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How to Rebuild a Ford 6.0 Powerstroke Diesel Engine - Specs and Tips
The Ford 6.0 Powerstroke started being used in the Ford Superduty pickups in 2003. While these engines did have their fair share of problems, they could be made to be reliable performers. We actually have several trucks in our shop fleet that have 250k+ miles on them and they run great. But sooner or late comes a time when you will need to rebuild the engine. There isn't a ton of solid reference material out there that covers everything you will need.
First things first, how do you know if you need to rebuild your engine? Besides the obvious hole in the side of the block or horrible tap noise coming from the bottom end, the determination usually is decided after doing a compression test. When you try to look up a spec for this you will find some confusing information. Ford does not actually give an actual number for compression. They only say that all cylinders must have no more than 25% variance between them. We'll give you some better guidelines.
How to do a compressions test: You can check the compression by inserting an adapter into the glow plug hole for each cylinder. If you do not have the adapater, one can be purchase from your local parts store. The OTC brand is what we use and the part number is 303-757. Remove the glow plug from each cylinder and insert the adapter. We recommend leaving the ignition switch turned off and using the starter relay wire behind the passenger side battery connected to a hand held trigger to roll the engine over. This way the fuel pump does not come on and the engine will not start. Roll the engine for 7-8 revolutions until the tester pressure gauge stabilizes. You will be looking for a huge variance between all the cylinders to find a bad one. Here are the specs:
6.0 Powerstroke Compression Specs
(These are not OE published specs but what we have observed in the shop)
Brand new engine - 350-400 psi
Worn engine - 320-360 psi
Bad cylinder - less than 300 psi
So if you check your engine and have two cylinders at 300 and six at 350, you may have the beginning of a problem. Usually engine will still seem to run ok around 300 psi, but they are getting worn out. Most of the time when you are looking for a problem you will find a cylinder that only has 0-100 psi. Then you know for sure the engine needs rebuilt.
When you have made the decision that the engine has to come out for a rebuild, removing them is very simple. The cab does not have to come off to pull the engine as many people tend to thing. Everything easily unbolts from the front the radiator/grill area making for easy removal. You will have to remove the turbo and filter housings on top of the engine, but everything else can stay and be pulled at once. The engine assembly can be pulled right out the front with a regular engine hoist.
Once you have the engine out, disassembly is pretty straight forward. There is a balancer on the rear of the crank that is held on by six bolts that will prevent you from removing the camshaft. You can take this balancer off, but make sure you keep it with that crank. They are machined at the factory and can only be used on that specific crankshaft. If swapped with another crank it will cause an engine vibration.
We always advise hot tanking the heads and block to clean them up. This removes all the deposits from the oil and coolant passage ways that could cause blockage. Starting with a perfectly clean block and heads gives you new motor a better chance of living the longest life possible.
The heads really need to be pressure tested and surfaced after being hot tanked. Sometimes a valve job is required if the valves are leaking and not seating. Valve guides are not usually a huge problem on these heads. No matter what anyone says, insist that the heads are surfaced. Here are the specs for surfacing a 6.0 Powerstorke cylinder head:
6.0 Powerstroke Cylinder Head Surfacing Specifications
Minimum Head Height – 3.74”
Valve Recession - .013 - .027”
Valve Height – 2.225 -2.230”
Maximum amount you can remove for a virgin head - .008”
If you find that your heads need more than the .008” removed to clean them up, we do have cylinder head shim kits available. These kits will allow you to take up to .020 off the surface of the head while still maintaining valve clearance and pushrod geometry.
Also know that there are two different dowel sizes for the cylinder heads. 2003-early 2006 trucks have 18MM dowel pins. Engine built after 1/2006 will have 20MM dowel pins. You have to make sure you order the right size head gaskets when you order your engine kit.
Next you need to inspect the cylinder bore. You want to be able to see the factory cross hatch in the cylinder wall. It is surprising how many high mileage engines we tear down that still have the cross hatches and very little cylinder wear. You will need to check piston to cylinder wall bore clearance to make sure it is in spec to see if you can reuse your pistons and simply put rings on them or if the block will needed bored to a larger size.
6.0 Powerstroke Piston to Cylinder Bore Clearance Specs
Piston to bore clearance - .0017 - .0036 inch
Diameter - 3.7401 - 3.7402 inch
Maximum 0.003 inch
Maximum out-of-round 0.002 inch
If you find that your bore clearance is out of spec or if you have some sort of cylinder wall damage, you will have to bore all the cylinders to the same size. It is not recommended to bore just one cylinder to a larger size. There are several sizes available in over size pistons for this engine.
6.0 Powerstroke Piston Sizes
Standard size - 3.737 - 3.738 inch
0.010 inch oversize - 3.747 - 3.748 inch
0.020 inch oversize - 3.757 - 3.758 inch
0.030 inch oversize - 3.767 - 3.768 inch
Select the nearest size that your cylinder will clean up with boring.