Finding TDC - non thirdgen

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Aug 14, 2002 | 09:18 AM
  #1  
I am replacing head gaskets on a 96 ford thunderbird 4.6 DOHC v-8 engine. I know that on a chevy v-8 you can just take the spark plug out and when the #1 piston goes all the way up and both the valves are closed then the engine is at TDC at #1 cylinder. Would it be the same with a DOHC engine? I don't want to screw this up as this is not a free wheeling engine and will bent the valves if i remove the timing chains if not at TDC. Thanks a lot for your help.
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Aug 14, 2002 | 09:28 AM
  #2  
Should be the same, just make sure all the valves in the #1 chamber are closed.
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Aug 14, 2002 | 09:56 AM
  #3  
check a manual #1 is most likely in a differant place than on a SBC
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Aug 14, 2002 | 10:06 AM
  #4  
remove the #1 spark plug from the head and place your thumb over the hole. Now have someone crank the engine over a little at a time. When you feel air begin to blow past your finger align the timing marks and your now at TDC compression stroke. The other method if you still have the distibutor in or if it has a distributor at all is to turn the engine untill the timing marks line up the rotor should be pointing at #1 terminal of the cap if not rotate the engine 360 deg. it should be now.
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Aug 14, 2002 | 02:02 PM
  #5  
Same concept. DOHC? A 96 T-bird wont have a DOHC engine unless someone swapped it in there. Generally #1 cylinder is the cylinder nearest the front of the car. I think the plug wires are all numbered, but I'm not sure where #1 is because I never bothered to look
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Aug 14, 2002 | 03:21 PM
  #6  
Thanks guys for all the replys. The head removal went pretty swift. Now if i could just put everything back together with all that electronis BS

madmax, i'm pretty sure you'r mistaken about the 96 t-birds not having a DOHC engine. Its in the chilton's manual. You must be thinking about the v-6 engines which were not DOHC. The 4.6 DOHC v-8 was just another option. thanks again for your help.
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Aug 15, 2002 | 02:58 PM
  #7  
Nope, not on a T-bird. Only Cobras and Mark VIII's could get the DOHC engine, the T-bird could only come with a SOHC engine from the factory.

<---- former Ford factory tech.
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Aug 15, 2002 | 04:34 PM
  #8  
madmax,

Just wanted to clear something up. I went to the auto store today to get new headgaskets and they didn't have a DOHC 4.6 v-8 on their computer for any of the thunderbirds. So they gave me the SOHC gaskets and even though it says SOHC they told me its still the dual overhead cam engine that i have. Now i'm confused about this. The engine has two camshafts, one in each head and two timing chains connected to the crankshaft so isn't is suppossed to be DOHC?
Anyways, madmax was right about the engine not being a DOHC and i'm sorry if i confused anyone. I guess a DOHC engine would have 4 camshafts total? (2 for each head?)
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Aug 15, 2002 | 07:15 PM
  #9  
Yepper. A DOHC engine has 2 cams on each head, SOHC has one per head. I guess it can be confusing if you realize there's 2 cams on the engine.
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