Head-gasket O-Ring question
 

Im about ready to button up my top end, but the O-Rings seem slightly too small. They keep popping out of their grooves.

I there a trick for helping them fit ?

* stretching around a slightly larger diameter object (or by hand)
* warming with a hair dryer
* jamming them into the groovs and boldting the head down
* using RTV to hold them

I thought perhaps they were for a 250 (Im upgrading to a 300 EC), but the ones from my 250 are way way too small.

Try a dab of grease to hold them in place, if required a little massaging wont hurt

I already tried RTV
 

I tried putting RTV in the groove and then laying the O-Ring into it, but it just popped out.

I dont want to pull on it and break it

I thought of using some hot tap water or boiling water to soften the rubber, but dont want to melt them or anything.

Thanks Widebear

Clean the RTV off everything. Grease the o-ring and pull it between your fingers, stretching it slightly over its entire circumference, it should also not be too cold, room temp is OK. Now, lay it in the groove and move finger over the entire circumference pressing down slightly until it stretches slightly and stayes in the groove. Place the head on in position and twist a few degrees back and forth with slight pressure, there should be a smooth even drag if the o-rings remained in place. Install head bolts.

I was not able to get the grease method to work well for me.

What I do is stretch the o-rings out to where they are slightly larger than the grooves and place the o-rings in the grooves. The o-ring will start contracting back so the trick is to put the head on just as the o-rings drop securely into the grooves. Wait too long and the o-rings contract too far pulling out of the groove.

The o-rings will take a surprising amount of force to stretch and have to be stretched pretty hard to make this work. I have successfully done it quite a few times now without any o-rings failing. It minimizes my frustration.

The way I just did it was I put a little grease on finger tips and applied to O rings, then lay O rings in the grooves and smooth into groove and if it doesn’t stay make sure the 2 are in the groove on the same side then slide your head in place Don’t push down, Then insert a feeler gauge straight in between O ring and head (make sure you capture both with the feeler gauge) at a point where the O rings are in the groove and then just slide around as you apply a little down pressure to the head.
You will feel them magically fall into the grooves then slide out your feeler gauge.
Works every time it’s tried.:D

Good luck.