Installed a New Temp gauge and the car was running fine never went past 195 while driving around with total timing set to 36* to just test it out. After 25 mins of driving around it began feeling pig rich @ Idle, no gas smell but I could tell when attempting to accelerate it bogged/ backfired once through the carb. Felt as if it was flooded. The odd thing it cranks right up and fine after I park it. For sure now it's turning into a carb problem. Screws are backed out 1 turn on all 4 corners. My thought is that when attempting to tune it I might have exposed the transfer slots. I will pull the carb and take a closer look. It was a brand new Holley DP 850 but who knows something might be wrong. I don't think it has a blown power valve since didn't holley add something to prevent it? I will take a closer look. Might just be a carb problem. Thanks for the help, and everyone! As usual Buick guys are always the most helpful :beer
How can it be running rich with black plugs yet be pinging too and be only a carb problem? Sent from my iPhone using Tapatalk
If the plugs are black, it is either a carburetor problem, weak ignition, or plugs that are too cold. Oil consumption can also play a part in pinging/detonation. Deposits built up over years can pre ignite the fuel mixture as well as increase SCR. There may be a lot of factors at play.
The shop that originally dialed in the car also mentioned that the car liked a lot of timing . My thought is could it be I had retarded the timing enough that it wasn't burning the fuel as efficient causing it to appear rich? Sent from my SM-N920P using Tapatalk
Just realized that I have jumped over setting initial and gone straight on the mechanical in the past. “People have 6-8 initial in most cases” Which means that they need 22-30* bushing to reach 30-36* mechanical. There are one company who makes 10* and 14* bushings for MSD and they claim that a higher initial timing would take away “stinky rich exhaust at idle” "most of you have already discovered to get a clean crisp idle out of your tune up and to make the carb adjustments respond to your tuning your performance engine wants more initial timing.". And gives example that their bushings makes 22* or 26* initial possible. (36* mechanical - 14* bushing = 22* initial) Smallest bushing included my distributor = 18*. (36* mechanical - 18* bushing = 18* initial) Question: Do we want as high initial and limited bushing as possible? Or is 6-8* initial most optimal? [Edit] I just studied the distributor curves and noticed that the distributor only can provide with ~28* mechanical advance. 36* Total - 28* mechanical = 8* initial. 28* mechanical – 8* initial = 20* bushing. But it’s still interesting if you should have as a goal to have a high initial.
Again you are overthinking this. The only reason for running 20+ degrees of initial timing is if you have a big cam which requires it. All you need is 12-14* of initial timing. Run the 21* bushing. If I was you, I would look for a shop in Sweden that works on older cars. You need a second opinion from a competent mechanic. I have a feeling that you have some very basic problems with your engine that you are missing.
I have a remanufactured HEI distributor. Installed MSD rotor , coil, cap and module with rev limiter. I purchased a Crane advance curve kit and a Crane adjustable vacuum advance cannister with a vacuum timing limiter/stop. I installed adj. cannister and limiter per instructions. Will redo limiter using your pics and method. My initial seems to be happy set at 12*. (Mild cam/build) I bought an MSD advance kit from Summit for HEI distributors, because it stated in the description it contained total advance bushings. It did not, bushings in kit are to use when replacing the centrifugal weights. It seems every kit I look at which contains the brass bushing to limit total advance states in the description it is for points style distributors. A link to the proper advance kit with the correct bushing to limit advance in HEI distributors would be great. I am assuming you need to remove the rollpin and gear to install this bushing. Looking forward to finishing up this distributor and getting on with power timing . Thanks Jim/Rott Tapatalk User
No, there is no advance stop bushing in the HEI Distributor. The mechanical advance amount is dictated by the shape of the center piece and weights. There are some posts here where members have come up with inventive ways to limit the mechanical advance. I know this thread is long, but you will have to read through all the pages to find the posts that apply to the HEI.
5 minute response time.... pretty dam good Larry. Thanks for the answering that question ,appreciated. The MSD advance kit which claimed to have limit bushings may do just that. Albeit these bushings go on the pegs for the centrifigul weights which are included in kit which also contains a new center piece. Perhaps this is what limits total advance, changing out center piece, weights and weight bushings? On another note, when I pulled the distributor from my engine after break in , I noticed I had dodged a bullet , catching the rollpin trying to exit stage left. I did neglect to mention this was a lowmile remanufacture , but still a used unit. I am going to replace pin with new. Can /should I use a lil dab of red loctite for insurance? Jim Tapatalk User
I'm not aware of any MSD advance kit with bushings for the HEI. Can you link me to what you are seeing? Advance stop bushings are used in the MSD distributors, and that is all they fit. The roll pin shouldn't need anything, but if it makes you feel better, use the lock-tite. A new pin installed correctly should do it unless the hole in the shaft is worn too big. Check that.
The bushings in this kit are for mounting the new weights onto the new center piece. I can't seem to link while using Tapatalk and Summit app. Summit part number for MSD advance kit is MSD-8428 . In description it states included are advance limit bushings. I believe that mech advance may be limited by using thier replacement centrifugal weights and center piece . Check out the pdf. file download. (Instructions ) and thanks, Jim Tapatalk User
https://www.summitracing.com/parts/...msd-ignition&gclid=CMv8t8DphtICFceLswodl3sLdA The plastic bushings you see are for the weight pivot pins. They have nothing to do with limiting the mechanical advance. Those bushings are common to just about ANY weight kit for the HEI. One review says 24* of mechanical advance with those weights, not bad.
12* initial + 24* = 36* right in the ballpark Then I'll limit the vacuum advance to 8 to 10* and that should do it. Jim Tapatalk User
Quick question, I did the tuning in this thread and here is where I'm at. Initial timing 14, mech. Adv. Starts coming in at 1200 rpm, all in at 2400, for a total of 48, so 34 for mech. Adv. No pinging under acceleration. Vacuum adv. Is giving me 12 deg. Of advance. 48 to high ? Should I put the bushing on ? Sorry , this is on a 350 , factory distribtor.
OK, you may want to recheck your numbers to be sure. If you have 12* of vacuum advance, and you are measuring 48* total including vacuum advance, that means your initial + mechanical must = 36*. So if your initial is 14*, your mechanical must = 22*. 14 + 22 + 12 = 48. Vacuum advance will only operate when the engine is developing vacuum at closed and light load part throttle. At WOT and high load, vacuum is low or near 0. The spring in the vacuum canister will pull the vacuum advance out leaving you with initial + mechanical. Is this an all stock engine?
Your numbers are correct. With vac. Adv plugged, I'm getting 36, with vac. Adv. Hooked up 48. The engine is stock except for the cam and a TA intake. I don't know what cam it has, the p.o. put the cam and intake, 4 barrel carb on.
