Itinerant Air-Cooled

Ahh, that Empi quality...

https://youtu.be/_BI1NksWpG4

My god. EMPI exhaust has gotten even worse since the last time I bought any of it. Didn't think that would have been possible -- the damn muffler shell seemed to be made of seven layers of compressed rust..

I sort of understand the slip-fit pipes to allow different engine build dimensions, throw in some clamps! but the muffler? Give 'em hell.
Colin

How did I not get notified? Grrr....

I bitched at CIP1, who I bought the exhaust from. They bitched at EMPI. EMPI sent me a new muffler. It's sitting in the box still... Haven't even opened it.

I've been dealing with pushrods hitting the tube ends. When I did the geometry, I was so focused on the rocker to valve alignment, I missed that at the bottom of the cam lobe the rods were hitting. Damn Scat rockers were simply too short. I tried different length pushrods, and they always hit at the same place. Replaced with the assemblies from the 2180 which were VW stock rockers on an Auto Craft solid shaft, and BOOM. Perfection.

Sigh.

Forgot the pics!

Damaged tubes:


Shorter 40hp rods:


Comparing the two assemblies:


Back to the originally installed longer rods with the stock rockers. Much better fit. Note the spring loaded tube I used to replace the damaged one. That is the only one that leaked, though the seals on the others were shifted around, so they may leak eventually. I'll be watching...

Ouch! What the h377?? There is no reason for that. Was it because the other rockers were *shorter* below the fulcrum of the rocker shaft? That didn't make sense. If this situation was caused only by short push rods, and the rocker arms were cocked so much that they lifted the push rods into the tubes, then the geometry would have to qualify as Worst Geometry Ever . . .
Colin

No, it was the rocker arms themselves that were short. I did try shorter pushrods to see if it changed anything, and it didn't. Only going to the stock rockers put everything where it belonged. Odd how short the arms were on the Scat rockers.

In the comparison pic, you can see the assembly on the right, the Scat ones, have the cup noticeably closer to the shaft than the VW ones.

DurocShark wrote: ↑

Tue Jan 01, 2019 1:54 am

Odd how short the arms were on the Scat rockers.

That is how they make them ratio rockers.
Imagine that you have just 12" movement to open a door.
At the door knob, 12" of travel is still not enough to slip through.
At the hinge, you will open the door fully pretty quick.
Colin

I'm just baffled how anybody makes these work.

I don't understand the manufacturers either. Selling a ratio rocker to use on a stock shaft is ridiculous; a proper ratio rocker would need a shaft with an offset drilling to get the proper alignment of adjuster to valve stem and rocker arm to pushrod, wouldn't it?

Robbie

asiab3 wrote: ↑

Tue Jan 22, 2019 11:21 am

I don't understand the manufacturers either. Selling a ratio rocker to use on a stock shaft is ridiculous; a proper ratio rocker would need a shaft with an offset drilling to get the proper alignment of adjuster to valve stem and rocker arm to pushrod, wouldn't it?

Robbie

Nope.
Envision a rocker arm with exactly the same architecture as the stock rocker arm between the pivot axis (rocker shaft/bushing) and the valve stem/adjusting screw. Now, bring the pushrod socket closer to the pivot axis. It still lifts .442" or whatever the cam lobes says, but because it is closer to the pivot, it makes the valve open an additional 6 or 7 feet. Now you have a push rod interference with the top of the pushrod tube (see Durocshark photos), you have a rocker shaft getting stressed out, you have valve springs binding up and valve guides getting hit by the spring retainer and valves smacking into the pistons and the dog runs away and the house goes into foreclosure. I seen it.
Colin

Ah, I see how that goes now. I didn't quite understand how ratio rockers were designed.

That head is too clean. It needs a few road trips. :)
Robbie