Another FE Runs!! 390!!

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Apr 24, 2006 | 10:47 AM

#16

FalconStng

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On a basically standard engine the purpose of vacuum advance is really for better gas mileage...and it's not necessary. For some of these built engines with cams that like a lot of timing then a trick that people do is connect the vacuum advance to straight vacuum....that lets the engine be timed not quite so high to help with starting but then immediately the vacuum advance pulls the timing up. Your engine does not need this. Rusty's biting his tongue because with your build the thicker head gasket is hurting you in the pinging department. I does sound like you may have a slipped harmonic balancer....I'd check that....find tdc of #1 and then see if the balancer shows to be right on tdc. If it's off then remark it so you know where you are. You should not have starting problems at 5 btdc. For your build I would think 10 to 12 btdc is where you want to be. If it pings then try some premium and see if it goes away...if it does then you're buying premium gas....or maybe dropping the steel shim head gaskets on there.

Good Luck!

Tracy

Apr 24, 2006 | 10:51 AM

#17

FalconStng

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Oops...on the vacuum secondaries....you should feel them come in when they open...if you can't tell then maybe they aren't dropping in fast enough. You adjust this by changing the spring on the vacuum secondary....lighter springs makes the secondaries drop in faster...heavier springs...slower. When it drops in so fast that the engine hesistates slightly before it pulls like a mad dog then you've gone too far. Go one spring heavier and that's where you want it.

Tracy

Apr 24, 2006 | 10:54 AM

#18

krewat

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From: Long Island USA

Quote:

Originally Posted by 73F100*8Mile

Well what exactly is the point of vac advance if you don't have to have it? What does it improve? Isn't more of just a responsive thing? I'm not sure where 57 came from but my max advance with vacuum advance is 36-38 at about 2500-3000. I just printed out the instructions for my holley from the holley website so maybe one day this week i can make sure everything is sealed off and right. Also the ported vacuum ont he side of my holley, I thought that shouldn't have any vacuum at all at idle but we're getting some which advances the timing at idle...are you suppossed to have a little vacuum? And last, is there a surefire way to know when/if you secondaries are kicking in besides watching the fuel gauge? I'm kinda fuzzy on how to adjust that so it kicks in and kicks in at the right time...i'm also gonna be reading up on how to adjust that too.

Sounds like the throttle plates are too far open, which uncovers the vacuum advance port. Put the timing at 10BTDC, and adjust the idle back down to where it should be - see if you still have vacuum on the vacuum advance at idle.

See, the more advance you have, the more vacuum, so you have to close the throttle plates more to idle it down. Without enough timing at idle, you have to crank open the throttle plates to get it to idle, and that opens up the vacuum advance port.

But are you connecting the vacuum advance or not?

How is the vacuum at 5BTDC?

Like Rusty said, maybe the damper ring slipped. Get the motor to TDC on cyl #1 and see what the damper says - should be "0"

Overall, sounds like you need to limit the mechanical advance some and crank up the initial. 5BTDC shouldn't make it hard to start. Once you get past 15-20, then it gets hard to start

art k.

Apr 24, 2006 | 02:47 PM

#19

73F100*8Mile

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From: NE Ga

at 5btdc I've got 15hg vacuum. also how could my balancer slip? Are you talking about it slipping on the rubber that insulates the outer numbered part to the center bolted part? Kind of confused there. How would you know if it slipped by visibly looking at the balancer? I know i can check by putting #1 at top but wouldn't there be signs on the balancer itself? Ok this came to mind, what would happen if my balancer is ok and I set it to 6btdc and then dropped the dizzy in to land right on #1. Its automatically got 6 degrees advancement right? I kinda think that may have been what we finally did. We did so many drop-in's with the dizzy just trying different things when it was on the stand that i can remember the final install. What would that do if that was the case?

Apr 24, 2006 | 03:05 PM

#20

krewat

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From: Long Island USA

Yes, the ring on the balancer can slip - there are usually no outward signs.

Are you using a timing gun to time it, or are you going by where TDC is and just dropping in the dizzy?

You have to use a timing light. If you didn't, you have a lot more advance then you think

Apr 24, 2006 | 04:31 PM

#21

73F100*8Mile

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From: NE Ga

oh no i've done nothing but use the light...after you burn a set of heads from having too much advancement...you don't want to mess up twice. I went and let my boss run and drive it today and he said right now i need to focus on getting a vacuum gauge on it and turning in the mixture screws for idle b/c it's really rich (smell) at idle. Then he said my timing should be set from 8-10 safely. Also he drove it and said my primaries are not kicking in so holley must have a stiff spring in there from the rebuild of the carb. Thats on the back burner though, i just want to make sure i'm not gonna go through another set of heads.

Apr 24, 2006 | 08:28 PM

#22

krewat

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From: Long Island USA

Make sure that damper didn't slip. Really, before you do anything else, verify TDC is "0" on the damper.

Apr 24, 2006 | 08:55 PM

#23

73F100*8Mile

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From: NE Ga

Verified! I talked to my dad and he said that it's fine...he remembers setting it to tdc on #1 and it being on zero. So what do you think from here? should i just leave the vacuum advance off for now?

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Apr 25, 2006 | 01:13 AM

#24

fordeverpower

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From: iowa

this is my last advice because i am tired of wasting my time.

1. Do not worry about the balancer

2. buy or find a adjustable vac cannister and install it. Use an allen wrench to adjust it.

3. remove the base plate from the dizzy and look at the weights, if they are 16L and 21L, install windshield wiper hose over the tab to limit the mech advance. Do not use any other hose!

4. don't be afraid to wearout the timinglight, they are cheaper than rebuilds.

5. use nothing higher than a 180 degree thermostat!

6. thats it and best of luck!

Apr 29, 2006 | 01:16 PM

#25

73F100*8Mile

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From: NE Ga

ok opened up my dizzy to find two weights labeled "G1" and "G2". Mean anything to anyone? Fordever- not sure what you mean by just throwing some windshiled washer hose in there...sounds kinda sketchy to me but if it works then i'm willing to try. How long a hose do i need and do you just wrap it or what? Also when i set my timing at 10 degree's, it bucks on startup and diesels on shutdown...detonation somewhere. My boss seems to really be leaning towards a vacuum leak. I leaned turned my mixture screws in until i lost vacuum and rpm and then brought them out about half turn to smooth it out so thats done. It still smells rich at idle though. Haven't had time to check my plugs yet so that might be an answer waiting to be seen. Any other pointers? It still runs rough at idle too and is really hard to keep going right after crank up. I've adjusted my choke but even in warm weather its still tempermental. I've plugged off all vacuum leads to carb except pcv and all ports on intake are closed and the port itself is tefloned. Also when i pull my pcv out, theres a mist that comes out of the cover...good or bad?? I know the 941 cam is supposed to have a "good" idle and not smooth but this definately is not good!

Apr 29, 2006 | 03:16 PM

#26

Hypoid

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Joined: Apr 2004

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From: Golden, CO

https://www.ford-trucks.com/user_gallery/displayimage.php?&photoid=115121&width=2

Look at the slots. If you are on the narrower slot, you can further limit travel by slipping washer hose over the pin.

Not to dis anyone, but Bear 45/70 explains things really well: Explanations so simple that even I "get it". Use the advanced search so you can search his posts for setting advance. Have some paper ready for making notes.

Last edited by Hypoid; Apr 29, 2006 at 03:19 PM.

Apr 30, 2006 | 12:26 AM

#27

"Beemer Nut"

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From: "Islander"

If you use different tube wall thickness besides the proper slot you can limit the mechanical advance in degrees. With a spring kit and vacuum gauge you can set when mechanical comes in and what rpm's it's at maximum. Then go back to the vacuum advance unit for when and maximum travel degrees. Better with the older vacuum units with spacer and washers. Then go back with initial timing and carb setting with a F/A gauge. A PITA with many hours of testing but the rewards are a sharp running motor. Air temperature, humidity, gearing, altitude, fuel grade, thermostat temperature, carb jetting, cam, exhaust system, there are many outside factors to tune to besides corrections to a possible mismatch of parts.
Wrong cam for compression, oversize carb, wrong gearing for cam, wrong intake for cam, on and on. Take a hell of a lot of notes on single changes, don't do a couple changes at once. Bottom line if DCR is too high or quench is no existant or low your screwed no matter how you try to tune to prevent detonation.
.....=o&o>.....

Last edited by "Beemer Nut"; Apr 30, 2006 at 12:41 AM.

May 1, 2006 | 07:54 AM

#28

73F100*8Mile

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From: NE Ga

Ok talked to a buddy builder of mine in MI and he said that it sounds like I've got a nice vacuum leak somewhere. When the engine reaches OT, it doesn't lope to where you can hear each cylinder hitting. Its an inconsisten misfire. Also when i shut it down now at 8 degrees, it diesels for about 5 sec's or so!! This is w/ the engine temp at about 140-150!! Since more than once cylinder is dieseling, it makes me think that i have a carb gasket leak that is causing multiple cylinders to get hot spots. Might be a possible warped intake too as i got this stock 4v outa the yard.