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I'm trying to install an effective evac system on a 468 BBC with about 14.5 to 1 compression for occasional street driving. I have a GZ vacuum pump on a similar engine which works great, but I hate to spend another $800+ if there is another way, being the cheap bastard that I am. I have never had much success with the standard evac systems, running hoses to the headers from the valve covers. Maybe I'm doing something wrong. Any suggestions? Thanks.
Reading the instructions for Moroso's Crankcase Evacuation System they stress the importance of properly positioning the check valve probe, both angle (opening flat to the exhaust flow) and depth, with the angle within one degree tolerance. They also answer a question, saying that running without their separators isn't a good idea due to oil losses. More important, I would think, is the Note on the purchase page:
The system is made for open headers, unrestricted flow with no back pressure pulses. Just my thoughts...Quote:
Notes: Cannot be be used on vehicles with mufflers.
Summit's Listing - https://www.summitracing.com/parts/m...a/instructions
Why not run a simple PCV setup?
Thanks for the reply... I did purchase the Moroso evac system in the past and you're right about not to be used with mufflers. I really don't think the pcv valve would do the job, with that high compression. I could be wrong, though.....never tried it.
A PCV valve correctly plumbed simply uses the manifold vacuum to counter any crankcase pressures that exist. Your compression ratio really doesn't enter into it, other than potentially leading to the crankcase pressures being higher due to more leakage. As long as your engine is pulling vacuum a PCV system will tend to balance the pressures, and the PC Valve will check off at speed, should manifold pressure exceed crankcase pressure, holding them balanced. Just my $0.02.