The Ford Barn

700rpm · 10-22-2015, 08:46 PM

My otherwise stock A engine, standard bore, not counter-weighted, has a B cam in it. I discovered today that even though I have timed the engine according to FSB p.346 instructions, the car actually runs cooler and stronger if my spark is at 10 o'clock instead of two notches off the bottom, or about 7 o'clock, where my other 2 A's run best. So I am wondering if the B cam requires a different timing setting that a stock cam. The timing cover is also A stock.

I have been experiencing overheating and what I believe is a spark knock. Today running with the spark lever at 10 o'clock the knock was gone and as I said, the engine ran cooler, 165-175 on the cylinder walls, 140-148 on the head.

So my questions: does the B cam require a different setting for timing, given my otherwise stock engine?

And: which way do I turn the distributor cam to get 10 o'clock performance at 7 o'clock?

mrtexas · 10-22-2015, 08:56 PM

Put the car at tdc for #1. Make a mark on crank pulley and timing cover. Take out plugs. Turn engine over with crank until #1 sparks. Look to see if the marks line up. Now you can be sure your timing is correct.

Synchro909 · 10-22-2015, 09:11 PM

You're going to get conflicting advice on this one but IMHO, yes, using the B cam, you should time it like a B engine. The pin that goes into the timing gear to give you your timing position is in a different position on the B timing cover and all the literature says that the A runs best at a max 28 deg advance while the B needs less. That's why you are running too advanced with your lever at 7 O'clock. You need to retard the timing a little. I set mine as you did and GRADUALLY sneaked the timing back a little at a time till I couldn't make it ping. Runs beautifully now. Trial and error got me there eventually and I marked the crank shaft pulley so I can find it again.
This is where you will get differing opinions but I think you should move the cam on the distributor shaft clockwise to retard it. Little by little does it.
I'll be going through the same exercise again soon when I assemble an engine I am building with B cam timing and electronic ignition designed for an A engine. I'll have to set it a little retarded at an idle to be right at touring speeds.

700rpm · 10-23-2015, 12:37 AM

Synchro, I'll give that trial and error method a go. I don't have a B cover, so it's by guess and by golly.

James Rogers · 10-23-2015, 05:32 AM

Along with what Vince said, what head do you have on the engine? A high compression head will be much more sensitive to timing than a stock head. Not enough info to make a determination.

Tom Wesenberg · 10-23-2015, 07:29 AM

Sponsored Links (Register now to hide all advertisements)

James brought up a good point about needing less timing advance with the higher compression head.

It's the B distributor that is timed with more advance to set the timing. The B camshaft won't change your timing. As Synchro909 said, you move the distributor cam clockwise to retard the timing. 10 degrees at the distributor is 20 degrees at the crankshaft.

Big hammer · 10-23-2015, 08:32 AM

Quote:

Originally Posted by 700rpm

My otherwise stock A engine, standard bore, not counter-weighted, has a B cam in it. I discovered today that even though I have timed the engine according to FSB p.346 instructions, the car actually runs cooler and stronger if my spark is at 10 o'clock instead of two notches off the bottom, or about 7 o'clock, where my other 2 A's run best. So I am wondering if the B cam requires a different timing setting that a stock cam. The timing cover is also A stock.

I have been experiencing overheating and what I believe is a spark knock. Today running with the spark lever at 10 o'clock the knock was gone and as I said, the engine ran cooler, 165-175 on the cylinder walls, 140-148 on the head.

So my questions: does the B cam require a different setting for timing, given my otherwise stock engine?

And: which way do I turn the distributor cam to get 10 o'clock performance at 7 o'clock?

What octane gasoline are you running? Higher octane keeps pinging away?

1931 flamingo · 10-23-2015, 11:22 AM

As I read this I had the same thoughts as forever4. Do a search as this question has been asked multiple times.
Paul in CT

700rpm · 10-23-2015, 11:37 AM

Quote:

Originally Posted by forever4

What B cam are you referring to? The distributor cam, or the engine camshaft?

Both cams are B. As I said, all other aspects of the engine are stock, including the head.

I tried a search, but the search options are pretty limited, and a complete question is impossible.

CarlG · 10-23-2015, 11:37 AM

Vince, Marco, Purdy and others have had great discussions on timing. Just search for these here on the Barn.

700rpm · 10-23-2015, 11:59 AM

I appreciate the suggestions for a search, guys, and I always try that first. I guess I just don't know how to pose the question in the search function, because I can't get an answer there.

d.j. moordigian · 10-24-2015, 01:48 PM

Well,..I've followed this post from Ray's first post,..here are some things to think about.

First off,..the timing gears for the crank / cam are the same for both A's and B's..

The distributor cams(A or B) are both timed the same in a A distributor,..they have
used them for years, interchangeably..

I learned about 50 plus years ago about the "back-lash" with the distributor shafts,
gears and the timing gears too get the timing CORRECT.. Turn the engine in a clock-
wise rotation, DON'T BACK IT UP, and take the back-lash out of the shafts..

So the timing issue,..could be the way your doing it..

Dudley

10-22-2015, 08:56 PM	#2
mrtexas Senior Member Join Date: May 2010 Location: Sugar Land, TX Posts: 4,395	Re: A timing issue Put the car at tdc for #1. Make a mark on crank pulley and timing cover. Take out plugs. Turn engine over with crank until #1 sparks. Look to see if the marks line up. Now you can be sure your timing is correct.

10-22-2015, 09:11 PM	#3
Synchro909 Senior Member Join Date: Jun 2014 Location: Melbourne, Australia Posts: 7,554	Re: A timing issue You're going to get conflicting advice on this one but IMHO, yes, using the B cam, you should time it like a B engine. The pin that goes into the timing gear to give you your timing position is in a different position on the B timing cover and all the literature says that the A runs best at a max 28 deg advance while the B needs less. That's why you are running too advanced with your lever at 7 O'clock. You need to retard the timing a little. I set mine as you did and GRADUALLY sneaked the timing back a little at a time till I couldn't make it ping. Runs beautifully now. Trial and error got me there eventually and I marked the crank shaft pulley so I can find it again. This is where you will get differing opinions but I think you should move the cam on the distributor shaft clockwise to retard it. Little by little does it. I'll be going through the same exercise again soon when I assemble an engine I am building with B cam timing and electronic ignition designed for an A engine. I'll have to set it a little retarded at an idle to be right at touring speeds. __________________ I'm part of the only ever generation with an analogue childhood and a digital adulthood.

10-23-2015, 12:37 AM	#4
700rpm Senior Member Join Date: May 2010 Location: Portland, Oregon Posts: 5,920	Re: A timing issue Synchro, I'll give that trial and error method a go. I don't have a B cover, so it's by guess and by golly. __________________ Ray Horton, Portland, OR As you go through life, keep your eye on the donut, not the hole.

10-23-2015, 05:32 AM	#5
James Rogers Senior Member Join Date: May 2010 Location: Asheville,NC Posts: 3,104	Re: A timing issue Along with what Vince said, what head do you have on the engine? A high compression head will be much more sensitive to timing than a stock head. Not enough info to make a determination. __________________ http://www.model-a-ford-4bangers.com/

10-23-2015, 07:29 AM	#6
Tom Wesenberg Senior Member Join Date: May 2010 Location: Mpls, MN Posts: 27,582	Re: A timing issue Sponsored Links (Register now to hide all advertisements) James brought up a good point about needing less timing advance with the higher compression head. It's the B distributor that is timed with more advance to set the timing. The B camshaft won't change your timing. As Synchro909 said, you move the distributor cam clockwise to retard the timing. 10 degrees at the distributor is 20 degrees at the crankshaft.

10-22-2015, 08:46 PM	#1
700rpm Senior Member Join Date: May 2010 Location: Portland, Oregon Posts: 5,920	A timing issue My otherwise stock A engine, standard bore, not counter-weighted, has a B cam in it. I discovered today that even though I have timed the engine according to FSB p.346 instructions, the car actually runs cooler and stronger if my spark is at 10 o'clock instead of two notches off the bottom, or about 7 o'clock, where my other 2 A's run best. So I am wondering if the B cam requires a different timing setting that a stock cam. The timing cover is also A stock. I have been experiencing overheating and what I believe is a spark knock. Today running with the spark lever at 10 o'clock the knock was gone and as I said, the engine ran cooler, 165-175 on the cylinder walls, 140-148 on the head. So my questions: does the B cam require a different setting for timing, given my otherwise stock engine? And: which way do I turn the distributor cam to get 10 o'clock performance at 7 o'clock? __________________ Ray Horton, Portland, OR As you go through life, keep your eye on the donut, not the hole.

10-23-2015, 11:22 AM	#8
1931 flamingo Senior Member Join Date: May 2010 Location: new britain,ct 06052 Posts: 9,393	Re: A timing issue As I read this I had the same thoughts as forever4. Do a search as this question has been asked multiple times. Paul in CT

10-23-2015, 11:37 AM	#10
CarlG Senior Member Join Date: Nov 2010 Location: Anchorage, Alaska Posts: 9,120	Re: A timing issue Vince, Marco, Purdy and others have had great discussions on timing. Just search for these here on the Barn. __________________ Alaskan A's Antique Auto Mushers of Alaska Model A Ford Club of America Model A Restorers Club Antique Automobile Club of America Mullins Owner's Club

10-23-2015, 11:59 AM	#11
700rpm Senior Member Join Date: May 2010 Location: Portland, Oregon Posts: 5,920	Re: A timing issue I appreciate the suggestions for a search, guys, and I always try that first. I guess I just don't know how to pose the question in the search function, because I can't get an answer there. __________________ Ray Horton, Portland, OR As you go through life, keep your eye on the donut, not the hole. Last edited by 700rpm; 10-24-2015 at 12:35 AM.

10-24-2015, 01:48 PM	#12
d.j. moordigian Senior Member Join Date: May 2010 Location: Fresno, Ca. Posts: 3,636	Re: A timing issue Well,..I've followed this post from Ray's first post,..here are some things to think about. First off,..the timing gears for the crank / cam are the same for both A's and B's.. The distributor cams(A or B) are both timed the same in a A distributor,..they have used them for years, interchangeably.. I learned about 50 plus years ago about the "back-lash" with the distributor shafts, gears and the timing gears too get the timing CORRECT.. Turn the engine in a clock- wise rotation, DON'T BACK IT UP, and take the back-lash out of the shafts.. So the timing issue,..could be the way your doing it.. Dudley