Engine: 169.6 flat 6 help again please

[bosshoss61]

I'm trying to figure out the engine balancer. I take my motor apart, sent it to the machine shop for their basic rebuild, get it back and all is going good. I'm putting the motor back together in accordance with the shop manual. OK........The balancer that was in the motor was only indented on one side(so only one of the rubber cushion fit in it, never did figure that one out) ---so I order a ( new) balancer from S.I. PN 519387 page 168, for a 50 Champion. The new balancer has NO timing marks at all of any kind for the Champion or Commander. There is a pointer on the cam and crank gear cover----so am I stuck guessing at the timing? The book says NEW-51937----I guess I misread things again

[bosshoss61]

Sorry, I meant---519387 vibration damper

[RadioRoy]

Why not put the new and the old on top of each other and transfer the marks? You can align them by the keyway.

[bosshoss61]

That would have worked out good except for one thing---The original damper only had one little dimple in it (where the timing marks should have been). Like somebody drilled a 1/32 inch deep hole with a 1/32 inch bit. I'm not even sure if it was a timing mark. But it was on the outer edge of the damper........

[PlainBrownR2]

On the damper, is there an offset hole? On the postwar V8 engines, there is an offset hole on the damper, and an offset hole in the rubber cushion. The damper only fits onto the crankshaft hub in one way in this fashion. The reason for the offset hole is because that indicates TDC for the #1 piston, and the mark on the damper would line up with the pointer on the block. People will think that all six holes are equally spaced, so when they install the damper to the cushion, end up tearing up the cushion because it doesn't fit correctly.

[bosshoss61]

Got the offset figured out and both rubber cushions fit just fine. But the new damper I ordered from SI[(519387) and my invoice that came with the damper said (used)--$20.00)] has it no markings at all. Is there a way I can put my own degree markings for a Champion on the damper? Now I'm not sure if it is for balancing or timing? The book says $27.00. What the heck happened? Did they run out of new ones so,,,,,,,,,,,,,,,,,,,,,

[PlainBrownR2]

This will be a little rough, but here goes.....

The offset hole is TDC on the #1 piston. The offset hole should be in relation to the piston, and the piston should be at the top of the stroke. On the crankshaft, get all of these lined up, and then mark the damper as UDC. Move the crankshaft counterclockwise a very short distance, until the distributor rotor(you need the distributor cap off to see this, is lined up with the #1 lobe in the distributor, and the points are open and riding on the top of the cam. Mark this on the pointer as IGN. Move the damper counterclockwise again, until the #1 intake valve just starts to open(head must be off). You'll have to move it back and forth a little bit to find where it initially begins to open. Mark this as In-Op or "Intake valve Open". If I recall, the damper functions as both balancing and timing the engine, as it's a large flat plate.

[PlainBrownR2]

On the postwar engines, those marks aren't divots or punchmarks. Rather, they're just lines, almost like chisel marks cut across the top edge of the damper to mark each of the points in the piston stroke. So when you would get to that point, you can put a Sharpie mark across the edge of the damper, or scribe a line across the damper, to mark where the pointer is at.

[Dan Timberlake]

Curiously this shows there should be an "IGN" mark on your damper, but actual degree marks on 1953 and newer.

http://www.carnut.com/specs/gen/stud50.html

My CD copy of the shop 1959-1964 manual shows an "IGN" mark on all but jet thrust engines.
My paper copy of the 1959-1960 manual shows an "IGN" mark.
They both show extra marks for "IN-OP1" (intake valve opening?) and UDC ( top dead center = 0 degrees).

I like to confirm the accuracy of the TDC mark on engines anyway. On overhead valve engines that is usually possible using a stop or pointer to contact the top of the piston thru the spark plug hole. Looking at the section view of the flat head six the spark plug is offset from the bore quite a bit, making it unlikely a stop or pointer could be used.

Some folks report good results using a balloon on a fitting screwed into the plug hole. At TDC the balloon is biggest.
Here's a little naughtier version of that method.

http://jalopyjournal.com/forum/showthread.php?t=778434&highlight=patent

[PlainBrownR2]

Yep, IN-OP1 is Intake Valve Open #1 piston, and UDC is Top Dead Center.

[Dwain G.]

Oh for #%&^@s sake! Not again! I think I'd be burning right now. I suspect they actually sold you a 515198 damper, which is for pre-war Champions. They had their timing marks on the flywheel.
Ask S.I. if they can look for a damper with all the marks on it.

[Skybolt]

Why not just use a used damper that one of us could send you? Easy for me to say as I have none but it might be easier that way.

[bosshoss61]

Thanks Dwain--I don't get it either. I'll call SI this morning. The book says 27 bucks, so unbeknown to me---they sell me a used one for 20 with no markings at all. Thanks for the chart Dan. I found it interesting about the firing order on the first out 1951-V8 Commander. It's the same as my 98- 350 Chevy ZZ4 motor. Is that just a coincidence, it's not a Chevy motor is it? Or just happens to be the same balancing act between cylinders. The head is off the motor. So finding TDC is easy with my dial indicator on top of the block. I have at my disposal a 7" timing wheel. That I laid over the 8" damper. So the annular space is about 1/2". Good for marking the balancer. PlainBrown-thank you, it also appears IN-OP1 is set from 15 degrees to UDC, and exhaust closes from UDC until 10 degrees after TDC or UDC. So what it boils down to is, forget the timing light and setting the distributor to a certain mark. Did anyone find a timing mark where the engine run best.....I got a real kick out of the distributor hold down bracket. The manual says it is for (back then) setting between regular and ethyl gas. The manual does not specify spark at a certain BTC or after TDC location. Thanks, I hope I'm moving in the right direction.