just added GT40s to my 87 pony and I cant get the timing straight

[sychomustang87]

I just installed some GT40s into my 87 and I set the timing to 15 degrees and when i put the jumper back in it turns off now if I turn the distributor all the way to the right it seems to turn on fine and it seems to run fine but it shouldnt be that way.
does anyone know what could be causin this to happen ??????

 

[old_blue]

I think we need more info on the engine/car. is it mass air converted? were there any other codes or issues before the install?

 

[sychomustang87]

The motor has a ford F-cam,1.6 rockers,pulleys,smog and Ac eliminated.
Now I never had any problems with the car before. Its always ran hard. Oh and no its not mass air converted

 

[mikepotts]

The motor has a ford F-cam,1.6 rockers,pulleys,smog and Ac eliminated.
Now I never had any problems with the car before. Its always ran hard. Oh and no its not mass air converted

there is your problem, you have changed the airflow of the motor and the computer has no way of knowing what is going on w/o a mass air meter.

 

[1990MustangLX50]

Time to invest in a mass air conversion or pay somebody for a custom tune. Your MAP sensor will not detect the added airflow of those heads.


Im not sure I would agree that is your problem are you sure you stuck the dizzy back in the same way and in time?

 

[mikepotts]

w/o a mass air conversion or reprogramed computer it will never run right.

the dizzy might be a little off too.

remove #1 plug, get the motor on TDC put the plug back in, and drop the dizzy in with the rotor pointing to the 1 on the cap, that will get it close enough to time it with a light.

 

[foxforce33]

w/o a mass air conversion or reprogramed computer it will never run right.

+1

The cam with the head change is too much for the SD. Time to go MAF.

 

[phutch11]

Just a sanity check here...b/c your symptoms sound just like what happens in you have the dizzy one tooth off, or if you have a couple of plug wires crossed.

Did you check to make sure you've got all the plug wires going to the right plugs? Are you 100% sure that you don't have the dizzy installed correctly?

I only say that b/c I can't seem to EVER reinstall a dizzy the right way the first time.

The easiest thing to do is to roll the motor over until it's at 10 degrees before TDC of the compression stroke on the #1 cylinder. Then stab the dizzy and adjust until the rotor is pointed directly at the lead for the #1 plug wire.

Good luck...

 

[v8only]

Lot of myths about speed density.

You can add nearly every mod in the world so long as you don't do something that lowers engine vacuum. I ran a ported explorer intake, 65mm throttle body and gt40p heads with 1.7 roller rockers with a stock HO cam and speed density, and she ran like a raped ape.

However, people are right in this case. Not because of the heads, but rather that cam. Speed density MUST see a vacuum signal of 17+ and with that f cam, you'll never see 17 pounds. Hell, I only see 10-11 pounds with my current b cam.

The computer things you've got your foot halfway down into the throttle at idle because it's not seeing full vacuum to the map. Because it's not getting full vacuum, the computer is saying, more fuel, more fuel, let her rip!!!!

You HAVE to convert to mass air at this point, or go back to a speed density compliant cam.

 

[sychomustang87]

I tried it all except for the mass air conversion. So ill be converting it this weekend.
Thanx for all the imput guys ill be keeping you guys posted on how all this turns out.

 

[sychomustang87]

Sorry guys i havent tried pulling the distributor and setting the rotor to #1 plug.
This is how i did the timing.
I turned the motor to TDC and pointed the rotor to piston #1.
Now im going to try mikepotts way.

 

[sychomustang87]

ok i pulled the distributor and i set the motor to TDC and set the rotor to #1 on the rotor cap now it turns on fine and runs good but it ran harder when it had the stock heads so i know there is a lot more power i just cant find it on the timing part.
NOTE: it ran harder the way I had it set before.
I set it to TDC and I pointed the rotor toward piston #1 but the only way it would run hard was with the distributor turned all the way to the right.
So something is wrong cuz i should be able to set the timing to 15 degrees advance and leave it there right.
Am i right or wrong?????????

 

[v8only]

i'm telling you man, it's gonna run like **** with that cam, period!