I looked at an 86 IROC today that was for sale. The owner said he'd replaced the 305 with a 350. He said after the engine runs awhile it starts making a noise. He was told it was a main bearing getting ready to "go". When he started it up today there was no noise (engine still cold) and it had right at 60 PSI oil pressure. It the clearance was excessive on the main bearings wouldn't the oil pressure be lower? If the clearance was too tight would it make noise all the time, or just when it got warmed up. I'm curious as it's a beautiful car and I'm seriously thinking of buying it. Any opinions/advice/information welcome.

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Z's r Best

 

not a good idea to purchase if a main bearing is getting ready to go.
when the motor is cold the oil pressure is much higher.
My engine cold does 60psi and only 18 when hot.
also he could have some motor honey in there to quiet it down, once a main bearing lets go it could only be a matter of a few miles before the motor completley siezes up....happened to me!

[This message has been edited by Joshua Leslie (edited November 17, 2001).]