timing

Marcis71 said:
Just a thought, but the .21480 measurement would only be correct if the piston is flush with the deck, wouldn't it? If the piston was down the hole .005 or had .005 pop up that would change the depth at 30*? If my math is correct, then every degree would be .013" of travel (2.437/180)? If so then the .21480 depth could be off by a couple of degrees?

I'm not positive that I'm thinking about that correctly, but it makes sense in my little brain :)
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Two things wrong with your logic; I didn't say from the top of the block, I said from top dead center, TDC.

The piston doesn't move at a uniform distance per degree of crankshaft revolution. To give you a small idea, here are some numbers showing how the distance changes as the crankshaft rotates.

As you can see, as the crankshaft gets closer to 90* of rotation, the distance traveled by the piston, per degree of crankshaft rotation, increases. You may notice some inconsistencies, but that is only because of the 3 Decimal Pl. notation. With more decimal places, you would see more consistency.

Stock clone bore and rod length. These numbers will change with a different stroke and/or rod length.
Travel & degrees
.017 9.0
.021 10.0
.026 11.0
.030 12.0
.036 13.0

.185 30.0
.197 31.0
.209 32.0
.222 33.0
.235 34.0
.249 35.0
If I changed the degrees of rotation increments from 1.0 to 0.1 the distance traveled increments become, not only more consistent, but with more resolution.
 
I ended up setting the timing close to what Al suggested, by putting the piston .215" in the hole BTDC, since my stuff isnt capable of measuring that many decimal points over, and after it was set, i borrowed a timing light to see where it was. This put me at 31.5* BTDC timing, so Al was actually pretty close, he could have been spot on if i had been able to set it at the exact number he gave me, im not really sure honestly. But since i was able to borrow a timing light, i was able to set my timing at 32* like i wanted in the first place. Engine fired right up and runs strong, i appreciate the help from everyone that chimed in
 
W5R said:
I ended up setting the timing close to what Al suggested, by putting the piston .215" in the hole BTDC, since my stuff isnt capable of measuring that many decimal points over, and after it was set, i borrowed a timing light to see where it was. This put me at 31.5* BTDC timing, so Al was actually pretty close, he could have been spot on if i had been able to set it at the exact number he gave me, im not really sure honestly. But since i was able to borrow a timing light, i was able to set my timing at 32* like i wanted in the first place. Engine fired right up and runs strong, i appreciate the help from everyone that chimed in
Click to expand...
"Al was pretty close"? No chance that your method of checking it was "pretty close"? I asked that because I know the math is exactly right! I say that because if I check the numbers at 180 degrees, they match the stroke of the engine. They match exactly at both sides of BDC. They match out to seven decimal places. Now that's "pretty close"!
 
W5R said:
I ended up setting the timing close to what Al suggested, by putting the piston .215" in the hole BTDC, since my stuff isnt capable of measuring that many decimal points over, and after it was set, i borrowed a timing light to see where it was. This put me at 31.5* BTDC timing,
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Before telling people "Al was pretty close" you could have consulted with me. I gave you the number for 30 degrees BTDC. Going back over the posts it's hard to know if you wanted 30 degrees or 32 degrees. By the way, it's hard to imagine how you got 31.5 degrees with the number I gave you. The picture shows exactly what the timing should be. Next you'll be telling me my $14,000 CAD/CAM program is "close"! Sometimes it's hard to tell what people's intentions are.
 
How were you able to determine it was at 31.5?
Getting it exactly where you want it can be tedious what with the flywheel or crank moving when you tighten the nut.
 
I did this to show the distance before and after 30 degrees BTDC. I can do this in half and quarter degree increments.
Stroke Rod Length
2.437 3.625
Timing Piston
BTDC FTDC
25 0.15092
26 0.16288
27 0.17526
28 0.18804
29 0.20122
30 0.21480
31 0.22877
32 0.24311
33 0.25783
34 0.27292
35 0.28836

Update, I can do it in 10'ths of a degree.

Stroke Rod Length
2.437 3.625
Timing Piston
BTDC From TDC
28.00 ? 0.18804
28.25 ? 0.19130
28.50 ? 0.19458
28.75 ? 0.19789
29.00 ? 0.20122
29.25 ? 0.20458
29.50 ? 0.20796
29.75 ? 0.21137
30.00 ? 0.21480
30.25 ? 0.21826
30.50 ? 0.22174
The Degree sign doesn't transfer, see ?
 
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W5R said:
Timing light with the engine running
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I see, the problem is not with the math, it must be some problem with where you "think" the coil has to be. Assuming you have a good timing light, there are bad one's, the only thing it could be is the positioning of the coil, or, long shot, some problem with the flywheel. Now that you know where it fires at .215" ATDC, go a little farther down in the hole. Find out how far you have to set it in the hole to get the degrees of timing you want.

It doesn't really matter where you set it, (in inches) it only matters if it runs it's best where it's set.
 
Why don't you check post number one. Animal with flathead crank and long rod, etc. Hybrid combination.
 
My guess would be longer than stock. He posted it was 3.625" rod length. He called it a stroker rod. On second thought, it might have actually been a shorter rod with longer crank. What's the difference? He gave you the crank stroke and rod length.

By the way, a simple google search reveals the stock animal rod is 3.287" long.

A stock flathead rod is 3.875" long.

And a stock flathead crank has a 2.437" stroke.
 
W5R said:
Timing light with the engine running
Click to expand...

I get that ,. You said you had no degree wheel have you obtained one .
Otherwise pretty had too get down to a half degree.
At least you got it close too where you wanted it.
 
flattop1 said:
I get that ,. You said you had no degree wheel have you obtained one .
Otherwise pretty had too get down to a half degree.
At least you got it close too where you wanted it.
Click to expand...

I'm thinking he used a dial back timing light with marks made at tdc on engine and flywheel. Just had to reset marks or pointer after adjusting flywheel.
 
That's definitely a must when using the flywheel for a timing point. After every adjustment you need to reset tdc.
 
01ron said:
My guess would be longer than stock. He posted it was 3.625" rod length. He called it a stroker rod. On second thought, it might have actually been a shorter rod with longer crank. What's the difference? He gave you the crank stroke and rod length.

By the way, a simple google search reveals the stock animal rod is 3.287" long.

A stock flathead rod is 3.875" long.

And a stock flathead crank has a 2.437" stroke.
Click to expand...
So he increased the Rod length .338" and increase the stroke, but he didn't say how he kept the piston from coming out of the barrel. Can you buy pistons with the pin that high?
 
alvin l nunley said:
So he increased the Rod length .338" and increase the stroke, but he didn't say how he kept the piston from coming out of the barrel. Can you buy pistons with the pin that high?
Click to expand...

No, but you can plate the top of the cylinder and re-sleeve it to accommodate the added length. This is one of those occasions that I mentioned that you have no knowledge about on an other post.......
 
tecbigdog said:
No, but you can plate the top of the cylinder and re-sleeve it to accommodate the added length. This is one of those occasions that I mentioned that you have no knowledge about on an other post.......
Click to expand...

Did you think I wasn't aware of that?? I asked a question, you start singing to the choir.
 
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