Stout Rocker Arm Suggestions

[TobyB]

I haven't seen that 'Schrick' rocker, either.  

 

3 thoughts: 

Holes???

That pedestal crimped over the ball of the adjuster looks... fractured.  That design looks... odd.  Maybe it's me.

Metallurgy.  It's a one- piece thing, and I can't tell how hard the slipper is, but it doesn't look... hard.

 

70Deluxe, you have to decide your rev limit before you assemble an engine.

Here's the longer version:

 

0- induction.  If you're limited by your carbs, fuel injection, etc in flow, then that limits your rev ceiling.

For example, the rules say you have to run a 32/36.  It won't flow more than 250 cfm*, so you do the math

and figure out that you may as well shift at about 6500.

Conversely, you have 50DCOEs, and they will flow 600 cfm*, so you can go to 10k.  (I made this up.  But 50s are sewer pipes)

 

1- head flow.  For example, if you have a mildly smoothed head that doesn't flow beyond 7000,

then there's no reason to spin beyond 7500. 

Conversely, big valves, single hemisphere and ports that you can reach in and set the plug gap by hand,

now you need those 50's, because they WILL flow 600 cfm.

 

2- now it's just strength and durability.  And there are lots of limits, but the 3 big ones seem to be

a. rocker/spring combos- as you're asking, heavier rockers with stiffer springs WILL rev higher.  But

the combination matters, as does (again, you note) the cam lift and profile.  

b. crank- the stock crank's good through 8500, and some go higher.  But as you go above 8500, wear goes 

up a LOT, costing durability.  Those who lighten the cranks change rod bearings like the rest of us change socks...

b1. oiling- keeping #3 rod oiled, in particular, takes a little attention.

c. rod bolts.  In the distant past, stock bolts were good.  Then, they weren't, and many went to aftermarket

rods to get around this.  Recently ARP's making bolts, so the stock rods, lightened and balanced, will run a LONG

time with a light piston... at revs up to 8500.  

 

If I wanted a durable, powerful street motor, I'd run your 304 with Febi rockers, slightly stiffer springs,

and a 7200 rev limiter.  A pair of 45s choked down a bit, and maybe a crank fired ignition,

just to be absurdist.  Or EFI, if I wanted better economy and less fussing.  But there's something silly 

about sidedrafts that's appealing.

 

t

 

 

*(I made the numbers up.  But 50s are sewer pipes)

schrick rocker.jfif

[visionaut]

38 minutes ago, TobyB said:

I haven't seen that 'Schrick' rocker, either.  

 

3 thoughts: 

Holes???

That pedestal crimped over the ball of the adjuster looks... fractured.  That design looks... odd.  Maybe it's me.

Metallurgy.  It's a one- piece thing, and I can't tell how hard the slipper is, but it doesn't look... hard.

Holes: looks light enough without em, must be for stress relief or balance/harmonics??

Single slim beam - big pad and wide bearing. My eye sees a 3D swiveling ball adjuster??

Could be hardened AND slippy ? Lots can be done in metal-magic nowadays.

 

$1700 seems expensive for a set of rockers - until it doesn’t..  (self-selecting audience).

[visionaut]

Kinda surprised no M10/M30 race builds of note, or mentions yet on using these Schrick rockers.

 

Must be new - that alone is noteworthy.. and they have a solid rep. Wonder if it’s their own design or ?

[Lorin]

That schrick rocker arm is exceedingly similar to an air cooled 911 rocker arm. 

[markmac]

No firsthand experience with the Schrick steel rockers.  With that said, it goes without saying that Schrick has been building the highest of highest end race parts for BMW, VW and others for a LOOOOOOOOOnnnnnng time.  They aren't a bunch of hacks that cobbled together some rocker design.  They don't offer up much any longer for M1o's other than the rockers, valves, and cams.  They aren't new, have been around for many years (long before some of the 'others').  Hmmmmnnn, maybe that is where they get some of their design ideas?

[cda951]

46 minutes ago, Lorin said:

That schrick rocker arm is exceedingly similar to an air cooled 911 rocker arm. 

 

Indeed. Though a bit less of an "elephant foot" shape than a stock 911 rocker. Stock, original 911 rocker arms are quite reliable, can be re-bushed and even hard-welded/reground for new camshafts, though when it comes to racing engines that regularly rev to 8K RPM, lightweight rocker arms with lash caps have been the norm since the late 1960s.

 

I prefer the standard threaded lash adjustment with locknut to the BMW M10/M20/M30 design. I know that many of you have used this for decades in racing engines, but it seems like keeping the valve lash in adjustment in a racing engine with the eccentric design could be a constant struggle. I have seen a lot of worn-out eccentrics in street BMW engines, but luckily they are very quick and easy to replace and adjust.

 

I would be interested to know more about the Schrick BMW rockers, how much they weigh, and who has used them---likely numerous historic racing cars in Germany, but useful feedback would be nice given the price.

[TobyB]

2 hours ago, markmac said:

No firsthand experience with the Schrick steel rockers.  With that said, it goes without saying that Schrick has been building the highest of highest end race parts for BMW, VW and others for a LOOOOOOOOOnnnnnng time.  They aren't a bunch of hacks that cobbled together some rocker design.  They don't offer up much any longer for M1o's other than the rockers, valves, and cams.  They aren't new, have been around for many years (long before some of the 'others').  Hmmmmnnn, maybe that is where they get some of their design ideas?

I was OK with paying the price bump for the name...

...until they started using the same $50 blank everyone else does,

but without reducing the price bump.

Seeing an AMC casting where it used to say Dr Schrick...  well,

I can buy 4 rewelds or 6 regrinds for one rather un-blingy 292 or 304...

 

BUT THAT'S ME!

 

t

 

[Tommy]

6 hours ago, visionaut said:

Holes: looks light enough without em, must be for stress relief or balance/harmonics??

I think lightening anyway. They are located on the neutral line where they're not making the part much (or any) weaker. There's compression above and tension below but the line between is not stressed. Forces find their way around the round hole as long as the upper and lower cross sections remain large enough.

I'm not a mechanical engineer but learning something from them every day.

[Lorin]

8 hours ago, cda951 said:

 

Indeed. Though a bit less of an "elephant foot" shape than a stock 911 rocker. 

I agree. 
 

The BMW rocker geometry is a little more “ballerina foot” compared to Porsche. 

[kbmb02]

I'm currently assembling my third M10 engine using the CatCam rocker arms, good experience and result thus far. I've also used L. Owen, KM and Ireland HD rocker arms (KM and IE both having QC issues at times). -KB

 

 

Edited March 16, 2023 by kbmb02

[markmac]

9 hours ago, TobyB said:

I was OK with paying the price bump for the name...

...until they started using the same $50 blank everyone else does,

but without reducing the price bump.

Seeing an AMC casting where it used to say Dr Schrick...  well,

I can buy 4 rewelds or 6 regrinds for one rather un-blingy 292 or 304...

 

BUT THAT'S ME!

 

t

 

Like I said, I don't have any first hand experience and quite honestly I really don't give a S.  For years and years Schrick made quality parts, do they today? No idea.  How much does any of it cost (no clue and don't care).  I don't own anything that that would have an application for any part they make.