Adjusting the timing for hilly driving..

[NZ28ModelA]

Hi Guys,

I have done about 200 miles in my new toy am are absolutely loving it. The only concern i have is the timing lever. At the mo I am retarding it when i start the engine and pulling it down to about 8 o'clock when i drive it. I don't do any fine adjustments. I don't feel like I have an ear for noticing any differences when driving fast or slow.
But I am concerned about hilly roads. I vaguely remember hearing somewhere about having to adjust the lever when driving up and down hills. Could someone please explain to me what is required when conquering mountain passes?

Also, I have attached a couple of pics of my new wheels and tyres. I can't believe the difference in the ride with the 16" radials! Its amazing! I didn't realise those old 21" crossplys are such a hard ride. i am very happy with the change, and not as much of a loss at top end as i was expecting!
Thank you all for your advice with choosing this combo.
Regards Steve

[Greg Jones]

What is your engine compression ratio?

[eagle]

It will vary based on which head you are running, condition of engine, adjustment of timing position, point gap... so heres how I do it. Lift the lever for starting, then pull down until, when pulling, you just start to get a ping, then lift it a notch or so. You want it to be as advanced as you can get it without pinging. Ping sounds like someone is tapping on the side of the engine block with a little hammer. Poor description but listen to your engine, youll soon start to really "hear" it. If someone has the lever not set up right, it could be that you cant advance it enough to get a ping. If thats the case readjust it. Running too retarded means reduced power and hot manifold, all sorts of bad things.

[NZ28ModelA]

Thanks Guys.. Its a newly rebuilt balanced engine with std head and compression..

[Synchro909]

The head you are running and its compresion ratio is only relavent as to the amount you advance or retard the timing. Even with a standard head, it is best to retard a bit on a hill. If you listen to the motor, you will hear it working hard if you put the boot into it on a hill. Working hard is OK but if it sounds what I call "harsh", you need to retard a little more.
Do you know someone who has experience and with whom you might be able to ride for instruction? I'm sure there will be planty in Te Anau next year and there will be hills!!

[wmws]

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I do it a little bit different. I was told by a very reputable engine builder in my aria that you should retard until you start loosing power and then advance it a little. Do not run any more advance than necessary. Your babbitt will thank you. With that being said I set my timing to 30* BTDC fully advanced. Even at that I usually run a couple notches up on the lever. If I am going up a steep hill and lugging down below about 1200 RPM I may retard a little more. I have a standard head and a tachometer. I have never heard my engine ping and it runs cool.

[Synchro909]

Persistant running with the timing too far advanced can damage the bearings and can easily result in a broken crankshaft. It's worth getting right and I'm not talking about how fussy some are about setting the timing when the engine is not going. I'm talking about learning to listen to the engine as it works.

[Chuck Sea/Tac]

Originally Posted by wmws

I do it a little bit different. I was told by a very reputable engine builder in my aria that you should retard until you start loosing power and then advance it a little. Do not run any more advance than necessary. Your babbitt will thank you. With that being said I set my timing to 30* BTDC fully advanced. Even at that I usually run a couple notches up on the lever. If I am going up a steep hill and lugging down below about 1200 RPM I may retard a little more. I have a standard head and a tachometer. I have never heard my engine ping and it runs cool.

That’s how I determine the “sweet” spot as well.

PS. If it’s timed properly, you should notice a big difference at idle between retard and advance.

[NZ28ModelA]

Oh I definitely do notice the difference between full retard and advance. But i wasn't sure about what to do when going up and down hills. I have heard about engines getting too hot when too advanced on hills and backfiring when coming down. So from what i understand, I am to back off a couple of notches when I am working the motor going up the hills??

[WHN]

After 60 years of running these cars I’m not sure there is a true answer to this question.

If everything were new and the timing was spot on, there is still a reason that the ability to adjust the timing to such a degree is there.

90 years later. 90 years of parts moving. A little ware here and there. More reason to be able to adjust timing.

I like to run at just the point where you can feel the car might lose power if you were to retart it more or about 9:30 (lever position) on our 1929 as of the last tune-up. On hills we are very careful not to lug the engine. Retart spark or down shift, do not lug.

Ping or knock, retart. Each car is different. Enjoy.

[BN]

There are several other things in addition to timing advance that will induce any Otto Cycle gasoline engine to detonate (ping).

Higher coolant temperature resulting in higher combustion temperature prior to the power stroke.

Higher compression ratio.

Preignition (which can cause detonation). Preignition can be caused by running too hot of a spark plug grade, carbon deposits, valves having too thin of a margin causing the outside edges to get too hot.

All the above can vary from one cylinder to the next. It has been said that #4 cylinder on a Model A engine runs hotter than the others. Compression ratio can vary due to slightly different combustion chamber volumes in the head. Obviously, preignition can vary due to one cylinder passing more oil into the combustion chamber causing more carbon deposits.

Due to all these variables, a timing advance specification must be based on testing a lot of engines of the same type. This results in a timing advance specification which is likely less than what would be optimal for your particular engine, even if it was fresh out of the Ford factory. Adjusting the timing advance control arm to achieve a momentary detonation and then backing off a little would be ideal. However, the question is – can you really hear when detonation actually begins?

[Synchro909]

I don't think the beginning of detonation can be heard and by the time we can hear it, it's pretty darned bad.
I have no problem with those above who said they find the sweet spot by adding a little advance to where they just start to lose power. Either way will work.
One thing that this thread proves is that the initial setting for the timing need not be anything to stress over. Many here go to extreme measures to get TDC right and the points opening just so. A few degrees here or there doesn't matter when we control the timing from the driver's seat while driving and use nothing but our hearing and the seat of our pants to judge how much.

[1929]

I was told by a few that they start it in retard, then after they start the car, they just advance it all the way, and someone else told me that he starts retard, and advances only 3/4. Which is the better way?

[eagle]

Originally Posted by 1929

I was told by a few that they start it in retard, then after they start the car, they just advance it all the way, and someone else told me that he starts retard, and advances only 3/4. Which is the better way?

No way to know! 3/4 verses full advance on the lever is very subjective, depends on the car. Need to listen to the engine to really know. A few years ago someone on one of the forums was insisting you had to jack the weight off of a tire to pump it up to the "correct" pressure. Some people love to make everything into a big know-it-all deal. In other words, use the ears you have and do the best you can. Don't overthink it, a Model A is tough.

[NZ28ModelA]

This might be a silly question, but can we mark up the front pulley and put a timing light to figure out the best position on the lever? I'm pretty sure the harmonic balancer that was fitted by my engine builder Murray Horn is marked up..

[Bill G]

Originally Posted by NZ28ModelA

This might be a silly question, but can we mark up the front pulley and put a timing light to figure out the best position on the lever? I'm pretty sure the harmonic balancer that was fitted by my engine builder Murray Horn is marked up..

I think you might be trying to over-think it and relate it to a more modern distributor. The correct position for TDC is when you set the timing fully retarded with the pin, per the standard timing routine. From there, you have to use the lever as you drive, and I don't think there is any one certain point for up hill or down hill. You just have to get a feel for it. I can't hear so well, and I haven't been able to hear pings for probably the last 30 years so I just look for the way it feels. Some people mark their pulleys with timing marks to avoid having to use the timing pin to set TDC. No matter what you do, you still have to start it fully retarded and then use the lever from there.

[Purdy Swoft]

I set my initial timing as right on as I can get it . If initial timing isn't right on you won't be able to get full advance or retard , depending on which side the timing is off on . The spark lever can then advance or retard as needed . As said before in this thread , A person needs to run as advanced as they can for full power and cool operation. There is three times that use of the spark is needed . I retard completely when starting the engine . I retard as many notches are necessary when climbing hills to prevent pings or timing knocks . When driving on back roads or trails at low speeds I will retard as necessary when running in higher gears to prevent bucking and lugging . A person can feel the strain taken off the engine when the spark is retarded as needed and this will allow running at lower RPM while avoiding lugging the engine and beating out the babbit . I avoid running in the lower gears for long distances on trails because the higher RPMs will cause over heating . Use of the spark lever has everything to do with listening to the engine for knocks and knowing the feeling when the engine is lugging . When running at speed , I run at full advance . I don't retard when going down hill .

[40 Deluxe]

Originally Posted by Purdy Swoft

I set my initial timing as right on as I can get it . If initial timing isn't right on you won't be able to get full advance or retard , depending on which side the timing is off on . The spark lever can then advance or retard as needed . As said before in this thread , A person needs to run as advanced as they can for full power and cool operation. There is three times that use of the spark is needed . I retard completely when starting the engine . I retard as many notches are necessary when climbing hills to prevent pings or timing knocks . When driving on back roads or trails at low speeds I will retard as necessary when running in higher gears to prevent bucking and lugging . A person can feel the strain taken off the engine when the spark is retarded as needed and this will allow running at lower RPM while avoiding lugging the engine and beating out the babbit . I avoid running in the lower gears for long distances on trails because the higher RPMs will cause over heating . Use of the spark lever has everything to do with listening to the engine for knocks and knowing the feeling when the engine is lugging . When running at speed , I run at full advance . I don't retard when going down hill .

What? You don't retard going down a hill? Where is the teenager in you?! That used to great sport-throw the spark lever up, close the GAV, and listen it pop and bang!

[Purdy Swoft]

iI did use to retard when going down hill to make it back fire as a kid .

[TerryH]

Very well said Purdy....every Model A is slightly different, and everyone’s timing will be slightly different. Driving and knowing your own Model A, and paying attention to how it is running and what you are hearing and feeling is important, and one can quickly develop a feel where the timing is best. I adjust mine frequently, depending on where and how I am driving.