A Series 1275 breathing setup

[AceOfHearts]

I have just bought a 1275 Sprite and was wondering if somebody could offer some pointers on the breathing system as it is spewing a fair bit of oil at the moment

It has an alloy rocker cover with no breather and a non-vented cap. The breather from the timing chain cover is just piped into a catch tank bungee corded to the front of the car. From what I understand this should be connected to the carbs but there does not seem to be a connection on the carbs for this. I will get some pictures tomorrow to help explain.

Anybody here with a 1275 that can maybe point me in the right direction?

[stevieturbo]

You can have a number of breathers....but if it's spewing oil out already I certainly wouldnt want it to be going back into the inlet manifold.

IMO you need that resolved before anything else.

[AceOfHearts]

stevieturbo said:

You can have a number of breathers....but if it's spewing oil out already I certainly wouldnt want it to be going back into the inlet manifold.

IMO you need that resolved before anything else.

By spewing I mean out of the rear seal (due to what I assume is positive crankcase pressure). Nothing appears to be coming from the breather hose

[Pumaracing]

Then the breather is fine and you just have a leaking rear seal.

[AceOfHearts]

Pumaracing said:

Then the breather is fine and you just have a leaking rear seal.

But on the A series it is not a normal seal, it is a scroll type thing that flings the oil back into the engine and requires negative crankcase pressure to work?

[Pumaracing]

Oh, you mean the crankshaft seal. The timing chain cover breather can get clagged up inside which is maybe why nothing's coming out of it rather than what I originally took you to mean that the engine wasn't actually breathing hard. Can you blow through the breather hose easily back into the cover?

[PeterBurgess]

The standard A series Midget engines do not have a rear oil seal for the crank, they rely on a scroll thrower system which requires a little pressure drop to stop it leaking, this pressure drop is applied via a pipe from the front cover breather to the canister air filter casings. With the engine switched off it tends to dribble at the back of the crank!
Usual practice is to fit a rear seal conversion. The best one we have used is the Keith Calver developed one. We have fitted around 10 of these and they are well thought out and very pleasing to the eye as a conversion whereas others look a little 'Heath Robinson' http://dt-vps.co.uk/calverst.com/cart/index.php?ro...
As Dave says, the breather has to be clear and free on the front cover. They can clog with age and we have even had to remove the original wire mesh filter and replace it with stainless steel mesh. We replace it with a stainless steel pan scourer...
http://www.amazon.co.uk/Jantex-Stainless-Steel-Scr...

If the engine is poorly, piston blow-by can show itself via the rear scroll, front breather , dipstick tube and the oil filler cap.

Peter

[Pumaracing]

Having gone round the houses several times and finally got things a bit more clear this is something of an object lesson in not explaining things properly.

AceOfHearts said:

I have just bought a 1275 Sprite and was wondering if somebody could offer some pointers on the breathing system as it is spewing a fair bit of oil at the moment

Which I imagine we all took to mean oil was spewing out of the breather as that was the only thing mentioned!

AceOfHearts said:

By spewing I mean out of the rear seal (due to what I assume is positive crankcase pressure). Nothing appears to be coming from the breather hose.

Ok now this looks like you're saying the engine isn't breathing hard or even at all and frankly what the "rear" seal means is unclear as this engine doesn't have a rear crankshaft seal.

Maybe in future a little more thought as to whether anyone reading what you post has a cat in hell's chance of understanding any of it?

[AceOfHearts]

Thanks guys I will check to make the front breather is clear.

My original post was clear in that I was asking how the 1275 breathing system should be laid out