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-   -   Trusting Empirical Evidence! (https://www.rx7club.com/race-car-tech-103/trusting-empirical-evidence-411384/)

John Senini 04-04-05 10:44 AM

Trusting Empirical Evidence!
 
For weeks now I have been chasing a poor running bridgeport 12A in my sports racing car, I have blown lots of cash changing things I really didnt need to. The engine was experiencing fluttering/ detonation sounds, no power no revs. But the timing said only 20 Degrees- What gives? Why do we trust guages/tests when the facts (Empirical Evidence) still points to too much timing? So we run the timing down to 0 degrees indicated and BOOM engine runs well. HMMM I say, Pulley must have sheared its keway and wedged itself into another position. Why did it take so long to come to this conclusion? Beware of trusting or believing Data when Empirically you know other things. Comments? War Stories? bring em on!

Re-Speed.com 04-04-05 11:55 AM

I heard Racing Beat shipped a bunch of mis-marked pulleys a few years (Maybe 10) ago. I wonder I you have a bad pulley.

-billy

C. Ludwig 04-04-05 12:17 PM

I got one of those pulleys. :D It had 5 marks on it instead of 4 and if my memory is right they didn't correspond to anything. That's a bit different that having the engine run one minute and then not the next though.

speedturn 04-04-05 12:19 PM

Are you using one of those timing lights with the advance degree knob on it ?

John Senini 04-04-05 12:23 PM

Just my old style dead simple timing light, looking through my books it seems to have gone a while back. some time soon I will pull it off and find out why. How do you find top dead center on a rotary? No one I know really knows how.

Re-Speed.com 04-05-05 07:34 AM


Originally Posted by C. Ludwig
I got one of those pulleys. :D It had 5 marks on it instead of 4 and if my memory is right they didn't correspond to anything. That's a bit different that having the engine run one minute and then not the next though.


I took it that it only ran correct when he changed the timing to make up for what he thought to be wrong and for the key to give out.


On the TDC, pull a search up top, I have seen this info on here but I do not want to repeat what I think I remember in case I am old and don't remember :)

-billy

EProdRx7 04-05-05 11:21 PM

I got one of those pulleys also. Mine had the correct marks and they were painted but then there were another set of marks that were unpainted. It was on my spare motor and I went to use it and the unpainted marks happened to be facing up when it was time to check the timing. Like the brainiac that I am I decided to paint them so as to make the timing easier. You can guess the rest of the story...

C. Ludwig 04-06-05 12:06 AM

Here ya go for TDC.

http://www.teamfc3s.org/info/articles/demystifying.html


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