Does The Rotor Point At #1 On SBC At TDC?

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jjj J When I get the distributor to seat on the intake and the damper is at 0 degrees/ TDC, my rotor either points just before # 3 cylinder or just past #1 cylinder. It does not point at the #1 plug, rather more towards the midline of the engine past he actual piston top. All-in-all it is closer to #1 than #3. Does just past #1 sound OK? I guess the Harmonic Balancer could be going bad- costing me the degree or two. Huh? Status Not open for further replies. #1 · Apr 13, 2019 When I get the distributor to seat on the intake and the damper is at 0 degrees/ TDC, my rotor either points just before # 3 cylinder or just past #1 cylinder. It does not point at the #1 plug, rather more towards the midline of the engine past he actual piston top. All-in-all it is closer to #1 than #3. Does just past #1 sound OK? I guess the Harmonic Balancer could be going bad- costing me the degree or two. Huh? Sort by Oldest first Oldest first Newest first Most reactions #2 · Apr 13, 2019 It doesn't really matter where it points to on the actual engine itself, it just has to point at the #1 wire in the distributor cap, wherever that may be located in the cap. All the rotor does is put the spark down the wire it is pointed to when the ignition module fires the coil....the rotor is completely brainless about where it is actually pointed. It is your job at distributor installation to sync the rotor with the distributor cap and wire orientation....not which engine cylinder it is pointing at on the engine block itself. If it actually messes with your OCD and you just have to have it point at the cylinder and spark plug #1, all you need to do is pull the distributor out of the engine, reach down through the distributor hole in the intake with a long, large flat blade screwdriver, and turn the oil pump slotted drive backwards(counter-clockwise) 10-15° so that it will engage the cam gear one tooth different but still lock into the distributors oil pump drive tang on the bottom of the distributor gear and allow the distributor to fully seat on the intake manifold. #3 · Apr 13, 2019 Before you pull the distributior: Mark the relation between the balancer outer and outer. This lets you know if the balancer has spun and you can correct it. Mark the relation of the distributior shaft to the hold down tab/intake. This lets you drop the distributior down and have it perfect off the bat. If replacing the intake remome the cap and rotor place a screwdriver in the rotor slot and mark a dot on the firewall. You can put the distributior cap any way but the wires are often to short if tring to flip it 180 for firewall clearance. #4 · Apr 13, 2019 I do get that Eric, the problem is that the rotor tip goes past the #1 terminal on the cap by about 7/8". I don't know that it could be off by a tooth; it seems more likely that the harmonic balancer is bad or the timing chain is worn or skipped. I guess the good thing is that if I have to change one, the other is right there and can/will be changed as well. Anything else I should check to explain why the rotor and ANY plug position will not align? #5 · Apr 13, 2019 Pull the timing cover. You will be out around $100 in gaskets (wp, tc, oil pan) but answers any timing questions. Letting you line the marks up and be good(if they used the 0 marks)to set the dizzy where ever you need to pick number 1. #6 · Apr 13, 2019 If you pull the distributer cap on a motor that was running correctly TDC on the balancer won't align with the #1 terminal on the cap. It will be past it. How much in degrees depends on how much advance your timing is set at. So if you have your base timing set at 17 degrees BTDC expect the rotor to be pointing 8 or so degrees past the terminal at TDC. This isn't to say you don't have a loose timing chain or slipped balancer just that the two shouldn't line up under normal operating conditions. #8 · Apr 13, 2019 engineczar, Yep, I know the marks won't align once the engine has been turned after finding TDC. I mean to say that I have the engine back at zero on the balancer, and the rotor tip points just past the #1 cylinder, but the rotor is past the position of the #1 distributor location by 7/8"; shouldn't the rotor point right at #1- wherever I choose to place it in the distributor? Or does the rotor point to #1 AFTER I achieve correct advance timing by rotating the distributor to 10 degrees or whatever? I've added a picture- the wires are not correct in it as I switched them around when choosing a different #1 designee. The picture just shows the wire pointer I rigged to show where the rotor was pointing when I placed the distributor cap back on.

0 Reply #7 · Apr 13, 2019 Just rewire the cap with number one on the terminal location where the rotor points when the crank settings are at TDC. Obviously there are two locations of cylinders that are firing at the TDC mark that being number 1 or number 6, these being 360 degrees apart in the firing order. That said each distributor gear tooth is about 24 degrees of crank rotation so if the distributor gear is off a tooth. Being off a tooth is common after removing the distributor as that action of lifting the distributor out rotates the distributor shaft because of the gear spiral shape, this drags the oil pump drive with it. So when reinstalling the pump drives don't line up. The way around this is to install for the desired or marked position for number 1 till the shafts meet but don't engage so the pump sits a little proud of the manifold. At this point you put a wrench on the damper bolt and crank the engine around clockwise till the distributor drops, this now has pump shaft to distributor shaft engagement and the rotor is set to number one firing. Bogie #9 · Apr 13, 2019 Thanks, Bogie. If I was out 180 degrees- timing mark at zero- wouldn't the rotor be pointing 180 degrees away from #1? As for the second paragraph, I have been fooling around with getting distributor by using an old distributor stripped of the cam gear, or a long screwdriver. Only this year did I get onto the Hold and bump/rotate method you outlined- it is brilliant- I don't know why I'd never seen it before. Anyways, as explained in my last post, the rotor- when the distributor is seated does not align with any post on the distributor, is the problem, so unless I really don't get it, it must be a timing gear/chain issue or bad balancer? Show more replies 0 Reply #10 · Apr 13, 2019 Chevy used a few different reference points for the distributor, all are referenced from TDC compression stroke and are reference points only. Rotor facing #1 (not exact) was one reference point, another was facing straight ahead (again not exact) and I believe there are a few other variations to this. Again, these are just reference points. Once the distributor is seated, the wire placement and rotation of the distributor's body in reference to the rotor does the rest. IMHO, the distributor's rotor will seldom point at #1 (or any other reference point) exactly. #12 · Apr 14, 2019 It's late here and it is raining again, but I just decided to rotate the distributor one tooth clockwise, and was able to drop the distributor right in so that the #1 position in my photo (post 8) is right in front of the business end of the rotor. Too wet and late to work on it tonight, but it's good to make some headway. As long as I have been working on small block Chevys and Clevelands I'm always amazed that I can still get stumped over seemingly basic problems. The kind where you scratch your head and utter "What the hell did I miss?" Thanks for all the help. I'll verify how I made out tomorrow. :welcome: #13 · Apr 14, 2019 Got it fired up before the rain today. Back in business; everything is running great. Smooth, solid shifting. No off idle hesitation. Cruises easy with surprising pick up. Just for grins I'm gonna check lash and valve seals when the sun comes out again. Thanks for all the help. See you out there. #14 · Apr 15, 2019 In the Pacific Northwest the sun coming out this time of year is maybe Memorial Day for a few hours or not until our summer starts on July 5th. Between those dates it will be chilly to cold, and cloudy if not raining. Sounds like you need a garage preferably with a concrete floor, insulated walls, and a heater. Bogie 0 Reply Status Not open for further replies. You have insufficient privileges to reply here.

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