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? |
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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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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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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Re: Could me engine timing be inaccurate
36 at 2500 could likely produce a lot of detonation!
What’s your initial timing? |
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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? |
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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Listen for it!
It’ll sound like a small rock rattling in a tin can. |
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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 |
Re: Could me engine timing be inaccurate
Your engine calls for 32 degrees,, you need to lower it.
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Total 32 but at what rpm?
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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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Follow those instructions and then come back and let us know what your initial timing is.
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George |
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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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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! |
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What can go wrong I'm new to this so I genuinely don't know. |
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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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I previously did put it at 35 degrees advanced at approximately 2000 RPMs. I didn't have a tachometer though. What I found out Sunday though was that it is supposed to be adjusted to 32-34 degrees advanced at 3500 RPMs. |
Re: Could me engine timing be inaccurate
Your best bet is to set your initial timing at 12 degrees.
Leave it there! Lock it down and leave it there! If you keep setting your timing at high numbers like 35 at 2000 rpm you’ll cause damage to your pistons! |
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Blueprints directions do not say to set it at 12 and leave it there. I'm just trying to get advice on following their specs. Not create new specs. |
Re: Could me engine timing be inaccurate
If you follow their specs you will end up with 12-14 degrees initial.
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Re: Could me engine timing be inaccurate
Yes!
That’s what initial timing means. Timing at idle. Idle needs to be below 750 rpm though. |
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It seems You didn't. mention lining up the rotor to #1 terminal on the dist cap.
George |
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Running 13 degrees advanced at 700 RMP and 32 degrees advanced total possible not going any higher no matter how high the ROMs,,,,, that's all with the vacuum advanced plugged right?
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Re: Could me engine timing be inaccurate
Usually the initial is with the vacuum disconnected.
BTW, I'm more a fan of experimenting with timing. The specs are just suggestions. As long as you can hear the knock (pinging, marbles in the coffee can, or whatever it sounds like to you), I'd advance the timing and see how it runs. If you have loud exhausts then stick to the specs. I had a Chevy S-10 pickup through the 1980s and 1990s didn't own a timing light. I just adjusted timing to get very light knock at wide open throttle. It ran much better when advanced from the factory/dealer tune-up settings. (I did some laboratory work with a Chevy 350 in the late 1980s also: https://www.sae.org/publications/tec...ontent/890161/) |
Re: Could me engine timing be inaccurate
Am I the only one that reads this title in a pirate voice?
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Set timing as said then double check advance at 3500-4000 rpm. This guarantees that the distributer springs let all that timing in. SbC usually like 29-36 degrees total timing not including vac advance. I set to 36 degrees at high rpm then test drive and back it down from there. Many aftermarket distributors will have base timing at idle around 16 or 17 degrees. Honestly you don't need a tach. Set over all timing at a high rpm then note what it is at idle for future reference
This is the only way to do it unless you are recurving the distributer. The curve is dependent on the distributer wieghts and springs and on some distributors, the bushings |
Re: Could me engine timing be inaccurate
Yar.
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