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Old 03-26-2021, 10:56 AM   #1
dbarton
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Default LH 2.4/EZK Flywheel 60-1 or 60-2 Reconciliation

While doing some obsessive research into the flywheel profile for EZ-116K, I now have some questions about some inconsistent information.

Volvo factory flywheels and flexplates have HOLES (or recesses) rather than raised "teeth." It's my understanding that there are 58 recesses and one solid gap that represents the length of 2 recesses.

The second image has info from the EZK ignition greenbook for EZ-116K. It discusses raised teeth instead of recesses. Volvo refers to this as a "60/1 toothed profile," described as 58 short teeth and 1 long tooth. I know that counting teeth is different from counting recesses. The count will be 1 tooth off.

I compared this info to the "60-2" LH 2.4 flywheel from STS Machining. It has 57 short teeth tooth, however if you count recesses, there are 58, the same number of recesses as a factory flywheel.

So is the Greenbook image and info just plain inaccurate?

Thanks, Dave
Attached Images
File Type: jpg flywheelLH2.4compare3lo.jpg (55.8 KB, 56 views)
File Type: jpg flywheelLH2.4compare2.jpg (122.6 KB, 56 views)
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'84 242ti, fourth owner, mine since 2003. Always garaged since brand new. Old-school rounds because I like. B21FT, SDS EFI/IGN, TD04HL-15G, T5Z trans with modded 0.73 OD, 3.91 diff, unmodified G80.
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Old 03-26-2021, 07:18 PM   #2
bobxyz
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Missing tooth nomenclature isn't fully standardized.

Per TP 31397-1 page 26, for Volvo, a NN/m toothed wheel means a spacing of NN teeth per revolution before any teeth are removed, with m regions of removed teeth.

For example:
60/1 "sixty by 1" is a 60 tooth flywheel (360deg / 60 = 6deg per tooth) with one region of removed teeth
60/3 "sixty by 3" is a 60 tooth flywheel with 3 evenly spaced regions of removed teeth
44/2 "44 by 2" is a 44 tooth flywheel (360deg / 44 = some weird # of deg per tooth) with 2 evenly spaced regions of removed teeth

For missing tooth wheels with just one missing tooth region, the NN-d nomenclature is used to mean NN teeth before any are removed, with d then removed.

For example:
60-2 "sixty minus 2" is a 60 tooth flywheel (6deg/tooth) with 2 teeth removed.

Note: the drawing on page 24 A correctly shows the 60-2 flywheel holes, but the waveform diagram B is inverted compared to a real LH2.4 CPS pickup. Also note that LH2.4 expects solid metal close to the CPS for the missing region (I think it was lookforjoe who found this out the hard way).

-Bob

Last edited by bobxyz; 03-26-2021 at 07:45 PM.. Reason: typo, but not bad for Friday of a long week
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Old 03-26-2021, 09:46 PM   #3
dbarton
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Nice clarification. I didn't catch the subtle difference "/" versus "-".
Thanks
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Old 03-27-2021, 07:37 AM   #4
dbarton
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Quote:
Originally Posted by bobxyz View Post
Also note that LH2.4 expects solid metal close to the CPS for the missing region (I think it was lookforjoe who found this out the hard way).
-Bob
Thanks. Regarding the need to have that solid long tooth for LH 2.4, I searched a number of related TB posts before posting and the consensus flip-flopped in this subject.

And regarding the Volvo drawing I posted above, I will conclude it's incorrectly drawn.
Dave
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Old 03-27-2021, 06:03 PM   #5
OttoB
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I copied hole/tooth length ratio and tdc position of Lh 60-2 B230 flywheel to B30E flywheel. Then checked VR polarity with scope. Little work with air gap it worked well.
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