HILLMAN CAR CLUB
OF SOUTH AUSTRALIA INC
Tech Tips:
Crankcase Ventilation
HILLMAN CAR CLUB
OF SOUTH AUSTRALIA INC

From: Miles Family [milesfamily(at)telus.net]
Sent: Thursday, 9 October 2003 5:37 AM
To: hillman@can-inc.com
Subject: "Hillman - " Rapier Engine Question

Hi All,
Quick question.  I've got a 1600 Alpine engine in my Rapier.  The oil filler cap sits on top of an extended metal tube on top of the rocker cover.  Part way up ther is another small tube sticking out at a 90 degree angle.  I noticed in a picture I saw on the web of an Alpine engine bay that there is a rubber hose attatched to this, mine has no such hose.  I've looked in my manuals and all the engine diagrams show the oil filler cap like the one on my Hillman which sit right on the rocker cover.  My questions are this, does anyone know where this hose goes to and secondly what is the reason for the extension on the oil filler cap.  I guess it's to accomodate the little tube halfway up so once I know what that's for and where it's going I'll have my answer.
Thanks in advance.
–Alan

From: Ed Meadowcroft [ed_meadowcroft(at)snap-tite.com]
Sent: Wednesday, October 08, 2003 4:27 PM
To: Miles Family [milesfamily(at)telus.net]
Cc: hillman@can-inc.com
Subject: Re: "Hillman - " Rapier Engine Question

Sucks crankcase fumes, usually rubber pipe goes to carb or air cleaner.  Older Hillmans just have a crankcase breather that releases fumes to the atmosphere, you will see a metal pipe below the distributor ending alongside the oil pan.
Is there a small tube on your air cleaner same diameter as the one on the filler?
If not, and you have the breather pipe on the engine side you can simply block up the one on the filler neck or put a valve cover off an earlier engine on it.

Ed


From: hughes [hughes(at)scides.canberra.edu.au]
Sent: Thursday, 9 October 2003 10:45 AM
To: Miles Family
Cc: hillman@can-inc.com
Subject: Re: "Hillman - " Rapier Engine Question

Hi Alan,

My Alpine has this set-up, as others have suggested it's to suck fumes back into the combustion chambers.  On my car the 'other' end is connected to the inlet manifold.  I have no idea whether this is the standard connection point or not - my car originally came with a Solex twin choke but a previous owner had converted to a 32/36 Weber with Lynx air filter.  I could post a question on the Alpine list if you like - in fact I might just do that anyway.

Cheers

Vic


From: hughes [hughes(at)scides.canberra.edu.au]
Sent: Friday, 10 October 2003 12:07 PM
To: Miles Family
Cc: hillman@can-inc.com
Subject: Re: "Hillman - " Rapier Engine Question

Hi Alan,
I posted a query to the Alpine list, this is a response from Jarrid Gross who knows these engines inside out.  Note his comment on the bird catcher filter engine such as you are running.

Vic,

The oil filler with hose connection is for an engine with a PCV system.
The oil filler is intended to go to the clean air side of the air filters, so as to provide the engine with clean air, which is exchanged with crankcase air and fumes, when the manifold vacuum pulls it through the PCV valve, from the side cover vent hose.

The gravel strainer filters (or bird catchers as sometimes called) wouldn't have used the PCV system, but there was a paper element filter for PCV equipped WIA/WIP carbs.

The proper connections to the PCV system are as follows (applies to all alpines with PCV).

Oil filler neck hose goes to the air cleaner(s) via the flame trap.
The PCV is screwed into the inlet manifold, and its hose goes to the side cover fitting.

HTH,

Jarrid Gross

I'm glad I asked – I now realise that the way the DPO (Dumb Previous Owner) set mine up is the exact opposite of the correct way – gee what a surprise :-)

Vic


From: Import Auto Supply [importautosbdo(at)juno.com]
Sent: Saturday, 11 October 2003 10:42 AM
To: hillman@can-inc.com
Subject: Re: "Hillman - " Rapier Engine Question

Any engine needs to have some way of venting the blowby gases – all engines pass a certain amount of unburned gas/air mixture past the rings, more or less depending on the condition of rings and cylinder walls.  If this doesn't vent, it will find a way out – through gaskets or seals if necessary.  The original way of dealing with this was the road draft tube, which came off the crankcase and was angled into the slipstream of airflow coming past the engine.  Then in the 50's, as pollution began to be worried about, the first answer on most British cars was a breather line between the valve cover and the air cleaner.  It turned out that using intake vacuum to suck the vapors up increased the efficiency of the engine, but the next concern was that cycling the unburned gas/air mixture into the air cleaner upstream of the carb was going to throw the final mixture out of calibration, so the later generation of PCV (positive crankcase ventilation) systems was to run from the crankcase into the intake manifold, controlled by a valve or metered orifice so that the idle vacuum didn't get too overwhelmed, with a balance line between the air cleaner and the valve cover.  Various manufacturers used all sorts of creative places to pick up the crankcase vapors – timing covers, tappet covers, oil fillers, valve covers, and in a few cases (Ford Cortina, about 1967) the fuel pump base.
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