It was time to address the exhaust on the 365GTC/4 I have at the shop. The center mufflers on this car were pretty rotted out and were probably filling the passenger compartment with fumes and CO.
The mufflers were rotting from the inside out due to moisture from the exhaust collecting inside the cans and slowly rusting the mild steel mufflers. Most of the steel was paper thin, so it was time for new mufflers.
I threw all the exhaust bolts and brass nuts into my vibratory tumbler to clean them up. I’m not making a show car, but it will make assembly of the exhaust system much easier with clean hardware.
As I was disconnecting the exhaust, I looked up at the headers and found the rubber motor mounts were pretty dry rotted and collapsed.
The left one was no better, so now was the time to try and get these out and replaced. I’ve gotten this type of motor mount out of other Vintage Ferraris, but have not done it on a C/4. The usually just enough clearance to jack the engine up to remove the motor mount bolted to the engine taking the bracket and the rubber insulator. With the assembly out of the car, you can unscrew the large insulator, but there is usually not enough room to clear the studs with the bracket attached to the engine.
Unfortunately, with the C/4, the engine would not move high enough to clear mount studs so I had to remove the exhaust headers. In order to access the nuts holding the headers in place, I had to remove the air cleaner assembly. In order to remove the air cleaner assembly, I had to remove all the velocity stacks to release the air box. You can see how the C/4 always offers this cascading issue of access to the engine based on the carburetor set up!
I lucked out when I found I could access the header bolts without removing the carburetors after the air filter assembly as removed. This saved a lot of time and disassembly that often comes with a C/4!
I managed to remove the rear exhaust header and loosening the front set of headers enough for the engine to move up a fraction of an inch more so I could get the motor mount out.
As much of a pain in the butt this was to get this stinking motor mount out, it was a much needed job. These mounts sit right below the exhaust headers and are exposed to a lot heat. Even with a heat shield installed, these mounts won’t last forever.
My parts supplier first sent me the wrong motor mount so after a delay of several days, I finally got the correct motor mount. Of course the new one was a little thicker than the collapsed motor mount I removed, so I had to get creative to get the new one back in place. After jacking the engine as high as I could in the car, I took a ratchet strap and pulled the mount down into place to line up the bolts on the side of the block and the chassis. It wasn’t easy, but I got them both back into place!
My exhaust vendor is going to custom fabricate a new center section to replace the rotted mufflers for this car, but he’s been back logged with work for over two months. He was about to begin work on the system, and I sent him pictures of the one I removed with measurements of where the hanger straps are located.
He has a USA version of the muffler I need that he uses as a template to fabricate a new one, but his straps are 1/2 different than the location of the one I just took off. This half inch may not seem like a lot, but this exhaust is hung on the car with large rubber o-rings that don’t stretch much.
There are three sets of straps welded to the muffler, and all the ones on this car lined up perfectly with the corresponding hooks on the car.
The second strap my exhaust guy has was 3/4-1 inch off, so I decided to have him tack weld the straps according to my measurements and once I have the muffler fitted to the car, I’ll permanently weld them in place. He usually tack welds the flanges in place so I can get the connections perfect, so I guess we’ll have a little more welding to do with these straps.