Hello, I posted my problems on another forum and didn't get a lot of help so I'm going to see what this one does.
I have a 1985 F-150 4x4 with an EFI 302 V8. It started out running ok but a little low on power. I switched to the rear fuel tank and it turned out to have old bad gas in it (truck sat for a long time). I drained the tanks and replaced with high test + sea foam. Fuel system is fine now but during that process the engine starting ticking.
Thinking it was a sticky lifter, I did a crankcase degunking with sea foam and all it did was add a beating noise to the ticking. Power is down even further. Low oil pressure at idle. Truck sounds horrible.
Next I did a compression test, here are my results (in psi of course):
155, 155, 160, 145, 140, 155, 152, 142
The 140psi plug looked about like the first one I posted; it looked ok.
I replaced the plugs but broke a plug wire in the process and so am waiting for some new plug wires to fire it up since the plug change.
What I am thinking is that oil is probably getting into the combustion chamber through the valves and not the piston rings due to the fairly decent compression results. Can I clean this up by just taking off the valve covers? I am also thinking a crank rebuild is needed to deal with the shaking and beating. I would also like to take a good look at the oil pump. I have never cracked an engine open before and so am unsure about this. What do you all think? Am I on the right track?
Boy, there are so many places to look. The compression numbers don't look very alarming...they are all fairly even there. Pull the valve covers and watch the rockers and rods...it spits a bit of oil, but often you can see things that are outta order quite quick. You'll need to replace the valve cov. gaskets-12$...super easy. Have you done an exhaust restriction test? I know it may be off base...connect the vac. gauge to the mani. vacuum and go to 2000rpm....note the vac. reading...if it goes down slowly while at 2000 steady, it could be a blocked cat. convert. or exhaust system. I doubt it's a burned ex. valve, usually those give low psi readings.
"Common sense is not very common".
Hey CropDusterMan, thanks for taking a stab at it. So you are saying the oil could be getting into the combustion chamber because of an exhaust blockage? I don't really understand (I'm still learning), but regardless I don't think this is the issue just because the exhaust system was replaced recently.
Do you think all that plug fouling could be caused solely by the bad gas causing commotion in the combustion chambers? I'm still waiting to see the effect of new plugs and wires. Got new wires today but not enough time.
I think crop man is saying you may have bad valve guide seals. I concur. This would account for the oily plugs. Also when ya got the valve covers off look for bent or loose push rods. This may be a lot of the noise caused from stuck lifters due to sitting. I would drop the oil pan and check a rod bearing or two and clean the gunk that is now laying in the pan from the sea foam loosing it all up. And it has prolly plugged the oil pump pick up screen as well making the oil pump starve. Doing theses things can tell you and us a lot more of the condition of the engine.
85 XLT Bronco 351W HO 4V Dual Pipes 33X12.5 BFG's 62 Uni 390 C6 Custom Cab Sold for 9.5K Don't just Modify it Fordify it
Ok, thanks for clearing things up. This is about what I have been thinking, my terminology is a little weak. Correct me if I'm wrong but new valve guide seals means I need to take the heads off. I was hoping for being able to just open up the valve covers and oil pan.
I'm a little low on funds, and I'm going to be working in a dirt floor barn (with a thick tarp of course) so I'm really trying hard to get a plan of action before I just go messing around.
I was very confused by this and did a little searching and now I see exactly what you are saying. That is very interesting and would save me a bolt kit + head gasket set since it seems my rings are probably still fine. I do not have an air compressor though. What are your thoughts on the rope through the spark plug hole trick? Regardless thanks for the tip!
While you have the heads off anyways head studs are cheap they will make your life easier if you ever have to remve your heads again and give better clamping power in my opinion. Felpro makes great head gaskets for these engine and at a cheap price too I think the last ones I looked at were 24$ each for the high performance set so a stanard set should be even better. But pull off the heads clean em up real nice and also while you have your heads off take a little time to index your plugs. Try going to I think the plug number is AR3924 these are autolite racing plugs the idea is that they leave the electrode unshrouding giving a better spark for more power and better fuel economy. They don't cost much more than a standard plug and you should see better returns from them.
Either way check with your partsguy for the autolites for the part number take the standard number for autolites they gve you and add ar in front of that
How long was this sitting before you fired it up? We pulled a motor apart on Thursday that had been sitting 5 + years I am guessing, what we found was cheap older oil, and sludge dried, had someone dropped 5 quarts of oil and cranked it over, woulda wiped the motor out completely. Pulling heads and oil pan is simple insurance, we pulled the entire motor out of the truck in under 2 hours. Good luck, keep us posted
I'm now trying to figure out why the pushrod bent. Everything else appears ok (need to take my calipers and micrometers to it to make sure). What I am worried about is some funny business with the cooling system. The passenger side coolant drain plug was missing and in its place was some crusty white/yellow stuff. I am thinking that one or more of the coolant channels was blocked, the engine heated up locally and caused something to seize and bend the pushrod.
aj197816134: I'm not sure how long it was sitting, I wish I knew.
USArmyTaterness: Thanks for the tip on head studs, I will look into it. I had never heard of them until you mentioned it. I was planning on getting the whole felpro gasket set for this motor. Since it sat for a while it looks like almost every gasket is in need of replacement. I had also never heard of indexing plugs. I looked this up and it sounds pretty interesting. Thanks for this tip as well!
It's really hard to tell from those pictures if the larger holes are in the gaskets or are stains left on the gasket by holes in the heads. Look closely at the gaskets for a Ford logo, which would likely mean they are original and thus correct.
Ford did changes over the years regarding coolant holes vs. small "steam holes". However, it looks like the rear coolant holes are open on both banks of the cylinder block. So coolant will come up to the heads thence, then go from the heads into the intake manifold and exit through the water neck to the top of the radiator. So that looks correct.
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