R75/5 Pushrods

[fredheiler@aol.com]

So, I think this is a dumb question, but I assume all of you will understand why I'm asking. Are the R75/5 hollow pushrods supposed to supply all the oil to the upper end like many other engines?

I've rebuilt hundreds of VW and Porsche 356 pushrod engines, but I'm rebuilding my first /5 engine. Usually, the standard check for pushrods is to blow compressed air through them, to make sure they're not clogged. Well, the /5 pushrods seem totally clogged (the engine did sit for years), so no wire will penetrate the ends. They were immersed in Safety Kleen last night, and in desperation, I even tried a 1/16" drill bit, but no go. It's almost as if the holes were never drilled all the way through those hardened tips, but if that was true, I assume the rocker shafts and valve stems would've seized up long ago.

Thoughts on this quandry? New ones are $260 a set.

Thanks, Fred Heiler

 

[kinterridge]

Go here for a flow image on Snowbums site https://bmwmotorcycletech.info/oilsketch.htm. Hope this helps.

 

[20774]

They were not hollow in order to provide oil to the rockers. Never were. That oil is provided through the hole in the heads where the head bolts go. It is via the small hole cut near the threads that go into the block at the top two head bolts. Oil drains back to the sump through two holes in the bottom of the head. Near as I can determine the small dimple at the end of the pushrod was used to allow for a little pressure relief during operation.

 

[ebeeby]

You can run the engine without the valve cover and see the oil drizzle in down the head studs. In fact, it is recommended to do so if you think you used too much sealant on the cylinder base.....

 

[fredheiler@aol.com]

Our pushrods are OK!

They were not hollow in order to provide oil to the rockers. Never were. That oil is provided through the hole in the heads where the head bolts go. It is via the small hole cut near the threads that go into the block at the top two head bolts. Oil drains back to the sump through two holes in the bottom of the head. Near as I can determine the small dimple at the end of the pushrod was used to allow for a little pressure relief during operation.

OMG! You've made my day! My mistake, assuming that all German pushrod engines would be the same!

Seriously, thanks again, Fred

 

[fredheiler@aol.com]

R75/5 Engine

Go here for a flow image on Snowbums site https://bmwmotorcycletech.info/oilsketch.htm. Hope this helps.

VERY helpful! Thanks, Dave.