Trollhole Distributor Install Help

[bmorefj40]

Well, finally got around to installing the trollhole electronic dizzy I bought almost a year ago. But I ran into some questions while pulling it apart and decided to stop before pulling the old one out.

Step 1. I timed the engine with the current dizzy (unplugged vac hose on dizzy) and marked the locations on the dizzy and the engine block just in case I wanted to throw the old one back in. Also checked idle and sits right about 650 rpm.
Step 2. Lined up the flywheel reference line (not the BB) with the inspection window pointer, pulled the cap and this is where it got weird. Every other post I've seen says that the rotor should now be roughly pointing to the #4 cylinder (counting front to back). Mine is pointing exactly 180 degrees the opposite direction. So, the metal tip on the rotor is pointing to the front passenger tire, not towards the engine block.

This has me stumped since it may be possible that the truck has the old dizzy reversed, but the truck has run fine for the past 10 years as is. It's a little rough at idle if I don't run it once a week, but after about 5 minutes, it's perfect. one pump of the gas and it starts right up, no stalling or backfiring. It's probably due for carb rebuild(Weber 38)- haven't done one since I bought the truck, which may explain the slightly rough idle on cold start. Is it possible that the back of the rotor should be pointing towards #4 and then I should install the new one in the same direction? Even though I have '73, the engine is a 2F from a 75 and no smog system.

Just want to be sure about the rotor position before pulling the old one out and if the new one should go back in the same way or not.

Thanks for any advice.

 

[bmorefj40]

ok, just went out to snap a pic, since this would be useless without pictures and I think I must be going crazy. I just went out did the "bump" method with the truck in gear to get the ref line to match up with the pointer, then popped the cap and viola the rotor is pointing right at #4. Seems like a there is no issue. Are there more than just the BB and one ref line on the flywheel? Would it be possible that there is another line on the opposite side of the flywheel?

 

[kjedmondson182]

4 stroke meaning the compression stroke is every other time the line is in the window. ie the pointer points at # 4 every other time the line is in the window.
my .02

also, if you put it in 4th and jack one rear wheel off the ground it's a lot easier to dial in the fly wheel by spinning that rear wheel if you have someone watching the window

ok, just went out to snap a pic, since this would be useless without pictures and I think I must be going crazy. I just went out did the "bump" method with the truck in gear to get the ref line to match up with the pointer, then popped the cap and viola the rotor is pointing right at #4. Seems like a there is no issue. Are there more than just the BB and one ref line on the flywheel? Would it be possible that there is another line on the opposite side of the flywheel?

 

[ColonelMustardFJ40]

You can actually put the #1 rotor position anywhere you want provided the distributor will fit in without interference with the external vacuum mechanism and that you align the oil pump drive (all of this assumes that you have the firing order correct - which it sounds like you do). The reason the manual says that it should be pointing towards #4 spark plug @ TDC compression for #1 is to have the vacuum device pointing away from the engine block and to make sure the plug wires fit, which I don't think is a problem because the distributor is central to the block. With the engine at TDC compression for #1, you can align the pump drive in the block to match inserting your distributor with the rotor pointing to #4 spark plug. Then set you timing as desired. Just like the FSM shows. My $.02 worth.

 

[vtgbeemer]

If you haven't changed a distributor on one of these , now would be a good time to read up on the second aspect of a successful distributor exchange and that is getting the new distributor fully seated in the oil pump drive. There have been a few engines damaged because of no oil pressure. The spade on the distributor drive gear must drop into the slot on the oil pump drive because the distributor actually transfers the rotation from the camshaft to the oil pump.