2500M: any benefit to adding a PCV valve?

[Renaldo]

Guys, small issue, but up to now, I've just had a breather (K&N) on my valve cover tube, allowing fumes to dissipate into the atmosphere.

A bit on the smelly side, and no help to pollution I'm sure.

I've seen a PCV valve on a TR6, set into a hose running from the valve cover and, indirectly, into the intake manifold.

Looks easy enough to configure.

Worth doing, do you think? Any down side?

Ron

[Hansoplast]

Hi Ron,

2 pics of the engine bay of my TR250.
Here you can see how it is done.
Another route is to the filter of the carburator.

Got tears in my eyes seeing my sold car.

Hans

[Mr Tiger]

Ron,

The fumes run back into the carbs on mine.





I don't know if the photos are good enough.

The TR engine bay look stunning Hans.

Chris

[Renaldo]

Boys, thanks for the pics.

Here are two pics of what I rigged up -- "modern(?)" pcv valve hooked up to intake manifold, via the brake servo hose.

Ron

[RCK974X]

From owning several 6 cyl Triumphs.. info in case it helps

Early Mk1 and Mk2 engines had 'short' manifolds, with PCV valve. Valve works well, but can get gummed up, and then you get fumes out the oil cap, so you should clean it now and then. English ones had Stromberg carbs.

Later engines had pipes into carb via restrictors so as not to upset the mixture. Still later engines had the 'long' manifold which takes up more room (and I think may not have been fitted in TVRs ?) and pipes into carbs.

A lot of manifolds had the hole for the valve, sealed with a frost plug when set up with pipes.

Probably not a lot of difference between them, but you should have something to suck up the fumes...

I haven't seen a manifold like the last photo - I guess that's a USA emission one ?

[Renaldo]

Andy, U.S. type manifold, yes.

Something just occurred to me: easy to see how the PVC could draw the fumes away and into the manifold, but doesn't the crankcase system need to draw fresh air in, also?

If so, where would that "inhaling" come from? The oil filler cap has a tiny hole, but I'm unsure if that's its purpose...

Ron

[Grantura MKI]

Renaldo said:

Boys, thanks for the pics.

Here are two pics of what I rigged up -- "modern(?)" pcv valve hooked up to intake manifold, via the brake servo hose.

Ron

I see some scary things in this picture! Be sure you are using vacuum approved hose...among other problems.
Best,
D.

[Renaldo]

D, if you see problems, I'm all ears.

Please share.

Ron

[Renaldo]

Pending D's concerns, I've removed the PCV "arrangement" shown in my photo,and reinstalled the K&N breather.


Ron

[TheRealFingers99]

I'd forget the PCV valve, just a pipe from the cam breather to the inlet manifold before the carb(s) will do fine. It should have a small flame trap in it.

Alternatively, fit a catch tank, out hose from that to the place aforementioned.

[Renaldo]

John, thanks for weighing in.

If there's little or no benefit to fitting a PCV, I simply will trash the whole idea.

Car has been running beautifully, so I'm gaining nothing there.

Thought it might be a good idea regarding crankcase ventilation, contamination and so on.

Ron

[RCK974X]

Renaldo said:

Andy, U.S. type manifold, yes.

Something just occurred to me: easy to see how the PVC could draw the fumes away and into the manifold, but doesn't the crankcase system need to draw fresh air in, also?

If so, where would that "inhaling" come from? The oil filler cap has a tiny hole, but I'm unsure if that's its purpose...

Ron

That little hole in the oil cap......at least in original setup, that's what it's for anyway.

If your engine doesn't fume much, then you don't have to bother, but it does help keep any smells down.

[Renaldo]

Still intrigued by potential problems (raised by D) with the PCV arrangement I set up.

I followed the set-up used by many TR6 owners stateside.

But if you guys see problems with it, please share.

Ron

[Slow M]

Ron,

If the fumes seem excessive, it might be time for a compression check.

Best,
B.

[Grantura MKI]

Hi Ron,
Would you be so kind as to PM a large picture of both sides of you engine bay?
Best,
D.

[Renaldo]

D, is this of any help? I'll take more if not...

Ron

[Renaldo]

By the way, I spoke to a mechanic friend of mine who was quite neutral on the PCV arrangement. He didn't see much benefit.

He liked the idea better if I included an oil "catch can" in the arrangement to trap any excess oil.

He wasn't too fond of the idea of an oily spray directly into the intake manifold.

Ron