I have 5.0 in a 1990 f150, I'm the third owner I know of and I've run into a issue I'd like some advice on.

Recently I had to replace the intake gaskets on the truck which wasn't to difficult just a little time consuming. Two days later my thermostat stuck shut while I was driving, I took it out to bypass so I could "limp" home. When I got home it started miss firing so I checked the plugs and discovered that the #8 plug had oil on it.

After I replaced my intake gaskets and did my plugs and wires I triple checked to make sure I had the correct firing order and position. I think I've lost a piston ring in #8.

So my question is rebuild and possibly have to bore out or hone, or crate motor or motor swap?

Just like most people I'm thinking of cost as well as performance but all opinions are welcome.

 

Excess oil in the rear cylinders is common as the PCV connects to the back of the upper intake, an improvement for this is to put a longer hose on the PCV valve and connect it to a spare port on the vacuum tree. So bottom line your motor probably isn't blown, a compression check would confirm.

 

I don't think thats it, my PCV is on the valve cover on the passenger side my #8 cylinder is driver side, and all cylinders compression tested good two different times.

 

If compression is good then you have not lost a piston ring so the oil is coming frm somewhere else, it could be a worn valve guide but then all should be worn the same amount, so it's more likely because of the PCV.

 

Ok I'll give that a try this weekend, thank you