Re: Engine wanted for a '35

Posted by Peter Hartmann On 2008/10/16 11:09:10

the reason the '35 - '39 V-12 rods were a one-piece forging was because of a "clearance" issue.

Here's the problem - look at a cross-section of a Packard V-12. When the stroke was increased from four to four and a quarter inches (for 1935 and later production), there WOULD have been "interference" between the crank-case walls, and a conventional-style connecting-rod.

You are correct that the '35 -'39 V-12 connecting rod was a superior VERY SERIOUS piece of metal ! It was a special chrome-moly, much tougher, more flexible, and durable than anything used anywhere in conventional automotive use.

I have seen LOTS of pre 1940 EIGHT cylinder Packard crank-cases with "patches" where a con. rod went thru the side of the crank-case. I have NEVER heard of a Packard V-12 tossing a con. rod.

Sad to say - the fastest way to RUIN a pre-war Packard engine, is to use poured babbit in the con rods. Even the Twelves have been ruined by that kind of butchery.

True, driven the way MOST people drove in the 1920's, at the speeds most people drove in the 1920's, you didn't see much rod bearing failure ( since most engines had to be overhauled by 30,000 miles anyway) (why ? well..no oil filters, no air/induction filters, primitive oil, etc.).

Trouble was, by the 1930's, cross-country high speed driving was possible, and con-rod bearing failures became epidemic.

Hopefully, this fellow who started this "thread" will get hold of a salvegable "Standard Eight" ( or 1937 - 1939 "Super" Eight) and get it fixed RIGHT (meaning "insert" type con. rod bearings).

One of our fellows here in Arizona made an interesting comment; poor fellow ran across some "experts" who got him into a VERY expensive bearing job. Sounds like it is a good job that should last well. In my view, was doing it the hard way.

I did not know that the "thin-shell" rod bearings designed by Packard and Federal Mogul, introduced in 1935 production, were "probmlamatical with many failures".

Packard didnt know it either (see the famous engineering test eval. after that famous "flat out pedal to the metal" demonstration Packard did with a Standard Eight to show off the then new technology).

I dont think Charle Last (R.I.P.) knew it either, as when I was in his shop, we turned out HUNDREDS of Packard eight and twelve cylinder engines, taking up any worn clearances in those original "problamatical" bearings with a little brass shim stock (that's how I did mine, in '55. )

Oh, by the way, my own Packard V-12 has now 160,000 HARD FAST miles on its original "thin-shell" rod bearings, 20 lbs. hot idle oil pressure with 10W-30 oil (yeah, gets nice and warm after an 80 mph "run" when it is over 100 degrees)...and it dosnt know Packard "thin-shell" rod bearings were "problamatical" either.

Oh - by the way, the only reason those pre war shells were thinner, is they thought that was the way to avoid re-engineering the con.rods, and get better heat transfer.