500i bottom end.

[Chainsaw Mick]

has anyone ever rebuilt 500i without the intake deflection part, type thing that is situated under the piston as it hits TDC?
Reason I’m asking is I have 500i and that part was badly damaged, as bottom end is scrap anyway I thought about grinding is down like normal Stihl crankcase and rebuilding to see what happens, how it runs.
Has this been done before and what would results be?

 

[stihl #1]

This is from the shop manual. I recall when I was in Germany for the intro of this saw that we were told the scavenging ramp was there to deflect the fuel oil mix up into the small end needle bearing, and prototypes without it had bearing failure with low run time. So the risk you take by running without it is bearing failure.

 

[huskihl]

I started removing them on the 661 and 461. No issues yet after 6 months in the hands of a logger

 

[stihl #1]

It might be the fuel injection path the fuel mix takes, but IDK for sure. The injector does aim the fuel mix right at the ramp as it mixes with the incoming air. Might be the difference between a few hundred hours of run time vs several hundred hours of run time. Won't know till you try.
What is the advantage to removing it on the normally aspirated models?

 

[huskihl]

It might be the fuel injection path the fuel mix takes, but IDK for sure. The injector does aim the fuel mix right at the ramp as it mixes with the incoming air. Might be the difference between a few hundred hours of run time vs several hundred hours of run time. Won't know till you try.
What is the advantage to removing it on the normally aspirated models?

The pistons are known to hit the flange and potentially blow things all to hell inside. If the flange isn’t there, it doesn’t hit anything

 

[Chainsaw Mick]

View attachment 466075
This is from the shop manual. I recall when I was in Germany for the intro of this saw that we were told the scavenging ramp was there to deflect the fuel oil mix up into the small end needle bearing, and prototypes without it had bearing failure with low run time. So the risk you take by running without it is bearing failure.

Thank you for input. That’s interesting about sending fuel up to the bearings. Do you think a different type of bearing could last without as much oil? I’ve heard of Ceramic bearings but never encountered them yet.

 

[Chainsaw Mick]

I started removing them on the 661 and 461. No issues yet after 6 months in the hands of a logger

I think I’ll clean it up then and throw it back together. Nothing to loose. I’ll let you know if it fails.