[TR] Vented Crankcase

[Randall]

> If some later TR4A engines were closed ventilation (improving 
> air quality at 
> no expense to performance), why then were the earlier engines vented? 

I can think of several reasons :

"We've always done it that way"
"Extra complexity and cost"
"One more thing to go wrong"

And IMO the Triumph crankcase emission control systems *were* rather
troublesome and not good for the engines.  Among other things, they promoted
oil leaks, especially in engines with significant amounts of blow-by.  Also
resulted in increased varnish and sludge formation (which tended to increase
blow-by); plus in some cases increased oil burning.

First time I "opened up" my "new" Stag, it left a huge cloud of oil smoke
behind me.  Problem proved to be the "PCV" system, a road draft tube
wouldn't have done that.  But I honestly thought I had broken a piston or
something from the amount of smoke it left behind.

I also owned an Oldsmobile for several years that would literally pump
quarts of oil through the PCV system if you kept the throttle open for very
long.  One good quarter-mile sprint would lose over a quart of oil that way.
Ran fine otherwise.

>         Also, I think we're talking vented engines as being:
> intake vent- at the valve cover
> exhaust vent- being the road draft tube
> Is this right?

There must always be a crankcase vent, so perhaps "vented" vs "non-vented"
is simply too confusing a terminology.  But you are right, that is the
configuration that OHV Triumphs used until 1963, when CA law mandated
control of crankcase emissions for any car sold here.

Randall