Hello All: Need some guidance on the differences between the Oldsmobile and Pontiac hydraulic lifters ( If any )? I am seeing some major brand companies advertising the same lifter for the olds/poncho engines! I did a search ,thinking that this had been addressed here on this site,but didnot get any return on an internal search! Can anyone please elaborate on this,as I was under the impression that they should be different for each application mentioned above....Any pointers to a particular company/vender to find proper lifters for the Olds engine would be appreciated...

 

All GMs will interchange the .842 hyd lifter.

 

That's incorrect. The oil band on the Chevy lifter is wrong for an Olds or Pontiac. There are lots of posts on the Pontiac sites with guys who tried to use the Chevy lifters. Seems they're even more frugal than us Olds guys!

 

Specifically when you get below a certain base circle O.D. as is necessary with cams above a certain lobe lift to achieve further lift, the oil band can be exposed on the bottom side of lifter boss with common Pontiac lifters, even factory GM Pontiac lifters. I had to buy purpose built lifters Crane used to have for specific use with a hot Pontiac mechanical cam with a oil band located higher on body and a overall shorter oil band (not 'tall' lifters), and the lifters also had special piddle valve (which BTW didn't work for top end oil control), like a Z-28 or LT-1 Chevy lifter. Even then it only had about .030 covering oil band when on base circle, broken in. That one engine made checking that condition routine for me.

 

Guess that shows ya what i know -eh? Thanks for the "lesson".

 

The bottom line is, I don't care which engine you're building, or who you're buying parts from -- it's smart to check the location of the oil ring on the lifters as you assemble the engine, just like you check bearing clearance and a gazillion other things.