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Any suggestion regarding motor oil?


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My 1950 Rocket 88 runs fine but has quite a bit of valve train noise after it warms up. During the light rebuild I took the lifters a part, cleaned out all the gunk and pre-loaded them with oil. I'm actually a little surprised that I have as much valve noise as I do. I put 20-50 oil in recently with no improvement. Just curious if there is anything I can do to reduce the noise or just consider it part of the "charm".

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I don't know if this is directly related to answering your question, but I would make the following suggestion for long-term use, and do so under the advisement of at least three engine builders/mechanics I know and trust.

Anyone with an old classic car should be using motor oil with zinc and phosphorus; I have been using Brad Penn (not to be confused with Brad Pitt) Motor Oil, but looks like Hemmings Motor News themselves has recently come out with out with oil that has ZDDP content...

Hemmings introduces zinc-rich motor oil formulated specifically for classic cars | Hemmings Blog: Classic and collectible cars and parts

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The 303 Rocket did have one weak area however, a noisy valve train! Much of the problem originated in the poor oils available in the early days and was increased dramatically by not paying strict attention to oil change intervals. If it is necessary to replace valve train components some of the scarce (read expensive) oe parts can be substituted with more common (read much less expensive) small block Chevy parts.

Olds FAQ -- 303 CID Engine Detail

It could be just as you suspect. The noise is in the design.

Edited by avgwarhawk (see edit history)
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Thanks for the feedback. I still need to complete the interior restoration and a few other minor mechanical issues so I think I'll just get used to the added sound of the engine. Of course without carpet in the vehicle to absorb the sound it probably seems worse than it is.

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I think others with the same engine will chime in. I would believe you are like me, any noise is a concern but in reality it is not. My 264 nailhead has a tap that comes and goes at will. It's one lifter that does it. Some days I hear it. Other days I don't. I can say I'm asked all the time if the engine is running. It is relatively quiet at a 500 rpm idle.

Might be the nature of this engine to exhibit valve train noise.

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I think there is something to that tapping just being inherent to the engine design; I have a '62 Olds Starfire, and a '62 Olds Dynamic 88 wagon, both with 394's, which as I understand it is in direct lineage to the 303, 324, and 371 engines Olds previously had before the 394 from 1959-64. I had the engine rebuilt in the Starfire about nine years ago, and although it has (maybe in my mind) quieted down, seems to me there's always that tapping there; I just had the wagon's 394 rebuilt a year ago, and it, too, has that sound when it starts up. I would say that it pretty much goes away after maybe a half-minute or so, and it is smooth sailing since; I've put 32K miles on the Starfire's engine since the rebuild, and about 4K on the wagon, and both will take me from coast to coast, and run smooth as silk even before its completely warmed up.

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  • 2 weeks later...

Every single thing wears; cam lobes, lifter faces, push rods both ends, both ends of the rocker arms and the lower half of the rocker arm shaft hole. Pushrod and rocker arm pushrod seat wear can be severe, assuming no lifters are collapsed the highest % noise generating potential is found in the wear of those two components. The shafts also develop visible wear but I haven't had that factor in on mine. Everything is available, at considerable cost. If you perform a valve job only, this is one instance where you advise the machinist to not equalize valve stem height to shortest corrected height - the extra height from sinking the valves when refaced can benefit you if you are trying to use old stuff. Also, the modern metalbestos head gaskets commonly available today are thick and consume more precious lash potential. Make sure you see visible oiling on the top side at +1200 rpm, very little oiling is visible at idle even when cold. If by some small chance your '49 has plugs in any pushrod side rocker arm oiling holes you might want to consider replacing them. Those were dealer added to reduce long idle tailpipe smoking but were later removed under a recall campaign, yet even today they are still showing up in engines - no good. I agree the zinc concern has merit, but no magic bullet is found to quiet Oldsmobile valvetrain noise in viscosity selection - CW

Edited by coldwar
zinc in oil (see edit history)
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