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Crankcase ventilation question

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Tabcon

Tabcon

Jedi Warrior
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Can anyone tell me the history of why Triumph removed the crankcase vent at one time? At least I think they did, or my engine just doesn't have one. It has the usual tubes running from the top of the valve cover to each air filter, but no crank case vent at the rear of the block like is shown in the Triumph factory manual.



I removed the PCV tubes running from the top if the valve cover today, I guess that’s what they are, when I was cleaning the engine area and noticed they were clogged with a gooey puss like substance, not at all unlike the plaque removed from clogged arteries. So I cleaned them out.



Is there any way to run this car without these things? I realize you need to vent the crankcase some type of way, so can you install a crankcase vent where it used to be and do away with the valve cover to carb setup?



Tab
 
What you have is an early form of crankcase emission controls. I believe 1964 was the first year for it, so the drawings were not updated, but my factory Spare Parts catalog does have it listed.

As I recall, the claim at the time was that roughly half the pollution from car engines came from the road draft tube.

Other than being a violation of Federal law, I don't know of any reason you can't pry out the plug and install a road draft tube from an earlier TR.
 
Ahh, so I have one of the first "green" British cars!

What about an oil catch system like they use on race cars?
I definitely don't want to leave an oil slick on the bottom of my car, but from what I've read and heard, these engines really need to breathe.

Tab
 
Your right, they do need to breath. I have a TR3 with a 64 TR4 motor that when I bought it was in disgusting shape. It had a breathable oil filler cap, but no draft tube installed in the top. Not surprisingly, it put out more oil than the Exxon Valdez, which I think was due to the seals and excessive crankcase pressures.

When the engine was rebuilt, I stalled the draft tube, and installed a K&N crackcase filter vent (internal diameter was .5 inches) on the tube sticking off the valve cover. I was able to purchase it at Advance Auto, for around $20. Fresh air comes in from the K&N filter, and exhausts through the vent tube.

I flirted with the idea of installing a small metal cup on the end the draft tube, which would be held in place with a pull-pin to catch blown out oil, but upon doing research learned that the end of the draft tube is shaped and positioned to create a slight vacuum as the car goes down the road, and as such, should not be modified in any way.

Just another episode of "Why did those crazy Brits design it this way?, Oh, that's why."
 
Atmospheric crankcase vents. Do you remember what it was like to sit in traffic and see and smell those hot oil vapors, or the oil slick that covered the center of all roads and highways? I do.

If I had a 4 without the crankcase vent, I would put on one and drive.
 
TR6oldtimer said:
Atmospheric crankcase vents. Do you remember what it was like to sit in traffic and see and smell those hot oil vapors, or the oil slick that covered the center of all roads and highways? I do.

If I had a 4 without the crankcase vent, I would put on one and drive.
Click to expand...

I was going to put one on my TR3, but other mods on the car and engine got in the way, as that was going to be the last thing on the list. It would be nice to re-circulate the crankcase vapors and I may still do it some day, but let's face it, there aren't many cars left on the road that don't have a PCV system so the overall effect of those spewing oil vapors is really quite negligible.
 
I added a raod draft tube to my TR4 and greatly reduced oil leakage (oozing gaskets, etc). When parked I do not see a puddle of oil where the tube exits but I suppose it really does it's work at speed.

BTW -- the installation of the tube was done with the engine in place. I had to dremel the edge of the plug to weaken its grip so it could be pulled out, then the tube (readily available for cheap $ on eBay) just pops in. Inexpenisve to try and easily reversible.
 
If you install a vent pipe, make sure that you put some sort of oil-resistant and heat-resistant sealant around the pipe where it is pushed into the hole in the engine block near the fuel pump. If you don't, oil spashing around in the sump will leak out the space between the pipe and the hole in the block. To make them mechanically tight, the factory designed it with a saw cut or two so the pipe where it is inserted, would flare out a bit inside the hole. It was mechanically tight but the saw cuts allowed the oil to leak out. I MIG welded these saw cuts and filed the tube round and, with the sealant (Loctite red if I remember correctly) I have no more oil leaking from there.
 
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