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PCV?

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M

mtlman8

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Can someone tell me why every couple of days the pcv valve on my 67 tr4a is filled with fuel/oil? well not filled but about an 8th of an ounce.whats wrong? this can't be normal.
 
I've heard you can use a tr3 breather pipe on a tr4a. what do you guys think of this?(the one in the block below the fuel pump)
 
I added the breather to my TR4 -- I believe it relieved a lot of crankcase pressure that was causing oil to ooze out of various seals and gaskets -- anyway I have less leak.
 
John,

Yes, you can use a TR3/early TR4 road draft tube on a TR4A. I would recommend getting the early valve cover and oil cap to match.

My first TR4A had the valve cover and oil cap and the intake manifold hole had been blocked off but they had not installed the tube! I finished the conversion when I rebuilt the engine and it worked fine. Just had to remove a plug in the side of the engine to install the tube.

Scott
 
John,

Sorry I don't have any answers as to your original question though. Never had one on the first TR4A and the second one hasn't been back on the road yet.

Scott
 
thanks scott. going to try and pick one up this week. can I leave the current pcv system in place with the road draft tube?
 
That's what I did though the PCV on a TR4 is pretty lame, just a tube directly from the valve cover to the air cleaners -- no 'V' (valve) and not very 'P' either. I think the 4A system is a bit more developed so that may differ.
 
On the 4A the tube runs from valve cover outlet to PVC and then to intake manifold. Along with adding the road draft tube I plugged the manifold and put a cute little K&N filter on the valve cover, my one piece of "high tech speed equipment."
 
If the Triumph PCV system is anything like that on an MG then the reason that you are getting oil in the valve is that there is no "seperator" that allows the oil to drain back into the sump while allowing only gas to pass up to the valve. On the MG's we have a small tank that allows for seperation.
I think that you said that the PCV draws from the valve cover? On an MG there is a piece of sheet metal in the cover that blocks oil from going directly into the tube. If this is also true on your car then it is likely that that baffel has been removed and too much oil is entering the tube and clogging everything.
Alternately you might be able to "T" the line (is there any place that you can hook into the crankcase for PCV?) and hook into the crankcase AND the valve cover to allow the oil to drain before it goes into the PCV valve.
Bill
 
The road draft tube was like a tracheotomy! suddenly it inhaled... and runs and idles sooo much better!
 
So much talk of this "The road draft tube"
What is it?
 
Well, it's a tube, right?
And it drafts, right?
On the road, right?

State of the art on my Flatmotors, something CARB (in California) HATES witha passion!

Hangs down, the best way to get it to function is a "baloney" cut on the end, so speed causes a vacuum behind the ledge.
 
Hi Don,

On my block you can see the metal plate blocking off the mechanical fuel pump inlet. Below and back from that is the road draft tube. Mine is turned upwards and has a hose attached to it that went to a catch can for racing. Normally, they are turned downwards towards the road, with no excess piping.

P1060598.jpg


Cheers,
Tush
 
Crankcase pressure vent, oil if present, keeps the gasses from building up inside the crankcase and sends it where it doesn't spatter everything under the bonnet.
 
That was my second guess.
Kind of a PCV area if it was invented yet?
Why Would CA have a problem with those :devilgrin:
 
Ah.
Partailly burned combustion gasses that leak past stems and rings, enter the crankcase, foul your oil, are, by (first) Callyforneea, taken in via PCV and re-burned.
Carb MUST be designed for the inherent vacuum leak of the PCV.
If you remove the PCV, plug the port, and re-introduce a road draft tube, yes, it will run better...because it's richer than stink!

You used to see clapped-out cars with road draft tubes....and a constant stream of smoke pouring out as they drove.
"Blowby".

Used to easy tell when you needed rings.

Have to have a vented fill cap to work properly.
Some cars even have a shield on the back side of the fill cap (and wire mesh, like coarse steel wool inside the cap for a "filter", mostly to keep from sucking in bugs) that the fan or wind pressure from driving at speed would tend to force fresh air into the crankcase and the road draft tube sucked.

My pickup has a straight tube, the passenger has a tube that runs down the front, along the pan rail, then angles down at about a 45 degree angle to give the "draft".
Or, "draught".

Just having the tube is part of it.
There should be fresh air intake at the top.
 
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