I've got a newly built 347 Ford stroker motor that I've been having some issues with.... but this is probably the most confusing one so far for me.
I've got what appears to be copious amounts of exhaust gasses escaping from the passenger-side Valve cover breather hole where my PCV normally hooks up. It looks and smells like exhaust fumes. So I assume this is blowby, and figure there's got to be something wrong... but both compression and leakdown tests appear to be checking out okay. I'm getting right around 180 PSI on all cylinders with the compression tester. A wet compression test showed the EXACT same results. Leakdown numbers were between 10-20%, which might seem high, but it's this cheapo Harbor Freight tester that has been compared to other low mileage, very nice running engines and it's actually getting better numbers on the 347 than it is on them.
Oh, and to top it off... completely contrary to what I'd expect, it ONLY seems to be happening at idle. I'll rev the engine up and the smoke seems to dissipate very quickly.
Any ideas what is happening here?
I've got what appears to be copious amounts of exhaust gasses escaping from the passenger-side Valve cover breather hole where my PCV normally hooks up. It looks and smells like exhaust fumes. So I assume this is blowby, and figure there's got to be something wrong... but both compression and leakdown tests appear to be checking out okay. I'm getting right around 180 PSI on all cylinders with the compression tester. A wet compression test showed the EXACT same results. Leakdown numbers were between 10-20%, which might seem high, but it's this cheapo Harbor Freight tester that has been compared to other low mileage, very nice running engines and it's actually getting better numbers on the 347 than it is on them.
Oh, and to top it off... completely contrary to what I'd expect, it ONLY seems to be happening at idle. I'll rev the engine up and the smoke seems to dissipate very quickly.
Any ideas what is happening here?