5.4 heads on 5.8 block?
- Thread starter hyvltge
- Start date
You'll need to have a machine shop add a water passage in the heads. It will be a cheap or free add on if you are having your heads ported.
That's what I was hoping to hear. My only concern was blocking them off with the head gasket and if anything else would need to be done. Further I am guessing I would want to use 5.8 head gaskets...?
Sub'n for more details on this
I know the answer to this one, but if I use the picture of the head I cut in half to explain it. I'm sure that will cause an issue.
You have to run the 5.8L cylinder head gasket
The extra coolant passage in the 5.8L blocks between the cylinders will still continue to cool between the cylinders properly with the 5.4 heads on the block
You'll lose the coolant passage between the 2 exhaust valve seats in the cylinder head, which is there to reduce valve seat temperatures under extreme loads for long periods of time. High valve seat temperatures for extended periods of time under high boost will cause a valve to tulip the head of the valve. As stated earlier the 5.4 head can be drilled to match this passage in the 5.8 cylinder head with a little effort from the machinist doing the work. I would think the machinist will charge extra to do this, because the angle at which the factory drilled this passage originally will require the cylinder head to be set up differently on his equipment to copy it than any other work he will perform to the head.
Hopefully my post doesn't create an issue
You have to run the 5.8L cylinder head gasket
The extra coolant passage in the 5.8L blocks between the cylinders will still continue to cool between the cylinders properly with the 5.4 heads on the block
You'll lose the coolant passage between the 2 exhaust valve seats in the cylinder head, which is there to reduce valve seat temperatures under extreme loads for long periods of time. High valve seat temperatures for extended periods of time under high boost will cause a valve to tulip the head of the valve. As stated earlier the 5.4 head can be drilled to match this passage in the 5.8 cylinder head with a little effort from the machinist doing the work. I would think the machinist will charge extra to do this, because the angle at which the factory drilled this passage originally will require the cylinder head to be set up differently on his equipment to copy it than any other work he will perform to the head.
Hopefully my post doesn't create an issue
Great info thanks. Why would you posting the pic cause an issue? I would love to see it.
I imagine it hast to do with the fact that he actually has a head cut in half... unfortunately it was probably because he had to prove a point to a shop or someone who screwed him over.. And because he doesn't speak of it on the forum I assume it was the screw up of a known builder who is a vendor here on the forums.
BC - just give me a wink if I'm on track here...
;-)
LOL
I was still thinking I'd drag out the head to slide a drill bit into the coolant passage so I can show the angle and post that picture. I only wonder if the vendor that has injected himself into the fray will object and get that post deleted too.
All right here we go. How long before the action starts? or disappears completely?
10, 9, 8, 7, 6, .......
The drill bit is an 11/64" diameter, which mathematically is 0.171875" in diameter.
The coolant passage runs to the bottom of the casting for the spark plug in the cylinder head. It exits just above the base of the spark plug coolant passage in the head. If by chance you drill with the angle off, you'll drill into the base of the spark plug hole and ruin the head or you'll be too close to the exhaust valve seats. Which weakening this area of the head and you're taking a chance of dropping an exhaust valve seat. I wouldn't try this mod without a 5.8L head as a reference guide to set up the angle correctly to drill a 5.4L head.
The mod can be done with a cylinder head drill press by somebody that does nothing but cylinder head work regularly. But I wouldn't chance it with a sub-standard machine shop that calls themselves an engine builder.
10, 9, 8, 7, 6, .......
The drill bit is an 11/64" diameter, which mathematically is 0.171875" in diameter.
The coolant passage runs to the bottom of the casting for the spark plug in the cylinder head. It exits just above the base of the spark plug coolant passage in the head. If by chance you drill with the angle off, you'll drill into the base of the spark plug hole and ruin the head or you'll be too close to the exhaust valve seats. Which weakening this area of the head and you're taking a chance of dropping an exhaust valve seat. I wouldn't try this mod without a 5.8L head as a reference guide to set up the angle correctly to drill a 5.4L head.
The mod can be done with a cylinder head drill press by somebody that does nothing but cylinder head work regularly. But I wouldn't chance it with a sub-standard machine shop that calls themselves an engine builder.
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Ouch!
Yep...........OUCH!!!!!!!!!!!!!!
Yeah, Catmonkey that is a $2000 piece of junk in those pictures. Because of a number of the exhaust lash adjuster pockets being cracked in the cylinder head due to the collision of valves and pistons. Slawko Racing Heads did a beautiful job porting them. They only charge an additional $800 for a true race valve job while doing the CNC port work, yet the engine builder did a factory valve job and charged the same price. That came direct from Slawko when he examined this head to CNC the replacement head to match the two of them to each other.
Here is a picture of a 5.4L cylinder head, so you can see the differences in the coolant passage between the exhaust ports of a 5.4 and a 5.8 cylinder head
OP is at lunch, documented just in case things disappear 
. Thanks for the input.
. Thanks for the input.Users who are viewing this thread
