GT40 head swap help

Falcons Talon · 03-19-2004, 03:07 PM

It's been a while since I've posted.
A little help would be appreciated.
I got to working on a gt-40 head swap.
It's all put back together, but it's missing badly. I thought that maybe I jumped a tooth on the distributor, but I jumped one tooth each way and it didn't help. I set it back to where it was and tried advancing and retarding the timing. No help. Yes, I checked and double checked the plug wire/firing order.
On the tear down, I set the engine at TDC and removed distributor, marking both dist position and rotor position. Both were set back to that position before rotating engine for roller rocker torquing.

What am I missing.

Dark_5.0 · 03-19-2004, 05:33 PM

mkae sure you are at TDC on the compression stroke.

What is your timing set at?

sedanman · 03-19-2004, 06:00 PM

Is it missing like running on 7 cylinders or missing like it is running on 4? If its four then odds are you are 180^ out. If its seven check the rockers, wires and plugs. Did you put a new cam in?

Falcons Talon · 03-20-2004, 12:41 AM

I'm still at 10* timing. Gas is too expensive to bump 14*

It seems like it's hitting on 7 cylinders. I'm going to take the valve covers off and check the valve train on Sunday. Hopefully it's something up top. If not, I'll have to strip her down again and check that I didn't bend a valve.

Wait a sec...TDC on compression stroke...that might be it. Check this...If I'm at TDC and the rotor is pointing to #1 does that guarantee TDC on the compression stroke?

stang_racer20 · 03-20-2004, 01:39 AM

tireburner163 · 03-20-2004, 09:38 AM

check your vacum lines, etc

Falcons Talon · 03-21-2004, 11:46 AM

gonna retorque all the rr's

Falcons Talon · 03-21-2004, 04:58 PM

Paydirt. I retorqued all the rockers and no luck, but it was sounding a little better. I took the heads off and checked out how the valves were seating. The number 6 intake is not completely seated. I think we found out culprit. The pistons are ok. I guess the heads came with that bent valve. I need to make a call and let this guy have a piece of my mind.

Has anyone here disassembled heads before. I would like gain some experience and save some money at the same time. I'll still take them to get planed...just in case, but if I can learn how to take apart and put together heads, that would be great!

Another Q...I shined a flashlight in the exhaust port and could barely see light around the exhaust valve on the number 5. Is this acceptable? Maybe I should just drop them off at a machine shop.

Falcons Talon · 04-01-2004, 09:10 AM

Thanks for you guys that offered assistance. I know that there are many more people here with knowledge enought to help answer this question, but I guess you're just too busy to help a guy out. Just so you all know, there were some bent valves, so I just had them all replaced and upgraded to Trick Flow Springs.

The heads are on now. Thanks again to those that offered assistance.

03-19-2004, 05:33 PM	#2
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	mkae sure you are at TDC on the compression stroke. What is your timing set at? __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

03-19-2004, 06:00 PM	#3
sedanman Registered Member Join Date: Feb 1999 Location: Indianapolis, IN Posts: 963	Is it missing like running on 7 cylinders or missing like it is running on 4? If its four then odds are you are 180^ out. If its seven check the rockers, wires and plugs. Did you put a new cam in? __________________ 04 Screamin Yellow Cobra KB 2.4 (585/556 pump 626/666 race) 00R brakes, DFX clutch, Level 5's, return fuel system, Lts with 3" exhuast, FR500 wheels and all the other fun stuff. GONE 1991 Lx sedan 5.0, 5spd (Liberty proshifted TKO) S-trim, Ported TF heads everything parted out.

03-20-2004, 12:41 AM	#4
Falcons Talon T.P.M. President Join Date: May 2002 Location: Brownsville Posts: 265	I'm still at 10* timing. Gas is too expensive to bump 14* It seems like it's hitting on 7 cylinders. I'm going to take the valve covers off and check the valve train on Sunday. Hopefully it's something up top. If not, I'll have to strip her down again and check that I didn't bend a valve. Wait a sec...TDC on compression stroke...that might be it. Check this...If I'm at TDC and the rotor is pointing to #1 does that guarantee TDC on the compression stroke? __________________

03-20-2004, 01:39 AM	#5
stang_racer20 Registered Member Join Date: Jun 2003 Location: Wisconsin Posts: 348	Yep __________________ 92 Mustang GT, 347 Stroker(Forged Steel Crank/Rods-Balanced, Forged Aluminum Dished Pistons), Trick Flow Track Heat Intake, Trick Flow Twisted Wedge Heads w/ Stage 3 port/polish, 80mm C&L MAF, FMS 30# Inj., BBK AFPR, Trick Flow Stage 2 Cam, Trick Flow 1.6R Rockers, BBK E.L. Headers, Flowmaster Cat-Back, MAC CAI, FMS Pulleys, Griffin Alum. Radiator, MSD Pro-Billet Distributor; AOD, Dynamic 3300 Lockup Converter, B & M Super Cooler, B&M Ratchet Shifter; 3:73 gears.

03-20-2004, 09:38 AM	#6
tireburner163 It's a lot like a race car Join Date: Aug 2000 Location: Meridian, MS Posts: 4,130	check your vacum lines, etc __________________ 1987 Buick T-type 1998 HD Electra Elide

03-19-2004, 03:07 PM	#1
Falcons Talon T.P.M. President Join Date: May 2002 Location: Brownsville Posts: 265	GT40 head swap help It's been a while since I've posted. A little help would be appreciated. I got to working on a gt-40 head swap. It's all put back together, but it's missing badly. I thought that maybe I jumped a tooth on the distributor, but I jumped one tooth each way and it didn't help. I set it back to where it was and tried advancing and retarding the timing. No help. Yes, I checked and double checked the plug wire/firing order. On the tear down, I set the engine at TDC and removed distributor, marking both dist position and rotor position. Both were set back to that position before rotating engine for roller rocker torquing. What am I missing. __________________

03-21-2004, 11:46 AM	#7
Falcons Talon T.P.M. President Join Date: May 2002 Location: Brownsville Posts: 265	gonna retorque all the rr's __________________

03-21-2004, 04:58 PM	#8
Falcons Talon T.P.M. President Join Date: May 2002 Location: Brownsville Posts: 265	Paydirt. I retorqued all the rockers and no luck, but it was sounding a little better. I took the heads off and checked out how the valves were seating. The number 6 intake is not completely seated. I think we found out culprit. The pistons are ok. I guess the heads came with that bent valve. I need to make a call and let this guy have a piece of my mind. Has anyone here disassembled heads before. I would like gain some experience and save some money at the same time. I'll still take them to get planed...just in case, but if I can learn how to take apart and put together heads, that would be great! Another Q...I shined a flashlight in the exhaust port and could barely see light around the exhaust valve on the number 5. Is this acceptable? Maybe I should just drop them off at a machine shop. __________________

04-01-2004, 09:10 AM	#9
Falcons Talon T.P.M. President Join Date: May 2002 Location: Brownsville Posts: 265	Thanks for you guys that offered assistance. I know that there are many more people here with knowledge enought to help answer this question, but I guess you're just too busy to help a guy out. Just so you all know, there were some bent valves, so I just had them all replaced and upgraded to Trick Flow Springs. The heads are on now. Thanks again to those that offered assistance. __________________

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