Engine Breather Removal

[and.nox]

In the interests of simplifying the top of the V12 motor and freeing it up to make it easier to work on, I'm wondering whether it's possible to remove all pipework associated with the engine breather. At last count, the pipework offers at least 13 opportunities at its various connections which could allow extra air into the system that leads to the 4 carburetors. If the pipework could be removed, the risk of extra air being sucked into the carbs would also be eliminated, so long as the inlets on each carb were capped off appropriately, allowing more confidence in the integrity of the intake system when tuning the carbs. Can the engine crankcase gases simply be expelled into the fresh air below the front of the motor, thereby permitting the removal of the breather pipework, or does it require the vacuum from the inlet manifolds to draw it out? :?

[PeterCrespin]

Breathers go into the inlet tract upstream of the fuel, so air leaks are not an issue, unless you think the intake openings each side are a cause for concern? :-)

I sympathise with your quest and did whatever I could to tidy up the valley on my V12 E. However, I don't think altering the breather pipework was top of my list in 2008. Vacuum retard and air injection plumbing are the low-hanging fruit on most cars (not UK-spec, admittedly).

[and.nox]

Thanks Peter. Yeah - air injection system and vacuum retard were the first to go along with EGR system. That made a huge difference to accessibility with absolutely no reduction in performance.

Still looking for more opportunities to simplify. One idea I had was to connect the main breather line to the manifold balance pipe, thereby eliminating the breather line connections into each carburetor. Don't know whether this is possible or whether it would instead create other problems? Any comments on this concept would be much appreciated.

[PeterCrespin]

From dim memory of my two UK-spec carbed V12s, and slight confusion over which plumbing you're referring to, your suggestion could equate to installing a large air leak into the inlet tract.

Doubtless this would provide hours of fun, and keep you off the streets, but is not recommended.

Pete

[and.nox]

I suspected there might be a downside. thanks again. I'll leave them in situ at this stage

[and.nox]

Peter,
On checking the carbs more closely, I've found that the breather pipe discharge into each carburetor is in fact downstream of the fuel inlet ie. between the needle/seat and manifold. Does this change your thoughts on the matter?
Thanking you for your patience in this matter.

[PeterCrespin]

Peter,
On checking the carbs more closely, I've found that the breather pipe discharge into each carburetor is in fact downstream of the fuel inlet ie. between the needle/seat and manifold. Does this change your thoughts on the matter?.

Sorry, missed this. No, in retrospect it's the same on late twin Strangleberg E-types or even twin SU XJ6s with the thin metal breather pipes that cope because there is a 'suck' effect as well as 'blow'.

Breather blow-by/output is highest at full throtlle but that's a low vacuum condition so not massive breather flow into the tract? At highest vacuum the car is idling or on the overrun, so not much breather output under those circumstances. Dunno. With mainfold breathers there's a supply/demand balance that doesn't exist to the same extent on the older cars that vent into the plenum upstream of the carbs, where there's only significant depression if the filter is clogged.