Trans Am Motor Mounts
I have a '79 Trans Am WS6 with a 400 and a four-speed. The car is mostly original-I know because I am the third brother to own it since new. Its engine has never been out, and the T/A is about to reach 100K miles.
In preparing to install a Canton oil pan, I decided it was a good time to also replace the OEM engine mounts. I have the original ('78) shop manual and the '79 supplement. The manual shows three bolts (or possibly studs) protruding from inside the boxed frame member, using nuts to secure the engine mounts from the top. Unfortunately, my car has bolts on top of the mounts with nuts/fasteners that I cannot reach inside the frame.
The shop manual clearly displays merely removing the top nuts/fasteners to replace the mounts, but it's nearly impossible to do. At the very least, it seems like I need to pull the engine and stand in the engine bay in order to see or maneuver the fasteners inside the frame member. Any thoughts?
Andy Hess
Spokane, WA
Rocky Rotella responds:
Changing the engine mounts in the late Second-Gen Birds can be a frustrating task. For whatever reason, the factory service manual makes it seem quite simple, but I've found it anything but. As you learned, the nuts used on the retaining bolts are well hidden inside the front subframe, and that can make it quite challenging.
Since the installation of the Canton pan may be much easier with the engine removed from the car, you might use the extra engine compartment space as an opportunity to accomplish the task of replacing the engine mounts at the same time. Removing the lower control arms is by far the easiest way to access the engine mount nuts, but it doesn't sound practical in this instance. I think you'll have the best luck snaking a 9/16-inch socket through the various holes found in the subframe. It may require extensions of various lengths, along with swiveling joints, to reach them. You may also be able to access some of the nuts using a combination wrench that's long and thin.
No matter the method, the task is one you shouldn't rush to complete. Just remember to take it slow and be patient. A little creativity may also be required, but it's not impossible to perform.
Stalling Bird
I have a '69 Firebird with a 400, a Turbo 350, and a 2,200-rpm stall converter. It has an Edelbrock intake and a 750-cfm carburetor. When I run it for about 10 minutes, it will stall and the rpm will drop to about 500. When I put it into gear, it will also drop down to 400-500 rpm and even stall.
The gas tank was replaced, as was the gas cap, to a vented one since the tank doesn't have a vent anymore. Nothing else was changed. Am I getting too much gas into the engine and shutting it down at idle? The timing is at 13 degrees at idle. When I take off the gas cap while running, it has air pressure behind it. Please help, as I want to drive my Firebird. I just finished it two years ago and now I have this problem.
David Ryan
West Frankfort, IL
Paul E. Spotts responds:
There is so much gray area in your question, it is difficult to answer without writing a book. Regarding the engine dropping rpm, it is normal to do so when shifting into Drive, as well as when the carb comes off fast-idle after warm up, so make sure the idle screw on the carburetor is adjusted correctly.
Most engines that run fine while warming up have the choke working and the carb is on fast-idle-off the idle circuit. In about 10 minutes it's warmed up, the fast idle comes off, and the choke is fully open. So make sure the choke is open as a closed or partially open choke can cause your problems.
The gas-cap scenario is interesting. If the cap is off and the car still won't idle, I doubt that's the problem. However, if the car runs fine and idles ok when the cap is removed, then it's the problem. You could have a defective gas cap, as many are now made overseas and quality varies.