My 1969 GS400

Today was a great Buick day!

I took the GS400 to work, then went to Walmart in Largo, then met some of the local Buick homies at Cracker Barrel in south Clearwater, then home. All together put about 100-miles on it today. It did great! I need to work out the really rich idle situation. That's starting to bother me a bit. I may also have to revisit the alignment. Seems to get a bit sketchy around 70-75 mph.

Here it is at Walmart...

 

Well this morning, the GS400 was officially registered in the State of Florida. Everything went smoothly transferring the Montana title/tag over to Florida. It now has a shiny new blue Antique plate! I had to drive it up there so they could do the required VIN verification. Ran great, too!

 

Super cool car and great build thread Rich! Hope to see it next year at the Nationals!

 

Thanks Jacob, we'll see what I can do next year

 

It's been a hot minute since I've update this. I've been posting most of what I've been doing to the car in the "What Did You Do To Your Buick Today" thread.

Up until a couple of weeks ago, I hadn't done much to it, except drive it when I can. I started to notice that it seemed to be having some vacuum issues at idle. It was idling excessively rich, and at times the power brakes didn't want to hold the car at a stop for very long. The idle was really not great, and there was very little vacuum at the manifold port on the carb. I had a brand new Performer manifold that I ordered in 2021 and got a year later. The one I put on the car a couple years ago had a notch cut between the right and left sides of the carb pad, on the secondary portion. My theory was that this was causing the problem. I ordered a new intake gasket, carb to manifold gasket, and thermostat gasket and tore it apart.

When I pulled the old Edelbrock manifold, I found the issue. You could see on the intake gasket where it did not seal really well and was sucking oil into the ports from the valley. This time I put High Tack gasket sealer around the ports on the gasket, before I put it on. Of course, that combined with the big bead of Ultra Black RTV on top of the China walls. Also, since the manifold was brand new with no coating on it, I went ahead and busted out the red Duplicolor engine paint and painted it. I also threw a new fuel filter, a new set of NGK plugs and an oil change at it.

When I buttoned it all up last night, it ran great for a while, with awesome manifold vacuum and a much cleaner and smoother idle. On the test drive I had an issue with the 400-430 carb, where it it acts like the needle is stuck wide open from the seat and flooding the motor with fuel. I barely made it home and into the garage (between stalls and flooded type restarts, about 3 to 4 of them). Tonight I got the eBay 350 carb out and tossed it on there and retorqued the manifold bolts. After some operator induced error, and a very brief tuning session, I'm happy to say it idles, runs, and drives great! No new fluid leaks either!

Start with carb off:


Done:

 

Well, when I said to someone a couple months ago that I hadn't had to do anything to the GS400, except put gas in it and drive it, I may have jinxed myself. Right before I left for BG it developed a miss from idle to about 1500 RPM, only after it was fully up to temperature. After 1500 RPM it was fine. It all started with an overly aggressive throttle input when leaving the salon (resulting in just a bit of tire spin and smoke). After that incident, the car would run great until it got fully up to temperature, then the miss would start again. I've been putting it off trying to get my truck together (91 Chevy).

Today was the day. Read some things on the Holley forums that lead me to believe that something was causing the MSD 6AL to overheat, based on a similar issue. The Holley response was that is was either a bad box connection at the battery or an issue with the coil. Armed with this information, the first thing I did was check the positive and negative connections at the battery. They were mint. Then I pulled the distributor cap and inspected all the contacts and the wires to the points and ground. Cap and rotor tip had some corrosion which I cleaned up, and everything else looked great.

Moving over to the coil, I checked the connections and noticed that the heater hose was right up against it. Tested the coil. Per the Holley tech's post, the Blaster 2 should be .7 ohms on the primary and 4.7K ohms on the secondary. Cold, my coil is 2 ohms primary and 5.2 ohms secondary. Way over the 10% +/- spec on the primary. When I pulled the coil wire to check the secondary, I found 2 small spits in it that went through to the inner part of the wire. These would be right where it rested up against the air cleaner bracket. So, I put a piece of fuel line over the area with the splits, moved the coil down an inch more in the bracket, and put a piece of thermal insulation covering over the heater hose, near the coil. I took it for a test drive on the same route as the last time, and no miss at operating temperature. I was going to keep driving for a while, to see if it started missing again, but there is a gnarly looking storm moving in, so I went back to the garage. Tested the coil again hot (ouch) and it was 3.1 ohms on the primary and 6.2K ohms on the secondary. Still seemed to run fine though.

Here is the plan... I'm going to replace the coil and coil wire. Will order some new ones today. I'm also going to order the right size high temp sleeve to put over the heater hose, where it goes by the coil, in hopes that it will extend the coil life.



After I get this wrapped up, it's on the the left front lower control arm to see what is making all the noise down there.

 

Personally I don't think that coolant hose is an issue. Although it gets "hot" it's not really hot enough to hurt the wire IMO.

 

I thought the same thing at first. However, my concern was with the coil. Previously the hose was resting right up against the top of it. Years ago I had a 2002 Mustang GT with a 4.6 in it. It was crapping out the #8 coil (coil on plug) every week at one time. It went back to Ford dealers 3 or 4 times for this same problem under warranty. Each time they put another coil and spark plug in it and called it fixed. Finally I took a good look at it and found the heater hose and clamp were resting right on top of of that coil. Got some high temp insulation, wrapped that section of hose with it. Let that coil cool off and never had an issue again. Not saying that contributed to the short life of this coil, but I'm going to do everything I can think of to keep it as cool as possible.

I also lowered the coil in the bracket a little bit to give it more clearance.

 

So I ended up going back out after the storm passed. Put the car up on ramps to see if I could figure out where all the noises in the front end was coming from. First thing I found was that I must have been really distracted when I was putting the right sway bar end link together. Fixed that and tightened up both end links. That took care of the jingling noise. The rest of the racket seems to be coming from the left lower ball joint. A few years ago, when I was rushing to get the car ready to go to the Nationals, I bought some inexpensive lower control arms off of eBay, to replace the badly beat up and butchered ones that came with the car. I had heard that the ball joints in those eBay arms weren't the best quality. I have a couple of new Moog ball joints and bushings that I bought back then. I'll probably try to put one of those in there this week. If they won't work in the aftermarket control arms, I do have a decent pair of stock ones that I bought from Dave a couple years ago, too. They also need new ball joints and bushings.

 

Make sure you check those control arms where the ball joints are pressed in. Some have become worn (inferior metal) and let the ball joint move around.

 

This is why I bough the used Buick lower control arms from Dave. I'm seriously thinking about rebuilding them instead, and just swapping them in. I got them down out of the attic yesterday, too. I have the bushings and ball joints already.

 

New lower ball joints & bushings in the used control arms over the past couple nights.



Got them ready for some VGG powder coating tomorrow.

 

Today I celbrated Independence day by evicting the aftermarket lower control arms form the GS400.


I was so tired and sore when I got it back together, I forgot to take a picture of the finished car all back together.

Here are the aftermarket (Chinese ?) control arms.


I'm going to let the suspension settle for a couple days, then get under there and torque the control arm bolts down.

 

Last night I was able to torque the lower control arm bolts and swap out the coil and coil wire with the new ones I ordered. Took the car for a drive tonight, up to the grocery store. I was sitting in the parking lot with it running, ordering a sandwich on the Wawa app, and it started missing again, below 1500 RPM, and the tach was spazzing out (needle just flutters). It cleared up a little when I was moving and the car was cooling down, but it was still not normal. Apparently the coil and coil wire were not the problem... I'll have to try a couple more things tomorrow.

On a positive note, the suspension no longer groans and creeks in the front, going over bumps and dips in the road!

 

Earlier today, I inspected all of the wiring to the MSD 6AL box. Ended up rerouting some of it, and insulating some crimp connectors better. I think that the positive and negative connectors to the coil may have had some metal to metal contact. After fixing all that, I swapped out the 6AL for the spare one that I have. I'll probably contact MSD and see if I can sent the one I took out in, for evaluation and/or repair.

Since it was so freak'n hot outside when I got that done, I did not take it for a drive. We had some other things going on this afternoon, a monsoon happened when we got home, and have company coming very shortly, so a test drive is probably not going to happen until Monday night.

Here's the finished product... not much different looking than any other under-hood photo, though.

 

I finally had an opportunity to take the GS400 for a test drive, after working on the wiring Saturday. Ran great, just as it has for the past couple years! Drove about 10-miles around town, stop and go, and no missing. When I got home, I swapped the 6AL ignition boxes again, and repeated my drive. No missing when hot! Me thinks it's fixed. I put the spare box in the trunk, just in case. It takes like 5-minutes to swap if needed. I think the connectors on the positive and negative wires to the coil, were the culprits.

It's funny, lot of people I talked to were quick to blame the MSD box for the issue. and told me to get rid of it Not that I'm absolutely sure it's not yet, but it sure seems that my oversight on the wiring connectors eventually caught up to me. No need to contact MSD yet...

Next on the Buick list is going to be fixing some exhaust leaks around the X-pipe. Since it's Prime Day, I ordered 8 of the 2.5" stepped band clamps for it. After that it's on to fixing/upgrading the AC.

Here's a gratuitous motor shot...

 

Showed the Buick some love tonight. Replacing all of the standard type exhaust clamps between the mufflers and head pipes (X-pipe joints) with the lap style band clamps. Got the head pipes and X-pipe connections done. Next I'll get the front muffler clamps done. I'm leaving the standard style clamps on the back of the mufflers because they also connect to the rear exhaust brackets. I'm also going to check the head pipe to manifold bolts and make sure they're tight.

Hopefully this will clean up the exhaust leaks and eliminate some of the noise inside the car.

 

Checked the exhaust for leaks tonight. It's better, but I could still hear what sounded like a leak. Started spraying the connections with soapy water while the car was running and got some huge bubbles out of the manifold outlet on the driver side. Sprayed closer and it was coming from between the manifold and heat riser valve. Tore it apart and here is what I found:



It's stuck in this position and has a huge crack all the way through:



Fortunately, I had purchased a heat riser delete spacer from Hector a couple years ago and it's been sitting on my shelf of unused Buick parts.



I'm going to put a gasket between it and the manifold outlet. I ordered a couple different size exhaust gaskets off Amazon, that will be here on Friday. If it doesn't sound better, I'm sure it will perform better without that valve in it, stuck half closed!

 

I got the gasket in today and installed the heat riser delete spacer. It's all tightened up and seems quieter up front. No more soapy bubbles either when it's running. Gonna call it fixed!

 

As I posted in the what did you do to your Buick today, I took the GS400 out to run some errands this morning. It started the miss thing again with the tach spazzing, after my second stop. Swapped out the 6AL again, in Walmart parking lot. It didn't solve the issue. It's something electrical, in the ignition, that is heat related. It gradually cleared up on my way home.

As soon as the car cools off some, I'll start some trouble shooting again. I have a spare points condenser, points, cap, rotor, plugs, and tachometer. I'll change out things one at a time and see what happens. I'm also going to check the grounds and wires in the distributor.

While I was driving home, I also thought that maybe the voltage regulator or alternator could be causing this?

I need to get this ironed out before I go to the next thing, which is fixing/upgrading the AC.