1275 Crank case breather question

[Neil MG]

MGA and early MGB have a scroll system same as the Midget and Minor. Interestingly the rear seal was introduced around the same time as the closed circuit system!

The draft tube on the minor runs from the front tappet cover. Part number 2A118 - crankcase vent pipe.

[philthehill]

Interestingly my MG engined Minor does not have a closed breather system - it just has the pipe from the breather on the timing chain cover and a pipe on the rocker cover both terminating in a catch tank with a contents level indicator. The rocker cover oil filler cap is the ventilated type with a gauze insert which show no sign of oil mist of oil ejection.
The engine does not suffer from any oil leaks or nasty smells and runs perfectly well but there again the engine is provided with plenty of crankcase breathing. The catch tank has never needed to be emptied and has never shown any signs of filling with oil. The bores on my engine are perfect but with worn bores it may be a different ball game.
I would agree with the comment regarding rear crankshaft seal kits. I had one fitted to the rear of my Midget engine and can honestly say in my experience it was more trouble than it was worth.

[bmcecosse]

Yes - but your engine will be in 'perfect' condition......the smells etc come with age........

[izzi]

Where can you get hold of a secondhand or new timing chain cover with new type oil seal, or even the one with breather part No 12G2507.

Roy

[philthehill]

'e' bay
Item No: 390655066132.
Cost £12.

[izzi]

'e' bay
Item No: 390655066132.
Cost £12.

That one seems to be a different shape, will this one fit a normal 1275 engine.
Roy [frame][/frame]

[philthehill]

Roy
That is a similar one to the one fitted to my 1275cc Midget engine. It looks to be the single chain type but with this cover I am certain you can fit the timing chain tensioner as well. You may need to drill a couple of more holes in the front engine plate to take the extra screws. Below is a photo of the timing cover on my 1275cc Midget based engine. The parts needed to fit the timing chain tensioner are Plate Tensioner Mounting 12G 2628, Pad Tensioner 12G 2621 and Pin Tensioner 12G2629 you will also need a bolt to fit the Plate Tensioner Mounting. All available from Somerford Mini Ltd[frame][/frame]

[izzi]

Hi Philthehill , That is good news. Thanks a million.

As you can guess I have acquired a 1275 engine,which has been rather "dare I say" bodged. Mainly on the areas to avoid oil leaks, yet the rear section of the engine did not have the usual oil leak. (never seen as much orange gasket replacement in a life time)
Can I ask does the double timing chain- Duplex 2H4905 need a tensioner, as there is none shown on the parts book.

Roy.

[philthehill]

Roy
Under normal use the double chain does not need a tensioner but I have a double row timing chain and chain tensioner fitted to my engine as I have been running an extreme cam (Kent 320 scatter profile) and it needs all the help it can get to keep the correct tension.
I have amended my post above to give you the part numbers and supplier of the tensioner parts required. If you go on the Somerford Mini Ltd web site and click on engine, internal, 998cc there is a very good illustration of the set up.
If there is anything else you need to know please ask.
Phil

[izzi]

Thanks again Phil.

You really have saved me from a large problem.
Roy.

[Neil MG]

Great! I will go for an open system.

It seems that Phil has answered my question and I am confident the set up I proposed will provide adequate ventilation. It's a completely rebuilt engine with new liners and pistons so there should not be any excessive blow by. I will vent the timing cover to atmosphere (with the addition of an extended and angled outlet pipe providing a vacuum when moving) and take filtered air in from the air cleaner box via the rocker cover. Basically standard Morris Minor breathing with the only exception being that the outlet is from the timing cover instead of the tappet cover. I will keep the standard manifolds and use the "carb. spacer with take off" for the brake servo.

I had thought about using that as the crankcase breather inlet and having a closed ventilation system, but it seems that is not necessary or advantageous.

I guess it makes no difference whether the filler cap is vented or not.

[bmcecosse]

If you don't want to be breathing carcinogenic fumes.....I urge you to use a NON vented cap....