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MG TD TF 1500 - TD oil bath air cleaner

As some of you have time, I would be interested in knowing about the following. I notice that with several TD's on the market the photos show the oil bath cleaner on top of the valve cover (such as mine) have been replaced by bright individual air cleaners attached to the SU's each. I wonder what is the advantage of this and should I consider the same replacement?
Thanks to any of you who might have an idea!

Dick Thomas
Wooster, Ohio
R S THOMAS

a friend of mine has had an engine overhaul shop for decades. he says the oil bath..if properly maintained... will do a great job. the operative phrase is "properly maintained". paper filters are less messy. regards, tom
tom peterson

I put a pair of Stellings on my 51 once and hated them. Makes the engine growl when you accelerate. I took em off and i think i have them in the garage waiting for a new home.
TRM Maine

Dick,

John Twist says nothing filters better than a properly maintained Oil Bath. See http://www.youtube.com/watch?v=1AbGCGa_PCQ for his YouTube video on air cleaners.

The individual filters are aftermarket, and were favored by racing groups, and hence became a sporty item. They have their place, but I've never been able to notice a performance difference on a straight or mildly tuned engine.

warm regards,
dave
Dave Braun

Dave,

Most kind. I really appreciate Twist's video! At my advanced age I am challenged by this moving wall of information covering us.

Warm regatds,

Dick Thomas
Dick Thomas

And if you do decide to use 'pancake' style breathers...your original air cleaner, aluminum manifold is worth upwards of $400.00
gblawson (gordon)- TD#27667

Dick,

If you poke around youtube a bit, you'll find John Twist has about 60 entertaining videos. Just search under University Motors.

warmly,
dave
Dave Braun

I wonder how this oilbath filter works. In which way does it catch the dust? Anybody knows this?
Greetings, Huib
Huib Bruijstens

AS THE INTAKE AIR PASSES OVER THE OIL IT IS WASHED BY THE OIL WHERBY THE DIRT AND DUST FALLS INTO THE OIL BATH. THUS THEOIL MUST BE CHANGED FROM TIME TO TIME. HOW'S THAT FOR A TECHNICAL EXPLANATION. IT PROBABLY WORKS DIFFERENTLY IN HOLLAND.

WARMLY,

Dick Thomas
Wooster Ohio
Dick Thomas

Mmm, I cannot see why dust and dirt would fall out the stream of air that is on the move to the inlet. What is the physics behind this?
Greetings, Huib
Huib Bruijstens

Huib, as I interpret the filter, the mesh on the inner part is wetted by the oil in the outer container, both by splash action and by wicking action. The oil covered mesh then extracts the dust particles by adhesion from the air passing through.

Dallas
D C Congleton

Basically like a spider web... the oil is the sticky stuff... dust just sticks to the mesh.
gblawson (gordon)- TD#27667

Dick
If you go with the dual pancake cleaners, you'll need to alter (slightly bend) the radiator stay bar to pass around the forward cleaner. My TD only had pancake units and the PO never put the bar back on (neither have I and still need to do come spring!). I searched around for a pair that would work without bar bending (and posed to the BBS) but never found any.
Randy
R Biallas

Randy,
After the remarkable search by Huib to understand the physics of the oil bath cleaner and the even more remarkable description of such physics by Dallas (although I'm not completely convinced that they do not work differently in Holland), I wouldn't dream of changing away from my oil (spyder web) unit.

Dick Thomas
TD13583
Dick Thomas

I have never seen an oilbath filter from a TD. I have, however, strong memories of the one in my dad's squareback Volkswagen when I was of oil-changing age.. I distinctly remember the steelwool-like "oil filter" in the sump and the absence of an actual drain plug... there were five studs with nuts to hold a plate on the bottom of the engine; no way to avoid oil running down your arm when you drained the sump! Stupid design!!!

Anyway, it also had an oilbath air filter. The air had to go through the pool of oil in it and change direction in the process (coming into the top of the filter, going through the oil, under a baffle, then up out of the oil and down into the carb. Btween the trip through the oil and the change of direction, the air loses a lot of contamination. Pain to clean it, however.
David "many fond memories..." Lieb
David Lieb

Oil sits in a circular bath in the bottom of the filter assembly. Incoming air is drawn down the sides of the cannister and through the oil bath, and in so doing, it leaves its particles in the oil. Engine vacuum causes the air to be drawn from the oil bath into the centre of the cannister thence into the inlet. Baffles prevent the oil from entering the air stream. Very simple system, once you see it.

A VERY ROUGH sketch is appended.

Gord Clark
Rockburn, Qué.






Gordon A. Clark

Nice Sketch. I have tried both the pancake air filters (with paper elements) and currently have the oil bath (original)installed. The oil bath is quiet and works well. As a physicist, I can tell you that the paper elements work by tortuous-path mechanical trapping (filtering) of the dust particles, while the oil bath works by both tortuous-path as well as wet adhesion filtration. In a very, very dusty environment, one could expect the paper filter to initially work better, since it is a more tightly sealed system and has very fine pores for filtration and airflow. However, once it becomes saturated, a paper filter first clogs, restricting air flow and choking the carbs, then becomes subject to breakthrough, that is, it clogs and then can fail and allow dust to break through under pressure. The oil bath allows a more free flow of air, so it is possible for some dust to get through, but, the engine probably also gets more air as well. So, given that SU carbs are venturi-based, I would prefer them to be mated to a system that has greater air flow at all ranges of the throttle. That is, the greater airflow capacity of the oil bath setup should allow the carbs to function better through their entire range, while the paper filters should have a theoretical limit to their air flow based on the limited surface area of the paper filter. I therefore believe there may be a flow advantage to the oil bath setup.
Ira Spector (PA)

Thank you all guys for bringing up these thoughts. Now things become clear. Adding up some of the above statement looks like the information I just now found in Wikepedia about the oil bath filter.
This states:
An oil bath air cleaner consists of a round base bowl containing a pool of oil, and a round insert which is filled with fibre, mesh, foam, or another coarse filter media. When the cleaner is assembled, the media-containing body of the insert sits a short distance above the surface of the oil pool. The rim of the insert overlaps the rim of the base bowl. This arrangement forms a labyrinthine path through which the air must travel in a series of U-turns: up through the gap between the rims of the insert and the base bowl, down through the gap between the outer wall of the insert and the inner wall of the base bowl, and up through the filter media in the body of the insert. This U-turn takes the air at high velocity across the surface of the oil pool. Larger and heavier dust and dirt particles in the air cannot make the turn due to their inertia, so they fall into the oil and settle to the bottom of the base bowl. Lighter and smaller particles are trapped by the filtration media in the insert, which is wetted by oil droplets aspirated thereinto by normal airflow.

And I also finally found it in the workshop manual: it is all in the back under the topic: lubrication. Added is the image of the filter. It shows that the description given above is applicable: the air passes over the oilsurface and whilst taking this U-turn it looses the heavy dust.
The image also made it clear to me that the gasket (see penpoint) is important to avoid the air taking a shortcut and in doing so, missing the final cleaning in the media-containing insert.
As written by you, the dust will be collected in the oil and also in the mesh in the insert. So, both need some regular maintenance and that is exactly what is written in the workshop manual.
Since I miss my original airfilter, I bought an aftermarket one. It looks like the original, but has no mark on the inside for the oillevel.
Greetings, Huib


Huib Bruijstens

HUIB,

I AM MOST PLEASED THAT WIKPEDIA AND THE WORKSHOP MANUAL TELL YOU EXACTLY THAT WHICH WE HAVE BEEN EXPLAINING TO YOU OVER THE PAST WEEK! I DO AGAIN CAUTION YOU, HOWEVER, THAT IT MAY WORK DIFFERENTLY IN HOLLAND. SO MANY THINGS DO.

WARM REGARDS,
DICK THOMAS
TD13583
Dick Thomas

Interesting. I don't know that I would really call this an oilbath filter, Wikiopedia notwithstanding, inasmuch as the air is NOT forced through the oil as it is in the oilbath filters I have used in the past, none of which had any mesh or other media inserts. This seems to be more closely related to the technology on my old Briggs & Stratton lawn mower with the foam insert you were supposed to suffuse with oil. Better than nothing, I suppose...

Why are you shouting, Dick?
David Lieb

MY KEYBOARD IS STUCK IN UPPER CASE.
Dick Thomas

That's a darn good reason, Dick ;-)
Or are you using an old Radio Shack computer that had no lower case? I would be much more impressed if you had managed to get one of those setup to talk on a BBS like this one...
David Lieb

Have you tried using the CapsLock function to reverse it?
David Lieb

David,

I'll attempt to take them one at a time:

1) I have absolutely no interest in impressing you.

2) I did not buy the computer from Radio Shack but from a private party in Illinois. I should have know better when I found he was an owner of a blue MG.

3) I did attempt your solution in reversing the Capslock function and, as you will certainly notice, it was highly successful. Your technical knowledge is really impressive.

With warm personal regards,

Dick Thomas
TD13583
Dick Thomas

David, a couple of questions for you, if I may --
1) Have you worked with a TD type of oil bath filter?

2) Have you ever seen the amount of crud that is collected in the bottom of the oil bowl of one? They really do work quite well. IMHO.

Much better than nothing.
Bud Krueger

Bud,
1) Please see my statement above of 01 April 2008 at 22:08:38, wherein I clearly stated that I have never seen a TD oilbath air filter, at least not internally. I have, however, seen far too many T-Series cars with nothing on the face of the carbs whatsoever and have always wondered about that.

2) I am glad that you agree that I was right when I supposed that it was better than nothing. I still think the units that force all of the air through the oil are better at cleaning the air. I HAVE seen the crud in those. It is probable that the TD unit yields superior performance over the VW unit... at least I hope so!

3) I would still love to own a TD someday. I blame all my MG leanings on a lovely red TD with cream interior that I met as an impressionable teenager. I am not attempting to denigrate any MG in any fashion. Just now Spridgets fit my wallet and my lifestyle a bit better.

Dick,
1) I guess my woeful attempt at humour fell a bit short. I certainly would be impressed with anyone who successfully interfaced with this page using a computer of such old technology that it did not use lower case. Not that it couldn't be done, but I would have to question the amount of time invested in such a pointless effort.

2) Would it have been better if his MG were red?

3) I am gratified to see that the workaround was efficacious. Yes, I work on computers in order to support my LBC habits. Glad I could be of some marginal assistance.

David "trying not to take myself too seriously" Lieb
David Lieb

I think that all the OLD TIMERS would agree that the oil bath did a better job cleaning the air than did the screen and paper filter. Most went away from the oil bath setup because of the spillage when racing on dirt track.
Jay Dyck

To All ---- Having lived trough the time when TD's were new, the reason you see so few oil bath air cleaners is that when you took off the manifold from the carb's to the air cleaner there was a very distinct improvement in performance. I don't know how much the manifold contributed to the performance loss versus the cleaner itself,

The fact that so many were removed and eventually lost is the reason the air cleaner/manifolds sell for such ridiculus(sp) prices today.

Cheers,

Bob
R. K. (Bob) Jeffers

I don't think that anybody should say that they know MG'S until they have maintained a T-series or older. Newer one just are not the same.
Sandy Sanders
TA-1938-Tickford (basket)
TD-1952
VA tourer 1938 (sold after 18 years ownership)
Sandy Sanders

This thread reminds me of the TD I keep going for an elderly friend of mine. He has a neighbor, bonafide, from England, actually worked as an engineer at the MG factory, that was shocked there was oil in the air cleaner. He had convinced my friend that the engine was pumping oil and needed extensive work. Luckily, I was able to produce the handbook, showing the need to "add" oil to the air cleaner. For an archaic system this works rather well.
mike barnes

To those of you very tired of reading about oil bath air cleaners, I appologize for starting this monster! I was just asking what I thought was a simple question. Apparently not so simple. I'm now leaving to check the oil level in my air cleaner.
Dick Thomas
TD135883
Dick Thomas

My dad's '64ish Ford diesel tractor had an oil bath air cleaner. Seemed to work very well- it had a pre-collector on top, and the oil in the bottom would get really filthy in a hurry. It was very efficeint in our dusty sandy soil. On the caps lock thing, I was using my nephew's new notebook computer yesterday- most shocking to me was a tiny green dot that lit when the caps lock was engaged. Brilliant! Now is someone could just put an "off" button somewhere- it still frosts me to have to click on start to turn the things off! George
George Butz

This thread was discussed between 22/03/2008 and 06/04/2008

MG TD TF 1500 index

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