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Discussion in '96-04 - 2V Specific' started by Burninrock24, Jun 5, 2013.
Good job man, glad you got back together.
Had some time to investigate a little more with npi heads and the verdict is good! I mentioned a few pages back that the 5.4l head is indeed NOT EXACTLY THE SAME as any other npi. The exhaust port is idea for performance. A normal 4.6l head exhaust port is severally pintched directly under the valve seat. Well,...not the case with the 5.4l head.
Here are some pics of a 5.4l head exhaust port compared to a 4.6l exhaust port.
I took the biggest socket that would slip through the 5.4l port to give a general idea of the differences. The conclusion is the 5.4l head port floor at the radius is well laid back. Also directly under the valve seat, the port is more open and around the valve guide boss the port widens.
The ports measure the same anywhere else I measure. But under the valve seat to about an 1.5" back is totally different.
The valves size are same, the valve distance the same, spring pocket is the same, combustion chamber is the same, sparkplug height the same, intake port shape same, valve seat angles same, valve length same, deck thickness is the same.
Very interesting. I had no idea that the modular heads were different from the 4.6 to the 5.4. I wonder what those 5.4 heads would do on a 4.6?
Well....the npi differences. Im not 100% sure if their is differences with the pi head 4.6l/5.4l. Im gonna say their is! Mmmm....gonna have to dig.
The 4.6l head exhaust is severally pinched. Sean Hyland claimed port stall at .300" valve lift. Im gonna say yes, the 5.4l head will be an improvement. Cutting out the exhaust valve guide boss supposedly was the 10hp flow gain. Also laying back the intake valve swirl dam was a 10hp flow gain, but I have mixed feelings doing that.
So if you port a set of 4.6 NPI heads, does that area open up to the size of the 5.4 head or is that way more than could be ported? Being that the NPI 4.6 heads flow pretty well once ported, would that level the field between the heads or can the 5.4 heads be worked over to flow more than a ported 4.6 head? If that makes sense lol
I get what your saying. The down fall here....only so much flow can pass through an orfice/valve hole. Flow through any exhaust valve is debatable, but intake valve has its limits just because of hole size. Max porting can make or break power potential within an intake port.
The 4.6l head can be ported just like the 5.4l with no problems.
Just did a little hand work to the npi heads on the wifes 5.4 f250. I don't have any pictures yet but I will report back with driving results.
Oh do tell! This is awesome. ...wait.....wifes truck? Are you experimenting? Did you cut the floor down about 2" into the port like the pics ive posted?
Something I never noticed while examining the heads. The 5.4l valve spring is deeper than the 4.6l heads. I though how weird! How is that possible! The intake port roof would have to be lower in order to accommodate the space needed for a deeper spring perch. So ...examining closer I realize the 5.4l head water cavities roofs have been expanded or raised up thus taking up open room. Headbolt perches along with spring pearches are indeed the same on both heads but the 5.4l water cavities roof has been raised and this is why the valve spring seats apear deeper.
This much water capacity could benefit any modular build especially a 5.4l.
Although ive never heard of any problems when using a coolant mod with normal 4.6l heads, these 5.4l heads are the ticket for the performance build.
The coolant mod refers to a machined pc designed to slip into the freeze plug location on the rear driver head. This allows trapped water around cylinders 7&8 to flow out. In turn equalizing both banks cooling properties.
This pic refers to the "crack pipe" version. This is a lincoln continental pc from the dohc 4.6l fwd engine. You can see the modifications needed for sohc. Real simple. The out put can either be plumbed into the line for the heater core or routed to the crossover on the intake. Basically opening the area for water to move.
Yup, wife's truck. 99 f250, 5.4l. Has 300k miles on it and needed valve seals, so I thought this is a good time to do timing stuff and pi cams. Then that turned in to porting the heads and intake (all your fault). I only cut the floor out and it is just like you said, about 2" in to the port, big time pinch. We got that taken care of now!
I did the coolant crossover on all 3 of my Terminator motors to stop the number 7 cylinder from getting too hot and dropping the valve seat which was a big headache for Ford to fix on '03 Cobras. Dennis "king of the mark VIII " Reinhart bugged me till I did it swearing it would stop the problem and the parts were already sitting in the Lincoln parts bin for years solving a problem they knew they had but had to go through the whole fix learning cycle again. I took allot of heat on the internet for listening to someone that knew what he was talking about VS what the big fix was from the dealers if you could get them even to admit there was a problem in the first place. Do it, it is cheap, the parts are factory, you can put them in from under the car, you do have to remove the rear trans cross brace to let the engine down a little bit but it only takes an hour to do and I never had one leak.
People on the Internet are dumb.....
really though, i need to do this on my 2v and have neglected to do so. I'll get to it one day. You talk about a bolting the transmission and letting the engine sag, I found out today that transmission free hangs on the back of the engine with no movement at all. Thank you solid engine mounts lol.
Thanks OLD H2S! Thats some good tech!
I think youll be happy with the improvement. Maybe not so much with low rpm, but like passing or on ramp rpm pull. You pulled the cork out!
First impression.....its awesome. I haven't driven the truck yet but its idled and revved a few times. Ive never hear the truck run so smooth, and it revs much faster than before. I will be driving it here shortly.
First drive went great. No leaks, no issues. Definitely more peppy. The roads are super wet right now so it spins a lot, but when I take off the truck moves easier almost like it takes less effort to do so. The rpm while taking off is up a little bit but its much more fun to drive. Ill be taking it home tonight and hitting the interstate so ill know what the top end is doing now. Ill report back later.
You work quick! I know if you were using cartridge rolls to cut out the pinched area, you spent some time porting! Did you happen to take any pics? Sure would like to see your handy work!
I used an aluminum carbide bit on an air grinder. It took about 4 hours to do the heads and probably an hour or so to do the intake. I only took 2 pictures of the heads. I'll post them up in a little bit. I've got about 150 miles on the new set up now and it's working great.