6 replies to this topic

[Clip]

I’ve read lots about crankcase breathing but just after a yes do it, or no don’t bother not necessary 😊

I currently have the rear tappet cover oil separator breather running directly into the carb, but I do have the original PCV valve setup somewhere but I know it needs new diaphragm. Should I use it? 

[timmy850]

When you say it’s currently going directly to the carb, is it going to the air filter or to the port on the carb in the middle of the carb body?

Generally speaking running a vacuum on the crankcase will be the best option. It normally means less leaks, gives slightly more power, less smelly

The downside it that if your engine breathes a lot of oil vapour that it can reduce the fuel octane and get a bit of gunk in the engine. You can use an inline catch can to get rid of this

You can also use a generic PCV from an auto parts shop, as long as it’s the right size for your hose

[Spider]

I’ve read lots about crankcase breathing but just after a yes do it, or no don’t bother not necessary

I currently have the rear tappet cover oil separator breather running directly into the carb, but I do have the original PCV valve setup somewhere but I know it needs new diaphragm. Should I use it? 

Yes, for a street car, I will say very necessary and silly not to.

There was a few arrangements the factory did over the years, but it sounds like yours maybe a CCV type. Are you able to post up a photo ?

[Clip]

Thanks guys, can’t post a pick at the moment as haven’t got it with me. This is on my 1100 (near new 60 thou engine rebuild, fast road cam, Spanish head that’s been worked, 3.9 diff), LCB extractors. It goes very well. 

Tim, it goes into the port on the carb. It’s the only breather apart from the vented cap.

[Spider]

They draw Air In (or should do) via the cap. In this way, there's a circulation of gases through the crankcase. This reduces moisture build up and acids forming in the oil.

[68+86auto]

Since it sounds like you are using the CCV port, I'd leave it like that. It's what they went to after the PCV type and is one less thing to fail.

[timmy850]

If you have a CCV system I’d prefer that to a PCV. There’s less to go wrong and you have all the same benefits