Well got my HEI installed. Also put in a new set of AC Delco plugs gapped at .060. I'm experiencing a slight hesitation when I really put my foot into the pedal. I'm running a 1411 Edelbrock carb. I had the timing set at 30 degrees but was experiencing some pinging. This was before I added the new plugs. Reset the timing to 28 degrees added the new plugs. No pinging but have a slight hesitation. It's like when your driving along and then you floor it there is a "uuuutaaa" then she takes off. No big deal just thought I'd post and see if anyone has any ideas. Gonna mess around with it some more today. Maybe I'll reset the timing to 30 degrees now that I have the new plugs in it and see what happens. Seems to have really picked up the performance other than the hesitation. Thanks.

[/url]
(http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/36/36_2_1.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/36/36_2_25.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/36/36_2_68.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/36/36_8_14.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) [url="http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS"]

Well got my HEI installed. Also put in a new set of AC Delco plugs gapped at .060. I'm experiencing a slight hesitation when I really put my foot into the pedal. I'm running a 1411 Edelbrock carb. I had the timing set at 30 degrees but was experiencing some pinging. This was before I added the new plugs. Reset the timing to 28 degrees added the new plugs. No pinging but have a slight hesitation. It's like when your driving along and then you floor it there is a "uuuutaaa" then she takes off. No big deal just thought I'd post and see if anyone has any ideas. Gonna mess around with it some more today. Maybe I'll reset the timing to 30 degrees now that I have the new plugs in it and see what happens. Seems to have really picked up the performance other than the hesitation. Thanks.


http://smileys.smileycentral.com/cat/36/36_2_1.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/36/36_2_25.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/36/36_2_68.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/36/36_8_14.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS)
Sounds like it's starving for gas at the mash. I'm not familiar with Edelbrock carbs but, I remember all the fun I used to have tweaking and tuning the Holleys. Check out your accellerator pump. If there are any adjustments you can make, that's where I would start.
Sounds like a brute!

Kev

I didn't have the problem with the points/condenser ignition so that leads me to believe that the carb is fine. I'm wondering if it's timing or maybe vac advance. The HEI dist. has an adjustable vac advance should I go with a different one. Also when you floor it you feel the hesitation and then it accelerates but if you back off the throttle just a bit, maybe a quater pedal, it feels like a power band kicks in and it really accelerates. Thanks for any help.

I didn't have the problem with the points/condenser ignition so that leads me to believe that the carb is fine. I'm wondering if it's timing or maybe vac advance. The HEI dist. has an adjustable vac advance should I go with a different one. Also when you floor it you feel the hesitation and then it accelerates but if you back off the throttle just a bit, maybe a quater pedal, it feels like a power band kicks in and it really accelerates. Thanks for any help.
As you said, "..when you floor it you feel the hesitation and then it accelerates but if you back off the throttle just a bit, maybe a quater pedal, it feels like a power band kicks in and it really accelerates.."
When you accelerate with a carburator, most carbs that I know of have an accelerator pump that gives the engine an extra intitial burst of gas to eliminate the symptoms you have just described. When you 'mash the gas' the engine sucks a tremendous amount of air because of the vacuum. If you don't include an appropriate mix of gas, you get that "wuuaaaah" sound and the car doesn't go like you want. Let off and the air fuel mixture balances out and you take off.

Kev

Why would I not experience it with the other ignition? Maybe because this one is stronger and requires more fuel? Thanks.

Could it be the fuel pump?

I wouldn't suspect the fuel pump yet. I took a second look at your timing, 28 degrees BTDC? That seems very aggressive. With the timing that far advanced, could it be that your centrifugal is throwing it too far upon full throttle?

Kev

I'm sorry, was thinking old school with points......
DUH!!!!!!

Kev

I still think you may have a balance problem between your timing and fuel mixture at full throttle.
Edit; So here's a thought. Try setting the timing at 10 degrees BTDC and see how she accelerates, then if you want, you can bump up in stages (3-5 degs) till you like the results.

Kev

Well got my HEI installed. Also put in a new set of AC Delco plugs gapped at .060. I'm experiencing a slight hesitation when I really put my foot into the pedal. I'm running a 1411 Edelbrock carb. I had the timing set at 30 degrees but was experiencing some pinging. This was before I added the new plugs. Reset the timing to 28 degrees added the new plugs. No pinging but have a slight hesitation. It's like when your driving along and then you floor it there is a "uuuutaaa" then she takes off. No big deal just thought I'd post and see if anyone has any ideas. Gonna mess around with it some more today. Maybe I'll reset the timing to 30 degrees now that I have the new plugs in it and see what happens. Seems to have really picked up the performance other than the hesitation. Thanks.

[/url]
(http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/36/36_2_1.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/36/36_2_25.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/36/36_2_68.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/36/36_8_14.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) [url="http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS"]
Maybe I overlooked it in your post but which car; engine and HEI are you working on? Your talking about 28-30 degrees timing, is that total, initial or what? The Edelbrock carb is that the one based on the old Carter AFB carb? I may be able to help if I have a better idea of the car and engine you are working on.

I'd say re-gap the plugs to between .045 and .050. my guess is that the .060 plug gap doesn't like the AFR. is the 1411 stock calibration or have you richened it up at all? if I remember right the 1411 was set to run a little leaner than the 1407... and the 1407 (stock cal.) runs about 14:1 AFR.

The car I'm running is my hearse with the 472. 28 degrees is the total timing. There is another thread that barge master suggested gapping the plugs at .060.

http://www.cadillacforums.com/forums/showthread.php?t=14525

Does anyone know what the factory timing was for the 500 with HEI? Should be the same for the 472. I believe the 472 never came with HEI therefor no factory timing for the 472 with HEI is availalable.

I don't know what the stock timing is, but I was googling around and found this page. I has a lot of basic info (which, turns out, I needed a refresher on) and also talks about replacing mechanical ignition with HEI. It may be of some help to you. :)

http://www.442.com/oldsfaq/ofign.htm (http://www.442.com/oldsfaq/ofign.htm#IGN%20PointsHEIIgnitionConversion)
Good luck!

Kev

More info;

Bog Control Question: I am the owner of a ’69 Mustang with a mildly built 289. When I rebuilt the engine, I added an Edelbrock 600-cfm Performer carb. When the car is stopped and I try to accelerate, the engine bogs for a split second. Some people tell me that this is just the way the pump in the carburetor is set up. Any help you can give me will be greatly appreciated.

Stephen Field

Locust, North Carolina

Answer: If you are not familiar with carburetors from Edelbrock (Dept. HR11, 2700 California St., Torrance, CA 91503, 310/781-2222), you should start by getting an Edelbrock owner’s manual that will at least show where all the parts are and what they do. Most bogs are caused by an excessive lean or rich condition or improper ignition timing. As odd as it may sound, half the problems blamed on carburetors stem from ignition timing. Generally speaking, shoot for 12 to 14 degrees initial and 32 to 36 degrees of total timing.

If you have already ruled out timing, check for air or fuel leaks around and inside the carburetor. Also, check the idle-feed restrictors; if they are clogged, an off-idle bog will occur. Next, tune the idle mixture using a vacuum gauge or the car’s tachometer. Tune each screw so that the engine produces the highest vacuum or rpm.

If all of that fails, move the pump-drive link to one of the holes closer to the carb body. That will increase the stroke length of the plunger and deliver more fuel during acceleration. Save that change for last, however, because it is too often used to cover a problem elsewhere in the carburetor or engine.

Edelbrock offers a tech line (310/781-2900) to help you trouble-shoot its carburetor or any of its other products.
Got it from;


http://www.hotrod.com/techfaq/41860/


Kev

I didn't have the problem with the points/condenser ignition so that leads me to believe that the carb is fine. I'm wondering if it's timing or maybe vac advance. The HEI dist. has an adjustable vac advance should I go with a different one. Also when you floor it you feel the hesitation and then it accelerates but if you back off the throttle just a bit, maybe a quater pedal, it feels like a power band kicks in and it really accelerates. Thanks for any help.
Sasquatch, if the engine was running ok before you installed the HEI (and you have checked all your vacuum connections for a leak) chances are timing is the problem.
28-30 degrees total timing is not enough in your ’69 472; 35-36 degrees total would be more like it IMHO. How are you determining your total timing? Is your balancer degreed or do you have the adhesive backed degreed timing tape attached to the balancer?
Ok the HEI from a ’75-’76 500 with a carburetor the initial timing is to be set at 6 degrees before top dead center. That spec is from a Chilton’s manual.

If you have an adjustable vacuum advance try setting it to 10-12 degrees. Set the initial timing to the 6 degrees BTDC as I stated above recheck for any vacuum leaks at the intake, fittings, and around the carb and then reconnect the vacuum advance line and drive it. If it cranks over hard when hot back a little initial timing out say drop it down to 4 degrees. If it turns over ok when hot and doesn’t ping under a load then add a little more initial timing say two degrees at a time, restart and drive keep experimenting 2 degrees at a time until it either cranks hard when warmed-up or it pings under a load. At that time take two degrees initial timing back out of the engine and the timing should be set for the fuel and conditions the engine is operating under. Your 472 has a 10 ½-1 compression ratio and was designed to operate on leaded fuel so on today’s unleaded fuel and at best maybe 93 octane your little jewel may want more total timing than today’s fuel will allow. The 500 the HEI came out of has an 8 ½-1 compression ratio.

BTW did you clean and lobe the centrifugal advance on the new distributor?

Yes I did and installed a curve kit. We originally had it set at 30 degrees total timing and she pinged and also experienced the hesitation. That was before I added the plugs. Went with the lightest springs in the curve kit. Maybe I should change those. How do I change the adjustable vac. advance? Thanks for the help. Going to get to it again on Monday at my buddy's garage so any info I can print and take with me is appreciated. When you remove the vac advance vac. line at the distributor you then hold your thumb over it and set the timing correct? We tried this and set it at 10 degrees and she ran terrible. I think my friend said that it was 45 degrees total timing at that point. So we backed it down to 28 since we started at 30. Haven't tried to go higher but that was my suggestion to him because of the "bog" I feel. Like it's not advancing enough? I have the port on the right side front of my 1411 Edelbrock carb split with a tee. One hose going to vac advance and the other to the tranny. When I remove the vac line from the dist. should I remove it at the carb and plug it there to set timing. What I'm asking is when I plug the vac line is this a true reading since there is another line tee'd and going to the tranny? I know we're close and like I said I will try all the suggestions on Monday.

Here's a pic of the Carb. and related ports.



http://images5.theimagehosting.com/Edelbrock1411.jpg

Yes I did and installed a curve kit. We originally had it set at 30 degrees total timing and she pinged and also experienced the hesitation. That was before I added the plugs. Went with the lightest springs in the curve kit. Maybe I should change those. How do I change the adjustable vac. advance? Thanks for the help. Going to get to it again on Monday at my buddy's garage so any info I can print and take with me is appreciated. When you remove the vac advance vac. line at the distributor you then hold your thumb over it and set the timing correct? We tried this and set it at 10 degrees and she ran terrible. I think my friend said that it was 45 degrees total timing at that point. So we backed it down to 28 since we started at 30. Haven't tried to go higher but that was my suggestion to him because of the "bog" I feel. Like it's not advancing enough? I have the port on the right side front of my 1411 Edelbrock carb split with a tee. One hose going to vac advance and the other to the tranny. When I remove the vac line from the dist. should I remove it at the carb and plug it there to set timing. What I'm asking is when I plug the vac line is this a true reading since there is another line tee'd and going to the tranny? I know we're close and like I said I will try all the suggestions on Monday.
What I would suggest doing first is replacing the light springs with the original springs that came with the HEI. Then disconnect and plug the vacuum line at the vacuum advance can. Next make sure the idle is normal 600 rpm or less (just trying to make sure there isn’t any centrifugal advance coming in to give a false reading on the timing) now adjust 6 degrees of initial timing into the engine. I think the timing marks on the timing tab are incremented at 5 degrees so just a tad above the middle mark should be close enough to 6 degrees and reinstall the vacuum advance line. Now take the car out and drive it. If these adjustments and changes help or fix the problem we know we are headed in the right direction and then we can try some fine tuning with the springs, timing changes and carburetor adjustments. I am just trying to get you back to the starting point where all was well with the engine but the HEI remains installed.
BTW you did install the new HEI with a new wire carrying full voltage not the old resistor wire?

Yes I did.

out of curiosity... i know that under the cap pretty muchall gm hei distributers are the same. but are everything else the same. like the gear on the bottom of the distributer? i have an hei for a chevy and i was wanting to drop in in my 425. would i have to swap the gears on the dostributers around?

out of curiosity... i know that under the cap pretty muchall gm hei distributers are the same. but are everything else the same. like the gear on the bottom of the distributer? i have an hei for a chevy and i was wanting to drop in in my 425. would i have to swap the gears on the dostributers around?
I doubt any of the dimensions on the two distributors are the same. I have never placed the two units side by side but the distance from the mounting flange down to the drive gear, drive gear diameter and the size and spacing of the journals on the lower body of the distributor may be different. The only two I know to be the same are the small and big block chevys. You could always place the two side by side and compare for differences.

Haymaker your post was dead on. The following is from my shop manual. I might add this is what I've done. No more bog but still a "slight" pinging at initial throttle up. When I bought the dist. the description said it was an adjustable vac. advance but in removing the cap to install the original wieghts I noticed the number AS-20 was stamped on the vac. advance. In another post a link was given on how to install the HEI and it stated this.

Tip#2: If you are experiencing part throttle pinging with the HEI, you probably have a 20 degree vacuum advance can. Most HEIs have a ridiculous amount of advance here, which is a detriment when you start experimenting for optimum timing. Pull the distributor cap and you will find a number stamped on the top of the support bracket near the can. This is the cans advance, it can be anything from 8 to 24 degrees. A 10 degree vacuum can is ideal. It is available from AC Delco Parts, or your dealership. Canadian AC Delco part number: D1370A

I've already called and ordered the new one and have removed the exsiting one. New one will be here tomorrow. I had retarder the timing from 5 degress (the middle notch) to 3 degress to try and get rid of the ping. As soon as I get the new vac. advance I'm going to set it back to 5 or 6 degress. Here is the shop manual version of how to set timing. Like I said before haymaker was right on. Thanks for all your help and suggestions and I'll post tomorrow after I install the new vac advance. I'm pretty sure we got her figured out. She runs real good now other than the slight ping. New advance and some good gas should make it right.


http://images5.theimagehosting.com/Timing1..jpg
http://images5.theimagehosting.com/Timing2..jpg

That’s great. I’m glad the engine responded so well. The old high-compression engines have a lot of trouble dealing with a bunch of timing advance on lower octane fuel. After changing to the 10-degree vacuum advance you may be able to run 10 degrees initial advance when burning 93-octane fuel, you just need to experiment with the timing adjustment to find what the engine likes. Keep us posted.

How does an adjustable vac. advance work? I went ahead and ordered the 10 degree can but still curious how the other is "adjusted".

hmm oh well that idea is out the wiindow then. i just wanted to put the chevy one in becasue the caddy hei needs rebuilt the advance stiks and stuff like that. and i drive it everyday so i wouldn't be able to do with out the caddy for a day.

well thanks anyway

How does an adjustable vac. advance work? I went ahead and ordered the 10 degree can but still curious how the other is "adjusted".
I don’t know what’s on the market today as per the adjustable vacuum advance and I have never owned or adjusted on one with my own greasy little fingers. Don’t hold me to it but the one I remember from an add was adjusted through the hole of the vacuum nipple using a small Allen wrench that adjusted a stop on the diaphragm to limit its movement.

hmm oh well that idea is out the wiindow then. i just wanted to put the chevy one in becasue the caddy hei needs rebuilt the advance stiks and stuff like that. and i drive it everyday so i wouldn't be able to do with out the caddy for a day.

well thanks anyway
Your old HEIs centrifugal advance weights and the deck area under the weights can be cleaned and greased with the distributor in the car. Most of the time this will free the sticking weights.

Alright here's where I'm at. Picked up the 10 degree vac. advance can yesterday. Got home from the dentist about and hour ago and got under the hood. Installed the new can. Dug out my timing light and started experimenting with different timing anywhere from 5 to 10 degrees. 5 was OK no more ping and good acceleration but the engine wasn't quite "smooth" when idling. So slowly, in increments of 2 degrees began playing with it. Finally around 9 degrees seems to be the best point. Super fast acceleration no ping. Although when stepping into it and letting it run through the gears (hauling butt at this point) if you abruptly remove your foot from the pedal the car decelerates and then backfires once pretty good. Now it did this even with the old dist. Don't know what the fix is or if there is one. Keep in mind this is a hearse and I'm not constantly into the pedal. I would always back off gradually before and never a backfire. Same thing now. Only happens if at high RPM's and winding it out I just pull my foot off the accelerator. Could this still be a timing issue? Timing chain worn maybe? I can live with it by just gradually coming off the gas. How often do you pull your foot completely from the pedal anyways. I think I'm getting a little picky but thought I'd share. Still need to try some better gas. Gonna go to the station here after I grab a bite to eat and put the good stuff in it. The HEI does make a tremendous amount of difference. For a 4300 lb. car with a casket in the back this sucker will get up and move. Thanks for all the help. Time to eat and then go driving. I'll let ya know how the better gas helps out.

http://smileys.smileycentral.com/cat/4/4_1_218.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/4/4_1_112.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/15/15_8_200v.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS)

I have a 69 472 going into a 74 which had a 472 which is knocking. The 69 had points, and the 74 has HEI. What do I need to do to use the HEI on the 69 engine?

Just install it and set the timing here's a link.
http://www.oldengine.org/unfaq/hei.htm

I am moving my '74 HEI over to a '69 engine. Both engines are 472's. It appears that with a stock intake manifold i may need a different spark plug gap.
Textbook says 0.035 vs the notes above of 0.060 inches, and timming of around 35 Degrees BTDC. What is the optimum setting?:banghead:

I went with .060 gap and 10 degrees intiall timing. Which I believe is the first notch on the front cover.

if you abruptly remove your foot from the pedal the car decelerates and then backfires once pretty good. Now it did this even with the old dist. Don't know what the fix is or if there is one. Keep in mind this is a hearse and I'm not constantly into the pedal. I would always back off gradually before and never a backfire. Same thing now. Only happens if at high RPM's and winding it out I just pull my foot off the accelerator. Could this still be a timing issue? Timing chain worn maybe? I can live with it by just gradually coming off the gas. How often do you pull your foot completely from the pedal anyways.

http://smileys.smileycentral.com/cat/4/4_1_218.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/4/4_1_112.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS) http://smileys.smileycentral.com/cat/15/15_8_200v.gif (http://www.smileycentral.com/?partner=ZSzeb001_ZNxdm414AHUS)

Are you still running the A.I.R. pump? If so, there is a manifold vacuum operated valve connected to the pump's outlet somewhere. If this valve fails or isn't hooked directly to manifold vacuum, the engine will backfire at deceleration.