'72 Engine Problems
In the quest for more power and quicker times, I bought (in early 2000) a new cam, carb, converter (used), and main studs (to help the motor withstand 6500 rpm shifts).
Here's one of the mains:
You can see where it's worn to the copper, right? Two others were just as bad. I had no idea what to do. I figured I needed to replace the bearings, and to do that, the crank needed to come out, and to do that, the rods and pistons needed to come out! What a drag. So I look at the rod bearings and #1-#4 are poor, but not horrible, but #5-#8 are really bad!
Bad main saddle alignment
Rotating assembly out of balance
Oil pump sucked the pan dry
Oil film breakdown (either air/fuel ratio bad or poor combustion, causing oil dilution)
Bad crank (bent, warped, etc.)
They turned the crank (eliminating a bent/warped crank as a possible cause of future problems).
They decked the block (giving a higher compression ratio but also better quench, and hopefully better combustion).
They align-honed the mains ensuring the crank would stay put.
I also purchased a 7-quart Moroso oil pan, pump pickup, scraper, windage tray, pan baffle, Melling M55A oil pump, and an oil temp gauge, so that should eliminate any worries about the oiling system.
I installed a bigger Comp XE274 cam, so that should bleed off a little cylinder pressure.
Also, as mentioned earlier, I'm putting oxygen sensors in my headers to monitor the air/fuel ratio as I drive.
The only unaddressed possible cause on my list is the balance of the rotating assembly, but since I only need this motor for 2-3 years and I really don't think that was the cause anyway (and it's expensive), I decided to skip the balancing this time.
Here are pics of the crank in the block and my new oil pan.
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Copyright © 2009 Bruce Johnson and Craig Watson