Bad experience with small crankcase breather

Many thanks.

Many thanks Dave,

that's really useful info. Strangely enough, my flame trap was down the engine end of the breather hose (and I'm relatively sure it has never been out of the car as everything is original). I'll move it up to the carburettor end now.

Cheers,
Dom.

halojm said:
Dom,
- If the flame trap was indeed clogging the breather hose and causing oil to come out of the crankcase seals, will prolonged leakage / pressure have resulted in permanent failure of these seals?
It could, especially if it pushes the seal's lip outwards (so it would no longer have the little spring lip inside holding pressure onto the sealing surface.

- does the air coming from the breather need to be filtered before being sucked into the carb, i.e. should it be on the inside or outside of the filter element?
No. The way the crankcase evacuation system was designed by Fiat is not filtered, but rather goes up into the already filtered area of the air cleaner assembly where the vapors can be sucked thru the carb and burned.

- how do you get this thing off? I undid and removed the bolt and pulled at the breather but it won't budge. I didn't use extreme force. Is there any trick to getting it off? Also, is there anything to clean in there once I remove it?
Once you have the bolt off, it's only held on by the very well stuck gasket. A little tap with a plastic hammer should break it free. Clean as much of the goo you can see, then put it in carb cleaner for an hour and it should be perfect. Also, make sure you install the cyclonic trap (that little spirally thing) near the top of the crankcase breather hose, because that's where it's supposed to do its job.
Dave
Click to expand...
 
The Flame Traps Can Slide Down

Over the years, the crankcase breather hose can swell, allowing thr flame trap to slide down toward the bottom. We used to "fix" it by putting a spring-type hose clamp like the one originally used to hold the hose to the air cleaner (come to think of it, we would often times just move that clamp down lower) down below where the flame trap was supposed to be, preventing it from sliding fdown the hose.
Dave
 
Hi all above, couldn't access pictures mentioned above. I am a little baffled as to how many cranks breathers there are on my 1500 carburettor X 1/9 engine. Went to have a look at mine and found what seems to be two hoses or pipes. Looked on web site pictures of 1500 motor from the UK at a FIAT dismantler. It seems my engine has this X 1:9 1500 breather view.jpg as well as a cyclonic breather with a hose. other hoses have gone soft and flacid ??? yikes !!
 

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The large hose that is attached at the bottom center and is open at the top is the breather. The two hoses attached at the bottom and to the left of the breather - one of them has a filter on the end - are fuel lines in and out of the mechanical fuel pump.
 
dcioccarelli said:
Sports air filter.

Just resurrecting this post.

I seem to have a similar problem with a car that is a twin of Pauls (except that it resides in the southern hemisphere). In my case, I have the crankcase breather vented into a "ramflo" sports air filter, similar to this:

rf445s.jpg


The crankcase is vented into an inlet in the air filter, although I seem to get oil accumulating in the filter itself and I seem to be loosing more oil than before. Admittedly, we are talking about a motor with 250,000 KMs, so I could have a lot of blow back, but I could swear that I have higher oil consumption with this filter.

In any case, I'll be reconditioning my engine (and fitting my new carburettor from Steve and 4:2 header) on my next trip down under. I'd still be interested in why a sports air filter could lead to higher oil consumption (and where the oil is going).

Cheers,
Dom.
Click to expand...
Dominic, wasn't able to open/view your interesting pic of cranks breather and its vent into a ramble. Was considering similar filter from Hank Martens with separate breather hose filter. Today went to look at my cranks vents and was confounded by two hoses from two locations. ?? Yours too. ?
 
milan1951 said:
Dominic, wasn't able to open/view your interesting pic of cranks breather and its vent into a ramble. Was considering similar filter from Hank Martens with separate breather hose filter. Today went to look at my cranks vents and was confounded by two hoses from two locations. ?? Yours too. ?
Click to expand...
Judging by the time stamps, it looks like you and EricH were posting replies at the same time.
As mentioned, the large hose in the center is the vent. The other hoses aren't part of this equation. The vent usually attaches to the air filter housing, from underneath.

If you are running a K&N style filter, most people vent to atmosphere or into a vented catch can.
Unfortunately the pictures link is dead, but on pg 1 I posted a pic of a metal vent tube I made on my previous '78 which vented into a small Bayless filter.
That filter had a small piece that consists of a bung with a flat backing plate. It fit/ was held between the upper and lower cover.
I might go back to this design on my current car, as venting to atmosphere has the forward side on my engine caked in "corrosion preventative".
 
Met with a team at Bonneville a few years ago. Their lead engineer explained in detail the reason for the elaborate crank breather assembly I pointed at. The guy was a no-s#$t fluid dynamicist. Through extensive testing, they found huge ammounts of wasted HP with poorly vented crank cases. He explained it was the single largest thief of power, more than all the other ancillary systems combined. He was talking 15-20%! I tend to believe him. They were running over 300mph with a twin squeezed small block. It looked like a space shuttle main engine with all the plumbing. FWIW, I have one big fat hose coming out the breather all the way up to a filter in the right side "engine slat". I can sometimes watch vapor come out after running hard. Never seemed to have an issue with over-pressure.
.
IMG_5397.jpg
 
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tigeravg said:
Met with a team at Bonneville a few years ago. Their lead engineer explained in detail the reason for the elaborate crank breather assembly I pointed at. The guy was a no-s#$t fluid dynamicist. Through extensive testing, they found huge ammounts of wasted HP with poorly vented crank cases. He explained it was the single largest thief of power, more than all the other ancillary systems combined. He was talking 15-20%! I tend to believe him. They were running over 300mph with a twin squeezed small block. It looked like a space shuttle main engine with all the plumbing. FWIW, I have one big fat hose coming out the breather all the way up to a filter in the right side "engine slat". I can sometimes watch vapor come out after running hard. Never seemed to have an issue with over-pressure.
.View attachment 34526
Click to expand...
There was a similar thing on a recent popular automotive TV show. They put an engine on a dyno and keeping everything else the same, recorded the output with different levels of oil in the crankcase. Their point is oil splashing around and hitting the crank as it rotates causes additional wasted workload and reduced power. The show's example wasn't exactly an empirical scientific experiment, but it helped to demonstrate what engine designers have known forever. That's where things like splash pans, scrapers, etc, come into play. Naturally it will differ depending on the specific engine design and lots of other variables. But in that particular example the engine's power was improved most with almost a quart less than the recommended level. Personally I would not sacrifice engine reliability, longevity, and other practical factors for a tiny increase in power. However the crank breather is an area where sufficient ventilation can be achieved without any trade offs in reliability, etc - in fact it will likely improve things.

A while back we talked about engine "catch can" breathers that are oil/vapor separators that ultimately vent to the atmosphere. That seems the best solution to me. Although venting any vapor to the atmosphere isn't the most environmentally sound practice, on a vintage collectable car that's only driven a few miles a year it doesn't bother me. And the old designs of engines like these tend to really clog up the internals with oil residue as described in earlier posts (in this thread).
 
milan1951 said:
Dominic, wasn't able to open/view your interesting pic of cranks breather and its vent into a ramble. Was considering similar filter from Hank Martens with separate breather hose filter. Today went to look at my cranks vents and was confounded by two hoses from two locations. ?? Yours too. ?
Click to expand...

I can't ind the photos either :( , but I only have one vent coming from the cyclonic trap. I would not recommend venting directly to the atmosphere as you really need a vacuum to provide negative air pressure. What I ended up doing was to insert a catch can between the breather and the carb, as per: https://xwebforums.com/forum/index.php?threads/crankcase-vent-hose.33012/#post-280821.

Cheers,
Dom.
 
The US-spec 1300 carbs have a vacuum port specifically intended for crankcase ventilation - it opens more as the throttle opens so draws more at higher power levels. The stock setup ran the breather hose to a Y built into the air cleaner housing, one branch of the Y went to the carb’s vacuum port and the other went into the housing inside the filter.

When I installed a K&N style square filter I lost the Y, so I modified a generic PCV valve to act as a check valve. The carb vacuum line applies vacuum to the breather hose below the valve, the valve opens and vents to the side of the filter only if there is positive pressure despite the carb sucking as much blowby from the crankcase as it can. So far it’s working really well, with much less oily grunge sprayed around the engine bay.
 
There are lot of oil catch cans on the market but most of them do no good as they don't have filters/baffel for trapping oil and contaminants. -An empty tank will not do a proper job.

Even vacuum pumps are available to eventually gain power. I am a little bit sceptic myself.
www.enginelabs.com

Tech: How External Vacuum Pumps Free Up Horsepower

External vacuum pumps are an ideal power tool for race and high-powered street engines. By reducing crankcase pressure, the pumps promote ring seal.
www.enginelabs.com www.enginelabs.com
 
Bjorn Nilson said:
There are lot of oil catch cans on the market but most of them do no good as they don't have filters/baffel for trapping oil and contaminants. -An empty tank will not do a proper job.

Even vacuum pumps are available to eventually gain power. I am a little bit sceptic myself.
www.enginelabs.com

Tech: How External Vacuum Pumps Free Up Horsepower

External vacuum pumps are an ideal power tool for race and high-powered street engines. By reducing crankcase pressure, the pumps promote ring seal.
www.enginelabs.com www.enginelabs.com
Click to expand...

A catch can dosn't need anything else to trap the oil, the breather hose goes in the top, any oil that gets in stays there untill you empty it. It can be vented via the engines air filter, or to atmosphere.
 
GregS said:
A catch can dosn't need anything else to trap the oil, the breather hose goes in the top, any oil that gets in stays there untill you empty it. It can be vented via the engines air filter, or to atmosphere.
Click to expand...

The baffles prevent the oil vapor from leaving the CC. They (the oil particles) hit the baffle & separate from the air. May not be an issue on an NA motor, however I can assure you on a turbo motor running 9K + rpm, using an unbaffled CC will create problems.
 
I agree with @Bjorn Nilson and @lookforjoe , a oil/vapor separator is much more than a catch can and will help allow ventilation of pressure without loosing oil. Also reduces the mess of oil collecting either on or in the engine (intake track) that you'll get with a typical breather or catch can. So it's good for an externally vented system (to atmosphere) or an internally vented one (to the intake).

Furthermore, not all oil/vapor separators are equal. There are many types, many of which really aren't anything more than a catch can with some steel wool stuffed inside. A true separator is designed with baffles, air flow control, a "filter", and a return/drain. Look online at the ones designed for 'big-rig' trucks to see how they engineered internally to get an idea of the difference.
 
GregS said:
There is an interesting thread on another forum that's worth reading if you are considering fitting a small filter to the crankcase breather.
Click to expand...
Something Guy mentions in that discussion is venting the crankcase to the exhaust system with a valve so that it creates a little vacuum to help evacuate the pressure. That's something that was very popular many years ago but seems to have fallen from grace for some reason. The 'special valve' he refers to is actually a common emissions part used on many production vehicles many years ago. Basically it's just a one-way 'check' valve to allow the crankcase fumes to flow out but not let the exhaust fumes flow into the engine. It's available at any parts store very inexpensively. Here are some images of the setup (not mine, just copied from online):

sp7318-100.jpg

evacsysteminstallsy2.jpg
Case Vent.jpg


As was stated in that GC discussion, there probably isn't much to be gained by routing the crankcase vent to a low pressure source - at least not on our tiny, low power, street engines. But if nothing else this system routes the vapor to the exhaust system rather than into the intake track or directly to atmosphere; perhaps the heat of the exhaust helps to burn some of it off. Personally I'm debated about whether it's worth doing or not. I think a oil/vapor separator should still be incorporated in the system somehow, maybe where the breathers are in that last image of a typical V8 setup.
 
Another interesting comment in the referenced GC discussion about crankcase ventilation and windage losses was that we're talking about something like a 5% difference. And that's between a worst case stock engine scenario and a very high tech dry-sump/vacuum pump/crank scraper/windage tray/etc. Bear in mind that 5% on these engines is around 2 or 3HP. GC made an interesting statement that he always considers the cost vs the benefit, and things like this are simply not cost effective - especially compared to many other improvements that can be made. Naturally that may differ if you are building a 'cost-is-no-object' 100% race engine vs a stockish street engine. And not that everything GC says is the gospel, I'm just commenting on some interesting things that were stated. Fun article to review.
 
well some months ago i decided to clean my cyclone fitting (128 coupe 1.3), i discovered that it was pretty badly clogged with rather solid black crap..i had it cleaned nice and fitted on the car (the hose was been routed the the ground by the PO and i never thought to attach it to the air filter again...) so i went for a run to see if there was some noticeable improvement..well really no difference at all..needle to say i was a bit disappointed and stopped to think about fancy stainless crankcase breathing bottles..
 
I never realised there was such a huge range of catch/breather cans out there. I fitted mine to comply with local racing regs to have a min 2 litre can if the breather is not fed into the air filter. I assumed the cyclonic oil/air separator is doing a reasonable job, but I can see some advantage in having extra condensing plates of some kind inside. After reading more about them I think I will make larger connections on the tank for better air flow, having previously replaced the small air filter on top with a hose to down below the car.
On SummitRacing they tend to list them as either breather tanks (plain tank) or oil/air separater tanks.
 
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