Need help with timing specs?!?!
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Need help with timing specs?!?!
Background first. I have a 400 out of a 1978 Lincoln that I am using in a 1950ish F1. I removed all the smog crap, and I am using an Edelbrock preformer intake and an Edelbrock carb (600?). I have a coil on distributor HEI setup.
Questions;
Do I need to disconnect the vacuum line off the vacuum advance when setting the timing at idle?
The book I have says 13 degrees advance (before dead center). With the intake and carb I am running and no emmisions crap do you think that is still the best bet?
Do I need to wait until the motor is good and warm and the electric choke butterfly is open?
I have it timed roughly right now (I couldn't read the marks very well until I cleaned them up), and it is probably more like 18 degrees BDC and it cackles a little when you lay the whip to it, although it does seem to idle OK.
Thanks,
CHAZ
Questions;
Do I need to disconnect the vacuum line off the vacuum advance when setting the timing at idle?
The book I have says 13 degrees advance (before dead center). With the intake and carb I am running and no emmisions crap do you think that is still the best bet?
Do I need to wait until the motor is good and warm and the electric choke butterfly is open?
I have it timed roughly right now (I couldn't read the marks very well until I cleaned them up), and it is probably more like 18 degrees BDC and it cackles a little when you lay the whip to it, although it does seem to idle OK.
Thanks,
CHAZ
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Yes, you will need the advance plugged when you are setting the timing. Also set the timing when the engine is fully warmed up. The "cackling" you are describing when you get on the gas is probably pinging - a combination of your running your base timing pretty high, and the fact that you removed all smog equipment. You can't simply remove the EGR and be done with it - you have to rejet the carb and replace the advance with an adjustable one and recurve it. It's much easier to leave the EGR functioning. It's not hurting anything.
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Oh man, I am an idiot. You wrote EGR, and I thought PCV. I was thinking I still have a PCV valve. It is an aftermarket carb and intake, I wonder if it is set up for the EGR?
CHAZ
CHAZ
Last edited by hoof; Feb 4, 2008 at 07:46 PM.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
A 400 out of a '78 Lincoln is without a doubt set up for EGR. You won't see any leftover EGR parts on the engine since your intake and 2 barrel spacer are gone, but you still have the crossovers in the heads. You have a different carburetor now but if you're running the stock distributor, it will be curved for EGR. EGR motors require higher advance. If you take away the EGR but leave the advance alone, you will get pinging, like you describe.
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I am using an aftermarket HEI distributor. One of the coil on cap ones. I don't know if it would be set up for EGR or not? It is kind of a generic fit deal so I don't know.
I remember reading about the crossovers in the heads when I had the intake off my motor, but I'll be darned if I can remember if I capped them or not?!?!? I think that maybe the Edelbrock intake didn't have ports there so I didn't need to worry about it?
CHAZ
I remember reading about the crossovers in the heads when I had the intake off my motor, but I'll be darned if I can remember if I capped them or not?!?!? I think that maybe the Edelbrock intake didn't have ports there so I didn't need to worry about it?
CHAZ
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Sorry, I see you wrote in your first post that you upgraded the distributor but I missed that. My fault. Anyway, I think 12-13 would be your best bet to get you in the ballpark, and you can go from there. If you still get some pinging on acceleration you can back off of that a bit.
Lead Driver
Joined: Nov 2000
Posts: 6,639
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From: Albuquerque
Heres a general suggestion.
Initial = 10-13
Vacuum =7-10 (you need vacuum advance to prevent pinging)
Total = 35-38 (without counting the vacuum advance)
Requirements will vary with altitude, modifications and the octane of your gas.
Initial = 10-13
Vacuum =7-10 (you need vacuum advance to prevent pinging)
Total = 35-38 (without counting the vacuum advance)
Requirements will vary with altitude, modifications and the octane of your gas.
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OK, I understand that initial is at idle RPM, no vacuum, and vacuum would be at idle with the vacuum advance hooked up, but what is "total" timing?
Sorry for the NOOB question, but while I have heard that term before I never heard what it is, or how to measure it.
Thanks,
CHAZ
Sorry for the NOOB question, but while I have heard that term before I never heard what it is, or how to measure it.
Thanks,
CHAZ
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Lead Driver
Joined: Nov 2000
Posts: 6,639
Likes: 349
From: Albuquerque
Well, intial measurement is without any vacuum. Vacuum advance is how much the timing increases when you plug it back in at idle. Total is the initial plus the mechanical advance in the dizzy without the vacuum hooked up. To measure total advance you either need a timing tape that goes to 40 degrees or a timing light that has a dial that lets you turn it back while you zero the timimg mark (at 3,500rpm or so) , then read the dial.
