tube is missing. So - questions. 1. Will the liquid oil return to the block without the tube ? (i.e. do I actually need this at all?) 2. If I do, where does the upper end of the tube have to locate - just in the central space, or is it more complicated? Thanks in advance - very grateful for any tips however meagre. Dave.

Are you referring to the Tube, Oil Return (Cylinder Head to Block) 835843
the silver tube behind the push rod cover from head to block.

If so may want to talk to Chistech, as he had to do this for his Engine. My 31' Spec. Sed. #18, Motor internals C

Or the the Pipe, Oil Separator to Air Cleaner 356041

the black L tube from oil fill to air cleaner.

I think he is asking about the crankcase vent tube that extends from the oil separator on the rear of the block to the air cleaner. The the oil fumes can be burned with gas and air added by carburetor.

It is actually oil vapors not liquid oil, and the vapors will not return to the air cleaner to be re-introduced into the system to be burned without the oil separator tube.

Hi. I'm not talking about the venting tube between oil separator to the air filter/carb. I'm talking about the oil return tube to crankcase from the bottom of the separator, which is missing on mine. I include a pic here:

The tube I mean has the two red arrows on it. In fact, when sharpening this image, I see that the oil return tube looks to locate in a hole in a baffle inside the separator (arrow 3), which answers one of my original questions. The manual says that the oil in the separator is removed from the mist and then drips back into the crankcase through the return tube. But it looks to me like such oil would drip out of that hole in the separator into the crankcase anyway, so my question is if you think I need to find/make a new tube, or just leave it off.
BTW Fig 9 shows that folks couldn't spell separator 86 years ago any better than they can now! I remember my teacher making us repeat in primary school: "a rat got caught in the separator"
Thanks again, Dave

ok, so we are in the right area then...

this is a pict of the Oil Separator on my 1929 Chevrolet.

It is a lot smaller then the one you have there. But I have the Early 1929 Engine with Sealed Valve Cover and Open Rocker Arm Cover.

But mine might have been changed or updated, maybe came that way

Based on the 1929-1930 MPL the list:
Tube, Oil Filler (1st Type)......835685
Tube, Oil Filler (2nd Type)......836157

But the pictorial they show in the MPL the second type looks like the one I have. JYDog / Chipper probably can confirm which is which.

Anagriff: It always helps to be as specific as possible with your question so that you get the correct answer the first time. The illustration that you show in your latest post helps us greatly and the illustration should have been included with your question in your first post. At any rate, yes, the tube going into the crankcase from the oil separator needs to be there so you should probably make one.

BearsFan315: The photo that you show of the "oil sperator" is not the oil separator in question. That is an oil filler tube and the oil separator (which is featured in Anagriff's illustration and it is part number 356039) is located at the rear corner of the engine block on the driver's side and it was used only in early 1929. When the oil separator was discontinued the hole in that location was cast over on all future engine blocks. In its place a return pipe was located in the side of the oil filler tube and the other end of the pipe went to the air cleaner so that the vapors could be re-introducted into the combustion chamber and burned.

Two oil filler tubes were used in 1929. The first type was part number 835685 and it was used in conjunction with the early oil spearator. The oil filler tube did not have the nipple on the side for a vapor return pipe for the air cleaner.

The second type of oil filler tube (836157) replaced the first oil filler tube when the oil separator was discontinued, and the second oil filler tube (like the one featured in your photo) had a nipple on the side for the vapor return pipe that went to the air cleaner.

By the way, when the oil separator was discontinued and the early 1929 engine blocks were upgraded to the new system by the Chevrolet Dealer Service Department, a plug was inserted in the hole in the engine block where the oil separator was once located.

Thanks JYDog that means there were 2 variations of the early 29 engine as we call it. the one with the Oil Separator then the one with out, then the later 29 engine with the vented valve cover and closed pushrod cover.

Nope! There was only one early engine and one late engine. The early 1929 engine had the oil separator, the non-vented valve cover and the open push rod cover. The late 1929 engine had a vented valve cover, a sealed push rod cover and no oil separator.

so then i have a hybrid ?!?

since i have the sealed valve cover and open push rod cover and NO oil separator !!

One of my '29s has that as well: No oil separator, no seals around the spark plugs, and a non-vented valve cover. It still has the boss for the oil separator, but there is no hole there.

Interesting.........

All the Best, WLB

Yes, it is interesting.

According to Chevrolet literature, in approx. July of 1929 the oil separator was discontinued and it was replaced by the oil filler tube and pipe, the sealed push rod cover and the vented valve cover. Since different factories did different things, there is no doubt that some 1929 Chevrolets were probably an exception to the complete changeover.....not to mention parts changes by the Chevrolet dealers and etc.

I know my code stamp on the Engine is E 1 9

looking at the picts i have, looks like the boss is on my block as well :!)

This what we are Talking about: Oil Separator Boss

Yep, that's the boss.

As a side note, in many cases the changes in production preceded the notifications to Chevrolet dealers of said changes by several months.

Thankyou to everyone participating in this thread. I've learned a lot. My engine has for example oil separator, vented tappet cover and flat (vented) side cover. Whether it came that way from the start, or the tappet cover got maybe switched at some later stage is not possible to know. It looks like proper ventilation is important. In a thread from 2011 (https://vccachat.org/ubbthreads.php/topics/221059/2), one person had big problems with rough idling and leaking carb that were cured by removing the seals in the side cover (he didn't have an oil separator, and had sealed tappet and side covers).

I stuck a piece of plasticine into the oil separator return pipe hole and measured the impression of it, and it's exactly ¼" OD, so I'll get on to bending up a tube for oil return.
Thanks, Dave

The problem with different factories is that only one in the USA (Flint) produced engines in 1929. They were all run in at the end of the production line and therefore would have enough accessories for that. Now the engines were shipped in boxcars (at least for most assembly plants [likely truck to Flint assembly] so they the engine numbers might not all follow in sequence in each assembly plant. Others might be sent to a parts warehouse. I am sure some of those ended up as replacements during 1929. Why am I sure, you might ask? Well our family purchased a brand new 1929 Convertible Landau Sedan from the Chevrolet dealer in Marshall, Michigan. According to my grandmother the cylinders were "bored on the bias". Translate that to: "It burned oil". They took it back in approximately 6 months and traded it in for a Marmon Sedan. I would expect that Chevrolet replaced that engine with another or at least did a major overhaul. Back in the day the early 6 cylinders had a bad reputation and many were advised to not buy them. I expect the mid-year changes were to correct some of those problems. I also expect that engines were changed so the cars could be sold.

Anagriff,
Because the unvented valve covers held moisture they fairly quickly rusted particularly in the corners. Many were replaced when the cars were relatively new, particularly in damp climates.

It is known that some of the early engines with oil separators had the non-vented valve covers changed to the vented type of valve cover by the car's owner, or the Chevrolet dealer. For example, if a non-vented valve cover was damaged years later and the car owner purchased a new valve cover from the local Chevrolet dealer he would receive a vented valve cover since the non-vented valve cover was discontinued. Also, it is not uncommon to see a 1929 Chevrolet with a 1930-32 "round top" valve cover instead of the 1929 "flat top" valve cover since they are interchangeable.