Sometimes a day turns out better than you expect. Today was one of those days.
I started with the rear axle seals as they were still leaking. I went back to the place where I bought the O Rings and bought the next size up in thickness, which was 0.5mm (.020″) thicker. I removed the RH axle first. it was definitely still leaking, and had leaked inside the brake cavity. I decided to clean everything up this time so there was no chance of any leaks inside the brake.
I cleaned everything up with kerosene to remove the grungy film which had formed, and also used some P800 emery paper to clean the inside diameter of the housing. I then followed up with Methylated Spirits (rubbing alcohol in the US I think) so they there was no oily film left on the parts.
I removed the old O Ring and cleaned everything from the bearing. I then gave the O Ring a smear of Vaseline before putting it in place around the bearing. I also placed a thin smear of Sika ‘Formed in Place Gasket and Sealant’ to ensure this time if there is a leak it does not find its way into the brake drum area.
When I inserted the axle, there was resistance when I got to the O Ring (unlike last time) so I used the retaining plate and nuts to press it into place.
I then repeated the process on the LH side, which also had the same old grimy film.
Once complete I put the wheels back on and took the vehicle off of the ramps and bricks which had been holding it elevated for the last few weeks.
The Big Moment….
Well the the time had come to start the engine and see how the exhaust turned out. I know the engine wasn’t running right last time I ran it, so I was a little apprehensive. I did a once over to check everything was OK, and then connected the battery. I took a deep breath and turned the key. It started easily, and my first impression was that it surprisingly quiet. I let it warm up, and then took some video (not sure why the sound is a bit crappy).
I then went to work to improve the engine idle. I suspected there was a problem with the carburettors which is why it wouldn’t idle below 1100rpm. I started by using an infra red thermometer to measure the temperature of each exhaust port once it had warmed up. The two front ports were 220 and 230 degrees Celsius, while the other four ports were between 315 and 325 degrees. I now knew that it was the front carburettor which was most likely leaking air and leaning out the mixture in the front two cylinders. This was good as I now knew where to start. I sprayed some engine start (ether) into the top of the carburettor to see if it affected the idle – the idle picked up every time I sprayed into the throat. This told me that the butterflies were not sealing. The process of deduction served me well!
Before I removed the carburettor I decided to check the linkages. I found that the linkage to the rear carburettor was loaded (i.e. not loose), and also the linkage between the accelerator pump lever and the throttle lever was loaded. I adjusted the linkage between the two carburettors so it was loose, and then removed the accelerator pump linkage and bent it until it was also loose. I started the engine. it was noticeably smoother, and made no difference when I sprayed ether in the throats. I was now able to adjust the primary throttle position and mixture screws to reduce the idle speed to a more pleasant 800rpm.
I now had a smooth idle at a realistic speed for the first time, so I adjusted the timing to 10 degrees BTDC which is the standard position for a tri-power equipped engine. The idle speed increased again, so I readjusted it back down. By this stage I was feeling pretty pleased with myself – I was anticipating more challenges to get the engine idling sorted.
I think it sounds pretty good – it is quiet, but that is how a Cadillac should be. I will try and take another video using a device which can capture better sound quality – I think the issue is the low frequency distorting the mic in my phone.
I noticed that every time I started the car when it was cool, there was a rattle in the exhaust. After spending about 30 minutes adjusting the pipework and trying to pinpoint the source, I discovered that it was in the LH muffler. I removed the offending muffler and found that the perforated pipe was not welded to the inlet and outlet pipes. It was fine while not installed however as soon as I installed the muffler and tightened the clamp around the outlet, it rattled. In the end I decided to let it go as it only happens when it is cold, and once it has been driven a couple of times there should be some soot and rust to bind it all together!
I now only have a couple of minor things to check, and a dash to bot in before I can try to get a roadworthy and registration. 🙂