Limited flathead timing?

S

Scarface5029

Member
Hey guys I was wondering about what timing should a limited flathead be running? I think this motor was turning 7500-8000. I’m tearing down my dads old limited from years ago to rebuild and it has a stock keyway in it and I thought this seemed odd for a limited motor but I could be wrong.
 

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That would be very odd for a limited to use a stock key. Generally you're upwards of 34*.
PLEASE replace that flywheel if you're going to build this engine up as a true limited (to be legal AND safe.)


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Brian is absolutely right.
36 is my preferred timing to start with and adjust after running the engine a little
The coil on the flathead will retard 3 to 6 degrees!
And that stock flywheel needs to go.
I always check timing on engines with a timing light and degree wheel. Find out exactly where it fires and mark that on the coil and flywheel, and then rev it a little and see how much it retards. I don't mean hold it wide open on the stand.
 
Thanks for the information guys! This explains why it never run quite right, this and it never had good compression, I just found out was because the valves are not sealing completely. My dad said it never turned more than 7200-7300 rpm and i will replace flywheel before I get on track with anyone else.
 
Limited mod's also utilize a tillison carb that is blueprinted to use Methanol fuel which is another reason for advanced ignition timing. What carb and fuel was used with that stock timing key?
 
Freezeman said:
Limited mod's also utilize a tillison carb that is blueprinted to use Methanol fuel which is another reason for advanced ignition timing. What carb and fuel was used with that stock timing key?
Click to expand...
Big dog stock looking carb on methanol, I sold the tillotson years ago while it was just sitting in the shop, now I wish I had it back!!
 
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Hey guys is it possible the timing gear was changed on the crank (similar to turning the crank gear on predator?) to allow the use of the stock keyway? Or is that even possible to do? It slides right off and has some kind of washer holding it on, I have a bunch of other 5hp flathead crank gears in an old tool box I got from another racer years ago and some have three different slots in the gear to install it which is what made me think about this.
 
Scarface5029 said:
Hey guys is it possible the timing gear was changed on the crank (similar to turning the crank gear on predator?) to allow the use of the stock keyway? Or is that even possible to do? It slides right off and has some kind of washer holding it on, I have a bunch of other 5hp flathead crank gears in an old tool box I got from another racer years ago and some have three different slots in the gear to install it which is what made me think about this.
Click to expand...
Yes there were crank gears with different timing, but like you said they have 3 different slots, back in the day we had some offset keys to change the timing slightly, the only way to tell is set up the degree wheel and run the centerline profile
 
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