Packard Forum Index » V-8 (1955-56)

So long ago, I've forgotten who held what, but there was a discussion about differing pushrod identification marks and lengths.

I decided to see what I could learn, so I bought a Starrett 10-11" micrometer.

The Packard V8 pushrod has a nominal length of 10.506". If I understand pushrod terminology, this assumes the 1/4" spherical ends are complete. The Packard V8 pushrod has a dimple in each sphere, thus making it shorter than the drawing dimension. With this precision instrument, I measured 128 pushrods. The variation was greater than expected. The length ranged from 10.462" to 10.502". The shortest group showed considerable wear, to the point the dimples were almost gone. Most were in the range of .474" to .484". There were sixteen which were in the .494" range and only two longer than .500".

So, yes there are differing lengths. No, I couldn't find any secret marks. Every one of the 128 looked identical to me.

Does the length variation matter? Not really. The hydraulic lifter has a travel range of .230" which should handle the .025" variation of most of the pushrod lengths.

However, the one thing I did learn is to inspect the tips of the pushrods very carefully and measure each one. Some may be too worn to reuse.

Now, for something new and completely different. I found a set of NOS aftermarket "Bulldog" pushrods.






Note the Bulldog pushrods have a black oxide coating. They are only 5/16" diameter vs. 3/8" for the OEM. The Bulldogs only weigh 2oz vs. 3.5oz for the OEMs. They just went into the engine for my Stude truck. If I were building a performance engine with stiffer valve springs and higher RPMs, I'd probably stay with the OEM pushrods, as they're probably less likely to deflect.

thnx, jack vines

Interesting that the Packard and Stude pushrods are same length. Do you suppose Packard engineering consulted the folks in South Bend while they were designing their V8??
I don't believe in coincidence.

The Packard parts book shows different numbers for 1955 and 1956 pushrods and I've always wondered why. There is no obvious difference between the two and no mention of the change in the Service Counselors or Bulletins.
Maybe it's something like a difference in hardness on the tips.

Brian

I found 2 or 3 of those BlullDog pushrods in one of my engines. They were apparently used as a service replacement.

See p 23 of the engine section of the service manual. Procedure titled "Checking Valve Tappet Clearence". On engines built up from miscellaneous parts or new new parts I always try to arrange the pushrods to attain a nominal 'lash' between the upper and lower limits. Especialy true when using any 'retro fit' lifters or pushrods not specifically catalouged for the Packard V8.

As for the different part number on push rods between 55 and 56 i can only guess at this point that it could also be due to the different cams. 55 had less lift than 56. Also 55 and 56 used different lifters so possibly the lifter seat was lower or higher or different in some way between 55 and 56. Therefore different lengths of pushrods between 55 and 56????


EDIT: I just remebered that i ordered 3 or 4 pushrods from Kanter about 8 years ago and they are just like the BullDog pushrods in the picture above.

JV.
About how old are the bulldog pushrods???? Are they made in Mexico????

The bullDog in the picture appears to be considerably longer than the oem pACKARD PUSHROD???

Quote: No way to ascertain age, but they are very old stock and as shown in the photo, made by Jambor Tool and Stamping in Milwaukee, WI

Quote:

Camera angle/optical illusion. The Bulldog pushrods are 10.490" length.


Quote: Are they? IRRC, Stude used two different lengths of pushrods, pre-and-post '62. I don't have one at hand, but will check next week. I thought Stude V8 pushrods were around 11.265" length.

thnx, jack vines

in the early 80's i built some 4 different VW bug engines. JCWhitney supplied pushrods identicle in appearence to the Bulldog pictured. Shorter i believe of course.

Nearly everything JCWhitney supplied for the VW engine was made in Mexico including HD oil pump for racing. The parts seem to hold up just fine for low budget Formula V racing.

Quote:

Randy, I think the labeling on the Bulldog push rod box indicates they are also for the Packard-built V-8 that was fitted to the '56 Stude Golden Hawk. Could be wrong, but ...

(o{I}o)