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08-11-2023, 08:18 AM | #1 |
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Could me engine timing be inaccurate
Thanks for looking to help me out. I really appreciate it. I have a crate blueprint 350 https://blueprintengines.com/product...ed-front-drive
I'm worried I have not done the timing process correctly. 1. I pulled all the plugs and put a paper towel ball in plug hole 1. 2. I turned the engine with a socket wrench and after a few turns the ball shot out. 3. I saw on the harmonic balancer this was top dead zero per the marking. 4. I dropped the distributer and as it lowered it turned ~50 degrees clockwise. I was worried this was too much of a rotation because I have never done this before. 5. I raised the distributer, rotated it ~55 degrees counter clockwise. I lowered the distributor in the exact same degree orientation I have seen in a dozen mechanic videos and it rotated itself ~55 degrees clockwise again just like last time. 6. I started the engine. At ~2500 RPM with my timing light I rotated the distribuer to show 36 degrees advanced on the harmonic balancer which is the value in my documentation. Is there anyway possible that my engine is not actually at 36 degrees advanced?
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1971 C10 manual cab. 76 4x4 chassis. Cut short frame. Carbureted Blueprint 350, automatic 700r4. ~ James |
08-11-2023, 08:29 PM | #2 |
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Re: Could me engine timing be inaccurate
My does that when I lower it too. I just account for it when I'm dropping it in. Probably normal.
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08-12-2023, 12:19 AM | #3 |
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Re: Could me engine timing be inaccurate
As you lowered the distributor into position, the rotor rotated a bit because the gears on the shaft are spiral cut.. This rotation is normal.. If the vacuum canister on the distributor is in a "comfortable" position after the timing is set, you're good to go.. Wanna see something that will fascinate and puzzle you a little more?? Put the timing light pickup on the #6 plug wire. Start the engine and check the timing as before...
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08-12-2023, 08:05 AM | #4 | |
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Re: Could me engine timing be inaccurate
Quote:
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67 C10 283 T5 swapped longbed fleetside = wife's daily driver 67 C20 292 (originally a 250)4speed longbed fleetside w/original wooden bed=my project truck 67 C10 283+.060 (so a 292 as well)T5 swapped longbed fleetside=my DD 72 C1500 Sierra Grande 350 TH350 longbed fleetside=wife's fair weather truck Can you tell we are fans of longbed fleetsides & 67s Chris |
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08-12-2023, 08:23 AM | #5 |
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Re: Could me engine timing be inaccurate
Thanks all. So it sounds like I have nothing to worry about and since the timing light is showing 36 degrees advanced on the harmonic balance at 2500 RPMs then it is infact 36 degrees advanced and could not be another value based on the correctness of completing the steps in the process?
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1971 C10 manual cab. 76 4x4 chassis. Cut short frame. Carbureted Blueprint 350, automatic 700r4. ~ James |
08-12-2023, 08:50 AM | #6 |
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Re: Could me engine timing be inaccurate
36 at 2500 could likely produce a lot of detonation!
What’s your initial timing? |
08-12-2023, 08:57 AM | #7 | |
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Re: Could me engine timing be inaccurate
Quote:
Initially, my idle screw was not adjusted well and the idle was too high, and I did not yet have a tachometer. At idle, the timing was around 16 degrees, but I may not be remembering correctly. Now that I have a tachometer, should I redo the process?
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08-12-2023, 09:05 AM | #8 |
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Re: Could me engine timing be inaccurate
Warm the motor up, plug off the vacuum advance, lower the idle to 750 rpm and then check your timing at idle.
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08-12-2023, 02:32 PM | #9 |
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Re: Could me engine timing be inaccurate
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08-12-2023, 02:49 PM | #10 | |
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Re: Could me engine timing be inaccurate
Quote:
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08-12-2023, 04:15 PM | #11 | |
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Re: Could me engine timing be inaccurate
Quote:
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1971 C10 manual cab. 76 4x4 chassis. Cut short frame. Carbureted Blueprint 350, automatic 700r4. ~ James |
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08-12-2023, 05:00 PM | #12 |
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Re: Could me engine timing be inaccurate
Listen for it!
It’ll sound like a small rock rattling in a tin can. |
08-12-2023, 10:30 PM | #13 |
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Re: Could me engine timing be inaccurate
Does the timing go up farther if you rev it up over 2500?
36 degrees is a bit too high using a street cam. 34 degrees is safer. Its better to err on low side. If you had access to a dyno & other equipment you could get it perfect. Rest of us just have to settle for best. George Last edited by Wrenchbender Ret; 08-13-2023 at 10:53 AM. |
08-13-2023, 10:44 AM | #14 |
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Re: Could me engine timing be inaccurate
Your engine calls for 32 degrees,, you need to lower it.
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08-13-2023, 02:44 PM | #15 |
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Re: Could me engine timing be inaccurate
Oh you're absolutely right. Thanks.
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08-13-2023, 03:11 PM | #16 |
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Re: Could me engine timing be inaccurate
Total 32 but at what rpm?
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08-13-2023, 03:15 PM | #17 |
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Re: Could me engine timing be inaccurate
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08-13-2023, 03:17 PM | #18 |
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Re: Could me engine timing be inaccurate
So if at 3500 RPMs and 34 degrees, if I raise the RPM to 4,000 and the timing advances further, I would then turn the distributor back down to 34 correct?
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1971 C10 manual cab. 76 4x4 chassis. Cut short frame. Carbureted Blueprint 350, automatic 700r4. ~ James Last edited by K10-Kansas; 08-13-2023 at 03:52 PM. |
08-13-2023, 03:27 PM | #19 |
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Re: Could me engine timing be inaccurate
Follow those instructions and then come back and let us know what your initial timing is.
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08-13-2023, 10:21 PM | #20 | |
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Re: Could me engine timing be inaccurate
Quote:
George |
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08-15-2023, 03:25 AM | #21 |
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Re: Could me engine timing be inaccurate
If your exhaust isn't too loud, you'll be able to hear the sound... Sounds like hand full of marbles rattling around in a shaken coffee can... Most prominent when lightly accelerating or under load. Disappears when you lift the throttle.
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08-15-2023, 10:37 PM | #22 |
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Re: Could me engine timing be inaccurate
I read in my documentation that there is a mark on the distributor for the perfect adjustment set by Blueprint. I found the mark and turned the distributor so the chisel marks line up. I'm going to start it up this weekend and check the timing but what do you think? It's probably right on the money now right?
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1971 C10 manual cab. 76 4x4 chassis. Cut short frame. Carbureted Blueprint 350, automatic 700r4. ~ James Last edited by K10-Kansas; 08-16-2023 at 11:17 AM. |
08-16-2023, 08:40 AM | #23 |
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Re: Could me engine timing be inaccurate
Maybe!
If you put the distributor and rotor in in exactly the same place as original then it could. My monies on you didn’t! |
08-16-2023, 11:23 AM | #24 | |
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Re: Could me engine timing be inaccurate
Quote:
What can go wrong I'm new to this so I genuinely don't know.
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1971 C10 manual cab. 76 4x4 chassis. Cut short frame. Carbureted Blueprint 350, automatic 700r4. ~ James |
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08-16-2023, 01:01 PM | #25 |
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Re: Could me engine timing be inaccurate
When you found the ‘mark’ and turned the distributor so the mark lined up, how far did you turn the distributor and which direction did you turn the distributor?
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drop distributor, setting timing, timing adjustment |
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