2004 ford f150 lariat 5.4L timing chain broke and knocked hole in valve cover. The truck was still running when this happened. Did I ruin the engine?

 

You won't know till you tear it down. It is an interference engine so it's likely you have valve and piston damage. You may be able to see something with a borescope.

 

Thank you for responding! If I can;t fix the engine, do you know where I might be able to buy a replacement? I have shopped around and was hoping to find something close to a 1k

 

How many miles on it?

 

Check yours for damage first. Used 5.4 3Vs and not cheap used unless you can find an individual who will sell one cheap.

 

It has 235,000 on it, which is a ton! But I have kept it showroom new

 

235,000 is just getting started -- for the truck -- not the "stock" engine...

 

Probably time for a good quality remanufactured engine.

 

Would running a compression test tell me I have valve damage?

 

Yes.

 

MAYBE, BUT you need to find out if anything is hitting first or you risk doing even more damage to the engine.

Since you already know that the engine is damaged and is going to have to be rebuilt or replaced I don't think that it's worth even doing a compression check. Furthermore since the valve timing is now OFF, a compression check will be completely inaccurate beyond the fact that you have or don't have compression in each cylinder.

My advice; pull the engine, take the heads off and see how much damage you have to the heads, pistons and valves. If those are salvagible, check the rods and crank for additional damage and then make a decision.

Speaking from personal experience, I wouldn't touch an engine from a wrecking yard! The operators all lie like hell! Either buy a wrecked truck with a usable engine straight from the owner or insurance company, buy a rebuild engine or rebuild that one. Each has it's pros and cons.

 

Before you do that, pull the plugs and borescope all the cylinders. Go from there.

You won't be able to do a compression test without replacing the timing chain and retiming the engine. Not worth it if there's visible damage.