My car is KILLING ME!!! Flat cam lobe last week turned out to be destroyed pushrod tips (likely no hardened as stated) New cam went in, break-in survived. I thought! Drove it to get upholstery done this am. Drove great for 18 miles, temps right at 190*. oil pressure at 60#. Then it happened! Leaving the last stop sign it started a loud almost "clanging, metalic" sound. It did not sound deep in the motor like a rod knock more like a screwdriver tapping (loudly) on a valve cover. It ran very rough so I shut it off and coasted into the shop. (full of Chevys and they were laughing at this FORD, sorry all) Once there it would not start but I heard pressure leaving every rotation like I had a plug out or an exhaust gasket missing. The car is there for 24 hours so I can just stew over what might be wrong. Ideas? Pull the cover and maybe slipped a pushrod? I did readjust the lash hot after the break-in, almost all were spot-on. Ideas please .... (anyone wanna buy a 1970 Maverick!!)
Follow-up dumb question. Assuming I slipped a rocker arm,or two. Where does the compression go on a cylinder that is firing (no intake charge however) but no valves are opening? My guess would be OUT! Via the head gasket?
NO way would compression come out head gasket ... probably going past valve ... and leaking around valve covers or at oil filler pcv valve. Could you have broke a valve, bent a valve, timing slipped, etc ...?
Dan, I guess anything is possible. I want to line up my ideas so I can show up there with a game plan. I at least will pull the v.covers off and see if the is a slipped or VERY loose arm. As it is, looks like a tow home :-(
Probably have a problem with the poly locks. That would explain the broken pushrod tips and the noise you have now. The hissing is likely exhaust gas making it's way out the intake valve. Check the valve train again. Solids are hard on parts.
Thinking a poly loosened up and caused the valve not to open? What would the sound be? Pushrod topping the cover? is that possible? Hmm, wonder if I will have dimples now!
There were several rockers with bad rods. I had the rockers checked out and given the thumbs up. The issue was being sold standard pushrods vs hardened the last time around. I inspected the rocker as well, no visible damage to the seat of the pushrod end.
If the lash went south on the exhaust valve, you end up with trapped exhaust gasses, and this will vent out the intake valve next time it opens. If an intake goes, you end up with a lessened intake charge, possibly not enough to fire, then you have nothing going out the exhaust. Nothing in = nothing out, that can build to a hisssing from the vacuum. Check the valvetrain out again. Bet something's still not staying put.
I had a rocker go once in my truck. I was in the middle of the desert and really had no way to get it home. So I pulled both rockers off that cylinder and drove it home 300 miles. Ended up replacing the push rods that were bent and replaced the broken rockers. Drove it forever after that and never had another problem. I can't say that's your problem or that you will have the same outcome, but engines are tough. You'd be surprised what they can go through and survive.
Bad, I think you have it nailed. I just called the shop and due to no rust on my floors (YEAH!) the interior will be done tonight. I am heading over there soon with my tools. I plan on taking the drivers side V cover off first as that is where the sound was the strongest. I bet I find a VERY loose rocker (or 2). That actualy would not be the ned of the world and the lesser of the evils I have been dreaming about while talking to clients today. Kind of hard to stay focused!!!
I don't want to be a kill-joy, but I hope this new cam didn't wipe a lobe. That would add insult to injury.
