The Ford Barn

38coop · 11-08-2015, 07:07 AM

Just want to be sure. At top dead center the tip of the rotor should be pointing at #1 spark plug in the cylinder head with the distributor installed. Hope this is right.

JSeery · 11-08-2015, 07:55 AM

Might want to read post 12-13-14-16 and make your own decision based on the inputs. Any position on the cap can be #1 as long as you follow the timing order. If you like the position nearest to the #1 cylinder that will work (but so will any of the remaining 7 positions!)

Bored&Stroked · 11-08-2015, 08:48 AM

Everybody has pretty much flogged this horse (for an 8BA) to death now haven't they!

On 32 to 48 engines, I'm not aware of there ever being a timing mark (at least that I've seen). So, I usually create one during the build process - using a degree wheel as well as a dial-indicator or dead stop before the heads go on.

Here is my latest creation for a 42 Merc engine that is going into my 32 Cab (being put in today . . . after 2 years of work . . . yippee!).

I modified an original 32 motor mount (fabricating some steel and a pointer to make it look like it came that way). Then I marked the crank pulley with TDC as well as 10,20,30 degrees.

FrontofMotorComplete2 copy.jpg

2015-11-07 18.31.21 copy.jpg

flatjack9 · 11-08-2015, 11:32 AM

Quote:

Originally Posted by JSeery

Might want to read post 12-13-14-16 and make your own decision based on the inputs. Any position on the cap can be #1 as long as you follow the timing order. If you like the position nearest to the #1 cylinder that will work (but so will any of the remaining 7 positions!)

It doesn't really matter how you install the distributor, but once it is in, #1 has to be the one the rotor is pointing at with #1 piston at TDC firing.

Mike51Merc · 11-08-2015, 12:26 PM

To answer the original question as simply as possible, there are 360 degrees in a circle, and there are eight cylinders that need firing so each cylinder gets 45 degrees of arc to play with. Since the cam turns at half the speed of the crank, this means you have about 90 degrees of crank turn that belongs to each cylinder.

So, as far as TDC and initial ignition timing (for the purpose of distributor installation), TDC is critical only to the extent of the 45 degree "range" of the #1 cylinder, otherwise you'll be in the range of a different cylinder. The fine tuning is going to occur in that 45 degree range that "belongs" to that particular cylinder.

So the bottom line is that if your #1 cylinder is somewhat close to the top (which is close enough to the crank timing mark) and you stab your distributor in so that the rotor is pointing to the 6 o'clock position (Assuming your cap is wired with #1 at 6 o'clock), you stand a good chance at having the engine start (unless you're 180 degrees off which is a whole other thread to talk about). Once it starts, then you do final tuning.

11-08-2015, 07:07 AM	#21
38coop Senior Member Join Date: May 2010 Location: Cocoa Florida Posts: 180	Re: how critical is TDC Just want to be sure. At top dead center the tip of the rotor should be pointing at #1 spark plug in the cylinder head with the distributor installed. Hope this is right.

11-08-2015, 07:55 AM	#22
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: how critical is TDC Might want to read post 12-13-14-16 and make your own decision based on the inputs. Any position on the cap can be #1 as long as you follow the timing order. If you like the position nearest to the #1 cylinder that will work (but so will any of the remaining 7 positions!)

11-08-2015, 08:48 AM	#23
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,067	Re: how critical is TDC Everybody has pretty much flogged this horse (for an 8BA) to death now haven't they! On 32 to 48 engines, I'm not aware of there ever being a timing mark (at least that I've seen). So, I usually create one during the build process - using a degree wheel as well as a dial-indicator or dead stop before the heads go on. Here is my latest creation for a 42 Merc engine that is going into my 32 Cab (being put in today . . . after 2 years of work . . . yippee!). I modified an original 32 motor mount (fabricating some steel and a pointer to make it look like it came that way). Then I marked the crank pulley with TDC as well as 10,20,30 degrees. FrontofMotorComplete2 copy.jpg 2015-11-07 18.31.21 copy.jpg

11-08-2015, 12:26 PM	#25
Mike51Merc Senior Member Join Date: May 2010 Location: Northeast Pennsylvania Posts: 1,582	Re: how critical is TDC To answer the original question as simply as possible, there are 360 degrees in a circle, and there are eight cylinders that need firing so each cylinder gets 45 degrees of arc to play with. Since the cam turns at half the speed of the crank, this means you have about 90 degrees of crank turn that belongs to each cylinder. So, as far as TDC and initial ignition timing (for the purpose of distributor installation), TDC is critical only to the extent of the 45 degree "range" of the #1 cylinder, otherwise you'll be in the range of a different cylinder. The fine tuning is going to occur in that 45 degree range that "belongs" to that particular cylinder. So the bottom line is that if your #1 cylinder is somewhat close to the top (which is close enough to the crank timing mark) and you stab your distributor in so that the rotor is pointing to the 6 o'clock position (Assuming your cap is wired with #1 at 6 o'clock), you stand a good chance at having the engine start (unless you're 180 degrees off which is a whole other thread to talk about). Once it starts, then you do final tuning. Last edited by Mike51Merc; 11-08-2015 at 03:00 PM.