350TBI 1500rpm knock

1slowbuick

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Buick Ownership
1992 Buick roadmaster wagon
Take a seat this is gonna be a long one. Back in June I bought a 1992 Buick roadmaster wagon that needed it’s 700r4 rebuilt. I was told it has 200,000km on it and the cluster which reads 300,000 was swapped out of a different car. So I’m not really sure the mileage on it. Anyway, the oil was pretty black when I bought it so I changed the oil to 5w30 conventional with a fram filter. Oil pressure was good. 50 pounds on startup idle and about 25 when warm. It had been warm basically every day so I always had the windows down and music playing. One day it was raining maybe a month and a half after I bought it, and I had the windows up. I noticed that about 1500 to 1550 there was a knocking sound. Louder when the car was cold and more quiet as the car warmed up. NOTE THAT IT ONLY HAPPENS IN DRIVE, NOT IN PARK IF I REV IT. And if you get up to around 1600rpm the noise went away. I thought that it was probably timing related because my four cylinder mustang sounded the same until I reset the timing, so I just drove like that for another couple months because the hold down bolt wouldn’t move. Maybe two weeks ago I checked the timing and saw it was set to 0 degrees. That’s when I became a little concerned. I was able to get the hold down loose and adjusted the timing to 4 degrees atdc. That did not help or change anything. I was thinking piston slap but I’m not sure sure as it’s still there a bit when the car is warm. The car runs really well and seems strong. Burns no oil.
Any thoughts will be appreciated.
 
Did you disconnect the Electronic Spark Control before setting the timing?
At that mileage you may want to consider a 10W30 oil.
 
Did you disconnect the Electronic Spark Control before setting the timing?
At that mileage you may want to consider a 10W30 oil.
Yes I disconnected it. It’s winter in Canada now so I don’t want to run 10w30
 
Yes I disconnected it. It’s winter in Canada now so I don’t want to run 10w30
I live in BC and run mine on full synthetic Motul 5w40. I just let her warm up a bit. I may be totally wrong but it’s possible that she has worn rings or rod knock and needs a bit thicker oil? Let me know🙂
 
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I live in BC and run mine on full synthetic Motul 5w40. I just let her warm up a bit. I may be totally wrong but it’s possible that she has worn rings or rod knock and needs a bit thicker oil? Let me know🙂
See, that’s what I thought, but it doesn’t make sense it would be a rod knock if the sound goes away when it gets warm
 
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