09-13-2017, 01:14 PM | #1 |
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Point cam
So, I'm just checking everything on my engine to make sure that settings are correct and was checking the ignition timing. Found the point a tad tight so set them to .020 but noticed about 5-10 degrees of free movement in the cam when turning it with a screw driver on the locking screw. Everything under the cap looks new but this movement in the cam doesn't seem right. How can one ever set the timing and keep the timing right if the cam is free to move back and forth several degrees?. Theoretically the rotation of the engine should keep it all the way over one way but should t not be free of any advance/retard play??. Also, could be related but I find very little difference in full retard to full advance on the lever as far as how the car runs. Lots of movement on the plate but would expect a more noticeable change in the engine for the amount of timing difference.
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09-13-2017, 01:43 PM | #2 |
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Re: Point cam
What you are experiencing is the play in the distributor drive linkage from the camshaft up to the distributor. When you set the ignition timing you must compensate for the backlash. There are some Youtube videos on How to set the ignition timing and also on (abarnyard.com)
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09-13-2017, 02:03 PM | #3 |
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Re: Point cam
I watched a couple youtube videos as well as read a writeup on abarnyard.com but they said nothing about compensating for the backlash.
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09-13-2017, 02:39 PM | #4 |
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Re: Point cam
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09-13-2017, 02:48 PM | #5 | |
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Re: Point cam
Quote:
"Begin tightening the screw. This removes the backlash in the system and the cam should remain as close to touching the rubbing block on the points as possible without opening the points. This may require multiple efforts to get it ideally positioned." Also see B in the picture. Bob |
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09-13-2017, 03:34 PM | #6 |
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Re: Point cam
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09-13-2017, 05:33 PM | #7 |
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Re: Point cam
Nu-Rex tool X 2
Paul in CT |
09-13-2017, 05:55 PM | #8 |
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Re: Point cam
Thanks for all the replies.
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09-13-2017, 07:44 PM | #9 |
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Re: Point cam
Yes to setting the points to .020" first.
Then once the timing is set correctly counting for the backlash, there should a big difference between full retard and full advance. Full retard should allow for a low idle speed and the timing will sound late as it should. 1/2 advance will/should have a nice slightly faster idle speed. Full advance the engine idle speed should start to 'roll' a bit. |
09-13-2017, 08:05 PM | #10 |
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Re: Point cam
Got the timing set and the points gapped to spec, found and fixed a vacuum leak and tightened up exhaust eliminating slight exhaust leak. Runs pretty good but still backfires through exhaust on deceleration. Been playing with the gav but even with it closed all the way, the plugs show rich (and wet). Should i not be looking for nice tan plugs like in other cars??. When in open the gav a bit (about 1 turn) it does seem to run a bit better but those plugs??!!!!!
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09-13-2017, 08:56 PM | #11 |
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Re: Point cam
I got reprimanded by an expert on here once, when I stated that mine does not run happy at 1/4 turn open. Mine seems to run best at about 1/2 to 3/4 turn open. I adjust mine while driving at about 25 to 30 miles an hour and it smooth's out at those speeds and idles perfect. I have heard of others who do the same thing. Just my 2 cents. As for the plugs,,,,,,,,which ones are you running?
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09-13-2017, 09:08 PM | #12 |
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Re: Point cam
If your timing is correct the usual causes of backfiring on deceleration are:
Mixture too rich Mixture too lean Burned valves |
09-14-2017, 08:49 AM | #13 |
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Re: Point cam
Loose connection where the down pipe on the muffler meets the exhaust manifold will let in air and re ignite the excess un-burned fuel in the exhaust. Air getting in at the intake gasket or further down at muffler can have the same effect. These are the details that are the extension of what barnstuf said above.
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09-14-2017, 08:50 AM | #14 |
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Re: Point cam
You can KNOW if your timing is RIGHT!
1 Spark up, should have a smooth, rhythmical sound, like TADA-TADA-TADA-TADA. 2 Spark 1/2 way down should have a FASTER, SMOOTH idle. 3 Spark FULL down should have an even FASTER, but somewhat "rolling" idle. IF YOU HAVE ALL THESE, THEN IT'S PERFECT!!!----NOW, you can "TUNE" yo' HORN--LOL Bill Ear
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09-14-2017, 09:21 AM | #15 | |
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Re: Point cam
Quote:
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09-14-2017, 09:26 AM | #16 | |
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Re: Point cam
Quote:
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09-14-2017, 09:39 AM | #17 | |
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Re: Point cam
Quote:
Bill Rollingaround
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09-14-2017, 09:57 AM | #18 |
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Re: Point cam
The picture that Bob C. posted from Marco's site,,,,,,will get you very close on timing. Just make sure your retard lever is all the way up. Then if it is timed properly,,,,you should notice a definite difference in RPM's when the lever is retarded and advanced up and down. Both of mine do not like to run at full advance around town. Half way down is where the sweet spot is on mine and that's where I normally run them. Good luck with yours.
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09-14-2017, 10:46 AM | #19 |
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Re: Point cam
New Autolites but what heat range. They may be too cold for short trips where you don't really get the engine up to temp.
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09-14-2017, 08:07 PM | #20 | |
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Re: Point cam
Quote:
Bill Semiold
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