next »

[Ken Stone]

Hi All:  I am restoring a 1966 4A, but the engine I have is an open breather (Breather Pipe).  The engine is being rebuilt with the 87mm pistons and liners (original was the 83mm) I want to restore the car to be as close to a 4A as possible which means a closed circuit system.  Moss sells a plug to put in place of the breather pipe.  One person told me this would be a bad idea without making other conversions due to the pressure building up in the crankcase and advised against attempting any such conversions in the first place.  The questions - what conversions would be called for beyond  ???a PCV Valve Assembly and a closed circuit oil cap?  Are there any internal engine modifications required?  Is any of this a good idea to attempt, should I just leave the system as it is, what are the pros and cons? Did 4A's ever come with open systems (I know some early 4s did, but don't think any of the 4As were open). Has anyone ever actually done this?  Thanks in advance.
Ken Stone

[charley fitch]

I am currently using a engine block from a 4A in my 4.  All I did was to remove the breather plug and insert a breather tube.  Then of course I used the rocker cover with no breather hole except for the filler hole.  As the engine block of the TR2 through 4A is virtually the same I can not imagine any internal differences caused by the breather.  Of course you will use a rocker cover with a breather hole, but other than that I sure don't know of anything else to do.

By the way your engine should have had 86 mm pistons not 83mm.  They switched over to 86 mm with the TR4 ( and late TR3B's).
Charley Fitch   

[Ken Stone]

Thanks Charley - BTW I did purchase an 87mm piston and liner set from Moss to install. Figured the little extra boost couldn't hurt.   As always, your advice is valued.   
-Ken