TR4A, What to do with crankcase/blow by fumes

[eng622]

What are the options

I don't want to leave an open pipe under the bonnet

I don't want to plumb what I have into a road draft pipe

So guess it has to be a catch can but should I be considering closed loop or venting to air. What should I do with the rocker cover pipe, leave as is with the PVC valve piped to IM, or dispense with the PCV and route to the air cleaners like in the TR4, or run both pipes to a catch can.

Should I even try  routing my crankcase breather pipe to the PCV valve and IM, thinking the PCV will not be able to cope.

There seems to be so many possibilities and I am now confused. I understood that you need to get air into the engine to get the fumes out. I can see in many cars like the MGB how this works but have never understood how it is supposed to work on the TR4A (remember mine had a unvented oil filler cap but I cannot see how such a small hole in a vented one can work either). But I'm looking for the best solution for my car, any suggestions from those who have had success appreciated.

[RogerH]

Hi,

 with a TR4A the only pipe is from the rocker cover to the PCV.

If you have another crankcase breather pipe then that may affect the way the PCV functions.

Is the PCV working correctly - is the diaphragm damaged etc.

TRy a catch tank and see how that goes.

I removed my PCVdue to high oil usage and routed the rocker pipe into a catch tank. It worked well. So I then fitted the TR4 snorkel next tot he fuel pump.

Nothing comes out of the snorkel.

 

Roger

[eng622]

Have checked the PVC valve had it apart and done the normal vacuum tests so think it is ok. The TR4A is the only classic car I know of that does not have a  proper crankcase breather, the rocker cover breather cannot cope with the blow by in the crankcase and in my opinion and a bad design. Cars like the TR4 , Morris Minor some MGB's have a RDT and rocker cover pipe going to the air cleaner which is the air source as the oil filler cap is unvented. Later MGB's have a crankcase breather via the tappet chest so can cope with the blow by.

Had a long discussion over the winter with Barney the MGA guru about crankcase breathing and PCV valves but he is not a TR expert and  unable to suggest how to solve my problem. 

[RogerH]

The TR4A PCV works well on a reasonable engine that does not have too much blow by.

What state is your engine in?.

Is it producing too much blow by?

Roger

[ctc77965o]

2 hours ago, eng622 said:

The TR4A is the only classic car I know of that does not have a  proper crankcase breather, the rocker cover breather cannot cope with the blow by in the crankcase and in my opinion and a bad design.  

I've driving a TR4A 30 years with standard PCV setup, no issues.

Suggest you look for 'root cause': if something is overwhelming the breather then any plumbing fix is just masking your underlying defect

[RogerH]

19 minutes ago, ctc77965o said:

I've driving a TR4A 30 years with standard PCV setup, no issues.

Suggest you look for 'root cause': if something is overwhelming the breather then any plumbing fix is just masking your underlying defect

+1