1974 2.0l w/dual 34ICTs having blowby Options

[justjoel]

Finally got my project 914 on the road and it's running really good with dual 34ICTs but I started noticing burning oil smells in the cabin. Now it does have a minor oil leak, I believe from the distributor o-ring and I will be addressing that but I realized it was blowing smoke/oil from the crankcase breather and the cylinder head vents. I installed a catch-can where I routed the crankcase breather and cylinder head vents to and have a filter on top of the catch can but it's still smoking out the filter and getting into the cabin where it proceeds to give me a nice migraine after 20-30 min drive.

I believe I should remove the top filter and run a line into the carbs for the vapors to be sucked back into the system, is that correct? Will that gum up my carbs?

Now the car sat for probably 20+ years prior to me picking it up and fixing it but it fires right up, no issues and runs "cool" and strong. Compression tests out good, valves have been adjusted to the best of my ability and there is no smoke out of the tailpipe. How concerned should I be about blowby? When I open the oil fill cap there is quite a bit of smoke and pressure coming out. I am unfamiliar with aircooled engines but I would think the piston rings are worn. Should I be thinking rebuild time? As in new pistons, cylinders, rings etc. If so, what "while you're in there" things should I start budgeting for?

Please let me know your thoughts.
Thank you.

[Ninja]

Most likely oil is leaking on the exhaust/heat exchangers.

They are bad about the pushrod tube O-rings.

Makes for nasty smells!

I wouldn't run that. Lots of "got it running after XX year threads" end up with a dropped valve/broken spring which equals a complete rebuild.

I have a 75 with 31K that hibernated for 33 years (1988 inspection sticker).

It also runs OK.

I will not run it again before removing the engine, replacing ALL of the rubber seals and replacing the valve springs.

Some (at least two) of the valve springs sat open (compressed) for decades. These are the springs I worry about.

The parts are not seriously expensive until you drop a valve.

I know my advice sucks but $300-$500 today could save 3000+ two months from now.

This is not 914 specific. Valve springs SHOULD be replaced every 20-30 years on anything.