Cylinder Head Gasket Oil Leaks

[dave.vitesse]

Yes, as air is drawn in through the crankcase breather and out through the rocker cover. That's the nature of an open circuit system.

The whole point of fitting a crankcase breather is to do away with the close circuit system. For track cars the close circuit system can create problems.

So a catcher tank or filter breather at the rocker cover outlet and blank off the PCV or carb breather pipe if you have a sump breather.

Dave

[Nigel Clark]

The TR6 doesn't have a PCV, merely a pipe from the rocker cover to the air plenum, which in practice is not adequate.

So this engine doesn't have significant vacuum scavenging. From the experience that Nick and John Davies have had, an extra atmospheric breather from the crankcase is the way to go for Triumph PI engines.

Nigel

[Iain T]

Aah but I have a Vitesse, surely air can be sucked in via the new crankcase breather to the inlet manifold thereby weakening the mixture. Or does the PCV prevent this? But then I am trying to prevent crankcase pressure (most of which is created by blowby?) so is air ever sucked in via the crankcase? 

Too many questions to which I don't know the answers🤔. I have a crankcase breather filter but don't want to to fit it and cause further problems. 

Cheers 

Iain 

 

[Iain T]

Sorry all for some reason I couldn't see some of the replies. John's logic, as usual, seems correct! I'll go for the crank breather filter route and let the PCV do its job. 

Iain 

[GT6M]

Nigel, did ye put a bead aland the outer cyl heed joint t,block

this is a last line of defence, but did,nt doo it toll the other mods..broke doon.
it works quite well too even on a already blow,n engine

see black line aloang cyl heed int pic

[Nigel Clark]

Hi Marcus,

Take a look at this. The extra bead of silicone isn't so easy to see on my black engine but it's there! As you say, the last line of defence.

Nigel

[Nigel Clark]

Time for another update...

As suggested in this thread, I've fitted a crankcase breather by making an adaptor plate bolted to the redundant fuel pump boss on the block. This connects via a 12mm ID hose to a vented and baffled catch tank on the inner wing. The hose rises about 20cm from the block to the catch tank.

Since then, the car has covered 60 miles with three complete warm up/cool down cycles. Previously, it was while warming up that the oil leak was worst.

I'm pleased to report there is no trace on oil from the cylinder head gasket. Better still, there's no oil coming through the oil filler cap vent and no oil collecting in the air plenum. The catch tank is also dry.

All told, a great improvement. Thank you to everyone here who contributed with ideas, experience and encouragement. I will show the details with photos in my Practical Classics Staff Car Saga, including a positive mention for the TSSC forum.

Nigel

[Dick Twitchen]

7 hours ago, Nigel Clark said:

I will show the details with photos in my Practical Classics Staff Car Saga

Sure The Courier readers would also be interested. Dick

[GT6M]

If yer no giv,n it some serious right foot,

then good chance it wont leak

 

real test its  WOT an high revs, for  a while, or repeated blasts

high revs an light throttles wont give pressure t,crank case as much as WOT will.

[Nigel Clark]

12 hours ago, GT6M said:

If yer no giv,n it some serious right foot,

then good chance it wont leak

 

real test its  WOT an high revs, for  a while, or repeated blasts

high revs an light throttles wont give pressure t,crank case as much as WOT will.

I haven't really ragged the TR since replacing the head and fitting the breather, so I take your point and realise the engine could still sweat oil.

However, under the recent driving conditions it would previously have leaked from the head gasket and blown oil into the plenum, so there certainly is a significant improvement. Time will tell whether it's entirely oil tight. I will give it a few more moderate miles followed by an oil and filter change before giving it full throttle and all the revs.

Time will tell!

Nigel