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Discussion Starter #1
I am trying to figure out what to do here. For a while now I have been aware of the fact that my valve seals are shot, and I am losing coolant through the head gaskets. It is getting to the point now where I need to do something about all of this. As much as I did not want to dump any substantial amounts of money, I am gonna have to.

So here is the million dollar question. Now, I already know that to have a shop fix the seals and replace the headgaskets I am looking at over a thousand bucks. So I figured why not just pick up a newer PI motor? The prices aren't that much more then what I am looking at to fix the one I have now.

I figured for the extra couple hundred bucks it would be kinda nice to have a new motor....
 

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Sounds like a plan buddy, and its almost a direct swap for you 96+ers ;) I got mine for $1200 or so.
 

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Only reason to get a new motor would be to go with an explorer block and save some weight off your front end. If you don't care about that, you could just do a PI headswap on your stock bottom end, which will bump up your compression ratio and give you a little bit more power. Either way it should be a pretty straightforward swap.
 

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Only reason to get a new motor would be to go with an explorer block and save some weight off your front end. If you don't care about that, you could just do a PI headswap on your stock bottom end, which will bump up your compression ratio and give you a little bit more power. Either way it should be a pretty straightforward swap.
However, doing a head swap on the 4.6 is so expensive after all the machining and such. It is almost more cost effective and time saving to just swap the whole motor.
 

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What machining is involved with doing a head swap?

I think the big question is if AlpineBird can do his own work or if he is going to have to farm it out to a mechanic. Most shops I know of would much rather swap an engine than pop the heads off an engine.

So it really depends. If you can do your own work, I would recommend a PI head swap. If you are going to have to pay someone, then I think an engine swap would be easier.

But just my .02. :thumbsup:
 

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Discussion Starter #6
Well I have a freind who would be doing the work for me so either way it dosent matter on that front, but when it comes to the whole money aspect of all this it seems more logical to just go with the whole new motor....

What kind of power gains would I expect from swapping in a stock PI?
 

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What machining is involved with doing a head swap?
Head swap requires machinging of the head to block surfaces. New head gaskets, valve seals (unless the heads are like new), the cost of removing the cams to install said seals, as long as the cams are off might as well rebuild the heads, new head bolts or studs, cam cover gaskets, etc, etc...
Granted, the guy said that the labor will be done by someone else so that takes a little labor off of his hands.
The compression bump with PI heads on NPI shortblock is another issue to sway the decision.
To me it boils down to whether you are looking for a quick low-mileage swap or a high performance upgrade.
The whole PI top end vs PI engine has always been a close call to me.
 

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WOT Junkie and avid corn burner
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I'm surprised there isn't a PI head swap sticky. Why does the head to block surfaces need to be machined?
 

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Technically, they only need to be machined if they do not meet the RA spec (which is a lot lower than most engines).
http://www.aa1car.com/library/ar996.htm
Ford specifies an unusually smooth surface finish for its 4.6L V8 engine. This engine, like a growing number of late model Japanese engines, uses a multilayer steel (MLS) head gasket. This type of laminated steel gasket is extremely durable because the multiple layers of metal (each of which is coated with a thin layer of rubber) prevents the gasket from losing torque over time. The design also reduces the amount of torque that is required on the head bolts to seal the gasket, which in turn reduces cylinder bore distortion for better combustion sealing and reduced blowby. The recommended surface finish for the OEM gasket on the 4.6L V8 is 8 to 15 RA!
 

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it is a close call but I the bump in compression I'd say is only good for 5-10HP. it's not a whole lot. If he goes with a low mileage Exploder which can be had for cheap then he's got a new motor that he doesn't have to worry about. And it's easier to do if you have a hoist.
 

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even a 02-04 Gt engine is good for the money. Think about it this way you can get a lower mileage engine for the same price as you could fixing yours with all those miles on it....
 

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explorer = happy!

You wont complain about the price, low mileage motor you just got and the power you pick up.
I recommend the explorer swap especially since its 80 pounds lighter and you get a lower mileage motor.
 

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check out ebay for cheap motors. im not sure how reliable the sellers are or anything. but most of the time the engines get pulled from totaled vic and mustangs or anything else.. but believe it or not the mustang engines sell for alot damn more, ive seen 36k mile crown vic motors sell for 900 buy it now. a steal in my opinion.

their pi too.
 

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Head swap requires machinging of the head to block surfaces. New head gaskets, valve seals (unless the heads are like new), the cost of removing the cams to install said seals, as long as the cams are off might as well rebuild the heads, new head bolts or studs, cam cover gaskets, etc, etc...
Granted, the guy said that the labor will be done by someone else so that takes a little labor off of his hands.
The compression bump with PI heads on NPI shortblock is another issue to sway the decision.
To me it boils down to whether you are looking for a quick low-mileage swap or a high performance upgrade.
The whole PI top end vs PI engine has always been a close call to me.
hmm...i dont necessarily agree with the "required" part of the whole scenario you just described...sure, it would be nice to have both the decks and the heads cleaned off prior to doing a headswap, but I didnt (my PI heads were pretty brand new though).....i got zero coolant/oil leaks....~180-190psi in all cylinders...all without machining anything when i did my PI heads swap on my NPI block....granted if the heads are all smudged up/scratched/gouged, then yes, i think machining would definitely be required

cost of removing cams to install valve seals????.....just what in the world are you talking about?.....it doesnt cost anything to change valve seals on heads that you have not put in your car already.....a 10mm socket will remove the cam caps so you can remove the cam, and voila, you have access to removing the springs (with a loaner spring compressor from an auto parts store) and thus the valve seals....so total cost to do valve seals on heads that are off-the-car: cost of 16 valve seals (~$30)

now, sure the idea of having a pretty new low-mileage engine is attractive, but if the car has been maintained and has less than 100k miles, its far from dying....therefore, i dont think a PI headswap should automatically be removed from the picture if the rings are still holding up the compression and it has never been run low on oil
 

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Discussion Starter #15
well i beat on my car pretty good, and it has about 101k on it now. Aside from that the motor needs a couple other minor things as well. I probly put about 400-500 miles on it a weak so im starting to think i would have more peice of mind with a newer motor to be honest
 

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The Band, not the Disease!
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You don't have to machine the heads or block UNLESS you suspect they are warped due to overheating / HG failure. I replaced the HG's on a 3.8L Bird and checked the block and heads for warping, none so I just replaced the headbolts (TTY) and HG's. Car ran like a champ, and still is. =) I'd say get some PI heads an just rebuild em yourself, if you are confident you can. It's VERY easy, but im a mechanic.
 

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