Timing Question

Dec 10, 2017 2:00 PM - 1445 Views Create A New Thread

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Bill33

Blaine, WA



Can't get my initial timing down to where I want it.
My '33 has a heavily modified 383 Chevy Stroker in it (turned just over 600 hp on an engine dyno) and needs 36 degrees total timing to get the maximum performance. I'm running an MSD 6AL system with an MSD pro-billet mechanical advance distributor, part number 85551. I changed the advance stop bushing to a 23 degree unit, which I thought would reduce my initial timing to a minimum of 13 degrees, although I'm ok up to about 18 degrees, Right now, the initial won't go below 22 degrees, giving some kick back at times when starting. Am I misunderstanding something here or could it be something else other than distributor. The engine will idle down to about 1000 RPM with a very lumpy idle, which I don't mind, although the idle will jump up to 1200 sometimes. I'm running two heavy silver advance springs at the moment, but am getting confused a bit about the actual results of the different spring combinations. I have the other springs if needed. Any help would be much appreciated. Thanks, Bill









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Comments
  • Bill33
    Feb 5, 2018 at 7:19 PM


  • Update: MSD was convinced the inablitily to set the timing properly was because I wasn't using one of the MSD self powered timing lights.. I finally was able to try one today and nothing changed, however, I think I'm down now to thinking it may be cam walk, as a couple people suggested in the past. I didn't think it was because the engine has a cam retainer plate, however, this last version of the engine does not have one. It's the same engine that had the retainer plate and I've always assembled the engines myself, but this version was put together by the machinist. I called him today and he confirmed he was unable to install the cam retainer plate because the Isky cam that I ordered for this build came with a flat end at the timing gear end, so he installed the old style timing gear. I'm not sure what he used for a thrust button, so I guess I'll have to pull the front off the engine and see what's in there. I may change to a full timing gear set up while apart and get rid of the chain altogether.

  • Bill33
    Feb 4, 2018 at 10:26 AM


  • Not solved yet. I've done everything physiclal I can think of, including trying another identical distributor, indentical MSD 6AL box, confirmed 12 volts at the MSD box, confirmed box wired directly to the battery terminals, changed the coil, removed #1 wire from the holders to give it isolation, tried timing it on #6 (no change) checked the distributor drive gear, changed the mag pick up in the distributor, new cap, new rotor, no play in the distributor shaft. MSD is convinced that it's the timing lights I'm using, although I've tried analog, digital non dial back and an old primitve snap on unit and run the power from a remote battery. There is a guy that has the proper MSD timing light, but he's not anxious to lend it, and would like me to take the car there, which is ok, but been wet every day for three weeks. Might be some dry weather later this week, if so I'll get it over there. Hard to believe it's the light, but I'll try it. I'd buy one, but their about $200 USD once I get it to Canada.

  • dwalters
    Feb 4, 2018 at 9:05 AM


  • Have you solved your problem? Make sure that the distributor gear is not worn. If it is, you will have timing issues that are erratic. Check for movement with the cap off, rotating the rotor back and forth. I ran into this on a BBC blower motor with a roller cam.

  • Bill33
    Dec 30, 2017 at 10:48 AM


  • Yes, I can try that, it gets dark here around 4:30. Good idea Verne.

  • crdnblu
    Dec 30, 2017 at 10:36 AM


  • I understand your concern for your neighbors vs a healthy exhaust, but maybe late this New Year's eve, idle it in the dark, attach a ground wire from a known good GND to a long bladed screwdriver, and pass it all around your plug-wires in those areas near the valve covers. It's an old-school trick, but can yield some quick info re/ possible plug-wire leakage.......

  • Bill33
    Dec 29, 2017 at 3:00 PM


  • I don't think I have any crossfire, but my wire separators for each pair of wires on the heads are aluminum. Maybe getting some leakage there.

  • 36sedan
    Dec 27, 2017 at 10:41 AM


  • Something I just remembered I did on my motor that caused crossfire problems and real bugger to find. I was careful with wire routing everywhere except under the header pipes (see pict).


  • Bill33
    Dec 23, 2017 at 1:30 PM


  • Ok, tried a new cap and new rotor, brushed dilectric grease on all terminals inside and outside the cap. No difference. I set the initial now at 18 with and 18 degree advance stop bushing, which should give me 36 degrees total timing. I set the initial at 18, slowly rev up the engine and watch the timing advance up to 30 degrees, then it appears to start going backwards and loses track of the mark. It pretty much has to be interference as I've now tried 3 different lights and the car seems to run perfectly and the engine starts and stops well, no kickback or run on. Once I get it out on the road for some serious testing if it doesn't feel right, I'll take it to a friend who has an old Sun distributor machine. He can check the total timing and the curve. Thanks for the advice. If I ever solve it, I'll post the solution. My friend had it happen years ago on an HEI distributor and he never solved it, just used the distributor machine to prove the total timing and curve.

  • crdnblu
    Dec 22, 2017 at 7:34 PM


  • Just for "grins"........Try putting some dielectric grease on the terminals inside of the cap, as well as the rotor tip, then see what you get for timing. The jury is out on this, (pros/cons), but it might be worth a try, since you're planning to replace the cap & rotor anyway.

  • Bill33
    Dec 22, 2017 at 3:20 PM


  • Thanks Verne, I do have some wear on the terminals inside the cap and on the rotor, so will change those this weekend. I normally do use the dilectric grease on the plug wire ends going into the cap. My wires are MSD wires and are about a year and a half old.



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