Bearing change question.
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Bearing change question.
I'm currently building a 400FMX to go into my '79 F100. I'm kinda on a budget, so it's gonna take me a little while to get all the parts together to build her up. In the meantime, the motor in currently in the truck, once it reaches normal operating temperature, ticks pretty loudly, and I fear she'll start knocking if I don't do something soon. Question is, is there an easy way to change out the bearings while the motor is still in the truck, or should I just bite the bullet and pull it?
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Just a tick currently, but the oil pressure is low, even at higher RPM's. I go by the 10 per thousand rule, and it's not even hitting that mark, unless you're decelerating, then it spikes. I have a spare crank, so if the one in it's smoked, i can change it, but I'm hoping it doesn't come to that.
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Have you had a mechanical gauge on it to see what psi it has ? Just putting a crank in might not solve anything for long. You need to tear it completely down and check the main bearing bores and all the connecting rod bores for straight and roundness with a good bore gauge reading in .0001". If they are not right you will be back to where you started in no time.
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Yup. Cold, it has great pressure, around 60 psi. Get her warmed up, however, and at about 2500 rpm, you're lucky to get 18 psi. On idle, maybe 5 psi that fluctuates with the tick. Getting ready to yank her out now, I'll keep you posted on what I find out.
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Got the motor out, pulled the pan, and yanked all the rod and main caps. As expected, they were pretty heavily worn. Two things did get my attention, though. The #8 rod bearing was worn to the copper on both sides, where all the rest were mainly worn on the rod side. Otherwise, no major scoring on any of the rods. Second thing I noticed was that both bearings on the front main were worn pretty heavily as well. Again, all the cap side bearings were down to copper, and the block side was pretty clean. Possible bent crank, or faulty balancer, maybe?. Crank definitely needs a regrind, but otherwise appears to be in good shape.
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