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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - TD intake manifold

I have a 1952 TD. It had the original air cleaner removed when I got it. The vavle cover breather and the crank case breather were plugged and a PCV valve was installed. I believe it has a TF intake manifold which was drilled to fit the PCV valve which was connected to the crankcase via a tube into the crankcase breather before the plug. It actually runs well but the oil filler cap comes off. At any rate I want to undue that but not go to expense of the original system. I belive the intake manifold is for a TF. I hope I attahed photos. Can I use TF air cleaners so I can vent the vavle cover breather to one as was done with the TF? Any fitting problems? A radiator brace is already bent to accept the current air cleaners. Also the current carbs are SU AUC 549. Is that the 1 1/4 TD or the 1 1/2 TF? Thanks for any help you can give.

Gary
Gary Krafft

A picture would be worth a thousand words...

Tom
t lange

I tried to attach a photo but failed. Guess I need help with that too.

Gary
Gary Krafft

Click Upload, then Browse to find the picture file, click on it, then click then Submit. It has to be a pretty small file size, like 500kb or so or it won't work.
George Butz

Thanks for the help. The photo is larger-1.93. Maybe a cell phone photo will work. I'll try that. Then if I can figure how to get the cell phone photo.....

Gary
Gary Krafft

If you have windows photo manager in your system, go in and change the size of the photo. It is easy to do, change it to web size 640 or so and it will load easily on ths forum. in window photo gallery, find the one you want, go to OPEN click Microsoft picture adn when that come up go to Picture and go down to resize and from there it is simple .
Tom Maine (TD8105)

I’m glad we have this post. I have a 1951 TD with pancake air filters. The valve cover breather is connected to the crankcase breather. What problems will this create? Looking forward to the comments.
Dave K
david kirkpatrick

Gary

You can also go to Start/all programs/accessories and open Paint. You can load the picture into paint and then resize it. Normally about 50% to 75% will work for download to this site.
Bruce Cunha

I hope this worked. I will also try resizing but the cell phone was only 692kb.

Dave, do you have any problem with filler cap coming off while driving? I'm not sure if it is pressure from breather being plugged or just vibration. The engine runs good after warm. Oil pressure is 60 and drops to 40 after running awhile but at idle is more like 10.

Gary
Gary Krafft

Here we go again--this time resizing
Gary Krafft

Gary,
This system works,,,

.
Just below the box that you add your comment in, find and click on the word Upload (underlined)
That will open another small window with a button called “Browse…”
Click on that Browse button, and find the folder with the picture that you want to upload.
Click on the picture, (JPG’s Only)
Then click on “Open” and the location will appear in the box next to “Browse”
Click “Submit” and it should appear with your comments.
You will get a message that says
“Thank you, your file (FILE NAME.jpg) was successfully uploaded.”
Close the window
Then click “submit” to submit your mressage

If you get a message that the file is too large, use one of the many “Image Resizer Sites’ available on the internet to make your file smaller.


.
Hope it helps,SPW
STEVE WINCZE

Gary, No the cap has never come off, however I would imagine that I am building up some pressure.

Dave K.
david kirkpatrick

Steve
THanks for the help. I'm sure this will work.

Dave, I'm going to try running a hose from the valve cover breather to the crankcase breather and see if that works. I am concerned that TF air cleaners won't fit either at the radiator brace or on the carbs.

Gary Krafft

This time I got . the message. Third-fourth-or whatever time must be the charm


Gary Krafft

OK, those are 1 1/4" carbs. Original on TD's. The air cleaners are aftermarket, but I'm sure you knew that.
Cheers,
Bob
Bob Jeffers

HHuummmm,, so the intake manifold is drilled and tapped right where the mysterious intake baffle/ballancer is locarted????


.
.
SPW
STEVE WINCZE

"The valve cover breather is connected to the crankcase breather. What problems will this create?"

Oil leaks, sludge formation, internal corrosion damage.

The point of the breather system is to ventilate the engine to get rid of water vapour formed by combustion, and to prevent any pressure build up due to blow-by.

Water in oil forms sludge, which forms acids, which eats engines. Things like valve springs and tappets get rusty, even though they are covered with oil; bearings dissolve slowly.

If the system is sealed, pressure builds up and oil escapes anywhere it can.

The original system lets clean air into the rocker cover via the air filter connection. Many other cars used a simple filtered cap breather on the rocker cover. The air goes through the engine, and is drawn out of the crankcase breather, properly called the "road draft tube". The tube is meant to go down under the car, where the airflow from motion creates a very slight depression at the end of the tube.

PCV valve replaces the draft tube by connecting to manifold vacuum. There must still be an inlet for clean air to the crankcase, so the road draft tube should be modified. It no longer needs to be in the airflow under the car, and it MUST be fitted with a filter as the system will suck dirt and water into the engine - ESPECIALLY if the tube is left down by the road surface. Or, the air filter-rocker cover hose can be left, and the PCV plumbed to the tappet chamber where the draft tube was, but it is better to pull air from the rocker cover, since that is where condensation is createst.
The PCV valve is more positive (Positive Crankcase Ventilation) than the draft tube, and burns the vapours instead of pumping them into the atmosphere. Some PCV are just a restriction orifice, but most have a ball check valve arrangement as well, to control vacuum leakage into the manifold to acceptable levels under various conditions. Cleaner engines and cleaner air are good, so it is worth figuring out how to make the PCV system work correctly.

FRM
FR Millmore

First, the good news: you have the right carbs and intake manifold. You may be able to screw in a plug where the PCV port is. You could either leave the plug, or grind it down flush. Other options would be to weld the hole or as a last resort use JB Weld.
The breather pipe comes off the tappit cover. The pipe and cover are each available.
Now the bad news: the TD air filter assembly will be hard to find. You may just have to live with the aftermarket ones you have. The TD aircleaner really choked the engine, so a lot of them have been discarded.
D. Sander

Instead of filling the vacuum port on the intake manifold, you might consider adding a vacuum gauge, which may actually be used in tuning the engine. Just a thought.
Larry
Larry Brown

Best explanation of purpose and how breather and PCV work. Can I use TF air cleaners which would let me connect one air cleaner to the valve cover breather? It looks like that is how the TF was done. Are there any other aftermarket air cleaners made to connect to the valve cover breather.

In the alternative any thoughts on the proper way to hook up a PCV valve system.

Gary
Gary Krafft

There are a lot of TD filters available. they are on E bay a lot and I may know one locally for sale. E mail me off line if you are interested and I will pass this on to one of our other local members who I think has the whole thing for sale. t maine 51@ yahoo dot com
Tom Maine (TD8105)

The TF has 1 1/2" carbs, so TF air filters will not fit your carbs. You could fit TF carbs, these are essentially the same carbs the TD Mk II had. You can put a "breather plug" in the valve cover, that will work fine too. Moss sells them, they are not too expensive.
My TD does not have a breather port in the accessory cast valve cover, so I replaced the oil filler cap with a vented one.
You could drill a hole in the back of one of your filters and weld a bung in for a breather hose. That would work too.
D. Sander

"The original system lets clean air into the rocker cover via the air filter connection."

Do you not mean the air in the rocker cover is being 'removed' by the tube that runs to the air cleaner....?
gblawson(gordon- TD27667)

Gordon-
No. Flow is as stated:
filtered/clean air from filter (or other filtered vent - see TR2-4 rocker cover or any pre-smog American car) >> through engine >> out draft tube.
When the car is stationary and therefore no "road draft" effect, vapours may escape out both tubes; at such time flow will be into the carb, but this is not the normal operational condition.
If the carb air filter is restricted die to crappy design or maintenance, then the resultant depression may exceed that of the draft tube, leading to reversal of designed ventilation flow.
Excessive blow-by might also overwhelm the draft tube system.
In either case, the result will be filthy and malfunctioning carb, especially if it is an SU. Followed by fouled plugs.
Temporary first aid for clapped out engines was always to disconnect the air filter connection and fit a filtered cap or vent line to the rocker cover.

FRM
FR Millmore

FR, you've got me puzzled (not unusual). The carburetor intake is a significant vacuum. The rocker cover tends to have a positive pressure from blow-by in the crankcase. I find it difficult to comprehend how the flow of air would be from the air cleaner to the rocker cover. I share Gordon's view. Bud
Bud Krueger (TD10855)

Bud and all-
The carb entry is not supposed to be a vacuum point, and will not be unless the air filter is hopelessly clogged or restrictive (like the stupid aftermarket ones so often fitted). It is, after all, directly open to atmosphere through the filter. Make that "before all", as once you get very near or into the carb throat there starts to be some vacuum, but only at high airflow, i.e. WOT - that's closer than the spigot for the vent hose.

Serious competitors, like industrial engines and big trucks, use an "air filter restriction" gauge, and it is calibrated in inches of water - something around 15" is time to service the filter, but this is measured only at maximum load/WOT/full boost conditions; at idle it will be unreadable even on a big sensitive gauge. My NTC400 Cummins always sat on zero until it was pulling, and open highway cruise was normally 3" or so, with heavy pull at max power around 8 or 10" with a new filter.
(note: roughly, 1 atmosphere = 1 bar = 15psi = 30" Hg = 30 ft or 360" H2O)

A few cars, at the beginning of smog restrictions, attempted to utilize the "suction" of the carbs to better eat vapours at idle, since that was where the measurements were originally taken. Some early TR4 had a Y pipe in the vent connected to tubes in the filters that pointed straight down the carb throats, but these were still far enough out to not have significant vacuum. Didn't work well, though it satisfied legislation to not be "open to atmosphere" as the earlier mentioned TR rocker box caps were, and the real PCV systems followed immediately.

Later (c1970 on) SU and ZS have a breather port after the carb piston but before the throttle disc; this is the "constant depression" area that gives such carbs their name. The depression is low but constant, and this is in essence a very precise PCV system - here, the vapours do flow into the carb from the crankcase, with airflow into the rocker cover from a filtered source.

FRM
FR Millmore

....well, thats a new one... As soon as an XPAG is started there is suction through the carb of air through the air cleaner...the tube from the valve cover connects to the air cleaner...so....can't help but suck air through the tube/air cleaner into the carbs....
(time to do a test....)
gblawson(gordon- TD27667)

Gordon --- you've got mail. Bud
Bud Krueger (TD10855)

I fitted the moss alloy rocker cover (part number 224-245) soon after I bought my TF (to make it look good!). It does not have an outlet for the breather tube from the air cleaner. Until I read this thread I did not realise that the engine required air into the rocker cover. I have just looked at the rocker cover page in the Moss catalogue which does say “ refer to the restoration section for breather systems” but I cannot find the system they mean. I suppose the easiest solution is to replace the oil filler cap with a vented type as suggested by Mr Sander. Can anyone suggest a supplier?
Regards

Mike
M Sutton

I got mine at Advance Auto Parts, but it is a common part. Take your cap to an autoparts store and ask for a vented cap.
Here is a link to my cap:
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_Breather-Cap-Oil-Filler-Twist-On-Chrome-Spectre_22905717-P_N5001_PGRP2019_____

-David
D. Sander

Dave,
I'll bet that an MG rad shell emblem or even a hub cap emblem would look cool if it was epoxied to it!!!!!!!!!!!

SPW
STEVE WINCZE

"I fitted the moss alloy rocker cover (part number 224-245) soon after I bought my TF (to make it look good!). It does not have an outlet for the breather tube from the air cleaner."

Mike, here is a link to the Moss tech paper regarding valve covers: ( if all the details work)

http://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=56699&SortOrder=1

There is not a 224-245 cover still listed at Moss, but the paper implies that you could use the MGTC vented plug ( 225-900 ), if you install a hole for it.
Dallas Congleton

Thanks David

Mike
M Sutton

At some point in its past, my aftermarket cover did have an MG medallion added....the cap is also the same as a rad cap....


gblawson(gordon- TD27667)

After reading and considering all the responses it seems there are two possible ways to address the problem. The first is to acquire and install an original oil bath air filter system. That is cost dependent.

The second is to install a K&N filter to the breather pipe on the valve cover and reinstall a breather pipe to the tappet cover breather. From the comments, that should duplicate the original method of providing air to the crankcase. Anyone doing that? Does it or should it work?

On a related matter any place to get foam replacement filters for air filters? They are circular and about 2 in. wide.

Gary

Gary Krafft

hmmmm..i'm not sure i understand all i know about this.. isn't the crankcase essentially vented into the rocker cover by the push rod tubes?...whether there is vacuum at the rocker cover spigot is moot if the pressure in the rocker cover is higher than the air cleaner.. i do not understand if the MG designers were just looking for an unfiltered air source into the rocker cover, why the expense of the tube to the air cleaner assembly and nipple on the air cleaner? if the air flow is INTO the rocker at that point why the service mod to reduce the spigot orifice?

hmmm..not sure i understand all that i know about this. regards, tom
tom peterson

This thread was discussed between 31/07/2011 and 07/08/2011

MG TD TF 1500 index

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