01-05-2017, 11:18 PM | #1 |
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Timing question
1970 c10 350 auto
Installed a new HEI distributor tonight. Gonna set timing tomorrow. My timing tab doesn't have any numbers on it. any info on reading the tab appreciated. Thanks. Mark Posted via Mobile Device |
01-05-2017, 11:39 PM | #2 |
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Re: Timing question
It should look something like this pic. Each mark represents 2 degrees timing.
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- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
01-05-2017, 11:44 PM | #3 |
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01-05-2017, 11:45 PM | #4 |
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01-05-2017, 11:48 PM | #5 |
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Re: Timing question
Only 10!!
Might be good for a stocker. (No pun intended). What mods to your motor you got? |
01-05-2017, 11:58 PM | #6 |
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01-06-2017, 12:05 AM | #7 |
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Re: Timing question
Might be a good starting point though.... Can't remember what mine is set at. I usually advance until it pings, then gradually back it down until it's quiet.
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01-06-2017, 12:05 AM | #8 |
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Re: Timing question
Is it a brand new motor or has it been run already?
Where in Ohio do you live? |
01-06-2017, 12:14 AM | #9 |
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Re: Timing question
It's an original 1970 350.
I live in Fairview park close to Hopkins airport. I've been searching for 8 years for a solid truck for a god price. I just about gave up and finally found a gem for a great price. I'm thrilled and loving working on it. I build custom kitchen cabinets on the side and finding it very difficult to build cabinets when my truck is in the shop. Mark Posted via Mobile Device |
01-06-2017, 12:22 AM | #10 |
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Re: Timing question
10 is good place to start.
Don't forget to plug off the vac advance line when you set the timing. I like 14 myself for stock motors. Are you gonna use a fuel regulator for that eddy carb set at 5 psi. Eddy carbs are sensitive to fuel pressure. |
01-06-2017, 12:29 AM | #11 |
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01-06-2017, 12:31 AM | #12 |
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Re: Timing question
Thank you I was wondering if I needed a regulator for the fuel pressure. One more thing to add to my list for summit. Driving there Saturday.
Wife keeps asking what all these deliveries are! Lol. "It's nothing honey" Posted via Mobile Device |
01-06-2017, 01:11 AM | #13 |
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Re: Timing question
With your hei, did you use a dedicated 12 volts to it?
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01-06-2017, 02:44 AM | #14 |
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Re: Timing question
As far as timing goes, it was common practice back in the 70s, right after the first oil crisis drove gas prices up, to buy a timing kit for the distributor. Basically, the idea was to advance the static timing, but limit the total advance by putting a limiting device in the distributor, so that the engine would not be harmed by detonation at higher revs. This gave the engine more torque and better fuel economy, but as others have posted, you had to be careful that you did not get ignition knocking by using too much advance for the compression you had and the fuel grade you were using.
Yes, the idea worked, my fuel economy with my 71 350 4 bbl improved quite a bit, and the engine had a lot more low speed grunt. I did all this in conjunction with adding dual exhaust, and the "famous" upside down air cleaner lid tuning trick!
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Rick -69 GMC 910 Long Box, 350 -98 Chev Silverado 1500, 350 Vortec 4L60e -08 Mustang GT Convertible |
01-06-2017, 10:08 AM | #15 |
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Re: Timing question
I couldn't get the mark to read right on my '67's 350 (older points distributor) so after swapping to the calmer cam it needed I had to tune it by feel. Started out way too retarded (don't laugh) and while it didn't exhibit any specific bad behaviors it ran hotter than normal, idled with a very deep, labored tone, and could barely hold 50-55 on hills. Bit by bit I advanced it to where I've had it the last 8 months or so, where temp is just above the line into the solid, center stripe (stock gauge), idle is as smooth as possible, plugs are a nice light caramel color, and mileage is as much as 14 MPG with the stock Rochester 4G. I've tried advancing it from there a smidge but that brings on a slight hunt/shudder at idle so I returned to the previous setting and called it good until I can spend enough time/money to alter the distributor curve.
Yours may not behave the exact same, but there may be some elements of my experience you can use in dialing yours in. Once it all gets close you have to balance timing with carburetor calibration to get it just so - I'm up to a 56? main jet from 53 or 54 (put in little jets when I changed the cam, just as a starting point) and since I'm confident my current distributor is timed to its current optimum I need to come up just a couple more jet sizes (58 or 59 is next) to get primary mixture just right. Not sure if I'll get around to secondary/power jetting before the 327 goes back in.
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Alex V. ------ 1967 C10 Suburban, 350/NP435, Green/Green, PS, PB, HD cooling, charging, shocks, and springs. 1985 GMC C3500 SRW, Sierra Classic, 454/TH400, white/blue. |
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