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My current and only Buick The B-59 has alot of valve knock. It started when I switched the oil to a 10W-30 weight full synthetic oil. I tried to compensate for the knock by adding a 5W-40 and alot of Lucas motor oil. Its not as bad but it still knocks. It dont run hot or misfires but it just sounds rough. What should I do?

Update,

I was messing with the idle on the B-59 and found out that just by idling it a little higher it stops knocking. So when I switched to synthetic I had to increase the idle just a hair or 2 and that stopped the knocking!

HI

Sorry for the delay here, but I've been off on other projects.
A "knock" that goes away may in fact be timing or gasoline related.

If you are one of the unfortunate ones who lives in a "reformulated"
area then gasoline quality is a growing problem for owners of old cars in general.
Ethanol only adds to the problem! I recently bought a 455 1973 Buick from
rural wisconsin (they get 100% gasoline up there). I brought it home to the Chicago area & after only 3 tankfuls of
"reformulated/ethanol" gas, ALL the short rubber connecting hoses from the gas tank
to the steel fuel/evaporator lines sprang leaks. They all looked fine
on the outside, but after cutting them open the inside surfaces were like
black bubble gum! We old cars guys MUST be vigilant on these
fuel vs. old rubber issues! Be watchful of carbs & fuel pumps, too!

After that little episode I put my 58 Roadmaster up on the lift and replaced the entire fuel
line with new steel tubing and all the rubber connecting bits. We must use
SAE rated fuel line for fuel injection to get the correct material that is
impervious to these new (inferior!) fuels and additives.

Check you timing/advance mechanism & make sure that you use good quality fuel
and it never hurts to throw in a bit of octane booster!

regards
Mike

HotRod58er wrote:My current and only Buick The B-59 has alot of valve knock. It started when I switched the oil to a 10W-30 weight full synthetic oil. I tried to compensate for the knock by adding a 5W-40 and alot of Lucas motor oil. Its not as bad but it still knocks. It dont run hot or misfires but it just sounds rough. What should I do?

You're very lucky the sound went away, I'd NEVER run synthetic oil in a non-roller lifter engine, (google it) actually I don't run it in any part of the car after getting professional's opinion on it...it's not all it's cracked up to be. I was told by my transmission mechanic not to run it in the trans or rear end, for one thing water mixes with 80/90 synthetic. Bad for rear ends.

These old engines and transmissions need some zinc in the oil too. Older oils and tranny fluids had it but newer ones don't have as much. There are some zinc additives on the market.

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