Friday, June 27, 2008

PCV Valve.

I've been struggling with my SU's for a couple weeks now. I just can't seem to get the mixture right - the motor feels weak under load unless I set the carbs so rich that I can smell strong fuel-ey fumes.

Even though I'm 99% sure that I've got the dreaded throttle shaft leak, I thought I'd replace the PCV valve and eliminate a potential vacuum leak in the crankcase ventilation system.

I was able to pick up a replacement PCV valve at my local auto supply (Fram FV237) and 18" of 5/16" vacuum hose for about $4 total. While I was at it, flushed plenty of gunk out of the flame trap with some carb cleaner.

Well, I've still got carb troubles, but for under $5, I've got a PCV circuit that'll hopefully last me another 500,000 miles.


Trevor said...

I bought a 68 at the beginning of the summer, the previous owner installed a weber carb but didn't hook up the EGR (or the electric choke) and did not swap over the vacuum fittings from the SU manifold. I managed to find pipe barbs that fit the new manifold I have but I don't know how big the Internal diameter of the fitting from the PCV valve to the manifold should be. I've been having trouble with the engine sputtering and sometimes dying after falling to idle speed from high revs. I think it might be because the tube leading from the valve to the manifold is not restricted enough. If you unscrewed it from the manifold would you be able to measure it?

This site is awesome I also have a broken temp gauge and will be doing your electric conversion asap. Great looking project, good luck.

J. Jai said...

Trevor - you may have already found an answer, but I measured my inlet manifold nipple today and the I.D. = 0.25". Sorry about the long delay in replying! Thanks a lot for checking out the blog! It's great to hear that it's helpful!