TR4/4A Replacement air filter for SU HS6

[Federalees]

Hello,
can anyone recommend an air filter replacement for my TR4A? The current filters are Kinby CA-1057 with the vent tubes. I was look at K&N 56-1400 but the inlet hole is a bit small and I would have to rig up a vent tube into it. Looking to see if anyone have dealt with this already.

thanks, Phil

 

[Merlin63Tr4]

The current crankcase ventilation system you have in your TR4A is really a TR4 crankcase ventilation system.
I replaced the center vent tube air filters in my TR4 with K&N 56-1400 filters many years ago (approx. 15 years). They are made for 1 3/4” inlet carbs like the ZS 175CD, SU H6 and the SU HS6.
At the same time, I replaced the original air filters with the K&Ns, I also got rid of the original TR4 crankcase vent system with the flame arrestor and the two hoses (like the one you pictured) and replaced it with a TR4A PCV system (picture included).
You might consider reinstalling the original TR4A PCV crankcase vent system in your TR4A, I found it to work much better that the TR4 crankcase vent system that you currently have installed.
M.

 

[Federalees]

Thank you! This makes sense. I can see that the PVC hose adapter hole in my intake manifold has been plugged. Moss has all the parts needed to revert it back to what you have pictured (thanks for the picture, very helpful). I know that the motor isn't original to the car, so who knows what was done when they replaced it. This change would open up air filter options, but it seems that K&N are the way to go in the long run.
Thanks again. I learn something new every time.

 

[Popeye]

Second thank you! I’ll have a similar need shortly… will get the k&n when I’m ready.

 

[Federalees]

The current crankcase ventilation system you have in your TR4A is really a TR4 crankcase ventilation system.
I replaced the center vent tube air filters in my TR4 with K&N 56-1400 filters many years ago (approx. 15 years). They are made for 1 3/4” inlet carbs like the ZS 175CD, SU H6 and the SU HS6.
At the same time, I replaced the original air filters with the K&Ns, I also got rid of the original TR4 crankcase vent system with the flame arrestor and the two hoses (like the one you pictured) and replaced it with a TR4A PCV system (picture included).
You might consider reinstalling the original TR4A PCV crankcase vent system in your TR4A, I found it to work much better that the TR4 crankcase vent system that you currently have installed.
M.

Hi @Merlin63Tr4

Is the vented oil filler cap necessary for the original PCV system like you have pictured? I am concerned that using the one I have (non vented) will cause pressure problems in the crankcase.

 

[Merlin63Tr4]

The vent hole in the TR4 A style oil fill cap is only 0.120" in diameter (a little less than 1/8" dia.)
I used an unvented TR4 cap for years until I managed to find and buy a TR4 A cap. I noticed no difference in performance or any new or worsening oil leaks with either cap, YMMV.
see attached pic.

M

P.S. TR4 A oil fill caps are unobtanium, once in a blue moon one comes up for sale in eBay, sometimes they are attached to a rocker cover...

 

[Federalees]

Gotcha. Thanks for the insight and information.