TOHC -

Yep - you are right. Not 10, only half that. I was thinking OHC for a second there, where the belt tension is set on the retard side.

My bad

Q

You guys are great. I'm glad I found this site, and people on the forum who have good knowledge and are willing to share it. I'm pretty good mechanically, but don't know Pontiacs (yet), or any GM, for that matter. I still can't get over the complex methods used to do the simplest things...a solenoid on the throttle lever?!

I swapped out the springs on the mechanical advance to the mid-tension Accel springs. I don't know where the curve starts yet. I also started adding vacuum advance in the adjustable canister, right now it's at a modest 4 degrees which is just enough to notice. I will disconnect it when dialing in the initial and mechanical, and will then start adding it back in. Does anyone have a guess at how much I will want to add back in? The stock can was 20 degrees, and I think that was too much. I would have liked to road test, but we had rain most of the day.

I've ordered the parts and I'll be installing in the next few days. I will post when done and let you know the results. Since I have to move or remove a bunch of parts anyhow, I will be changing all the belts and hoses at the same time. Is it necessary to remove the radiator to do the timing chain swap?

I know this sounds stupid but if the car has been sitting for a really long time.
You may have a plugged muffler.
Sounds stupid but it happened to a guy here in town.
He bought a survivor 68'catalina conv. that's been sitting for years and the car had no pep and sure enough the muffler was plugged.

Firstgenfirebird.org forum members, you have my thanks. I've owned my Firebird for a year now, and have been enjoying it while learning about it, and am just now getting serious about putting in the work the old car needs. I've changed my screen name to Yellowbird and have posted a little info on my car at Yellowbird\'s Yellow Bird

I will post a follow-up on the results of the timing set swap early next week. Once again, thanks to one and all.

Once you have the power (mechanical) side of the advance set up, you get to start on the economy (vacuum) side. Make sure you're not getting any vacuum advance while doing the mechanical side though. I'd disconnect the vacuum line just to be sure (plug the line).
The answer to how much vacuum advance is as much as it can stand without detonation. You should have a little notched piece that limits the amount of timing your canister can give you. I'd start with about 14 degrees of advance and adjust the canister so that you get just a trace of detonation as you increase the throttle reasonably quickly (poked but not floored). A quick note, your engine will tolerate light detonation with light throttle for a while (in terms of seconds) but be careful, don't overdo it. The trace of detonation should be quite short (5 - 10 pings) before the canister adjusts the timing to the new throttle setting and load. Then adjust the canister back just enough to eliminate the transitional detonation, and whatever safety margin you feel comfortable with.
As far as ported or manifold vacuum source, start with ported vacuum but try them both to see which the car likes.
It is quite possible to have the carb and distributor tuned so that the engine responds almost as good as with fuel injection. I think there are posts already here that cover tuning the carb, so once you have the chain and distributor done, have a look or just ask.
One final note, I played with my advance curve at the dragstrip and managed to slow down by about .3 seconds by putting in too fast a curve (no detonation!). The best way of determining what your combo needs is to lock the distributor so it has no mechanical advance and time your acceleration in 500 rpm stages, i.e., from 2000 to 2500, 2500 to 3000, etc. to 4000 rpm in your first gear while adjusting the timing to get the best accel (quickest time) in that rpm range (no pinging allowed). You then graph the timing points at the average rpm (2000 to 2500 is an average of 2250 rpm), get your mechanical advance curve to match your graphed curve and you're set! And do your tuning on a hot day.

Doug, I've seen that muffler problem before. I forgot all about it, but I once had a 318 Satellite that ran just fine when I put it in the field, but six months later when I went to move it I couldn't get it started. I looked under the hood and found the mice had done their usual nesting in the air cleaner, and cleaned it out and figured everything would be fine. Sure enough, the car started, ran awhile...and died when I put it in gear. Tried twice more before the battery flattened out. Plugged it into the charger overnight, and the next day went out to try again. Got the engine started and let it idle for about 15 minutes. I started getting gray smoke out of the tailpipe, and when I shut off the engine the smoke kept going. Turns out another family of mice had gone up the tailpipe and nested in the muffler. I used a coathanger to fish out as much crud as I could, started the engine, and burned out the rest. It really stunk for a while, but no permanent harm was done.

Put a piece of cardboard on your rad to keep from rubbing the fins and scraping your elbows. Make real sure that you have the marks on the gears lined up (hard to see in the car). I use a ruler.

Is the TVS switch provided to switch between ported and manifold vacuum sources for the vacuum advance?

Well, so far I've found more trouble than I was looking for. I'm dealing with a broken bolt right now, and I'm kind of glad because when I pulled the intake I found the gaskets were leaking between cylinders (intake 2 & 4 and intake 6 & 8). The head casting looks like it has a mold seam across the middle of the ports, and the irregularity in the casting is just enough to prevent a good tight seal of the gasket. I hope the new gaskets take care of this.

On a good note, the timing chain replacement should help as when the chain was rotated tight, the loose side had about 1" deflection.

I am now taking the time to fully detail out all the removed pieces, and deep clean the crossmembers and everything else that is now exposed.

It's amazing what you turn up when you start to dig into these old Birds ...

The gasket surface should not be affected by the casting seam, but if you need to clean it up, a deburring stone would be a good pace to start. Just make sure you catch anything that might try to make its way into the port.

Q

Thanks. I have a good selection of mill files, I'm not sure about a deburring stone. I will have to check my inherited tool and die box.

I posted a new thread about the Q-Jet well plugs...how to epoxy them as recommended. There appears to be leakage on the base gasket from several spots. I don't know Q-Jets, having played mostly with Carter T-Quad and Holley 2 bbl.

HUGE difference in the chain tension with the new chain installed! No real slack at all, just enough to keep it from binding. I actually had to keep the cam and crank gears moving in evenly to install. Taking it off I was able to pull the cam gear nearly off before moving the crank gear.

Off to the EDM shop...

The well plugs (4 or 6 of them - I'm forgetting at the moment) should be thoroughly cleaned with lacquer thinner, then epoxied with a fuel resistant epoxy. It's done from the bottom of the main body. Simple and very effective.

Q

Manifold is back, good job by the EDM guys at Nitro EDM . They have an EDM mounted to a Bridgeport so they could accommodate the intake on end. One of the guys at the shop has a '67 coupe, and they went out of their way to help me, and gave me a referral to a local source for parts that I would NEVER have encountered on my trips around town. "Next Generation" is the name of the company, the shop is called "Pontiac Ranch", and it's not far off the main road but somewhere you'd never drive without a reason. They have about a dozen STUNNING Pontiacs including a '69 TA, a couple of '68 and '69 coupes, and much more, plus more used Pontiac parts than I've ever seen in one place . As luck would have it, just inside the door he had the correct chrome top air cleaner I've been looking for, and he fabricates exhaust brackets to original specs. I walked out with my wallet a little lighter but with a load of parts I needed, including the timing cover to manifold bolt to replace the one I broke.

Everything is painted and reassembly has started. Lifter cover and gaskets, intake and gaskets, timing cover and gaskets, thermostat housing and gaskets are tonight's goals. Carb will go on tomorrow, after I replace the (previously unnoticed) cracked power brake vacuum pipe . The PCV valve also fails the check valve function test, so that will be going too. The auto parts store is beginning to expect my daily phone call :rolleyes: .

Oh well, back to the garage, my new home...

Guys, I just read through this whole thread and I didn't see any mention of the kickdown switch...is there one and is it working properly? I know this won't make any difference on initial tire spinning torque but it still makes a big difference on the overall 0-40mph performance.

I to have a '69 400/400 and I've fully ported the heads and have had the original carb fully rebuilt and dialed in professionally but my car still doesn't have tire spinning power. Through numerous conversations with the list the only thing I have left to check is the torque converter. I'm not sure what's in mine but I'm eventually going to get a new one with a bit of stall conversion.

With my '69 400, #48 heads, "041" cam and a 2.56 one-legger, I got about 5-10 feet of rubber at 3200 feet altitude with a stall speed of about 1500 rpm. By hitting the high-stall switch, I went to about 2500 rpm and 50 feet! Makes a big difference!

I burned a lot of rubber on the street and on the strip a generation ago. Now I just want to put the power to the pavement. With 2.78:1 posi I won't get neck-snapping performance, but I'd like the car to get up and go.

Only a few more parts to go...

I still haven't learned much about Q-Jets...where and what is a kickdown switch? I've found enough things disabled or miswired that anything is possible...

A kickdown switch is what tells your TH400 transmission that you have your foot to the floor.
Do a search for carb jetting or look up the thread "Quadrajet Question".

The kickdown switch is the switch that is mechanically activated (usually by your throttle linkage on the carb or by the pedal inside the car like mine is setup) and tells your trans to drop down into passing gear when you are on the highway. If you go WOT from a dead stop it will change the RPM that your tranny shifts at, making it much more aggressive. Without it you won't get up to speed very fast.

There are some good pictures here on Jim's site: http://www.geocities.com/jims68fb/DownshiftBoot.html

The 'bird is alive! It survived my ministrations and started and ran once the fuel pump and carb were refilled. Rotating the distributor produces consistent changes in timing. Unless I equip the 'bird with pontoons I can't do a road test, but in the garage the sound is awesome.

I found and repaired leaks I didn't know I had (intake passages were crossing over, oil galleries were leaking into exhaust port, lifter pan had little gasket remaining, and front oil pan gasket was dust. The known leak at the front timing cover was a timing cover front seal that didn't have any rubber left.) I should be saving on my oil budget now. I located and restored an original air cleaner, degreased and painted everything with the correct colors, replaced the heater and radiator hoses and thermostat (also not working) and fixed the original timing chain issue.

Tomorrow the testing and tuning begins in earnest. I ran the engine only long enough to fill the cooling system completely and to set the initial timing back to 9 degrees.

The carb had epoxy on the well plugs already. It was rebuilt in 1999; it is autographed Barry. It works, and doesn't leak. The carb has a kickdown switch, but it appears to be improperly installed and is missing the boot. I will try to figure it out tomorrow.

With the change in advance springs, the timing advances about 7 degrees by 1200 rpm. While the balancer was off, I added a 30 degree mark for tuning ease. I will continue tuning to try to achieve the right settings. Too bad there isn't a way to read the timing while driving.

I found a great article on the net about rebuilding and tuning quadrajets. It's so good I don't want to share it!

Just kidding ... I have it at work ... I will post as soon as I am in my office.

Q

Quenton, I am looking forward to reading about the Q-Jet. It's obviously a reliable design, with millions built over the decades. For my purposes the performance should be sufficient.

The car is still not at its best, but there is definitely an improvement. Off the line there is still not a whole lot, but throttle response is crisp and immediate, the secondaries kick in, the kickdown switch does function (I'm not sure if there are any adjustments, but when I floor it, it's there). At 30 mph plus it really moves out when I mash the pedal. I will have to play with the timing a bit more. Initial timing is at 9 BTDC and that is the optimal setting for starting and idle. So I will need to play with the springs and weights to find the optimal configuration for acceleration, and with the vacuum advance for economy.

Most of the diagrams for the TVS show the 1968 5 lead, or carbs with different port layouts. I wish I had the diagnostic manual for 1969. I'm not sure which of the vacuum ports on the carb should be used for the ported vacuum and which for the manifold vacuum.

I would never have attempted this without the support from the members of this forum. My thanks go out to you.

TOHCan, you mentioned that the distributor end clearance should be .010-.015. When I installed the Pertronix, I checked the end clearance and it was .052". I thought this might be an issue, and talked to the local shop guy, who said that if it was a Chevy it would be bad, but because of the counterclockwise rotation of a Pontiac V-8 the gear pulls the shaft down on the cam. I'd like advice from this Pontiac-experienced group on whether or not I should pull my distributor and shim it. I couldn't even find shims for it at the NAPA dealer.

I'll be posting new pictures of the detailed engine on my site. And my garage floor doesn't have any more spots!

Nice looking car Yellowbird!

Thanks, Bjorn! Your car is very sharp. Mine was repainted c. 1981 and is showing its age, but to repaint again will require paint removal first, so I'll live with it. Zaino does wonders!

If it ever stops raining long enough to wash it, I'll post a picture in the show.

Vikki

The end play in the distributor allows the shaft to move up and down while the engine is running. This lets the timing change because the gears are cut on a slant, so as the shaft moves, it turns slightly. You can see the fluctuation in the timing when you check it with a timing light. You can try an experiment. Check it before and after you shim it to the correct end play.

The distributor shaft shim washers didn't come with your Pertronics installation kit? Pertronics provided two in my kit. You might be able to get a .032 thick stainless steel washer from Lowes that will work. They have a better fastener selection than Home Depot. Or have pertronics mail you some.

Even if the Pontiac distributor rotates in such a manner that it pulls down I still think you should get it right the first time. If you don't fix the .052 end play to within the pertronics limit, you will always wonder if its causing your car to run worse. I've been down this road...drove it for a while with an end play of about .06...then pulled it back out to shim it right. I havn't had a chance to drive it yet with my new end play tolerance.

Thanks Vikki, I also use Zaino...(the best , in my book)...my car was re-painted 2.5 yrs ago in two stages,first front fenders( one was a different shade than the other..), hood (I replaced it w another used , blue)and cowl....4 weeks later had doors, rear fenders (had some patch work), tail and trunk done...
found out that most painters are hesitant to paint an entire "classic": car, I heard "owners are very demanding", but not so hesitant to do 'repairs', so I 'repaired' mine...lol
paint matches fine...just made sure I got enough paint the first time , so it was from the same 'batch'....

I have the Pertronics Lobe Sensor, I don't know if it makes a difference as it senses the points lobes directly. The unit does not give any specifications other than maximum amperage based on coil voltage and resistance. I found the literature to be less than thorough, though the product works great.

I will try to find a shim set. I believe Accel / Mr. Gasket sell them. The shims should be common for all Delco non-HEI distributors, correct?

Vikki

A full new exhaust system, manifolds back, did not increase the apparent power. The thermostat, timing set, and Turbo Blue 110 definitely did. The fuel economy is also up to around 16 mpg if I keep my foot out of it.

An exhaust leak that I hoped would be solved during the exhaust replacement turns out to be a leak on the passenger side between the manifold and head. Is this a common problem, and if so are there any on-car fixes? I have A/C and can't even SEE the manifold from the top.

Also, from underneath, the driveline does not appear to be "square". This is the first time I had the car on a hoist. The axle appears perpendicular to the axis of the car, but the driveshaft appears to cant off about 2 degrees to the driver's side of center by the time it reaches the trans tailpiece. Comments?

The engine is offset towad the passenger side by 1-1/2", not toward the driver's side. The pinion shaft is offset toward the driver's side, amking me think the angle should be toward the passenger side rather than the driver's side. I've yet to have my car on a lift.

You can replace the exhaust manifold gaskets with copper gaskets and the exhaust leak problem should go away. You'll probably have to unbolt the compressor to get to the manifold, but you shouldn't need to undo the plumbing.

Q

I should have just replaced that gasket over the winter when the fender was off to do the blower motor. With my luck a bolt or stud will break; I might wait until fall. The heads could probably do with a rework too...