Find answers to Frequently Asked Questions for First Generation Firebirds that have been asked and answered on FGF. Special thanks needs to be given to all the FGF members who took the time to respond to other member's questions.
Engine - Ignition System
Q: Starting Problem (Bypass Solenoid)
Tip for bypassing the solenoid if will not start but still have power.
A: I was stranded last night for 3 hours because my car wouldn’t start. I had power so I figured its the solenoid. Finally a good old boy stopped and showed me how to bypass the solenoid with a screwdriver. All he did was lay it across the positive battery cable post on the solenoid terminal post and the closest terminal (drivers side)and I cranked it at the same time and it started right up! This takes 2 people as one is under the car and the other inside. I drove home no problem and right away jacked the car up and dropped the starter.
A: You don’t need 2 people, just turn the ignition to the run position and get under there with your screwdriver it will start.
Content last modified: January 16, 2014 at 2:25 pm
Q: Starting Problem
What could cause a car to not start when turning the key results in absolutely nothing. No clicks, nothing. Charging system works, battery has juice ( at least to operate lights, etc.). I went out over the weekend and it started fine. Drove it, stopped, and when I tried to start it again, nothing. Got a jump and it started. Since then, it started every time just fine.
A: I had a starting problem that was really intermittent at one time. Turns out the nuetral safety switch (term?) on the transmission (67 400 w/ TH400) was not hooked up correctly or loose, and I would have to shift into park, then re-shift into park to get it to start. Same as you, no clicks or anything, but the rest of the electricals worked fine.
A: For that kind of no-start, it may be a “dead” spot on the starter, usually caused by a dirty commutator/brush contact. Next time, give the starter housing a tap with a hammer while somebody turns the key – if it starts then, replace the starter. Another case may be a loose cable connection at battery or starter, even though it feels tight, it may need to be a bit more secure. If a dead spot, you just got lucky while the jumper cables were connected.
Content last modified: January 16, 2014 at 2:26 pm
Q: Determining Correct Plug Gap
For those of you who made the conversion from the stock heads to a set of 6x’s – What plug gap do you use now?? Since GM went to the HEI when these heads were used, I would guess that the plug gap should be .055 – .060″[?].
A: You gap the plugs to correspond with the ignition you are using, not the head castings. If were running a points distributor, you gap the plugs according to the typical points gap of .040. If HEI, use the HEI .055 gap.
Content last modified: January 16, 2014 at 2:26 pm
Q: Electronic Ignition (HEI)
I’m open for advice on this one. I’m considering changing over my 69 Firebird 350 to Electronic Ignition. The car is used mostly for crusin with no strip action. Think this is a good idea? Where is a good place to get the parts needed for conversion?
A: The cheapest by far is to convert it to HEI. You can pick one of these up at a salvage yard for about $10. If you decide to do this, you’ll need to run a 12 volt wire to the distributer (the existing wire is a resistor type and will only supply about 6-8 volts).
One trick I did so I could change it back later (for show purposes) is I traced the wire back to the firewall connecting block and soldered a #16 wire to the same terminal (This parallel the two wires. I then taped the new wire to the harness and taped up the old wire there it comes out of the harness. Looks clean and there’s no hacking involved.
Another would be to buy a kit to convert your points to electronic breakerless ignition. Check the ads in the back of Car Craft, Kit Car, etc. or contact you local speed shop.
A: I got mine of a 400 firebird in the junk yard. It bolted right on. Make sure you get the little wire clip that connects to the distributor or you will be going back. Also check to make sure you do not have a resistor wire going to it. The + side of the distributor should connect to +12 volts that goes on and off with the ignition key.
A: The fit of the HEI is close but it worked on both my 350 and 400 (same block). You may have to rotate the oil pump keyway (stick a long common screwdriver into the distributor hole) to get the HEI in the approximate location as you’ll only have about 20 degrees of rotation. If it still doesn’t fit, check to make sure the transmission and motor mounts are in the correct location. The other problem could be position of the sub-frame relative to the body. If everything is pushed back for tight body seams you could run into clearance problems.
A: The GM HEI will NOT fit. The firewall is too close. You can install the distributer, but the cap will not go on. Another option is the Mallory Unilite. I installed this on my 69. So far I like it. The cap is red, other than that it looks stock, and you have a choice of vacuum or mechanical advance. Most of the Performance catalogs list them. Good luck!
A: The HEIs are virtually maintenance free. Stock and performance parts are cheep and easy to find. They outperform stock breaker point distributors in all areas. Unless you are running some serious compression ratios or are going to be drag racing and consistently revving your motor above 7500 RPM, the HEI will serve all your spark needs.
A: The guy that rebuilt the 400 in my 1967 replaced the stock distributor with an HEI unit. No modification to the firewall was necessary, but there certainly isn’t the room around the distributor like there was with the original unit. I’m into originality and as a rule don’t think that aftermarket parts are up to the engineering standards or quality of genuine GM parts. (Please no flames!) So the HEI distributor is a nice compromise.
I’ve been driving 1967 400 firebirds since 1979 and I have to tell you the performance with the HEI is much better than the breaker/points unit. The advantages of using the HEI unit that I’ve seen are: the spark plugs don’t foul out anymore, the car cold starts much easier, and I’m not forever messing with dwell settings. My ignition system used to always be a concern, but it is not anymore.
The only disadvantage I see is for us purists. Like I said before, it’s hard to get use to seeing that big distributor in the back of the engine where a little on used to be. If you plan on driving the car a lot, do it. If you plan on showing the car, don’t.
A: I’ve been very happy with the HEI system in my 1968 Firebird 400. The maintenence can’t be easier, just replace the cap and distributor every once in a while, and do a recurve every once in a while. No need to have to deal with gapping the points every other month, or having to adjust the dwell. You can also run a gap of .060.
I can’t be happier with the HEI setup in my ‘bird. The only disadvantage is that GM HEI distributors are known to drop a lot of current above 4600 rpm so if you’re running at high revs, you may want to get an aftermarket HEI style distributor.
A: put in an acell electronic. they are trouble free. mine is 5 years old and never been touched!! it fits the firewall and 14″ air cleaner great.
Content last modified: January 16, 2014 at 2:27 pm
Q: Electronic Ignition (HEI): Revisited
i have a 1967 firebird with a 326ci it has a 4 bbl carter carb and it had factory air but i took it out cause it didn’t work at all and had no hope off fixing. anyway i called a couple of places cause i wanted to drop an electronic distributor in it, but a couple of places said it couldn’t be done, that i would have to put an ignitor in my old distributor to convert it, is this true if not what other stock gm electric distributors would work in it (off what other cars?)
A: Concerning the electonic distributor issue, you have many options to choose from. First, just about any Pontiac late model HEI distrubotor will work in your engine. My 400 currently has an HEI distrubtor from a 1977 TA. Works great. The second option is a points replacement kit. This replaces the only points and condensor in your current distributor with and electonic unit. Both Mallory and Accel offer these units. Your third option is to replace the entire distributor with an after market electronic distributor unit. Once again, Mallory and Accel have excellent units for the Pontiac motors.
Content last modified: January 16, 2014 at 2:28 pm
Q: HEI Distributor (Revisited Again)
I’m thinking of getting a HEI-distributor for my 1968 bird. But I wonder, will the larger distributor require body modification? I’ve heard so much good about the HEI so I’d like to give it a try in order to save some gas. (Could you imagine living in a country where you have to pay almost 4 dollars/gallon??) And if body mods will be needed and before I go crazy with my big sturdy hammer, whats behind the firewall? …anything fragile?
A: I swapped to HEI on both my 1967 and 1969 Firebirds. On the 1969 I had to pound the firewall in about 1/4″ to 1/2″ to make room for the Accel Supercoil I added to the HEI. On the 1967 no modifications were required. The best way to modify the firewall is to use a big splitting mall or big hammer when the engine is out of the car. If you’re careful how you do this it’s hardly noticable after you have installed the HEI. Good Luck,
A: If your body bushings and subframe position is all good there should be just enough room for the HEI. Before you go pounding on the firewall, check the bushings.
A: I have a 1968 400 and HEI fit with no modification…
A: I installed an HEI in my Bonneville. I just bought a new unit from a local shop that had a distributor machine. They set it up and I installed it. Simple.
My Firebird was missing the original dist. and had an Accel dual point completely worn out POS. But, there was not enough room for the cap to clear the firewall on my bird. Before you invest in an HEI, make sure you have the room! Some birds do some don’t (borrow one, drop it in, then install the cap). You can take a block of wood and a hammer to make room on the firewall too. I didn’t like this idea.
If the HEI fits, it’s pretty straight forward to install. You will need to re-gap the plugs (.045 ?), and new thicker wires are a good idea too. In fact, I think you will need them to attach to the new style cap.
Grease: yeah you need to grease ’em up. A new unit comes with it. If you go the used route, just get some di-electric grease. The HEI units have a coil built into them.
Also, and I don’t remember why, but stay away from the Accel clone (anyone know why I’m saying this?) Get the genuine article. It was worth a few extra bucks to me to buy the new unit from GM. By the time you rebuild a used unit with the usual components they need, you have a lot of your resources invested. New stuff is so clean too.
For my Firebird I settled for the Mallory Uni-light with mechanical advance for added simplicity ( I have a 4 speed). I think you have more options to trick these out than the HEI. Besides, that red cap is prettier (here come the flames).
Content last modified: January 16, 2014 at 2:29 pm
Q: HEI Upgrade
Thanks for all the input. What I’ve read is that the increased efficiency of electronic ignition will enable the end gases to burn normally, rather than contribute to knock. It seems to me that to reduce knock, I’d have to replace the coil and wires, and regap the plugs, along with replacing the points and/or the whole distributor. Can anyone confirm that knock was reduced/eliminated by installing HEI, or am I setting myself up for disappointment?
A: Installing an HEI is unlikely to reduce/eliminate a knock problem other than by coincedence.The advance curve(s) are what will make the difference.If the HEI you install happens to have a minimal amount of centrifugal advance and/or a vacuum advance unit with a stiffer spring than the original unit then knocking will be reduced. Also the vacuum advance units have differing amounts (in degrees) of advance.
If your only complaint with your points distributor is the knocking problem then you may want to check its advance operation and correct/modify as required.It is not difficult to do but requires some amount of know-how and a few tools such as a accurate tachometer and a timing light (dial-back type) and a dwell meter.For starters make sure the dwell is set correctly and the initial timing is set to spec.Then with the engine warm increase the engine speed while watching the timing mark,when it stops moving as the engine speed increases further dial back the timing light (obviously you will find it easier if a friend works the throttle while you watch and manipulate the timing light) until the mark lines up with the TDC mark on the timing cover.Now read the dial (or display if you are using a digital) on the timing light,this is your TOTAL mechanical (or centrifugal) advance.It should be around 30-36 degrees.
At this point (if the numbers are O.K.) you might try disconnecting (and plugging) the vacuum advance hose,then drive the car and see if the pinging is gone.Be sure and try both hard full blast runs as well as light throttle/lower rpm/higher load situations.If the car works O.K. then you may concentrate your efforts on the vacuum advance.There are a number of ways to go about this including:replace with different unit with less advance and/or stiffer spring,replace with adjustable aftermarket unit or modify your existing unit.By the way,most units have the amount (in degrees) of advance stamped on them (usually 10,15, or 20).You could of course,leave it disconnected but fuel economy and throttle response will suffer.Sorry I’ve been so long-winded about this, of course there are other things to consider like engine temp,combustion chamber deposits,fuel/air mixture.I hope this helps,feel free to email me privately if you have any questions.I don’t have all the answers but I may be able to help.
Content last modified: January 16, 2014 at 2:30 pm
Q: HEI Fit
I am about to throw the engine back into my 1969 bird and thought I’d go ahead and replace the distributor with an HEI unit. As the clearance is so tight to the firewall will any poncho distributor fit or do I have to get the “small cap” one?
A: I’m not aware of any small cap versions that fit a Pontiac block. Installing an HEI in a Firebird is a little of a crap-shoot. Some owners report that they had to “clearance” there firewall with a BFH before the HEI would fit. Others, including myself (in a previous coupe), didn’t have any problems.
The difference may be in the condition of the bushings and sub-frame. When I pulled the sub-frame out of my convertible, the mounting pads that are welded to the sub-frame (which bolts to the base of the firewall), had a hole about as big as the bushing itself. I have serious reservations that an HEI on this car without extensive repair or modifications.
Content last modified: January 16, 2014 at 2:31 pm
Content last modified: March 16, 2017 at 9:08 am