Oil thrower orientation

This question has been asked many times before, but I found a way to complicate it even more. I'm rebuilding a '69 MGB. The oil thrower is the type that has a circular indentation about half way out from the center, but the outer edge is flat. In the Haynes manual, it says to install the oil thrower concave side forward or letter F forward. However, with my thrower, if you orient it with the letter F facing out (in other words, you can see the F as you look at front of engine), then the concave side is then on the inside (so it looks convex as you look at the front). So apparently it contradicts. Which way is correct? Does it even make a heckuva a lot of difference how you orient it?

I'm gathering there are two different kinds of throwers. I'm guessing Haynes is trying to describe either case both by saying letter F forward OR concave side forward, each being a different case. Or maybe when they say "letter F forward", they mean the F faces the front of the engine. Either way, it ends up confusing anal people like me.

David,

Forget convex/concave. The "F" goes toward the front of the car/engine. This puts the bulk of the body of the thrower forward and the flat of the thrower flat against the crankshaft sprocket. It's designed this way so that the thrower will be clamped tightly between the sprocket and the harmonic balancer when the balancer is installed. If you were to install the thrower backward it would not seat against the sprocket and so would be distorted and damaged when the balancer is installed.

Dick

The concave side is supposed to go towards the engine, however they will work if placed either way, we used some German made Iwis timing chains in the past on the race cars they have larger rivets on them than the AE and the normal offering timing chains so I flipped the orientation of the oil thrower to have the concave area facing outward/forward to buy a little clearence on the rivets on the Iwis timing chain and the engine worked fine, no leaks in that area. You can test the fit and clearnece of the oil thrower to the timing chain by installing the harmonic balancer and torquing to spec without installing the timing cover and see what clearence you have towards the timing chain. The oil thrower will not hit the timng cover in either orienintation, so you don't have to worry about that.

The only job of the oil thrower/slinger is to shield oil from direct spalsh towards the back side of the seal, and it will do that installed either way.


Hope this helps.

Thanks, Dick and Hap. Between what both of you told me, I got it figured out. Very helpful indeed. - David