GIXER7502006

Hopefully someone has had this issue b 4 and can help me, I hav a 1985 Mercury capri 5.0 5 spd , the motor it had b 4 would pressureize the radiator, so I pulled the heads found one cracked so I replaced it thinking that was my problem yeaaaa, put it all back togeather and it did the same thing, not happy at all, so I find a 2000 explorer with GT40P heads and 5.0 runs great sounds great, thinking all my problems are gone, yea right lol
I basicly use the long block the only thing i used off my motor is the intake, carb, oil pan and oil pump, harmonic balancer, timing cover water pump,
So now the radiator is fine not pressurizeing, yeaaa but when I advance the timing to where the motor runs great in nutural revs fine and sound great so I take it for a ride, the valve are chatering so bad I hav to back the timing to where the valves don't chatter, now when I give it gas and the 4's open up it starts backfireing and missing, only when the 4's open up 3/4 throtle it runs fine but as soon as I floor it it starts braking up bad, with the timing advanced to where it runs fine in nutural it has plenty of power while driving but the valve r chattering so bad, and when I deadvance it so the vales r not chattering thats when it starts missing and backfiring, after warm and the timing advance to where it runs fine except for the valve chatter, it starts fine no rump rump like the timing is to far advanced either.
when I first got it running and it didnt run right I thought the firing was acting up so with new plugs cap n rotor wires all new, still the same so I buy a new distrobeter thiinking it was breaking up on higher RPM'S, nothing and I replaced the ignition modual on the fire wall, O and I replaced the coil too lol
So with an all new ignition system I think it should be fine, not
The carb is a new holly 600 cfm, the only thing old on the car motor is the intake, the previous owner took the egr valve out and put a spacer plate in its place, Ive had Chevy's all my life and not to familer with fords so PLEASE HELP I just want it to run right and hope someone has ran into this same problem, I am useing the 5.0 ho firing order also, it runs great untill I kick it in the ***
thanks again for any help and Im sure I will be around here looking for more things to do to my 5.0
sorry for the long post also

GIXER7502006

140 People looked at my post and no 1 has anything, Im stumped here and thought someone would have a suggestion atleaste
even if it is simple and maybe I forgot something
please help, going to check for a vaccume leak tonight

tohoopty

whats your timing set at and was that holley on the old motor

GIXER7502006

The holly is new and I had a 650 duel feed with vacum secondary's on the old motor and when i thought i fixed the head gasket the header was glowing red on the last cly so I was thinking it was running lean so that was why I got the new carb, the car was sitting for a while b 4 I got it back on the road, I even checked my fuel pressure, it was @ 3.5 lbs so I just replaced the fuel pump last night too
all the vaccum lines r disconected except for the one going to the brake booster and the one to the a/c door so I can have the A/C working and it does beautifully, now if i can get this motor running right I would be very happy and able to start the mods

thanks for the reply, on the timing the pre owner took the timing marker off, so as of now I am timing it by ear, bought the tioming tag from Ford and it's the wrong one, but what i did do like on my older race cars I advanced the timing till it started to ping and them backed it off just a little, when the timing seems right free reving the cars has all the power but pings like crazy, when I back up the timing so it dosnt ping it starts missing bad at higher rpms ie cause of the timing be so far retarted, one other thing it runs great till the motor starts to get warm then it really starts acting up.
gona try and get a vid of it tonight, this motor runs beautifuly driving with just 2 barrels will rev up to 5k never miss a beat as soon as the 4's kick in it misses and backfires into the exhaust
thanks for any help

mjr46

you can't time by ear, you can be more than 20 degrees or more off the way you are doing it, get the pointer on and use a light, are you sure you have the correct firing order on??

GIXER7502006

firing order is right and the car does not miss a beat, engine runs perfect except for the hard load and the 4's r open, the car runs fine all the way to 3/4 throtle, I have timed cars b 4 by ear and they were fine, if i advance the timing till i hav the power like it should, the lifter chatter very bad and when i back it up enuff to run without the pinging, it starts missing at higher rpm's ie the timing being off, I will get a pointer on it to dbl check, the thing is I hav timed many cars by ear and it might not be exactly spot on the money but If I advance it till i hear the pinging then back it up just enuff to make the pining go away, that way i hav it advanced as far as possible without the valve chatter, but that was 15 years ago, maybe motors hav changed in the last 15 years idk, thinking I might hav a vacumm leak some where making the car run extra lean ie causing the pinging at higher rpm's, 1 other thing when i plugged the pcv valve it made it run better, but not perfect making me think a vaccum leak
the only vaccum lines i hav on the car now is the brake booster and the a/c vaccum door, gona try and plug the brake booster to make sure it is not leaking and causeing a lean condition
sorry for the long posts but this car is driving me FKN nuts, I hav never had a car I couldn't make run without any hickups
Again thanks for everyones help

I also was hopeing someone has done this swap and seen a simular poroblem

mjr46

also what plugs are you using?? what distributor?? and make sure balancer hasn't spun.

GIXER7502006

Got the plugs from the ford store they r motorcraft part# AGSF32FM, when i took the motor out of the explorer it ran perfect from a to z so I origianly used the plugs that was in the motor thinking it was not missing so use the plugs that r in there, then it didnt run right and i thought maybe the coil I am useing would not make the plug fire right being that it came from a coil pack witch has a little more wollop then my coil, the distributor is new and I used the one that was in the origianal 5.0ho I replaced it with a new one 2 weeks ago, there r 2 different one's and I matched it up at the parts store
again now it seems like the motor will run perfectly untill under heavy load, I hav ran the motor up to 5k rpm's and it never missed a beat untill I open the 4's holding it @ 3/4 throtle , when the motor pings it has all kinds of power and when i back the timing up so it dosnt ping that is when it starts missing and acting up, so IM thinking that i need to put it back to where it has all the power cause that is where the timing needs to be and look for a reason why it is running lean causing the pinging lol if that makes sence

GIXER7502006

O and the harmonic balancer is new also from b 4 on the old 5.0 the origianal one went bad on my in the drive way, man what a vibration lol

mjr46

does the dizzy have vac advance?? also don't run a platnuim plug since it is carbed, run a standard resistor core plug