Sensenich FP prop/Saber crush plate query

Hi, we have a flying 7A with an O-360 and a Sensenich 72FM8S9 FP metal prop with the Sensenich spacer. We need to pull the CG forward and are looking at fitting a Saber Crush plate complete with the Saber 2.25" spacer. We have only had the prop off once and can't remember clearly, but can anyone help...we vaguely recall that in the prop and spacer setup there were dowels, some were recessed and some were proud, but can't remember where in the setup they were. The query is that the Saber spacer comes with six proud dowels between the spacer and prop. Is there anything we need to do with the prop regarding dowels. Again can't recall whether we managed to separate the prop from the Sensenich spacer when we sent it off for service so are unsure as to the setup.
Just don't want to take the prop off just to have a look. Thought someone may have already been here.
Thanks
Derek

Saber crush plate

I just went thru this. Remove prop, knock out the 2 dowel pins that locate the Sensenich spacer to the back of the prop. In order to fit the Saber prop extension, the 6 holes in the spinner rear bulkhead will have to be enlarged to fit over the prop drive lugs in the prop extension. Now it will all bolt together as before. Don't forget to get the proper length bolts for the prop extension to engine, and bolts for the prop to prop extension. Bolts available from Saber.
The heavy crush plate helped my CG.

Gary

Thanks Gary, when you said the "heavy" crush plate did you go for their 18lb one over the 14lb one?
Thanks, you have explained this clearly! having looked at diagrams I now realise where our confusion was...when we took the prop off a long way back the spacer came with it and we didn't knock the dowels out due to nerves! What we are confusing ourselves with is that the crankshaft drive flange has four long drive lugs and two shorter ones. The Sensenich spacer seemed to fit one of two ways to possibly aid with indexing the prop and that was probably the way Sensenich drilled those lower spacer holes.
I get exactly what you have said above and am therefore assuming that the two different lengths of the crank drive lugs don't matter with the Saber spacer.
Thanks
Derek

The crush plate I received from Saber was 17 lb. The Saber prop extension is not indexed, and will go on in any orientation. To knock out the dowel pins, set the prop on 4 x 4's next to the rear spinner bulkhead, a punch and a heavy hammer will knock out the dowels. The Saber prop extension does not use the dowel pins.
My CG moved forward ~ one inch.

Gary

Hi Derek,

Gary's advice is solid. I would only add that you should not hesitate to call Sam at Sabre Mfg. I am doing the same thing as you and I just spoke with Sam yesterday. He is very knowledgeable and patient and talked me through all my questions and concerns.

Here's his contact info:

Sam Tilleman
Saber Manufacturing Inc.
Phone : 817-326-6293
[email protected]

Thanks for the extra help. i have been boring Sam with my questions and wanted to give him a break!
Looks like I'll go with heavier plate in that case and the point on indexing has just answered my latest question that was coming.
Do you know why The O-360A1A prop flange has two short dowels and four long ones?
I'm guessing from comments that this does not matter with the Saber spacer...just curious.
Thanks again

My understanding is that the prop flange is configured to only allow the flywheel to fit in one orientation so the timing marks are right. The spacer can be clocked any way.