Valve lifter broke off during engine assembly!

[Lars S]

During assembly of my stock -70 1.7 I was by hand wiggeling in the #4 exhaust lifter and it fell apart , no force at all was used. All other lifters seems OK, should be stock lifters.

Have been running this engine in a 411 for the last 50000 of its 100000 miles, did not notice any strange sounds last time I started it which was a short run after sitting for 10 years.

Only thing I can remember as strange was one rocker shaft came lose for about 4000 miles ago...retightened it and everything looked and sounded OK since then...dont remember if it was this side though and if it could have any influence(?)

Looking at the broken ends (pic at the bottom) it seems that some of the fracture is hammered (but not wery much) so it might be that it broke during running and have been held together by the force from the valve springs.
Lifter bore and cam lobe looks unharmed.

What can the reason be and is this a known issue with Type4 lifters?

//Lars S

[Piledriver]

Many lifters seem to be hollow these days and held together with snap rings, like hydraulics with different guts.
This makes for a very light lifter as oil weighs less than iron...
The snap ring grooves combined with the deep cut away on the OD of the bodies make it easy for it to crack and eventually break.

FJCamper lost a similarly constructed T1 lifter in their last race.

[Lars S]

Many lifters seem to be hollow these days and held together with snap rings, like hydraulics with different guts.
This makes for a very light lifter as oil weighs less than oil...
The snap ring grooves combined with the deep cut away on the OD of the bodies make it easy for it to crack and eventually break.

FJCamper lost a similarly constructed T1 lifter in their last race.

Thanks!
Agree, there is not much steel where it broke.
This should be a stock lifter...I guess the "disc" that came visible has the groove for the pushrod machined in its other end and was pressed in from the pushrod side into the bore of the lifter. The disc add some support of the closed half of the lifter.


Lars S