51-53 oldsmobile stem heights?

Hi there fella's!


Have a 51 olds 303 at the shop with 1953 303 heads on it ....

The hardened seats, new valves, and guides have been installed but I cannot find the stem heights anywhere!

Without the adjustable valvetrain as you all know setting proper stem height is very critical!

I've been looking for this information for around a month now and even the AERA (automotive engine rebuilders ***ociation) can't find anything for me.


Any help would be greatly appreciated as this is all I need to get the motor back together...


Thanks!!

--Brad

 

spring height (closed) for '54 is 1.829 same valves as '53 i think.

 

intake valve length overall = 4.965 to 4.985
exhaust valve length overall = 4.989 to 5.009
yorg is correct on spring height

 

Thanks for that information guys!

But I am looking for the measurement between the bottom of the spring pocket to the tip of the valve stem.


I have had no luck finding this spec ....

Any links or phone number would be appreciated!!

Thanks!

-Brad

 

so you're gonna make me go outside and pull some springs?
send me a PM,if i have time tomorrow i'll checkit out.
i hate to see a Rocket kept off the road...

 

Your not finding the measurement you need because nobody in the industry uses it. The measurement your looking for is not precise because of tolerance stack-up due to variability in the machining steps that effect it. Machining the spring pockets, the OAL of the valve, the valve seat depth and the final valve job all effect the measurement your looking for.

Instead you'll need to do it like the rest of the engine building world.

First, you need correct valve spring installed height (aka - retainer to spring seat distance - somebody already gave you this figure) and correct valve spring pressure at the specified installed height (depends on factory and/or cam manufacturers specifications). Those two figures are critcal. Once you have the spring installed height and seat pressure sorted out (by machining or shimming the spring pockets as needed and using a correct valve spring) THEN you adjust the push rod length to correct for any issues with valvetrain geometry. That is why you can order under and oversize pushrods and why companies offer U-fab push rods.....to adjust for minor issues with tolerances and machine work such as milling the deck surfaces and that pesky fourth or fifth valve job. If you need to adjust for correct lifter preload (and maintain proper geometry) you'll need to raise or lower the entire rocker via shims or additional machine work under the stantions, fulcrums or stands.

You CAN accomplish optimized geometry via trial and error machine work on the valve seats and valve tips alone to adjust valve tip height, but its VERY time consuming and there's no going back if you sink a seat too low and/or trim a valve tip too short...hence the availability of various length push rods and rocker stand shims to accomplish the same thing using other methods.

-Bigchief.

 

Hi there again, ... sounds like a good option too! ... I guess the reason I am looking for the stem height spec is the seats were all cut to the same size and the spring pockets were machined to the same size so setting proper stem heights wouldn't be much work perhaps.....


Thanks again guys and if anyone has the specs please let me know, that would be great!

--Brad

 

Any places I could call?

Any olds clubs to get ahold of?


Thanks!

 

just got back from Phoenix,so i have not checked that spec. for you yet.
thursday i will.