Classic Mini Engine Parts
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 Posted: Jun 25, 2020 03:52PM
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If you're feeling bored you could always make up the kit that Vizard describes in one of his books.  Basically you fit a venturi into the exhaust system that produces a negative crankcase pressure...  

That should reduce any oil leaks and is supposed to provide a small power benefit..

Cheers, Ian

 Posted: Jun 25, 2020 03:28PM
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US
All great ideas guys!!  I will just keep it as is and vent out to the atompshere.  

 Posted: Jun 25, 2020 02:19PM
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Quote:
Originally Posted by FAB60
Hmm i only have that crank case breather and have been running this setup for about 10yrs now.....I know the saying is if it aint broke dont fix it, but im bored so i wanted to improve!  lol.   



If i do decide to add more venting/breathers....where can i have them done?  I dont see anywhere else i could.  My engine is a Metro
A Metro engine usually has two breather ports afaik. One is on the timing cover the other is on the clutch housing you said you only have one where is it a picture may help.
If you are using an electric fuel pump there is a kit to add a breather onto the rear of the block where the manual fuel pump would normally be or you could add an older vented rocker cover.
For now i presume you have the timing cover vent so just plumb that into the carb and see if it helps, if not you have other issues.
It has been said many times an A series cannot have enough vents.

If in doubt, flat out. Colin Mc Rae MBE 1968-2007.

Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.

 Posted: Jun 25, 2020 11:31AM
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CA
This is how my two crankcase vents are routed to my HIF44 carb. No PCV valve involved. It doesn't draw a lot of air volume - just provides a slight suction to take up expansion and blow-by gases. Since blow-by gases are partly unburnt air-fuel mixture that gets past the rings during compression and/or partially combusted blow-by during firing and power stroke, it is OK to be introduced into the carb's air flow. As for any oil vapour that isn't caught by the vent canisters, it would normally be much less than what gets past the rings, so doesn't cause a significant contamination of the cylinder charge. I'd rather my car consume any crankcase fumes than allow them to spread out and muck up my engine and compartment.

I imagine if your crankcase vents get dirty inside, either there's dusty air coming in (vented cap?) or the oil needs changing more often.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Jun 25, 2020 10:59AM
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I have two vents, one from the timing cover, the other from the clutch cover.  Both are vented to the atmosphere.  As part of my normal maintenance program, I remove the one from the clutch cover and clean it using Brake Kleen to get the gunk out.  The other one to too large a PITA to get the same amount of attention.  I considered connecting the two hoses with a "t" fitting and routing to the HIF44 but the thought of those nasty gases being introduced into the nice clean fuel/air mixture put me off.  So, to offset any pollution from routing to the atmosphere, I planted a tree in my back yard.  My conscience is clear.

 

"To catch one, you need one"....John Cooper

 Posted: Jun 25, 2020 08:23AM
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Hmm i only have that crank case breather and have been running this setup for about 10yrs now.....I know the saying is if it aint broke dont fix it, but im bored so i wanted to improve!  lol.   



If i do decide to add more venting/breathers....where can i have them done?  I dont see anywhere else i could.  My engine is a Metro

 Posted: Jun 25, 2020 08:05AM
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It would work as that is the way the factory did it from the 70's but that being said they also had another breather later on on the clutch housing if you don't have that i would add a second breather somewhere.

If in doubt, flat out. Colin Mc Rae MBE 1968-2007.

Give a car more power and it goes faster on the straights,
make a car lighter and it's faster everywhere. Colin Chapman.

 Posted: Jun 25, 2020 07:19AM
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Ok so with all those suggestions is it a good idea to run that vent hose from the crank case back into the carb or should I leave it as it’s been and re rout it under the car into atmosphere???  I was concerned that with my 1380, if I vented that tube back into carb it wouldn’t have enough venting and I would be cause leaks and blown seals?  What you guys think?  

 Posted: Jun 25, 2020 07:07AM
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I've got an extension on the exhaust pipe of my Traveller. Without it the fumes inside are unbearable.

 Posted: Jun 25, 2020 04:26AM
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CA
As Ian says, it is likely exhaust fumes. Even if your exhaust system is absolutely perfectly sealed, exhaust fumes can be drawn in by the negative pressure he describes. At speed, there is a low prssure area behind any vehicle. A mini is not very aerodynamic, so it generates quite a bit for its size. Thus there is a cloud of fumes following behind. Besides the boot lid seal, Minis have an assortment of openings that will let fumes in - shifter, hand brake cables, rear side window seals, door seals, to name a few. There are a bunch of possibilities in the boot too, and each rear quarter panel has a finger-width gap between it and the rear bulkhead.

Outside the car, the type and location of the tailpipe is also a factor. A centre-exit tailpipe dumps exhaust directly into that low-pressure zone. A side exit (left side) is better. The tailpipe should extend beyond the bumper. I have a 1275 high compression engine with a RC40 stainless steel single box side exit exhaust system. (I have been chasing this problem for years...)  One mistake I made was getting the tapered tailpipe. It looks (and sounds) good but it lowers the exhaust velocity so it isn't pushed quite out of the low pressure cell. My car is OK to about 40mph/ 60kph, but above that, I have to consider closing the windows.

.

"Hang on a minute lads....I've got a great idea."

 Posted: Jun 24, 2020 11:03PM
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Hi Ricky, some carbs have a connector that can be attached to a breather tube.  However, I would be inclined to have more than one breather outlet (my 1330 has 4) and just vent to atmosphere ..maybe through a catch tank.

My experience is that fumes from the engine vents are unlikely to make it into the cabin.  More likely you have an exhaust leak ... or maybe even just the stuff coming out the end of the pipe... with the fumes making their way into the cabin through the boot/cabin floor or the rear firewall.

With a front window(s?) cracked open the cabin runs at a negative pressure that sucks fumes from underneath or behind the car...  Fumes can be sucked from behind the car into the boot through gaps in the boot lid seal.  These will then make their way behind the C pillar trim and into the cab though (hardly noticeable) gaps between the shell and the roof lining...

Cheers, Ian

 Posted: Jun 24, 2020 08:32PM
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Hey guys so I have noticed through out the years I have always been having fumes present in the cabin.  I have searched past threads about venting but I assume that they were applying it to stock engines.  So question is on my 1380 do these same principles apply? My current setup is with a canister with filter that comes from the crank case.  This thing is super duper stinky with fumes.  What I wanted to do is to run a hose from that canister on the crankcase and run it into the carb inlet vacuum.  Of course I would be using a vented oil filler cap to offset this.   Would this be the correct way about going with?  What are the pros and cons of running it this way as opposed to pcv?  Thanks in advance fellas!