Alternative venting of top-alternator V1100/1200

[johnr]

Just throwing this out.. the small block does *all* it's venting trough the valve covers. At a casual glance, I don't see why you couldn't do it with a big block, too, if the other methods aren't working out. I, of course could be all wet. 

You could be on to something there Chuck. I have this nagging doubt though that if it were that easy then Guzzi would have done that.

[John A]

Volume of the big crankcase may be such that venting thru the heads doesn't have enough capacity. I donno, just throwing that on the pile

[rodekyll]

I'm pretty sure the early EVs returned via the breather lines.  There is no hole in the bellhousing for the old school drain pipe, and I don't recall any other dedicated return. So I think it's possible to at least return oil via head spigots.

[twhitaker]

The lower part of the frame tube is plumbed to the head breather lines and the condensate runs down them. Nothing wrong with it going both ways.

[Muzz]

The lower part of the frame tube is plumbed to the head breather lines and the condensate runs down them. Nothing wrong with it going both ways.

No head breathers. Pretty sure that John thinks they may be worth adding.

[rodekyll]

I think either the later Ev timing cover with the breather in the side or an 850T-type mechanical tach cover will offer a return line without having to get intrusive on the engine.

I'm forced to use a Convert cover, or I'd try the above to breathe the 1200 Breva engine.  As it is, I'm planning to duplicate the above idea by drilling the cover and adding a pair of Toyota PCV valves.  I'm using two because they are a little smaller than the EV's PCV valve.  I'll be returning via head spigots and the oem return system.

[rodekyll]

I bored two holes in my timing cover 15mm down from the center of that near bolt hole and 35mm in from the outer edge of the cover.  This is a location that is above oil level, somewhat protected from the turbulence in the timing cover, and not somewhere where spinning things will chop anything up.







I found a grommet and pcv setup for a Toyota that has a fair tube diameter and a shallow depth inward, again, to not get chopped up in the cam wheel.  Since the tube is smaller than the oem hose I went for two pcv valves.




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Then I added the valves.





I'm going to start with just the head breathers for oil return.  If I need more I have a 4-speed case vent barb that screws into the sump plug hole.  I'm not going to use it unless I have to.

Any thoughts?

[Howard R]

On my 1996 Sport 1100, the stock breather system consisted of the "standard" port out the back of the block, with the pipe elbow running up out of the top of the bell housing.  This pipe connects by the big rubber pipe to the front of the frame spine (functions as breather box/separator) and two banjo bolts with hose barbs at the bottom of the frame, one on each side, for oil return.  The "vent to atmosphere" is a small rubber hose from the top of the frame spine down to the airbox.  There were short rubber oil return lines, connected to an aluminum "V" pipe assembly which went to a large economy size banjo bolt which was also the oil pan drain plug. (Note that this put the oil return below the oil level in the sump.)  I put a Harper outsider on it for easier filter changes, which presented a problem because the filter was on the right side where half of the aluminum "V" pipe ran.  My block still had the distributor boss in the casting, with a flat blank off plate.  My solution was to replace the plain blank off plate with one from the hi-cam engine, which has two barb fittings for hoses from the valve covers.  I used these two barbs for the oil return lines from the frame and replaced the banjo bolt with a standard oil pan drain plug.  (Note that this now put the oil return above the oil reservoir in the pan.)  There is a ball check valve in the bell housing pipe, I don't remember if it was originally there or if I added it when I did the conversion.  If the latter, it might have come from Guzziology but I don't remember, it has been nearly two decades since I implemented the changes and I have never had a problem.

All this is a long-winded way of saying that it's probably not critical where the oil return goes.  It looks to me like your PCV valves will perform the same function as my ball check valve so my guess is you will be good.  Look forward to seeing your results.

Howard

[rodekyll]

Good description!

I'm committed to going this route, so I really hope it works.  Plan B is to add the below-oil spigot -- but only if I have to.  I'll have the overflow hose routed out the back rather than into the airbox.  I understand why oem puts it at the box, but with the horror stories of it backing up into the intake, I'd rather not.

[johnr]

Good description!

I'm committed to going this route, so I really hope it works.  Plan B is to add the below-oil spigot -- but only if I have to.  I'll have the overflow hose routed out the back rather than into the airbox.  I understand why oem puts it at the box, but with the horror stories of it backing up into the intake, I'd rather not.

Should work RK. Can I suggest putting in a pcv valve in the vent to the atmosphere. This would prevent the ingress of moisture laden air into the system and help prevent any problems with Mayo.   The other thing I would do is test the system in such a way that I could see the output of the overflow pipe.

[rodekyll]

I've got a catch can for the overflow already built.  I'm very interested in collecting what comes out and seeing how much of it there is.  So far no mayo problems with the hydro engine and this breather system.  I'll give an additional pcv valve some thought, but my first reaction is that air needs to move both directions in the breather system, and another valve would let high pressure relieve, but not low.

Got the pcv valves installed for real today.  Hope to have the engines swapped over the next couple of days.