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Just purchased a 39 Formal Sedan. Engine runs but has 2 issues. One head has been welded in the past and is leaking. I plan to replace both heads with new manufactured heads from Empire. The valves seem to make more noise than I would expect. My plan of attack here is to remove the oil pan and then remove the oil pump clean the metering valve. If anyone has experience with the V12, I would certainly appreciate some insight here. Are there any O-rings or seals on the metering valve? Is there any adjustment on the valve silencers or tappets? Should I try the metering valve and see what happens or go ahead and remove the intake/exhaust and valve cover to inspect the Silencers? Car has 44,000 original miles in very good condition been in the same family since 1960 with good care. Also the shop manual is ok but would really like a better "how to" book on the engine. Is there anything available? Anything to watch out for during this work?

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If the oil pressure at speed is low the problem could be the metering valve, but unlikely. The valve train should be virtually silent on a V12, do you have a few valves ticking or all of them?

Usually the noise is caused by a stuck valve silencer and that usually happens after long periods (years) of unuse.
These are not valve lifters but a novel system of taking up all valve clearance. I would think that a solvent/cleaner like Rislone would do the trick but the car I tried it on had no effect.

If this is the case you need to remove all the valves, make a puller for the valve guides and rebuild the cam follower blocks and silencers. You could have bad cam followers which I recall run on needle bearings.

This project is not for the faint of heart.

G'day rhanna,
to PackardInfo, I invite you to include your '39 Twelve in the Packard Owner's Registry.

Thank you for the reply. To clean the silencers, do you have to pull the carb, intake and exhaust, then remove the valve cover?

I'd recommend you pick up the Lone Star Region of The Packard Club's publication The Lubrication System of the Packard Twelve Engine. In addition to the obvious, some good illustrations and explanations of the hydraulic take-up or silencer units.

Im not a great fan of SNAKE OIL but admit ive had some luck with SEAFOAM. Its the first step id take. Just me - but id change ur oil to a 5-30 and add a couple of cans of the SEAFOAM and give it a 100 mile run. If u have a Valve sticking u might want to try a couple of can in the gas tank also.

Im in the middle of a 12 rebuild right now so can tell u the 12 valve train is a MAZE of many moving parts, thus ur noise could be many things.

Thank you for the great suggestion - where can I pick this publication up?

Thank you for the great suggestion - where can I pick this publication up?

If you're a member of The Packard Club (PAC), you'll find it advertised in the monthly newsletter. And if you're not a member, you should be - especially with a Twelve!

The valve silencer preload adjustment process involves stem grinding.

As mentioned the valve silencer system (used by Packard under license from GM) will make noise given dirt or wear, but the system usually will last over 100,000 miles in a properly maintained engine.

If the guides are worn, valve stems gummy, springs hitting each other that will also cause noise. However, you are correct in checking the bypass as a first step because if that isn't working the system will be starved for oil.

All of the comprehensive inspection and adjustment involves removing the manifolds and cylinder heads. I always used a dial indicator to set the silencer preload with the valve springs removed. It works like this: You place a .056 feeler between the stem and the unloaded silencer and measure the lift on the dial indicator by pushing on the valve face to bottom the silencer. The reading should be between .01 and .026. If it is more than .026 the difference needs to be removed from the stem. If it is less than .01 a longer stem is required to reduce the clearance.

The way they used to fix this was to measure all the clearances and move the valves around to minimize the amount of stem grinding or valve replacement required.

I am just getting into my dads 12 ,

have silencers apart, they went thru fire, were rusted, but the springs still feel robust,

I did buy new springs many years ago, A guy in st. louis had them, there was an ad in PI,

I was back there one year and bought the heavier spring from him too..

all of this will be in my 56 ultra blog, I do have a question on top part with holes in it, does it fit tight or loose..?.. once I got them apart, some fit tight, others loose, as in slips in and out..