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Hey Packard world!

I'm a new Packard owner and brought home an original condition 1952 300 with a 327 straight 8 paired with an Ultramatic transmission.

I was told that this was running and driving several months ago but a cracked head that was weeping coolant prompted the previous owner to source a replacement head and pull the old one off.

Due to time and money, that's as far as they got.

I've since collected a gasket kit, radiator hoses, fuel filter, spark plugs, and found a cast water neck that fits the head off an unknown (possibly an another older Packard) car. It's cast and I'm sure the original stamped neck was destroyed when it was removed.

The biggest hiccup I have now is I'm debating how to put the head back on. None of the stud nuts were included with the car, so I was able to order some generic 7/16-20 nuts that should do the trick. However, 5 of the studs are missing and at least one of the threaded holes is stripped.

My question is 2 parts...

First, would I be better off using a helicoil kit on the stripped hole or just drilling/tapping to a larger size?

And second, is it reasonable to remove most of the studs (except 3-4 for locating the head) and replace them with bolts? Maybe with some thread sealer added?

I've read that this can cause coolant leaking problems since the coolant passages are open at the bottom of the threaded holes but I don't see how it would be any better or worse for studs/bolts unless you had to do some work that required taking the head bolts out but not draining the radiator.

Long story short, I'm just trying not to spend a fortune on new head studs as I'm finding them to be between $7-9 each.

Thoughts?

Thanks!

Here's a picture of the car!

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I will let others suggest the best repair method for the stripped hole but you can get the missing studs from Kanterkanter.com/packard/ or probably Max Merrittmaxmerrittauto.com Some of the various stud lengths needed on some engines are still NOS and others have been done in repro.

I would be concerned about using bolts for two reasons. First is thread length and whether the bolt would bottom before the head had the proper torque. There would be no way of knowing if the final torque reading you are looking for was due to the thread bottoming or was in fact correct. Improper torque on the heads is the primary reason for blown head gaskets.

The second reason is that by the time your 25th series 52 car was produced all the blocks had rolled threads. Modern bolts could well have threads more resembling the cut type and may have issues either with sealing against the water leaks Packard was trying to control or threading in properly. Whatever method you use to repair the hole will determine what type thread is needed there but it would probably be the standard or cut type.

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Good Morning to you and welcome to our site and welcome to the wonderful world of Packard Automobiles.

You will find many people on this site to help you. Kanter 800-526-1096 and Max Merritt 800-472-2573 are good places to start for parts.

You might find that you can purchase good used or new old stock head bolts and nuts for your new Packard for less than the price that you have quoted from the firms above.

Depending on where you are located, you might find help from another member of the site.

One note of caution, Packard Engines were at the top as regards quality...put it back together as it was intended to be assembled. Helicoils work fine.

A shop manual is really helpful if you are doing the work yourself or if you are going to have a shop do the work, they will appreciate the information in the manual. It should be available on this site or on Packardclub.org.

Easy does it and you'll have the old girl running before too long...Ernie in Arizona

I believe the hex nut size of the originals is larger than the modern day replacements. I don't know whether this would be a problem, but wanted to point out the possible size difference. Also, the washers used are thicker than normally found ones used these days. The tapped engine block holes for the studs may not tolerate the torque of a bolt. The studs are just screwed in to a firm tightness, but the bolts will require about 65 ft. lbs. of torque. I have heard of going from bolts to studs, but not the other way around. Howard makes an important caution about the cut and rolled thread types.

Forget about changing from studs to bolts, not a good idea!!

Purchase any required new studs from Kanter Auto or Max. I've used Helicoil to repair bad threads in the block, there are other types as well and I suspect most any of them would work. Install the studs with thread sealant, I prefer old-fashioned gasket shellac (Indian Head or equivalent). You can get thicker washers, even aircraft quality ones if you wish with both sides ground flat and parallel to very tight specifications, from places like MSC Industrial Supply, and probably McMaster. For proper clamping force you'll want nuts that are 3/4" across flats and suitable for 65 lb-ft of torque. After installation, retorque after 15-30 minutes of running, again after a few hours, and again annually until no further tightening is needed.

Yup. what Dave said. And all of this will be cheaper than buying 38 grade eight 7/16 fine thread bolts.

G'day tnum,
to PackardInfo and, I invite you to include your '52 300 in the Packard Owner's Registry.