Full Pi engine or Pi swap?

[justinschmidt1]

Most of you know my car...its got full bolt ons, long tubes, procharged @ 10 psi. etc.


Im having trouble finding a decent PI engine so I was wondering if its a good idea to do a pi swap.

I mean, my bottom end is probably old and tired.

If I do a pi swap I will be porting the heads lightly and removing the emission vane so I will probably have a little more flow.


What would I need to do the swap?

Can I pretty much drop pi heads/cams in there and roll with it?

Ive heard removing that vane in the combustion chamber will lower compression like a half a point anyway so it should keep the compression down a bit.

 

[GDTrumbo]

These are the same things I've heard and read. I don't know if removing the intake valve "shroud" will drop the comp ratio a full 1/2 point or not but that seems to be a popular practice. That was supposed to create a swirl to better fill the CC but that is debatable. I would spend the time "degreeing" the cams though. You could be leaving 40 hp on the bench if you don't.

After turning 157K recently, I think I'm just going to go the '04 long block route. It runs really great and has never leaked or used much oil, so I'll probably be looking hard for an excuse to do that.

GT

 

[MustangChris]

i dont understand this thread at all.... i should go read a book... lol...

whats an emission vane ?
what vane in the combustion chamber?
Degreeing the cam? doesnt that have to be dead-on?
valve shroud?


im scared... and confused...

 

[D3VST8R96GT]

like a teenage homo in a whore house

 

[MustangChris]

well... .... maybe not the homo part. lol.

its hard to explain... but right when i think im getting a fairly okay chunk of knowlege about my car leave it to GT to ruin it...

 

[justinschmidt1]

i dont understand this thread at all.... i should go read a book... lol...

whats an emission vane ?
what vane in the combustion chamber?
Degreeing the cam? doesnt that have to be dead-on?
valve shroud?


im scared... and confused...

Its this shitty thing for put in the combustion chamber...its supposed to help lowend and emmissions.

But with forced induction it is robbing power.

Im not sure about the degreeing of cams.

 

[blown98gt]

i thought the point of a PI swap was the boost in compression is what makes the real difference in the power. I can tell you the difference now.
do the full pi swap, heads cam, pi intake mani (or your choice of mani)

as far as the port goes, my first motor PI swap had tons of power, then blew that motor on nitrous and I had to have my heads fixed so i had them done to about a stage 2 port equivalent and after that the power was still there just not even as much. If it was me i'd just do a PI swap and not worry about porting the heads. inless you have mods that are going to support the more airflow then you wont see the full gain of the port.

 

[glittle75]

the "Emissions vane" is the little "shroud" over the valve in the chambers. most people shave it off when they port heads to unshroud the valve and improve flow a bit, you uncover the curtain area more when you take it out.

It actually a "Swirl Dam" to help get the fuel and air mixed in there good to lower emissions and improve power by getting more of a full burn of everything. but it also shrouds the valve up a bit.

and to the OP, i say if you can find a good PI motor for a decent price, go for the whole thing. if you look around for a bit and come up with nothing, Do the PI Swap. If you do grind down the dam, your compression should be in check for the boost.

and if your just going to throw stock PI cams in there, just throw them in straight up and you'll be fine. degree'ing them stock cams aint gonna do much for ya. but if you get anything above a "Stage 1" degree them.

my $.02

 

[MustangChris]

okay. 1 question down... lol...

 

[GDTrumbo]

well... .... maybe not the homo part. lol.

its hard to explain... but right when i think im getting a fairly okay chunk of knowlege about my car leave it to GT to ruin it...

Sorry. I've been messing with cars since I was 14 (1975). I still learn something new about these Mustangs every day it seems.

glittle75 is right though. Degreeing the stock cams is a bit obsessive. That's just me. The cam timing on these "interference" style engines has to be dead nuts and double checked though, or carnage will ensue.

GT

 

[justinschmidt1]

the "Emissions vane" is the little "shroud" over the valve in the chambers. most people shave it off when they port heads to unshroud the valve and improve flow a bit, you uncover the curtain area more when you take it out.

It actually a "Swirl Dam" to help get the fuel and air mixed in there good to lower emissions and improve power by getting more of a full burn of everything. but it also shrouds the valve up a bit.

and to the OP, i say if you can find a good PI motor for a decent price, go for the whole thing. if you look around for a bit and come up with nothing, Do the PI Swap. If you do grind down the dam, your compression should be in check for the boost.

and if your just going to throw stock PI cams in there, just throw them in straight up and you'll be fine. degree'ing them stock cams aint gonna do much for ya. but if you get anything above a "Stage 1" degree them.

my $.02

Thanks, thats pretty much what ive been doing...

I really want to find a whole engine from an explorer so I can drop some weight off the front.

 

[JDwhite98gt]

bill fox think its called fox motors in on the outskirts of the york pa area about 45 -hour away from baltimore. I got the 03 motor from him and its been running dead on for about 3 years now never misses a beat. He has a bunch of options even ranging to termi motors, interiors, exteriors this and that. He is kind of a jerk and wouldnt recomend him for anything but buying the parts...I had it installed by him in my old gts and all said and done cost me almost 3100 (needed this and that...so he said) . I swapped the motor myself into my gt I have now. but the motor had 65k on it I picked it out myself I think ran me about 2300 just for that though.

 

[MustangChris]

well... .... maybe not the homo part. lol.

its hard to explain... but right when i think im getting a fairly okay chunk of knowlege about my car leave it to GT to ruin it...

Sorry. I've been messing with cars since I was 14 (1975). I still learn something new about these Mustangs every day it seems.

glittle75 is right though. Degreeing the stock cams is a bit obsessive. That's just me. The cam timing on these "interference" style engines has to be dead nuts and double checked though, or carnage will ensue.

GT

what more degreeing is there other than lining up the timing marks/chains?

 

[glittle75]

the stock cam gears have a tolerance of +/- about 5 degrees from the factory, they can be way off.

and if you put cams in with alot of lift and duration and LSA, and its off by that much, you will have problems.

and lots of your "Stage 2" and up cams they need to be dead on, and they are ground to be at specific centerlines.

so, say your stock cam centerline is at 109 degree, for example, and your nice new stage 2's need to be at 114 degrees C/L, then you need to degree them in relation to the crank centerline so they will have no issues with PTV clearence.

 

[GDTrumbo]

^ Your just good! On some engines, I assume nothing.

GT