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 Posted: May 24, 2017 02:50AM
Total posts: 7256
Last post: Sep 23, 2017
Member since:Aug 14, 2002
CA
Fair enough... though I don't know about you and tattoos... 

.

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

 Posted: May 23, 2017 03:49PM
Total posts: 1037
Last post: Jul 28, 2017
Member since:Nov 3, 2011
US
Perhaps we could agree that "works ok" and "de-tuned" mean different things to different people!   And Dan, I try to explain things that I understand to people, using terms and examples that most can relate to.  Even when I do that, folks can get up in arms about me putting free information and my view and OPINION (pretty normal for a forum setting) about a topic.  I don't get offended if you or anyone chooses to do things a different way, I'm simply telling you what works and why.  I've talked to both you and Mur and find you to be reasonable people, and likewise, you know that I'm not an obnoxious tattooed character from Orange County Choppers (not that there's anything wrong with that, mind you!)

Tell you what... if you make it down here sometime, come and have a ride in my Green Cooper S!   You will understand what I mean by the de-tuned state of the standard engine! 

Jemal

Yes you can reach me at

CooperRoadMini.com

 

 Posted: May 23, 2017 12:14PM
Total posts: 7256
Last post: Sep 23, 2017
Member since:Aug 14, 2002
CA
Quote:
Originally Posted by Jemal
What an interesting topic this must be!   First, "design engineers" are under a different set of directives than we as owners who understand how to improve our cars!  Volumes can be written about how design engineers got things very wrong!

Don't worry Mur.... You aren't doing anything "wrong"!  That system works ok most of the time!  But we know how to make it work better!  You have to understand that my engines, and most of the ones I build and spec for people are well above what the "design engineers" had to work with!  Your engine will work better if you just leave those vents open, and cap off the "special port".  If you feel bad about about contributing a small amount of pollution, you may run it into the air cleaner as a more benign solution.

And let me clarify how power brakes work!  A (relatively) great big hose goes to your manifold, but if it's working properly there is no outlet!  It only "sucks for a short time until the vacuum is "created".  Vacuum is another funny thing... not very intuitive to create something by removing molecules!  Quite a different thing to connect a hose to your carb that can suck through all manner of orifices! When that was in the Rover showroom, all those hoses were nice and new... none of the plastic elbows had cracked, non of the hose ends had melted and flared, all the seals were nice and new,  the breather cans were intact and had nice clean oil-screens,  nobody had applied duct tape and bailing wire to "fix" something!  The engine was tame and quite de-tuned. 

Finally, if your blow-by is coming up your guides and pressurizing your valve cover, you have far bigger problems!  Given that the valves are (or should be!) closed when you have compression, a much larger and more obvious issue exists! 

I really can't understand why some of you have such a militant attitude!  I very clearly state how I would do things and why!  Take from it what you want, or don't!   You must be open to making improvements and not hung up on the way it was originally.   So many people think it must be best "the way Sir Alec designed it"  I am not one of them.  We have realized a few things in the last 50 or 60 years, and I'm not afraid to make things work much better!
I'm not being "militaristic" (if you were referring to me). However, you are coming off as being condescending.

First off, we are not talking about the engineers who built the first "tractor engines" as you call them. (Even they knew what they were doing.)  The "directive" for managing emissions, say in the mid 1980's, would have been along the lines of "reduce emissions but keep the engine efficient, make more power and make it more economical." That is what they did. Infinitely more volumes have been written about how engineers got it RIGHT, by the way.

You don't have to lecture about how vacuum-assisted brakes work. My point in mentioning them was to present the analogy that, yes, they are a closed system (barring worn or broken components): likewise, an engine in decent shape does not have "all manner of orifices" and is a closed system.

The engineers that designed my HA83AA high compression MG Metro and its crankcase emissions management knew what they were doing. Despite having been worked hard and having suffered a loss of coolant resulting in the paint on the head being scorched, and not having being rebuilt, it works quite nicely, thank-you. I would not call its design "detuned". Yes, it is showing a respectable amount of age, but it does not leak oil, or coolant and probably provides close to its design output.





.

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

 Posted: May 23, 2017 11:15AM
Total posts: 1037
Last post: Jul 28, 2017
Member since:Nov 3, 2011
US
What an interesting topic this must be!   First, "design engineers" are under a different set of directives than we as owners who understand how to improve our cars!  Volumes can be written about how design engineers got things very wrong!

Don't worry Mur.... You aren't doing anything "wrong"!  That system works ok most of the time!  But we know how to make it work better!  You have to understand that my engines, and most of the ones I build and spec for people are well above what the "design engineers" had to work with!  Your engine will work better if you just leave those vents open, and cap off the "special port".  If you feel bad about about contributing a small amount of pollution, you may run it into the air cleaner as a more benign solution.

And let me clarify how power brakes work!  A (relatively) great big hose goes to your manifold, but if it's working properly there is no outlet!  It only "sucks for a short time until the vacuum is "created".  Vacuum is another funny thing... not very intuitive to create something by removing molecules!  Quite a different thing to connect a hose to your carb that can suck through all manner of orifices! When that was in the Rover showroom, all those hoses were nice and new... none of the plastic elbows had cracked, non of the hose ends had melted and flared, all the seals were nice and new,  the breather cans were intact and had nice clean oil-screens,  nobody had applied duct tape and bailing wire to "fix" something!  The engine was tame and quite de-tuned. 

Finally, if your blow-by is coming up your guides and pressurizing your valve cover, you have far bigger problems!  Given that the valves are (or should be!) closed when you have compression, a much larger and more obvious issue exists! 

I really can't understand why some of you have such a militant attitude!  I very clearly state how I would do things and why!  Take from it what you want, or don't!   You must be open to making improvements and not hung up on the way it was originally.   So many people think it must be best "the way Sir Alec designed it"  I am not one of them.  We have realized a few things in the last 50 or 60 years, and I'm not afraid to make things work much better!

Jemal

Yes you can reach me at

CooperRoadMini.com

 

 Posted: May 23, 2017 03:19AM
Total posts: 7256
Last post: Sep 23, 2017
Member since:Aug 14, 2002
CA
Quote:
Originally Posted by Jemal
Well, given that "pressure" can only get up the pushrod holes from the crankcase, then the lack of a vented fill cap won't "create" pressure any more than a vented one. 

If you plumb vents to the air filter housing BEFORE the element, then yes, you are going to soil your filter!  If you have an old wheezing engine, yup the filter gets soggy quick.   Use a bit of common sense!

Under no circumstance would I run vents into carb vacuum.  The rest of the world uses a simple PCV (as in Positive Crankcase Ventilation) valve.....   But that's just me...  you can do anything you want!   The next guy can call me to straighten out the mess!
Just to be technical, it isn't 'given that "pressure" can only get up the pushrod holes from the crankcase". The bulk of blow-by is from getting past worn piston rings, but there is also the possibility (albeit less) of leakage past worn valve stems, guides and seals. And then there is the issue of heat and expansion of air in the rocker cover.

To be fair, Jemal's suggestion about connecting the vent hose to the air filter base was with respect to a cone type. One can only port such a connection after the filter element on a cone type.

The early 850's had a rocker cover vent (only) that was connected to the stock air filter housing - outside the filter element. With no form of oil trap whatsoever, the element did get dirty in one spot - opposite the small tube connection. The small amount of oil deposited did collect dust from the air ingested through the air filter housing on its way to the carb.

Jemal seems to be in denial that well trained and experienced design engineers could (and did) develop a port in a carb that is capable of generating a small partial vacuum on the otherwise closed (sealed) crankcase system. Why he can't accept this is puzzling, consider he apparently does accept the principle of vacuum-assisted brakes which use a much larger port directly on the intake manifold.

Jemal: the chuffing you reported seeing on a brand-new engine might be attributed to the engine not being broken in - the rings may not be fully bedded in, resulting in blow-by.
If you want to talk "old-school", one guy I worked with was of that opinion that a new engine that consumed a bit of oil would eventually prove to be a better, longer serving  engine than one that was too initially tight. It gave the rings a chance to settle in better.

.

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

 Posted: May 22, 2017 06:25PM
mur
Total posts: 5665
Last post: Sep 21, 2017
Member since:Nov 12, 1999
Jemal:

You are serious here?

You are saying that what I have been doing for decades and hundreds of thousands of miles is wrong?

I seriously don't understand. 

If this is your practice, what happens when you actually go somewhere in your mini?

 Posted: May 22, 2017 12:47PM
Total posts: 1037
Last post: Jul 28, 2017
Member since:Nov 3, 2011
US
Well, given that "pressure" can only get up the pushrod holes from the crankcase, then the lack of a vented fill cap won't "create" pressure any more than a vented one. 

If you plumb vents to the air filter housing BEFORE the element, then yes, you are going to soil your filter!  If you have an old wheezing engine, yup the filter gets soggy quick.   Use a bit of common sense!

Under no circumstance would I run vents into carb vacuum.  The rest of the world uses a simple PCV (as in Positive Crankcase Ventilation) valve.....   But that's just me...  you can do anything you want!   The next guy can call me to straighten out the mess!

Jemal

Yes you can reach me at

CooperRoadMini.com

 

 Posted: May 21, 2017 07:15AM
Total posts: 7256
Last post: Sep 23, 2017
Member since:Aug 14, 2002
CA
Quote:
Originally Posted by 1963SV2
Fig 2 refers to the "filtered filler cap"...  the black ones I have are but, don't know about the red type..

Cheers, Ian
Ian, I'm not sure what you mean by "fig 2", but checking Minimania's online parts listings, the black ones are indeed vented and filtered (and are intended to be replaced periodically). The comment says they are for motors that do not have a separate breather on the rocker cover. The red ones are described as "Current production engines are equipped with this improved cap. It has a large grip and a improved lock system that insures a tight fit. Red in color."
The "current production engines" phrase is a bit out of date!
My engine, being a MG Metro has the finned, slope-top rocker cover which is a non-vented type. I guess the implication is that the oil return passages from the rockers to the sump are sufficient to vent the rocker chamber.

.

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

 Posted: May 20, 2017 08:56PM
Total posts: 1369
Last post: Sep 9, 2017
Member since:Oct 18, 2011
Fig 2 refers to the "filtered filler cap"...  the black ones I have are but, don't know about the red type..

Cheers, Ian

 Posted: May 20, 2017 03:11PM
Total posts: 7256
Last post: Sep 23, 2017
Member since:Aug 14, 2002
CA
Alex and Ian:

Thanks for straightening out those issues.

You have confirmed my experience in connecting the vents to my cone-type filter housing - it didn't work well. The capture of fumes is much better when connected to the proper port on the HIF44, with no apparent reduction in engine performance. No oil leaks or weeping gaskets either, on a high compression 1275 that has not been rebuilt.

Can you clarify for me which system should have a vented or non-vented filler cap? Which one do I have?

.

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

 Posted: May 19, 2017 11:11PM
Total posts: 1369
Last post: Sep 9, 2017
Member since:Oct 18, 2011
Quote:
Originally Posted by Jemal
............... Connecting to the carb port 'creates' a big invisible vacuum 'leak'.... that port doesn't "know" it's crankcase venting!  It just sucks, and the crankcase has many seals that are not designed to seal air pressure, so air is drawn IN to satisfy that vacuum.  That air messes with your mixture, and it's not easy to 'adjust' for it. .............ls, not to mention a vented oil fill cap that works both ways!
You really would think those idiots at BMC should have known this when they designed the system.... and published pictures of the connections in their workshop manuals......along with the "filtered filler cap"....

(Publication TP832C Section Ac-2 Fig. 2)

Its almost like we have two "specialists".....

Cheers, Ian

 Posted: May 19, 2017 11:48AM
Total posts: 9447
Last post: Sep 23, 2017
Member since:Mar 24, 1999
GB
Two pistons go up, and simultaneously two pistons go down.  In an ideal world the air displaced by one pair moves seamlessly to replace the vacuum created by the other pair.  With perfect ring seal no tuffing or breathing would occur...

Obviously, the inside of a Mini engine is far from ideal - there is a bath of churning oil being flung around from the gearbox, and rotating parts ruining the smooth transition of air.  There is also the inevitable ring blow-by adding extra gas to the crankcase.

By attaching the crankcase vents to the carb, all you are doing is removing the excess gas caused by blow-by and adding it to the intake.  Unless you are stupic enough to couple only one breather to the carb and run with a vented oil cap, the carb can and will only be able to draw out positive pressure - it will not create a vacuum in the crankcase.  If you run with a vent open then you will get air drawn through the engine and it will ruin your mixture control.

There is also little point in connecting the breathers to the air filter housing unless you wish to crap-up your filter with oil vapour and spend extra money of changing it regularly.  The suction there is minimal anyway.

Metric is for people who can't do fractions...

 Posted: May 17, 2017 03:30PM
Total posts: 1037
Last post: Jul 28, 2017
Member since:Nov 3, 2011
US
Fab60, if you have the K&N cone filter, you can drill a hole in the carb mounting plate  to mount a brass elbow that will accept a 3/8ths (or even a 1/2 inch hose for a hot rod).  There is some 'vacuum' there from the carb suction, but it will not affect the way the engine runs like feeding into carb vacuum does.  Connecting to the carb port 'creates' a big invisible vacuum 'leak'.... that port doesn't "know" it's crankcase venting!  It just sucks, and the crankcase has many seals that are not designed to seal air pressure, so air is drawn IN to satisfy that vacuum.  That air messes with your mixture, and it's not easy to 'adjust' for it. This condition gets worse with older engines that have more blow-by the rings, and old sketchy seals.... timing cover, primary seal, axle seals, not to mention a vented oil fill cap that works both ways!

Jemal

Yes you can reach me at

CooperRoadMini.com

 

 Posted: May 17, 2017 01:16PM
mur
Total posts: 5665
Last post: Sep 21, 2017
Member since:Nov 12, 1999
Fumes are not just a part of driving a mini.

I use the draw port on the carb and connect it to the available breathers.

1300s and big bore engines benefit from having a vent everywhere possible: drop gear housing, timing chain cover, valve cover, and I guess it was 1991 when I first made a messy but practical breather for the fuel pump mounting boss.

Looking back at earlier replies to this thread, I think Ian answered sufficiently.

 Posted: May 17, 2017 11:29AM
Total posts: 530
Last post: May 23, 2017
Member since:Jul 22, 2003
US
Jemal thanks for the intuitive response!  Might as well connect the crankcase breather to the air filter so the mini can suck up its own waste!  Brilliant!  My KN filter doesn't come with a vent to make it an easy application.  I know some of the KNs do but for the mini they don't have it??  

At the end of the day your right.  We can only do so much with the fumes issue, that's just part of driving a mini!  ??

 Posted: May 17, 2017 09:51AM
Total posts: 1037
Last post: Jul 28, 2017
Member since:Nov 3, 2011
US
Very well explained, except....  You do NOT want to connect the crankcase vents to the carb!  engines with "closed loop" PCV are designed much 'tighter' than our old 1950s Tractor engines!  When Rover did this in the 80s they went to some lengths to try to "seal" the engines.  They used non vented oil fill caps, ran all vents to common plumbing, and still, A+ Metros liked to coat themselves with anti-rust!  Connection to vacuum with large diameter hoses really messes with your mixture and idle speed and quality.  Run the vents to your air cleaner housing if you feel bad about releasing to the atmosphere!  

It's not just blow-by either!  It's not a measure of how much an engine is 'worn'.  The 180 degree crank means two pistons are ALWAYS moving in unison (and so are the other two!), and with the really absurdly long stroke, the air IN THE CRANKCASE moves a tremendous amount UNDER the pistons.  A brand-new engine will show significant "pulses" of air at the vents even without 'smoke'.

Valid explanation of exhaust flow!  Notice how newer SUVs have gone away from having roll-down rear windows? My late 90s 4-Runner was un-driveable with the back window down, even just cracked would make your eyes water with fumes! 

Of course the Mini carburetor is within reach of the driver, and most earlier Minis only have the plastic speedo separating your lungs from the carb throat.... Ever drive a hot-street Mini with the Weber DCOE right behind your speedo?  About makes your ears pop competing with you for air!  Oh yeah, you can smell gas!

Jemal

Yes you can reach me at

CooperRoadMini.com

 

 Posted: May 17, 2017 03:23AM
 Edited:  May 17, 2017 03:30AM
Total posts: 7256
Last post: Sep 23, 2017
Member since:Aug 14, 2002
CA
Exactly. or at a slow speed or stop, the fumes would rise back into the engine bay and travel through the holes in the firewall into the cabin.

Somewhere prior to emissions control, American engines typically had crankcase vents called draft tubes - a simple pipe hanging straight down into the air stream under the car. When the car was moving at speed, the flow (draft) of air past the end of the tube would cause suction on the tube, pulling fumes from the crankcase and dispersing them. If the engine was tired and needed work, you could see puffs of blow-by coming out the tube. With no oil trap (like Mini engines have), these engines were almost always undercoated in a layer of oil film and road dirt.

.

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

 Posted: May 16, 2017 03:45PM
Total posts: 530
Last post: May 23, 2017
Member since:Jul 22, 2003
US
Dan so maybe routing that breather all the way to the bottom of the front wheel well won't work as the air might circulate up to the drivers window.  


As far as blow by how do you tell how much?  

Adjusting the mixture with the added hose from the crank case will result in a lean or rich condition?

 Posted: May 16, 2017 05:03AM
Total posts: 7256
Last post: Sep 23, 2017
Member since:Aug 14, 2002
CA
To add to what Alex says about Mini aerodynamics...
All vehicles produce a low pressure cell behind them. Watch any car go down a dusty road - it is the negative cell that pulls the dust up into the air.

Problem 1: a Mini, being boxy produces a pretty good one for its size. Dumping exhaust into the centre of that low cell results in the Mini dragging a cloud of exhaust fumes behind it. A side exit exhaust tends to release fumes into the air that passes by the car, but if it isn't long enough, the fumes disperse between the bumper and body and get into the low air pressure cell. 

Problem 2. At speed the mini also produces low pressure cells on each side of the windshield. Next time you drive in the rain, watch how drops of water on the door glass move upward or forward as you drive along at speed. This negative pressure sucks air out of the cabin if the window is even slightly open, which explains why you get more fumes at speed when the door windows are open. even with the windows shut, there are enough cracks and holes in and around the doors and windows to let air seep out. (Rear wind windows can add to then problem.) Even the bottoms of the rear companion bins are open to the sills, which are... vented.

Problem 3: Mini body shells have numerous openings between the engine bay and the cabin, between the cabin and the road below, between the cabin and the boot and between the boot and the exterior. That means a pretty free flow for any wayward fumes.

So, if your Mini produces exhaust and you don't release it well, the negative pressure in the cabin sucks the fumes through the boot or floor into the cabin.

.

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

 Posted: May 16, 2017 04:43AM
Total posts: 7256
Last post: Sep 23, 2017
Member since:Aug 14, 2002
CA
Rick, since your original post is about fumes, the suggestion was to not let the fumes escape into the air, but to route them back into the intake system. The HIF44 port is (generally speaking) intended to cause reduced air pressure in the crankcase, rocker cover etc. so that fumes are drawn off rather than allowed to escape.  The port size on the carb is (presumably) the right size to do the job of taking care of normal blow-by. If it doesn't then your engine needs work. The hose connecting the breather system to the carb needs only be the right size for the port. You can buy in-line reducer fittings to transition from one hose size to another, or if the sizes are appropriate (usually not), you can seal the smaller hose inside the larger one. Or perhaps the last hose can be clamped tight enough to the port. The hose connections need to be airtight.

If your carb has been set up with the vent port capped, you will likely have to adjust mixture a little to compensate for the slight increase in air volume. The fumes being drawn from the crankcase are not flammable, being exhaust or partially burn air/fuel mixture that has got past the piston rings. Consequently, the carb port provides a wee bit more air, for which you may need to compensate.

If your engine is in good condition then you should have little blow-by, and the suction from the port should establish an almost steady state of reduced crankcase pressure. That means very little air is actually moving through the port.

Perhaps Mur or Alex can confirm which type of rocker cover cap should be fitted - breather or non- breather type. Also if it needs a proper seal.

.

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

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