what is the number of breathers needed on a 1275 with work done?

where would be a good place to have the breathers? Photos would be good reference if possible.


if there was only one breather that was the standard one out of the rocker cover would this be insufficent and cause the engine the blow oil out of somewhere and cover my engine in oil?

Cheers Dan (thanks for your replys in advance)
Frustrated mini owner

If the piston rings are good, on a road car you only need 1 breather.
When running a PCV valve on a non-S 1275 I found:
Breather on flywheel housing = sucks oil into manifold on long LH bends at high rpm.
Breather on timing cover = I can't use one (belt drive kit fitted). Not much room there on a roundy either.
Breather on fuel pump hole = sucks oil into manifold over 4500 rpm.
Breather on rocker cover = works perfectly. I'm now using a Toyota PCV valve there...

On track days, I ran both the rocker cover and flywheel housing ones into a catch tank, and plugged the PCV valve.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

so where should the breather run from the rocker cover to charcoal cannister?
my engine is a new engine i had trouble with oil sprayed all over engine bay and when cleaned down and dried i cannot find a oil leak any where ,would it be possible that the oil came out of that breather out of the rocker? if so should i run a pcv valve out of the rocker breather and into a filter?

and if ran back into the manifold will it cause a vaccum in the sump

Cheers dan

If you run it to a PCV valve on the manifold, yes, it creates a partial vacuum in the sump. It is designed to do this.
However, the PCV valve controls the flow- it is minimal at low throttle openings.
The benefit of using a PCV valve plumbed this way is you don't suffer engine fumes in the cabin.

Here's a pic of my 1412 with the $27 Toyota valve fitted- it all works great up to 7000 rpm, no oil leaks anywhere.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

do you think it was possible that my that that top breather could throw oil tho?

i think i will run the pcv setup now that i seen that picture thanks Doc.
that breather out rocker cover should i just cut the end off and rund it straight to pcv valve or leave it as factory with little ball bearing in end and have hose over the end?


Cheers Dan

Not unless you have blowby past the rings, ie they ain't bedded in yet.
When engine is running, take the oil filler cap off at idle. Is it blowing fumes out?

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Cut the end off the breather on the rocker cover so it is plain pipe.

Here's the pcv valve I used- got it from Repco.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

ok thanks doc if its blowbye past rings will it settle down engine done like 30kms max.

Yeah it should, go climb some hills in 3rd and 4th gear at 2000-3000rpm.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

ok thanks heaps for your advice :