TEA 20 Tappet Cover Vent Tube

[Waudby]

Hello,

I have a bit of a basket-case TEA 20 that I've got to a decent running condition. I am trying to replace the missing re-circulation tube that runs from the top of the tappet (rocker) cover to the intake manifold. I understand this can cause idle issues (which it seems to be), but also there is significant blow-by from a pretty tired engine, and it's shooting straight up on the gas tank through the currently empty hole in the cover. I'd like to avoid the gas-boiling condition if possible (who wouldn't?), and when I've had it running it has heated up pretty rapidly.

Does anyone know what size of banjo bolt the boss in the top of the tappet cover takes? I don't think there is anyone making a direct replacement for this assembly. I believe there is a schrader valve that is supposed to go in the banjo bolt as well to prevent air-fuel mixture from entering the tappet cover; can anyone confirm this?

Also what size is the vent tube itself? I think the fitting in the manifold is a pipe thread (1/4" maybe?). My manifold has a pipe plug in it currently.

Any help is appreciated. Cheers.
 

[John Deere D]

Good day Waudby

At some point over the next three days I shall be able to check into your concerns....as well as part numbers..

Possibly another "YTer" shall assist you by then...............:)

What is your location.?

Bob. Owner TEA-20











 

[Charles in Aus.]

It is not a Schrader valve , but rather a jiggle pin the diameter of a paper clip passing through a small hole just larger than the pin in a small copper or brass disc a size smaller than that of a one cent coin .
The hole and pin restricts flow of gas while the pin keeps the hole clear of carbon . It is a complicated little device , you are doing the right thing to replace it as idling is atrocious without one .
 

[Charles in Aus.]

Some photos of the valve , there are two sorts one early one later , the principle is the same .




 

[Waudby]

Thanks Bob, appreciate any help. I'm in Ontario, Canada.

Charles, thanks for the clarification on the "jiggle pin" (technical term?). I'm optimistic that I can either make one with some off the shelf parts or else source one. Maybe I'm looking in the wrong places, but it seems surprising to me that I can't find anyone selling these seemingly important parts, especially since (from my understanding) they have often been removed by someone who thought they were making an improvement.

It does indeed idle terribly right now; it will only idle on full choke, although it comes out of it at around half-throttle. Some of that is probably a disintegrating manifold gasket (part ordered), but hoping that the breather tube will help the issue out as well.

If anyone has an idea for parts (even used) in my area, I'm all ears.

Cheers
 

[Duner Wi]

You could try contacting Old20parts company . Grey Fergies is/was their specialty.
 

[Charles in Aus.]

Second hand is your best bet for one of these . Be sure to get one from a TEA , TED versions have different pipes that go through the manifold to aid heating .
The jiggle pin can be made from a paper clip or fine cotter pin . The disc with hole is almost always missing ( they burn away ) make one from some brass or even better a small copper coin .
 

[John Deere D]

I have a spare "TUBE" as per picture.....

I would send you the "TUBE" at cost for shipping....Canadian Postal..

Tube is an original......flattened so as to provide proper clearance due to fuel tank and manifold..
Both of my spare parts Tractors have been robbed of the mechanism that attached to Rocker Cover..

Bob......Dawson Creek BC Canada
If interested send me your mailing address.....







 

[Charles in Aus.]

The thread size is very useful to know and have so clearly confirmed . Thank you Bob , one for my archive of obscure Ferguson sizes .
 

[John Deere D]

Quote:
The thread size is very useful to know and have so clearly confirmed..

Your welcome Sir......

Bob..
 

[John Deere D]

Check out. Send them an inquiry......

https://www.silverfoxtractorspares.com

Bob..No connection to the above in any way ...
 

[Charles in Aus.]

Silver Fox have a reputation for supplying very good quality odd parts that are not often available elsewhere.
 

[Waudby]

Thanks folks, I will see about Silver Fox spares. Also I think Charles might be correct that one from scrap might be easiest. There is a large agricultural equipment scrapper in southern Ontario that I will check out.

One thought though since Bob has confirmed the thread size on the rocker cover - I think I can probably put one together from parts I have around or can get at.

It think I have all the information I need except for the diameter of the tube itself (something like 3/8" copper tube maybe?), and also the size of the hole in the bottom of the banjo bolt that the jiggle pin goes through (looks perhaps about 1/8" in the photo that Charles provided?).

Should be able to get a banjo fitting for the top, and can likely tap the inside of the banjo bolt to thread in a smaller hex bolt with a clearance hole drilled through it for the jiggle pin (which is what the factory style appears to have). After that a little flaring and maybe an adapter as it looks like most of the banjo fittings I can find around the internet have JIC style hydraulic fittings, but local farm stores sell adapters to go from JIC to NPT so that shouldn't be an issue. Anything else I'm missing that might be important?

When in doubt, make it yourself?

Thanks all.
 

[John Deere D]

As per picture.
Copper tubing.

Bob..