Quote:
Originally Posted by icarp
Ward , sorry I'm late to the party , it looks like nice work.
Just a note about new timing sprockets , in post 73 the new shinny sprockets have a reputation for being soft or not heat treated correctly.
The correct new sprockets have a grey tone to them .
Just thought I would share this with you
Carry on , VERY NICE CLEAN WORK
Ian
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Thanks for the comment, Ian...I appreciate it!
I've read those discussions about the soft sprockets. Hoping, that Porsche would ensure they were up to spec, I bought genuine Porsche sprockets from our host. Appear to be manufactured 3/9/2019?
But me being me, I purchased some HRC files to see if there was a difference.
First up was the original sprocket at HRC40. Scratched...
Next up was the new sprocket at HRC40. Scratched, but not as easily as the original...
Just for fun, I tried to scratch a con rod and it didn't scratch using the HRC40 file.
What to do? Since both sprockets have an HRC less than I can test with my files, I don't actually know which one is harder or softer, but both are less than HRC40. Anyone have an HRC tester to check for an exact number?
Tsubaki suggests an HRC of 35-50 for small sprockets. According one of their tables, HRC30 sprockets have a tensile strength of 138,000 PSI and HRC35 sprockets are 160,000 PSI.
I'm not sure what I'm going to do yet, but I think the genuine Porsche sprockets seem okay.