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TR4/4A PCV System

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carpecursusII

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Ok, last year I rebuilt my engine and things were going pretty well over all. Two months ago and about 1400 miles into the new engine I noticed that I was still burning a significant amount of oil and could see smoke on acceleration. I suspected either leaking valves or a ring issue. I tore the motor back down and had the head checked, I had a noticeable amount of build up on my valves especially considering they only had 1400 miles on them. I was able to conclude that the PCV valve was allowing oil through and I was burning it all.

Now I am 300 miles into the second attempt at this, I made a change to the valve cover cap after realizing that I was using a cap with a vent on a system that should be sealed. I switched to a sealed cap but I still seemed to be burning oil.

This is the kicker: I just took the valve cover cap off with the engine running and could feel the air pressure coming out of the opening, it felt like my hand was infront of the exhaust pipe just not quite as strong. Should I have this much pressure being built up even at idle or is something wrong?????
 
Is there any way on a trial basis you could eliminate the PCV valve and have the carb at the air cleaner suck directly on the valve cover ?
 
Sure, I could just run a hose between the cover and the intake manifold. I'm still baffled by the amount of air I feel pumping out of the valve cover
 
I don't know if a direct connection to the intake would be the right thing to do without a PCV valve. I was thinking something along the lines of this, not necessarily exactly like this but the same principle, letting the carbs do the suction. It would require a nipple installed somewhere on the air filter housing.


Or... if you did choose to go to the intake manifold for the suction, you might try this PCV kit from GoodParts.
https://www.goodparts.com/shop/index.php?productID=253
Although it shows "T" ing into the brake servo vacuum hose, it is the same as the intake manifold vacuum.

Here's the installation instructions for a TR6, but like I said, tapping into the intake manifold would be the same as tapping into the TR6 brake servo vacuum hose.


The pressure you feel at the oil fill cap could be excessive or normal depending upon the piston ring situation.
If they are not yet bedded, the blow by and crankcase pressure will be high and if a ring or two were broken during the piston install, the blow by and crankcase pressure will be high.
You will always be able to feel some pressure trying to escape when the cap is removed...it's just a question of how much in comparison.
 
I have a 4A intake manifold so it is already tapped. I would have expected newer rings to have seated in 300 miles but I guess it's possible they did not. I have 130-135 psi compression on all cylinders, 87mm pistons, stock head.
 
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