Packard Forum Index » V-8 (1955-56)

352 heads, no valve adjustment correct? Just tighten the rocker shafts to spec? Thanks guys.

Nope, none needed, unless you want to do it "Duesenberg Racing" style.....

No adjustment. HOWEVER this assumes correct lifters are in the engine. There are 2wo different MoPar lifters that will FIT the lifter hole but only ONE of the MoPar lifters will work correctly. The other MoPar lifter has a push rod seat that sets too high.

SO, assuming that the lifters are Packard lifters or the correct MoPar lifter then NO adjustement is neded. IF the tall MoPar lifter is unwittingly used then it is quite possible that they either will not pump up or may just hang the valves slightly open.

Look in the service manual. There is a procedure outlining the anount of collapse that each lifter should have. About 2/10" minimum if i recall correctly.

ULTIMATELY tho. There is NO adjustment for the PAckard V8 valve lash. Definately a poor engineering decision on the part of the "Master Engine Builders" of Packard.

Quote:

What problems have we encountered which would have been solved by adjustable rocker arms?

FWIW, few-to-none of the OHV engines designed since Packard offered valve adjustment. Of those few who did, some, such as the small block Ford, in its' later redesign went to fixed valve train. The experience was most mechanics and owners did more harm than good with adjustments.

thnx, jack vines

To a great extent u're rite. I'm tempted to retract my statemnt. I suppose the best answer to your question is another question:

Why does the service manual on p23 of engine section define a valve lash check procedure???? Incidently, it gives NO correction procedure either. No over or under length pushrods listed in the parts cataloug???? I believe Ford offered such over and under length pushrods for their engines.

Somewhere about 60K to 70K miles the lifters will get noisy in any engine due to wear, dirt etc. Especialy of the pre-1980's era. Replace the lifters????? WHY??? because they are worn???? They usualy wear at the base that rubs the cam. On the engines with adjustable push rods or rockers one can simply give the adjuster nut a quick 1/4 turn and noise problem solved for another 20k to 30k miles until the bottom of the lifter wears thru.

It's not like Packard was offering engines for the commoners of the world. They were supposed to be offering quality, long life and service.

Build a new or newly rebuilt engine and ship it out with a 3 year or 30K mile warranty is one thing. Run one 150K miles and squeeze another 50k out it is another.

Isn't it pretty analagous to the L-head engines with hydraulic lifters; when the seats were ground deeply enough you had to grind a bit off the valve stems to bring the system back into the range of accomodation of the lifters? Not that I've ever done a V8, but I'd think that's a standard part of the service procedure.

owen, that is definately true for smaller L heads, including lawnmowers which have NO adjustments and solid lifters. you get your adjustments in by valve seat grinding or grinding the stem.

TRue. But most engines prior to the HP revolution of 1955 were only good for about 40K to 50K miles until required rings and a valve grind anyway and most likely bearings or shimming. In the ford plymouth and chevy class the transmissions/clutch were only good for maybe only 40K to 50K miles and it's not like they were driving those cars at SUSTAINED interstate speeds or any kindof conditions resembling modern demand, not even of the late 50's.

Sure, even 6 cylinder AMC up thru the early 80's that i know of had no valve lash adjustment and the head had to be removed to change the lifters, another BAD design for service convenience.

But what are we talking here???? F, Chev and plymouth or Packard built by "Master Engine Builders"????

What about engines in the same class as the Packard V8 of the mid 50's????? What about Lincoln, Chysler Imperial, Cadillac/Buick V8's and the like???? Did they have adjustable valve lash????

We need to distinguish between adjustable valve lash (mechanical lifter adjustment [hydraulic lifters make such systems "zero lash"]), and adjustments sometimes necessary after grinding valves and faces, milling heads and decking blocks, etc. to get the velve to static lifter dimension back into the range of accomodation of the hydraulic plunger. Though this is a common procedure on the L-head engines with hydraulic lifters, it is also occasionally required on hydraulic lifter-equipped OHV engines as well.