HAHA Compression test

[Jrgunn5150]

from what i understand from talking to mechanics and stuff....9:1 is 9:1 on all cars. I'm assuming that the 5.0's are 9:1 also... Did you have a screw in type? Did you bump it over at least 4 times? Was the battery fully charged? Was the coil disconnected and ALL your spark plugs out? Was your throttle blocked open ? Thats all i can think of the proceddure i was told... let us know.

i thought the 4.6 and the 5.0 had different compression ratios?

They do have slightly different C/R's, but not enough to show that kind of difference. What a cranking compression test really show's you is how much pressure is leaking past valves, ring's, etc. Sometimes this can happen due to the cam you use, long duration and a dual pattern give it an opportunity to blow out the exhaust before it register's. Sometimes it's just indicative of a worn out motor. This is why I prefer a leakdown test.

 

[voidfinger]

Yea i hear ya. Hey Jrgunn... you said you were looking into the 4v swap too right? Have you ever seen how the hoses run on those things?? i'm trying to figure out how i'm going to swing that. I think the thermostat housing is at the botom of the motor between some hoses...

 

[Jrgunn5150]

It comes out on the front cover near the water pump. I just figured I would try Cobra hoses first.

 

[voidfinger]

I saw a pic in my haynes manual and i saw the coolant cross over.... it had one pipe going to the crossover from the radiator...then another going down from the cross over... i then found a pic of what i believe to be the 4v and it had the hose going down run into what they called "Therastat Housing" and then it had two more hoses running from it..... I"m so confused....

 

[Jrgunn5150]

Yeah I think the heater hoses also run from there, basically, think, below the alternator, that's where the crossover runs.

 

[voidfinger]

I need to see some better pics and shit.... I don't want to start this and then relise i don't have some of the shit.

 

[reivaxtorres]

still interested in hearing what you think of the pi swap though

if you are still interested, i got done with the swap last night

power mods before the swap:
k&n intake, 75mm t/b, 75mm plennum, PI intake, PI cams, NGK Iridium Plugs, Nology Hotwire spark plugs, MSD coil packs, u/d pullies, frpp k/c clutch, aluminum flywheel, aluminum driveshaft, catted x pipes, 3.55 gears (out of 04 cobra), 190lph fuel pump.

added this weekend: PI heads, lokar dipstick tube( :rant: ).

truth be told, since i already had the PI intake and cams, i really wasnt expecting to get much power out of the heads, expecially since they were 100% stock of an 03gt. since i got them for pretty cheap, i figured id might aswell go for it.

the swap went really smooth with very, very few hiccups.

hiccup #1: you need an air gun to remove the crank pulley. tried doing it a few different ways, but wasnt able to get it loose. friend came by with his air compressor and we got it loose. use the air compressor to put it back on at the end as well.

hiccup #2: everyone says to drain the coolant, so i drained the coolant from the radiator and i unplugged the lower radiator hose figuring that would be enough (also removed the coolant tank, fan, and radiator to get a little more work room for the front accessories). well i was wrong. no one said to drain the block of coolant (apparently there is a drain plug on the passanger side of the block) or how, so i got a nice surprise when i tried to remove the heads, and got a nice bath of coolant all over my pants, on the floor, and in the cylinders. blah. cleaned up easy enough tho.

hiccup #3: the head bolts are a little tricky to remove since about 6 of them (2 on passanger side, 4 on drivers side) dont have enough room to come out of the head all the way, but they do clear the block enough to be able to twist the heads away from the block.

hiccup #4: and the biggest hiccup of all was that i forgot to put the new dipstick tube into the engine when i should have. its supposed to be installed at the same time the heads are installed, and we completely forgot until after the heads were torqued down and timed and everything. so i had to buy the flexible lokar dipstick off of summit, and had to wait a few days to finish the project because of this mistake. the new dipstick tube that came with the FRPP headswap kit didnt work either, and we bent that one to hell. the stock one broke on its way out

anywho, back to the headswap results. fired it up last night and topped off all the fluids and made sure i wasnt burning oil (was smoking up a lot because you have to oil the cylinders before you put the heads back on, 1 cap full of oil per cylinder). then i took it for a quick test drive around the block to make sure there were no noises or anything, rechecked fluids, and took it on the freeway. like i said, i honestly didnt expect any difference, but wow, there sure is. even with the PI cams and intake, my car seemed to be out of breath by about 5-5.5k rpms, and you begin to notice it more in the higher gears. now my car just keeps climing and asking for more as the RPMs go higher! even in 3th gear, where you used to be able to tell the car was out of breath, it keeps pulling to redline. throughout the lower ranges of the RPMs you can feel the difference as well.

overall im pleased with the results of the swap. going from full NPI to the complete PI swap would be really, really worth it for any NPI stang. if you have the time and money to wait, i would suggest you get the PI heads ported along with getting a decent set of cams (stage 1 or so) and a tune, then it will really shine.

- going to wait a few weeks before i take it to the track, just to make sure everything is ok with the car. have some before time slips (1/8 mile) and looking to get some after time slips.
- i had been running 91 octane gas for about 2 tanks before the swap. i suggest you do this so you dont get knocking or pinging. might try to see what happens if i switch to lower octane gas, but kinda dont want to risk it.
- still on the stock tune, even with all the bolt ons. no CEL light either.

 

[voidfinger]

very nice... did it run rough when you started it up or anything? thanks

 

[reivaxtorres]

nope, you primer it first before you start it, which is just once everything is plugged in, you unplug both the coils and crank the car. crank it for about 20 seconds at a time, and always turn the key to the off position (to avoid the CEL light). do this for about a minute or two, then plug the coils back in, say a prayer or two, and turn on the car.

doing this, i had lifter noise for about the second or two that it took the oil to reach the lifters (same as when you do an oil change), no biggie. the only thing i kept a very close eye on was the coolant and the oil. the coolant because since the car was cold, the t-stat would be closed and not allow any of the coolant from the tank into the engine, so you had to wait until the car heated up and the t-stat opened up, in which case it sucked the tank dry. took about 2-3 gallons of coolant/water to fill it up.
when you remove the heads, you are supposed to oil the cylinder walls. what i did instead was asseble it and before i put the plugs in, i dropped about a lid full of oil into each cylinder. cranking the car w/o spark would insure that the oil would be pressed against the rings and oil them as needed. because of this, once i turned on the car, it was spewing out white smoke (like a damn train) out of each pipe for about 10-15 minutes.

 

[voidfinger]

lol i hear ya. I'm thinking of switching to royal purple when i swap the heads and stuff... also, when you have the motor apart and you haven't cranked it yet, you could take the t stat out and pore the coolant in there ... enought that it wouldn't get hot and warp anything i think. ANyway good.

 

[reivaxtorres]

lol i hear ya. I'm thinking of switching to royal purple when i swap the heads and stuff... also, when you have the motor apart and you haven't cranked it yet, you could take the t stat out and pore the coolant in there ... enought that it wouldn't get hot and warp anything i think. ANyway good.

im using a somewhat new mobil 1 filter (had less than 2k miles on it, and it usually lasts well over 5k miles) and motorcraft synthetic blend 5-30 oil in it right now. going to run it like this for another day and then do an oil change on saturday and switch back to mobil1 synthetic 5-30 and get a new mobil1 filter.
*if there is a lot of coolant in the oil pan (if you happen to get any in there), its recomended you turn on the car, let it idle for about 10 minutes giving it a little gas every now and then, and then change the oil and filter. this way it will flush any coolant out of the oil system w/o damaging anything. on mine, i had very little coolant mixed in so i just re-drained the oil (drain it before you start, then again before you re-fill the car with oil) to get the rest of the oil out and filled it up with new oil. checked the oil and it looks good, looks pure.

as for the coolant re-fill thru the t-stat housing, yeah, you could do that too, but i was lazy and didnt want to take it off. :angel: just kidding, the stupid t-stat housing is stuck on there good so i would have had to use a hammer to knock it loose, which prob would have bent it or broke it, and i didnt want to have to wait even longer to drive it because i broke that part. ive re-filled the system thru the coolant tank before and it never caused any problems, so i wasnt worried about doing it again. for the record tho, its only about 5 minutes or so from when you turn on the car that the t-stat opens up and you can fill the system.

 

[voidfinger]

yea i know, i changed the intake more than a couple times lol

Anyway, yea i'm going to drain the coolant and oil before i start..... I got a lot going on in my head right now... lol