Quote:
Originally Posted by GeneBob
Of course, it may be something obvious like your radiator is not cooling. No contact thermometers are pretty cheap and you can check to top of the radiator (at the return spigot) compared to the bottom tank. You should see at least 20°F difference.
If you are running hot with the timing set right, you might want to check your air/fuel ratio on your carb. If you are lean at idle, your parade speeds might be too lean? If you don't have an air/fuel meter, I use the smell vs eyes burning method. I know this sounds crazy. If your exhaust burns your eyes, you are lean. If you smell sweet gas, you are too rich. Those are wildly opposite ends of the spectrum but without a gauge, you need somewhere to start. The problem with reading the plugs at idle is it takes a while to get anything on the plugs that is meaningful.
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GeneBob, thanks for your reply!
I have been so focused on the timing I did not think about running lean. I had no issues with overheating in the past, when I replaced my head gasket in July I flushed the cooling system. I made a 110 mile round trip ride with no issues with my stock distributor and Zenith carb.
After installing the FSI ignition system, I had no issues for 2 months, so my timing should be good with max advance at 28° and my base timing at about 3°.
So now I am focusing on the carb, I was in 2 Christmas parades, the first one was December 3rd. I installed the Stromberg 97, Burns intake, new stock exhaust manifold and new Aries high flow muffler and tail pipe a few weeks before the first parade. I had only made a few short trips with the new carb to lunch and to the gas station. I had my idle adjustment close to 1 ½ turns out. I had no issues in the first parade but I pulled the plugs and they were black with soot. I did run my car up to 55 mph on the 11 mile trip home from the parade.
Before the second parade I increased my base timing to 8° BTDC with a max advance of 32°. I also adjusted the idle setting on the carb using a vacuum gauge and hand held tach. After the second parade my plugs looked good, my only issue was overheating after I got home. I am beginning to think my overheating was cased by low water level.
Today I reset my max timing to 28°, flushed my cooling system, checked my compression, I have 60 psi on all 4 cylinders. I retesting my idle settings with a vacuum gauge, i'm at almost 20 inches of vacuum at idle.
I went for a test drive, I have a backfire through the carb under load, if I run out 1st and 2nd gear, I loose power and backfire through the carb. I have plenty of power up until the backfire starts. In the shop it back fired through the carb at about 2500 rpms. My fuel flow and fuel pressure are good when it starts back firing.
So my next step will be a new set of jets, the stock jets are 45, I am going to order a set of 46 and 47.
So far I am pleased with the increase in power from the ignition and the carb, just need to get everything dialed in.