93 4.0 heads
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93 4.0 heads
I'm about to replace both heads on my 93 4.0. It got hot and cracked both heads. I have read on this board and elsewhere that these heads aren't the best from the factory, and I'm having a hard time finding a rebuilt set here in San Diego. Has anyone got any ideas? New ones are available and I will probably go that way. Are there any manufacturers I should avoid??
Bruce
Bruce
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93 4.0 heads
The machinist that built a set of heads for my Aerostar said to stay away from the heads made in Spain. He said that the heads made in Mexico were actually pretty good quality (believe it or not). Unfortunately, you don't always know where they are made and after all of the calling around to various dealers, none of them could tell me where they were made. So, the machinist bought a set of aftermarket heads that were made in the UK, put a three angle valve job on them and assembled the heads with new valves and springs. This cost me $700, compared to $500 for a new set from Ford. I didn't mind paying the extra $200 for a better set of heads because it ain't no fun taking the heads off an Aerostar and I didn't want to ever have to do it again (and neither will you if you do it). The heads I got were made by AMC. Never heard of them before but the machinist tells me the desert racers in the V6 class like them for the bigger runners. I don't have a part number but could get one if you're interested.
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93 4.0 heads
Thanks,
I've got a source for a set of new heads at $400 a piece. This guy is a pretty good source so I'm pretty sure I can find out where the heads were made. Yea, I've already got them off and you're right, it really isn't the most fun I've ever had! Actually, I'm fortunate as to not have to rush this job. When it gets done, it gets done and that is always easier than having to have it on the road right way. I found a set of heads at a internet site that may be the ones you are refering to. They are supposed to be beefed up in the boss's and are used for off road racing. They were also cheaper by $100 a head. The only problem is I lost the web site.
Actually, I'm considering pulling the block and going through the bottom end. It has over 100k on it, but there is minimal, if any ridge and the crosshatching is still visable. I wasn't blowing any oil prior to this problem. The piston tops all look good. Actually, I was expecting to find a burned piston, but I guess I got lucky. Actually, if it had been burned, the motor pull would have been an easier decision.
I've got a source for a set of new heads at $400 a piece. This guy is a pretty good source so I'm pretty sure I can find out where the heads were made. Yea, I've already got them off and you're right, it really isn't the most fun I've ever had! Actually, I'm fortunate as to not have to rush this job. When it gets done, it gets done and that is always easier than having to have it on the road right way. I found a set of heads at a internet site that may be the ones you are refering to. They are supposed to be beefed up in the boss's and are used for off road racing. They were also cheaper by $100 a head. The only problem is I lost the web site.
Actually, I'm considering pulling the block and going through the bottom end. It has over 100k on it, but there is minimal, if any ridge and the crosshatching is still visable. I wasn't blowing any oil prior to this problem. The piston tops all look good. Actually, I was expecting to find a burned piston, but I guess I got lucky. Actually, if it had been burned, the motor pull would have been an easier decision.
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93 4.0 heads
How many hours did it take you to pull the heads? I have been debateing on pulling and rebuilding my complete engine or just pulling the the intake manifold and replaceing the gasket. My 4.0 93 Aerostar runs perfectly except it uses oil. Five hundred miles to a quart in the cooler days and 8oo in the hot days. The center plug on the driver side gets crud in it an all the others are perfect. I read some posts that the intake manifold gaskets were problems and leaked causeing that plug to foul up over time. Ford came out with a new one to cure the leaks. Any info on your experience on pulling the intake will be appreciate. Thank you.
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93 4.0 heads
May have solved part of the oil consumption problem. A leaking oil filter bracket gasket is letting oil out at a good drip a minute when running. But when stopped there is very little under the van. Under throttle it must really come out at angle that comes down some metal lines into the little heat shield below the exhaust pipe. No drips on the garage floor & you never see smoke because it is coming out the most when you are on the highway and it is cooking away. Still would appreciate info on pulling the heads. Thank you.
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93 4.0 heads
As far as pulling the heads, I'm a little embarassed to say that it took me about 26 hours to remove and replace them. It took me 5 hours alone just to remove the exhaust bolts that hold the exhaust manifold and exhaust system together. I should have just cut them off (which is what I ended up doing) after one hour. Also, I had to chase the threads in the upper and lower intake manifolds several times to get all of the glass bead material out that was left over from when the machinist cleaned everything. And, I took my time and used antiseize on all (or most) of the bolts and torqued everything to spec. In addition, I disassembled the fuel rail/lower manifold assembly (which is not necessary to remove the lower intake) and replaced the injector pintle caps and o-rings. The injectors were cleaned ultrasonically 9 months ago. I would recommend you have this done if you pull the manifold and have a good amount of mileage on the motor because you won't want to go back in and have to do this later.
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93 4.0 heads
Thanks for the info on head pulling. It is a wonder you had enough room to torque some of the bolts. How hard was it to disconnect the wires to the fuel injectors? On my Bronco II where you have plenty of room it was tough getin g the clips to release. Does the 4.0 also have clips? Thank you for the info.
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From: PNW
93 4.0 heads
There's room to torque the bolts if you've got a good selection of extensions and if everything is out of the way. It was not too difficult to remove the wiring connectors for the fuel injection once you get the upper intake manifold off. Although I didn't do it when I first pulled the injectors, removing the alternator and moving the A/C compressor out of the way would have probably made the job a lot easier. I'm not familiar with the clips used on the Bronco II. The injector connectors on the Aerostar were easier to remove than the connector for the temp sensor and in my case seemed almost like they weren't being retained sufficiently to stay on but I've had no problems.
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93 4.0 heads
Actually, removing the heads wasn't as miserable a job as I expected.
As I took them off over a week or so with no rush involved, it probably took about 4-5 hours of actual wrench time.
The main thing is to go deep enough to get things out of your way.
Disconnect and move harnesses, etc.
As I said in my first post, both my #2 and #5 exhaust valves were burned in an eliptical pattern. If you want me to e-mail pics I can do that.
One thing I did notice when taking it apart, the design of the intake sealing surfaces is miserable. The front of the manifold is a prime candidate for leaks. And because the valve covers bolt to both the head and the lower intake it leaves room for leakage there also.
My oil filter adapter is also leaking. So I will take care of that along with the heads.
The only tough bolt I had was the upper aft exhaust manifold bolt on the left side looking forward. By the way, the heads can be removed with the exhaust manifolds attached. I finally did it that way and used a tourch to heat it up and break it loose.
I should have my new heads tonight so the installation process is about to begin. I'll let you know how it turns out.
Bruce
As I took them off over a week or so with no rush involved, it probably took about 4-5 hours of actual wrench time.
The main thing is to go deep enough to get things out of your way.
Disconnect and move harnesses, etc.
As I said in my first post, both my #2 and #5 exhaust valves were burned in an eliptical pattern. If you want me to e-mail pics I can do that.
One thing I did notice when taking it apart, the design of the intake sealing surfaces is miserable. The front of the manifold is a prime candidate for leaks. And because the valve covers bolt to both the head and the lower intake it leaves room for leakage there also.
My oil filter adapter is also leaking. So I will take care of that along with the heads.
The only tough bolt I had was the upper aft exhaust manifold bolt on the left side looking forward. By the way, the heads can be removed with the exhaust manifolds attached. I finally did it that way and used a tourch to heat it up and break it loose.
I should have my new heads tonight so the installation process is about to begin. I'll let you know how it turns out.
Bruce
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Joined: Apr 2000
Posts: 1,746
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From: PNW
93 4.0 heads
Don't forget to use silicone goop in the corner where the head, block and intake manifold join. The factory manual says to use it on both sides of the manifold gasket. Also use it where the valve cover gaskets overlap the intake manifold.
When you button it back up, watch out for the #6 head bolt near the firewall. I broke the Torx bit on that bolt (it was the last bolt to be tightened) and had to make a mad dash to the auto parts store before it closed for the night. Make sure your Torx bit is in good shape. It's tough to keep the bit aligned strait when tightening due to the lack of access.
By the way, what brand of heads did you end up buying?
I would be interested in seeing the pictures of #2 and #5 valve seats. I'll compare them to my heads. Maybe the valve guides were bad on those cylinders?
When you button it back up, watch out for the #6 head bolt near the firewall. I broke the Torx bit on that bolt (it was the last bolt to be tightened) and had to make a mad dash to the auto parts store before it closed for the night. Make sure your Torx bit is in good shape. It's tough to keep the bit aligned strait when tightening due to the lack of access.
By the way, what brand of heads did you end up buying?
I would be interested in seeing the pictures of #2 and #5 valve seats. I'll compare them to my heads. Maybe the valve guides were bad on those cylinders?
