Timing degrees after top dead center ??

[dobro1956]

Can someone refresh my memory. How many degrees do we turn crankshaft after top dead center when setting the timing to full retard position. Or another way is what time on a clock is it. ? I think I always found TDC of #1 cylinder and marked the top of crank pulley. Then turn the mark to 1:00 but my memory is not what it used to be .

[CudaMan]

http://www.dauntlessgeezer.com/DG97.html

[Mark Gregush]

I just bring to TDC where the pin in the pulley horizontal then turn till piston just starts to go down. Heck the only time you need it after top dead center is for starting on battery anyway.

[dobro1956]

Thanks Mark. I knew I had seen it somewhere. I knew how to do it, but I just could not remember the degree or time on the clock. In my case it will be 1/2 way between 12:00 and 1:00 on the clock. There is one variation to the rule. On a EE crankshaft, the pin will be at 12:00 and 6:00 when on TDC instead of at 3:00 and 9:00 as Steve mentioned in the link. Im not sure if "all" EE crankshafts are drilled at 12:00 and 1:00. But every one of them I have ever had is drilled that way.

[Mark Gregush]

I remember reading here about a crank years ago that the pin was vertical at TDC. I don't recall that there was a consensuses at the time of it being an EE or not.
Thanks

[Ron Patterson]

The Model T Ford initial timing was originally factory set at 15.5 degrees ATDC with the spark lever fully retarded.
There were two reasons for this; first was for safety when starting on battery and the second was to facilitate hand crank starting on the magneto.
Here is a link to an article Steve Coniff and I wrote several years ago explaining the system and how it was intended to work.
http://www.funprojects.com/pdf/Model%20 ... iticle.pdf
Ron Patterson

[Ron Patterson]

If you imagine a clock face and the crankshaft pin pointing at 9:15 am and 3:15 pm the piston will be at 15.5 ATDC.

[Quickm007]

Did someone having a picture what TDC look if you remove the top of the engine... I alway's adjust the TDC without seeing what is looking inside the engine by following Ford book . Maybe a curious question but I woulk like to know.

The picture bellow is an example what I'm looking for. The first Cylindre is at TDC I thought but what about valves?

[Steve Jelf]

If you imagine a clock face and the crankshaft pin pointing at 9:15 am and 3:15 pm the piston will be at 15.5 ATDC.

That's horizontal, isn't it? Wouldn't that be TDC? I thought it was 15º ATDC when Mickey's little hand is halfway between 3 and 4. Are we saying the same thing in different ways?

[Quickm007]

Hi Steve,

I'm in the same page than you. Here bellow is what I'm doing usually like you said the crankshaft pin pointing at 9:15 am and 3:15 pm. I'm just curious to see what happen inside at 15º ATDC??? I'm a visual person.

[DanTreace]

Yep, 15 degrees ATDC on the compression stroke of cylinder.

I like to use the handy tool for measuring, it has a hole at the base so you can hear air hissing out on that stoke on # 1. So you know you are on the right stroke. Then crank over a bit more to get 15 degrees ATDC.

As for the crank pin hole, all T cranks are the same. If that pin hole is horizontal, two of the pistons are at TDC. But you set timing on the compression stroke.


Here is pic from forum a while ago, the next to the last crank on the right is a EE, the far right is the diamond throw crank, note the pin holes are identical .

Model T cranks next to last EE (550x533) (500x485).jpg (144.1 KiB) Viewed 8255 times

[Norman Kling]

It really doesn't make any difference which piston is at top dead center as long as one is. I rotate the engine until the pin is about 10:00 4:00 Then I turn on the ignition switch to battery. Then I rotate the timer until I get it to stop sparking as I rotate it counter clockwise or start to spark as I adjust it clockwise. Then I push the spark lever all the way up and adjust the spark rod to fit without moving either the spark lever or the timer. With the spark lever all the way up, I turn on the switch to battery and rotate the crank very slowly until one coil begins to buzz. The pin should be beyond horizontal. You will notice that each coil will buzz with the pin just beyond horizontal, because the sparks come with every half turn of the crankshaft. I have never seen a crankshaft with the hole for the pin in the 12:00 6:00 position, but I suppose there are some or it wouldn't have been brought up.
Norm

[Quickm007]

I have the handy tool for measuring as said Dan but unfortunately doesn't work any more, It's stuck . I Thought I bought it at Lang's but not able to find another one.

In the same topic, I alos learnt this:

How to Time a Model T
1. Turn crank shaft around until crank pin is horizontal
2. Turn key to Batt.
3. Retard spark
4. No coils should be buzzing
5. If coil buzzes go to step 8
6. Advance spark rod 3-5 clicks on quadrant a coil should buzz; If coil
doesn’t begin to buzz go to step 9
7. Retard spark, coil should stop buzzing everything okay!
8. The timer control needs to be lengthened return to step 3
9. The timer control needs to be shortened return to step 3
10. Coil should buzz and quit buzzing every time you advance and retard the spark!

But again I would like to have a picture to see what happen on the top of the engine at 15º ATDC ...

[hah]

Dan, Question- What is, looks like brass, on top off the knurled piece?

[Bill Robinson]

Timing indicator- good picture
https://www.twracing.com/the-accurate-timing-indicator

[DanTreace]

John

That's the round head brass screw top of the screw used to move the marker sleeve up and down. The end of that screw is right angled to rest on the piston, the wing end tells you that it is in position, since you have to screw the tool into plug hole, so the piston drives the marker up and down as you hand crank over the engine.

84c6a6_cdb79a9b944c4858ab1865634895333a.jpg (20.27 KiB) Viewed 8115 times

TW Timer Tool

And use it with indicator lamp wired to # 1 coil post, (not the plug wire post!) and that lamp lites just as you reach the timing mark 15 degrees, since the rotor in the timer is just contacting # 1 timer terminal. Helps you really dial in the ATDC spot by using piston travel.

For showing too that the clock face look of your crank pulley pin works, you can see it rests at the proper spot.

Hint: If you use Dan M.'s alum flanged split pulley, the slit is right dead center of the horizontal crank pulley pin.

You may see my black ink marker spot on the slit and the timing cover parting line, I marked black ink on that too. When they were lined up, the timing tool showed exactly TDC! So you can see where another ink mark on the pulley is made at the correct 15 degrees ATDC.

Have always checked my timer and timer rod setting (bends) with timing tool indicator and lamp, confirming too the useful 9:15am and 3:15pm clock face method.

[Quickm007]

I will try to take some pictures tonight of the engine without the head to see what is look inside at 15.5 degrees ATDC at valves and the first piston.

Or if someone have a picture please post it here that will fill out my curiosity.

[Ron Patterson]

Mario
If the piston has been correctly set at 15.5 degrees ATDC it will have traveled .093 thousandths down into the cylinder on the Power stroke.
Ron Patterson

[Poppie]

Ron, Would the 93Thou include the big end and little end bearing clearance? Just thinking, though I don't think it will make much difference to a back fire...N.

[Quickm007]

Hi Ron,


I did the 15.5 degrees ATDC. I opened up the engine top and here bellow pictures showing at 15.5 degrees ATDC at valves and the first piston. Please let me know if that make sense or I'm the left field? I want to learn .

[CudaMan]

Look right to me, well done!

Now make sure that the timing lever on the steering column is fully up, and adjust the timing rod length (by bending as required) so that the end slips into the timer arm without disturbing its position.

Then, have a helper move the timing lever through its full range and verify that the timing rod doesn't touch and short out any of the timer terminals.

Also make sure that the timer terminals don't brush up and short out against the two nearest front oil pan bolts. Most folks install those front pan bolts opposite from the rest so that the nuts face down towards the ground and the heads point up. This gives a little more clearance for the timer terminals to pass by without hitting those bolts.

Once you have things set the way you want them, install your fan and belt and make sure that the belt doesn't rub on the timer. If it does, it will eventually wear a groove in the timer. To fix it, try different length belts until everything clears.

[Mark Nunn]

Ron, Would the 93Thou include the big end and little end bearing clearance? Just thinking, though I don't think it will make much difference to a back fire...N.

Technically, the .093 varies with connecting rod clearances but not much. The .093 dimension is for a stock 4" stroke and 7" connecting rod length. Changing either of those will change the amount of piston travel ATDC. When a crank is rotated 15.5 degrees ATDC the rod journal travels down .0727". That pulls the rod big end down by that amount and also rotates the rod 4.38 degrees from vertical. The piston can only move down and rod rotation adds .0204" to total piston travel. Add those to get .093".

I made an offset tip for a dial indicator that looks like the tool in Dan's post. I used that to find 15.5 degrees.

[Quickm007]

Thank you all, very nice insights and information. Now we have the info and the pictures How much tork is recommended for the head bolt on the top of the engine?

[DanTreace]

Snug those head bolts. Torque measures weren't around in Model T days.

So be sure bolt holes are clean all the way to the bottom. Be sure to check hole depth to have proper length bolts for the style of cylinder head.

Then really important to snug down bolts, then torque if you must use a torque wrench, but do that with the center bolts first, in a line.

Then alternate to the other bolts as you work out and up and down. If rare early block, 45 lb/ft. You can go 50-55 lb/ft if all holes are nice thread and new head bolts. Factory wrench is always safe if you checked out the cleaned holes and bolt threads too. Anti-seize on the bolt threads helps a bunch.

A busted head bolt or one spinning in a hole due to poor threads or dirt at the bottom of hole makes for a bad day.

[Steve Jelf]

There are a few variations of the sequence. I use this one.

As Dan says, they didn't use torque wrenches in Model T days. The Ford head bolt wrench #2335 is the right length to get it about right if you go as tight as you can with muscle power.

[Quickm007]

Last night I was in fire and decided to clean up all the bolt holes all the way to the bottom. I also check hole depth to have proper length bolts for the style of cylinder head. All my bolts are very tired, so I decided to order new one's at Lang's this morning. Also the Magneto is really tired so I decided to remove the pan and start to remove the Magneto in the goal to restore it too. I will remove the Magneto this week-end and recharge the magnet. I will post how I will do in another post... Thank you Steve for the sequence, I will follow it for sure.

Make a short story, it's like an open hearth surgery in the goal to survive another 100 years.

[Mark Gregush]

From reading in the past, on the early blocks keep the torque in the 45FP range.

[Steve Jelf]

The most effective way to recharge the magnets is the most complex, with all of them removed from the flywheel and charged individually.

http://dauntlessgeezer.com/DG88.html

[Thorlick]

Last time I had my engine out I marked TDC, 15 degrees after TDC, BDC and 15 degrees after BDC on the aluminum pulley (TTP after market I think). So to find 15 ATDC I just turn the engine until the 15 mark lines up with the cast boss I use as a degree wheel pointer.

Engine set to 15 ATDC

[CudaMan]

Note in Steve's photo how his front pan bolts are installed upside down from the rest to provide more clearance for the timer terminals.