73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: LTZ C20 on April 05, 2012, 07:04:04 pm
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I was recently told that along with setting the timing on my 350, I should check my dwell angle. I know about timing and how it works but the dwell angle concept I know nothing about. My timing is set to 10 degrees before TDC, if someone could explain how the dwell angle concept works, that would be much appreciated. Thanks ya'll.
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If you have a points type ignition, then you should ditch it for HEI instead. If you have HEI already, you won't need to worry about that.
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I seriously miss the good old days... with points.. Had some great times with my Dad tuning up the car.
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I seriously miss the good old days... with points.. Had some great times with my Dad tuning up the car.
All I miss from the good ole point days was the time with my dad.
I had to laugh, My dad loved his ford 302 in his mustang, but he complained that ford didnt have the little door on the dist cap like chevy did to set the dwell angle while it was running. ;D I do have to agree with him though, The distributor being in the back sucks.
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check this out
http://moodle.student.cnwl.ac.uk/moodledata_shared/cdx%20etextbook/dswmedia/electrical/ignition/conBreakIg/dwellangle.html (http://moodle.student.cnwl.ac.uk/moodledata_shared/cdx%20etextbook/dswmedia/electrical/ignition/conBreakIg/dwellangle.html)
I have this tool for setting dwell. It cost me like $20 bucks 15 years ago. It does the job real good.
http://www.google.com/products/catalog?ix=ucb&q=Actron+CP7605&um=1&hl=en&ie=UTF-8&tbm=shop&cid=4300780604577980948&sa=X&ei=lUF-T623CYbk9ATY6v25Dg&ved=0CF8Q8wIwAA (http://www.google.com/products/catalog?ix=ucb&q=Actron+CP7605&um=1&hl=en&ie=UTF-8&tbm=shop&cid=4300780604577980948&sa=X&ei=lUF-T623CYbk9ATY6v25Dg&ved=0CF8Q8wIwAA)
Points have to be reset every 5000 miles, and if you dont drive it for a month they foul up and you have to clean them and reset them. which is a pain in the butt unless you like tinkering. if you want to set it and forget it, I suggest a pertronix replacement. Points aren't much good unless you want to be original on a judged showcar. Put one of those on our 69 mustang and it ran perfectly for 15 years until we sold it. Otherwise swap to HEI, but you will have to do some rewiring. with the pertronix module there's no rewiring of the car itself.
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Well I do have HEI and I was told its still adjustable or something like that. I would still like to learn how the system works. And to Kenny, the black letters at the top of the site, up in the left corner, yea, those mean Chevy. :D Haha, I know what you mean though, one of my good friends has a stang with 302. But enough with this ford bs. LOL Thanks for the links, very helpful.
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In the first HEI, I remember rotors burning through and pick up coils braking the little wires. Chrysler's burning their little box or ballast resistor or the Ford brain box. One second they were running fine, the next nothing. At least when the points started going it wouldn't stop all together... Maybe it was just me and part of what drew me into auto repair was the simplicity but after the zillion vacuum lines and emission junk I hated working on them and decided to just do it as a hobby. Dad always was on call and work frequent OT so some of the highlights were the tune ups and oil changes...
Still have the old Neihoff Tach and Dwell Meter and the timing light we used...
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HEI "dwell" is controlled by the module and varies with RPM. In the early days (developmental stage) of HEI, a technician was severely injured/killed by the energy produced during ignition discharge. Subsequently, as the story goes, a current limiter (variable dwell) was engineered into the module to decrease the risk to service personnel.
Although, 'dwell' is not adjustable on HEI, if an oscilloscope indicates a "fixed" dwell with changing RPM, the module is faulty and should be replaced. However, purchasing a dwell meter just to check HEI 'dwell' is a dubious expense, at best.
As a sidebar, I'm with Zieg; if points are so "bad," how did automotive engines run for the first 70 years, before electronic ignitions? Electronic ignition is a definite improvment, but the primary problems with point ignitions were improper lubrication of the rubbing blocks and wear in the breaker plates. They were adequate and quite effective for their purpose.
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lol old mechanical technology.... We're almost at 40 years since points went bye bye. Even using a timing light is nothing more than a tool to baseline and record your measurements. Setting your timing at 10°BTDC really means nothing other than you have a scribe for your baseline.
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20+ MPG with 500 HP.... There's no question technology has advanced. My Grandmother, rest her soul, arrived in California via covered wagon as a tiny girl, and lived to watch men land on the Moon. It's an age of technological (r)evolution. But, I digress....
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That was some philosophical stuff right there. I'm 18, ya'll are old haha. Most that know me say if I wasn't old school I wouldn't be much though.
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Point systems were great when that was the technology, there is nothing wrong with points, you just have to adjust/replace them more than HEI.
The Cougar I just picked up has them and I will keep it that way until I rebuild it and set it up with a newer fuel injected engine. I have the same analyzer as 78 chevyrado mentioned and it works great. I believe any one who wants to know how to work on vehicles should learn how to work on a points system and how to adjust the dwell in older vehicles.
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...I'm 18, ya'll are old haha....
Like fine red wine or a good single malt!
Point systems were great when that was the technology, there is nothing wrong with points, you just have to adjust/replace them more than HEI....
...I believe any one who wants to know how to work on vehicles should learn how to work on a points system and how to adjust the dwell in older vehicles.
I agree with this statement completely. In addition, dwell meters are useful when adjusting certain feedback carburetors; but they have limited application to all-electronic ignition systems.
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I can't agree with that statement. There is a LOT wrong with points. They work but that's about it.
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It's just old technology.
Would you rather have an OHV cam engine or a flathead? If I had a concours restoration vehicle, a flathead. if i wanted performance and ease, OHV
As far as points working in 70 million or so vehicle, well so did vacuum operated windshield wipers and bias ply tires and flathead engines. It's just old technology. if you like it, keep it. if you want to upgrade do it too. If your car is gonna sit around a lot, I will say points are the worst ever.
Just don't ever expect points to perform like HEI will. it won't happen, ever. Of coarse there's always the dual points upgrade so you have twice as much work when things go wrong.
HEI is an upgrade in technology. I love HEI and have only had one module fail, ever. from what I've seen with people who had modules fail all the time, when they replaced or removed the module, they didnt put the heat conducting grease back under it when the re installed it. I'm not saying they wont fail as long as you do this, but that's been the main cause I've seen. you gotta remember, you only hear about stuff when it fails, people dont talk about it when it works. how many people said HEI sucks vs how many owned one and never said anything about it at all?