1977 Spitfire - Stopping Oil Leakage with Crankcase Vacuum - Adding a PCV Valve

This video show the design of a PCV System for a 1977 Spitfire with Dual Su HS4 Waxstat Carburetors.
The intent of the design is to add vacuum to the Crankcase to reduce or eliminate oil leakage caused by blow-by.
The PCV Valve used in the system was sourced from Autozone (Part # PCV1137DL) and cost $2.49 (oooh... big spender) in August 2023.

[@jackchandler5315]

Hey Mike. Praying that you and your wife (and your garage) weather Idalia without damage. Your right about that seepage…my ‘74 MGB was a sieve and marked her territory wherever we went.

[@MikeHammill-TheShop]

Hey Jack, Thank you for your thoughts and prayers. We are good. There are no issues at this time. We are on the tail end of the hurricane now and will get some wind later today (~40mph). Hopefully, no tornados spin off. The low-lying areas in our county (Crystal River) are expecting a 10 to 15 ft storm surge. I'm really concerned for them. Hope all is good with you and Phyllis in Texas. Regarding leaking British cars, I got some feedback from proud car owners that none of their British cars leak oil. So, it is probably just you and me.

[@williamlongyard5887]

Thanks for the video Mike. Where is you air inlet for the crankcase? Is it metered in any way?

[@MikeHammill-TheShop]

Hi William. There is no air inlet except through piston ring blow by. The oil cap is sealed. If there is no crankcase pressure, the PCV is shut. If the needs to be consideration of an additional air inlet, I'm all ears.

[@williamlongyard5887]

@@MikeHammill-TheShop Air has to get in somewhere for the system to flow. I've seen references to a leak at the oil dipstick, or drilling a 5/32 hole in the oil filler cap. I purchased today the pcv valve you recommeded and installed it. I may go the 5/32 route for the air supply.

[@MikeHammill-TheShop]

@williamlongyard5887 that sounds reasonable. Let me know how it works. Always willing to do a part 2 video. 😀

[@JeremyBillow]

I’m going to do this to my spitfire. One question though, where are the 2 hoses coming out of either side of the intake manifold routed to?

[@MikeHammill-TheShop]

Hi Jeremy, that is a coolant line that is routed through the manifold. This is intended to warm up the manifold to help keep fuel atomized (no droplets of fuel) while going into the combustion chamber.

[@JeremyBillow]

@@MikeHammill-TheShop thank you, great idea as well. Did you end up ever adding an air inlet as another commenter mentioned or is the setup working well without one?

[@MikeHammill-TheShop]

@JeremyBillow the coolant line is a factory design. I did not add an additional source of air as suggested. That is the intent of the PCV valve.