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TR4/4A TR4 Upgraded inlet manifold/valve cover question

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TR3driver said:
...2) Remove the plug and install a road draft tube from an earlier TR...
Click to expand...

That is what I did. My late TR4 had the correct equipment which meant a sealed oil fill cap and the only venting thru a little tube to the air filters. This was just not adequate to relieve crankcase pressure which meant oil oozing from every pore.

Reluctantly I concluded it made sense to add the road draft tube and that has worked out fine.
 
Thanks. On Number 2 - do you mean the plug on the intake manifold? I thought the road tube was supposed to run from the valve cover, but I don't see a plug or nipple where it would go?
 
Geo Hahn said:
TR3driver said:
...2) Remove the plug and install a road draft tube from an earlier TR...
Click to expand...

That is what I did. My late TR4 had the correct equipment which meant a sealed oil fill cap and the only venting thru a little tube to the air filters. This was just not adequate to relieve crankcase pressure which meant oil oozing from every pore.

Reluctantly I concluded it made sense to add the road draft tube and that has worked out fine.
Click to expand...

Got a picture? Thanks.
 
If you like the look of what you have, yes, get a road draft tube, which is fit into the block in the neighborhood below the fuel pump. It can be a headache to install when the engine is in the car.

The other option is to install a later style valve cover, and install a TR4A pcv valve.

Of the two options the second would be easier if you can find the various missing pieces.
 
I've seen some valve covers with an outlet in the middle, but just a hose running down past the carbs, presumably below the the engine - is the road draft tube different then?
 
F1LOCO said:
I've seen some valve covers with an outlet in the middle, but just a hose running down past the carbs, presumably below the the engine - is the road draft tube different then?
Click to expand...

It's pretty much the same idea, but the road draft tube is much more efficient - located at more of the source of the problem, bigger, and designed to act like a venturi I believe to promote flow out of the crankcase.
 
Here's a pic. Would this with a breathable filler cap like I have solve the problem?

Seems like the easiest solution. Would it unnecessarily suck in any road debris, water, etc? I've seen some just put a filter on the nipple to the valve cover as well? Seems like it would potentially spray through, thow...

RoadTube_zps6f36e3b9.jpg
 
I doubt it solves much if the line is just hanging in space below the engine. You are building positive pressure in the engine and you need an effective way to pull that pressure down to atmospheric pressure or lower. I believe the factory draft tube tries to pull a vacuum by design, also the setup that Geo shows on the TR4, and the 4A was doing the same.
 
The road draft tube fits into a hole in the block that is closed with a sheet metal plug on late TR4s (sort of like a small cup-type freeze plug). The plug is somewhere near and below the fuel pump.

As noted, that tube is a much more effective relief of crankcase pressure.

Used tubes are commonly found on ebay and elsewhere:

https://www.ebay.com/itm/Triumph-TR-3-Eng...c14&vxp=mtr

https://www.ebay.com/itm/Triumph-TR4-TR3-...639&vxp=mtr

https://www.ebay.com/itm/Triumph-TR4-TR3-...c82&vxp=mtr

https://www.ebay.com/itm/Triumph-TR3-TR4-...a76&vxp=mtr

https://www.ebay.com/itm/TR2-TR3-TR4-oil-...142&vxp=mtr
 
Thanks. I guess that is probably my best route, though from what I read that "plug" is a bear to get out with the engine in. How does the tube fit and stay in the hole once the plug is out? Seems the oil would just blow out around where it goes into the block.

After install, would I leave the breather cap in place or get one that closes at the valve cover?
 
PS, if my block ends up being a later model TR4A, then I presume the plug won't be there and I have to go the PCV route?
 
Assuming this is the infamous plug:
Plug_zps2d8e1576.jpg


Waiting on feed back for those who run the k/n filter on the breather tube...that doesn't look like fun removal...
 
F1LOCO said:
Assuming this is the infamous plug:
Click to expand...

Yep, that's it.

F1LOCO said:
Waiting on feed back for those who run the k/n filter on the breather tube...that doesn't look like fun removal...
Click to expand...

For me, just venting at the rocker cover with a little filter on it wasn't enough ventilation.
 
The plug is just stamped sheet metal, but it has been in that spot since Johnson was in the White House so it will need some help coming out.

I dremeled the center a bit to weaken it, then I was able to drive a stubby screwdriver thru the center. That let me twist and once it was twisting it was loose enough to pull/pry out.

The tube is a snug fit in that hole (has a split along the end that allows it to compress a bit as it goes in). Some of your favorite sealer around it will help to. It stays in fine, there is a little metal piece that bolts it to the oil pan (uses a longer oil pan screw -- like the long one used for the slave bracket brace.
 
Here's the diagram from the parts manual, which shows the little bracket that holds the tube in place. That pan bolt is 1-1/4" long, 5/16 NC according to my notes. Not shown is the thick washer (two regular washers will do) that goes between the bracket and the pan, so the bracket doesn't try to crush the rolled edge on the pan.
 

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BTW: Don't think you might drop the oil pan and push the plug out from the inside... there is a baffle area as part of the block casting that prevents getting at it from in there.
 
F1LOCO said:
PS, if my block ends up being a later model TR4A, then I presume the plug won't be there and I have to go the PCV route?
Click to expand...

The plug is there on a TR4A engine as well. The engine on my TR4A looked similar to yours when I got it as the previous owner had swapped out the valve cover for an earlier one and removed the PCV valve and hoses feeding the intake manifold.

I merely completed the job by installing the road draft tube as well.

Scott
 
TR3driver said:
Here's the diagram from the parts manual, which shows the little bracket that holds the tube in place.
Click to expand...

Looks like there might be two versions of the draft tube, the one I picked up and installed on my car has just a flat bracket, the mount on the tube is horizontal.

-Darrell
 
Yes, the later tubes had the tab rotated so the bracket didn't need to be bent. Either one will do, as long as you have the bracket that matches the tube.

But my scan of the later parts manual doesn't look as good :smile:
 
Geo Hahn said:
The plug is just stamped sheet metal, but it has been in that spot since Johnson was in the White House so it will need some help coming out.

I dremeled the center a bit to weaken it, then I was able to drive a stubby screwdriver thru the center. That let me twist and once it was twisting it was loose enough to pull/pry out.

The tube is a snug fit in that hole (has a split along the end that allows it to compress a bit as it goes in). Some of your favorite sealer around it will help to. It stays in fine, there is a little metal piece that bolts it to the oil pan (uses a longer oil pan screw -- like the long one used for the slave bracket brace.
Click to expand...

Thanks, good to know. I guess I'm going to break down and get one and try to install it with the engine in the car...Glad you were able to "twist" it out...
 
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