Timing Mark Indicator

[Charlie ny]

IMHO the time to think about TDC and degrees is when the motor is on the stand. TDC
comes first using a dial indicator. While rotating the crank in running direction bring #1
piston to it's highest travel......file a notch in the pulley that coincides with your fabbed pointer or factory pointer. I'll reiterate what's been said, measure the circumference of the pulley we'll say 6.750 diameter x 3.14 = 21.195 which is the circumference........divide that by 16 ( the equivalent of
22 1/2 degrees ) and you get .755. The .755 is the distance from TDC to scribe/file
your mark for engine degrees. Doing it this way there is not a lot of marks and you'll be so close to perfection you'll buy me a Jameson double on the rocks. Si ?
Charlie ny

 

[flatjack9]

I also put a timing pointer on every non-8BA engine I build. I too want to be able to check what is actually going on. + or - 6 deg. can make quite a difference in engine operation.

 

[johncusano]

Thanks for all the great advice. Having trouble pulling the valve guide now the tool isnt ingaging in the notch and I think i stripped them. Will have to cut the valves inhalf now. I hope it goesnt go this way the whole job. Haha.It's still cold here in the Northeast!!

 

[51 MERC-CT]

6.750 diameter x 3.14 = 21.195 which is the circumference........divide that by 16 ( the equivalent of
22 1/2 degrees ) and you get .755. The .755 is the distance from TDC to scribe/file
Charlie ny

Perhaps a little clarification.
21.195 ÷ 16 =???

 

[Charlie ny]

51,
My math says .755 from TDC equals 22 1/2 degrees figuring your pulley is 6 3/4" dia....pretty close to max advance for a Flathead... .755 from your TDC mark is where to scribe your 22 1/2 degree mark.
Charlie ny

 

[Hoop]

Charlie,

As embarrassing as it may be, your math is wrong. .755 is not the answer. And 22 1/2 degrees is not really relevant.

Additionally, if you read "Bored & Stroked's" post #4, he correctly uses a degree wheel to mark the pulley. You can make a cheap "degree wheel" by drawing a circle on a piece of paper the same diameter as the pulley and marking it off using a protractor.

(Cheap plastic protractors, those half-moon things we used in grade school, can be bought at any office supply store.)

These marks can easily be transferred to the pulley.

I'm surprised nobody mentioned the -6/+6 degree stuff. We are talking about crankshaft degrees in marking the pulley. -12/+12 ... this can be very misleading. Add up the max initial advance and the max centrifugal advance to find what marks you really should have on the pulley.

Again, just trying to keep Charlie out of the Jameson's.

 

[JSeery]

I'm with Hoop, I would work with degrees and not linear measurements. It is very difficult to maintain any kind of accuracy attempting to measure around a curve. I would want it marked off is something like 5 degree increments, say out to 30 degrees.

 

[BUBBAS IGNITION]

I think everyone seems to be correct in one way or another.
Buts lets go back to finding TDC to start with.

There is only on way to do it right !!! Plastic wire ties etc isnt perfect.

The only perfect way is with head off, install a strap of steel across the cylinder with bolt in center sticking down in the cylinder. Rotate engine until piston hits the bolt and mark location on timing pulley. The rotate the other direction untill piston again hits piston. Mark this location on pulley as well. The exact center between the marks is exact TDC..!!!

A dial indiactor isnt the best as the piston rocks at tdc and the engine will turn a few degrees before moving the dial..

 

[BUBBAS IGNITION]

repeat sorry

 

[Charlie ny]

Thanks guys....sincerely...drinks are on me. Lots of PMs on this !!
Charlie ny

 

[Bored&Stroked]

The 'Hard Stop' method of finding TDC works best for most folks (as Bubba noted). The easiest way to make a hard stop for a flathead is just to use a big thick washer with a 7/16 coarse bolt to hold it down. Don't get all "strong man" with turning the crank - just gently bring the piston up against the stop - both directions!

Below I show both methods (in one picture) --> A dial indicator as well as a hard stop. If you're not really used to doing this with a dial indicator and understand dwell at the top, then use the hard stop method.

Also, here is the big degree wheel that I use - bigger is better folks! I mount it to the end of a 40 flathead crank pulley - using the 4 bolts. LOL

Have fun boys . . .
B&S

 

[big deuce]

My '49 8BA has a timing pointer and a dot on the wide rim at the rear of the crankshaft pulley, but I'm not sure how to mark the degrees of the pulley. (Like what is the distance between "0" and "5" degrees?) I have a Chevy distributor and need to ensure the advance doesn't go over about 24 degrees.

Apparently, no one makes adhesive timing pulley tapes, anymore.

Does anyone know the circumference of a '49 V-8 F-1 pulley? Mine is in a place that's difficult to measure.

https://www.amazon.com/MSD-8985-Timing-Tapes/dp/B000COUSK6?tag=atomicindus08-20
MSD makes a 6 3/4" tape

 

[G.M.]

I just did some work on my 34 roadster and wasn't sure
the distributor was timed to the engine. Removed # 1
spark plug held my finger over the # 1, front spark plug
hole on the passenger side. Timing light was 12 volt so
I hooked it to the 12 volts from my booster jumper.
Watched with my finger in the plug hole as someone
slowly hand cranked and as the compression popped my
finger the timing light came. on. Marked the crankshaft
pulley with soap stone and it was right on time and started
on the first turn. Timing light was hitting right on the mark
at fast idle. G.M.

 

[Ggmac]

That's allot of marks that will have a cumulative error, guaranteed. By the time you get around the pulley you could be off by 10 degrees! Or more!

No you remove the tape , measure divide and mark it . I've been doing it that way for decades . It's super easy and easy to verify . Esp with today's small cameras to verify Pistons location . Or do it the old way with a dead stop rotate till stops again then Mark . If you didn't screw up the math the 2 marks will be the same .

 

[Flathead Fever]

They sold a timing mark kit. I doubt it was very accurate but its still neat.