dprantl

Hopefully not one with too many venturis in it

Hmm, most people may not understand that...

Dan
'91 928GT S/C 475hp/460lb.ft

Leon Speed

Boy, I've seen the sliding slope (gliding slope, sliding gliding slope??) more than once this month

123quattro

I am running the lightweight hydraulic lifters you posted further up the page in my Audi 200 20v. I spin that engine to 8200 rpm regularly. It's gone about 15k miles since I rebuilt it. It could spin faster, but it's just harder on all the parts so that's where I set the limiter.

For a street engine the light weight hydraulic lifters will spin to 8500 easily (assuming you have appropriate valve springs). The problem is with high rpm prolonged (track) use they will partially collapse and the valves hang open. So, over 8k rpm they recommend the solids for race engines. Those lifters coupled with bigger cams have been spun to 9500 without issue.

The solid lifter came about for the big turbo I5s because spool wasn't happening until after 5000-6000 rpm. To get all the potential out of something like a GT42R you have to spin the engine silly fast.

IcemanG17

I'm also wondering what Tom is building? But no matter what it will be cool......

jleidel

+1, thoughts on the OB's?

LT Texan

Wow Tom, been a while since you've been around this forum. Welcome back and good luck on the project!

LT Texan

the use of solid lifters keep coming up, but in all of my seperience, solid lifters = manual valve lash adjustment (usually with hot engine).

how could you possibly adjust valve lash on a 928 engine?

BC

With big holes in the side of the cam box, or some other serious work on the 32V motors.

dr bob

Or stacks of shims in a bucket on top of the lifter body.

fraggle

I think the questuion is how the heck you'd do it with the engine hot. I have no clue how to even measure the clearance, itkd take so long to remove the covers everything would be cold!

Lizard928

you dont need to adjust when hot.

However unless you are spinning seriously high RPMs constantly, stay hydraulic.

And dont run solid lifters on a hydraulic cam. A cam with a grind for a solid lifter will have a quieting taper to it of normally around 13mm.

GregBBRD

I've used these lifters...but have only used the ones made in Germany.

Even with that, we are running at a somewhere between 20 to 35% rejection rates. (I threw away 17 lifters out of the last 50 we "inspected".) This is very high rejection rate, even for us. Because of our rejection rate is so high and because of what we have to do to find the "bad" ones...we have to sell these pieces at a slightly higher price...to literally make up for the ones we throw away. It is kind of a joke at the shop. I claim that I loose money on every one I sell, but I'm trying to make it up in volume! (The INA reps aren't interested in taking them back, once we have "inspected" them.)

The VW guys claim to have had problems with breaking ones made in Brazil. If the ones made in Brazil have a higher rejection rate than the German ones...it would be completely impractical for us to use them.

GregBBRD

The GT3 engines are hydraulic and run way more rpms than most 928 owners will ever consider running.

Colin: You need to go grab a cam from a GT3 engine and see what they have been doing over the past few years with the opening and closing ramps...you'll be stunned.

BC

I see a big bull nose:

BC