buickbrothers Posted October 24, 2023 Share Posted October 24, 2023 Ok veterans. I've been unhappy with my engine smoothness, so I've been going back through tuning activities. I thought is was the carb because my plugs had a black soot build-up and was running too rich. I've resolved that but engine was still not smooth, so I've been playing with my distributor/timing (I have electronic ignition, so points are not in the equation). My engine runs smooth with the balancer timing mark about one inch away/past the timing scale. How do I get the balancer mark in alignment to the scale with it correctly indicating if I'm 5 or 7.5? I pulled the distributor out and set the balancer mark on 5 degree's and reinstalled the distributor pointing at plug 1. After starting the car it still wants to be past the scale to run smoothly. Any thoughts? Link to comment Share on other sites More sharing options...
NC-car-guy Posted October 24, 2023 Share Posted October 24, 2023 when I went to pertrontix in my 57 it's 14 degrees advance at idle. Link to comment Share on other sites More sharing options...
packick Posted October 24, 2023 Share Posted October 24, 2023 I don't know where I got this, and I apologize to the author, but modern fuel can alter the timing marks on an old car. Here is what anonymous said: "In the early 1950's Regular was 79 octane and Premium was 85 Octane. Regular is now 87 or 88 Octane in most cases. The point is; when manufacturers like Buick called for Premium fuel, you can now use Regular that actually has a higher octane than the Premium when the car was built allowing you to buy gas at the cheaper price. But, for those who insist on Premium because it says so in the Owner's Manual, to get the bang for the buck, you need to advance the timing further than the factory specs. By mid-late 50's octane was increasing because of the higher compression engines that were now being used - all the old straight 8's were now gone and the horsepower race was on." Hope this helps. Link to comment Share on other sites More sharing options...
buickbrothers Posted October 24, 2023 Author Share Posted October 24, 2023 Good inputs. I think my issue is due to having pertronix installed. So it sounds like I just need to set the timing based on the car running smooth and ignore the fact its off the scale - right? Link to comment Share on other sites More sharing options...
old-tank Posted October 24, 2023 Share Posted October 24, 2023 Is the vacuum advance disconnected and the engine idling at 200to 300 RPM? 3 1 Link to comment Share on other sites More sharing options...
Bloo Posted October 25, 2023 Share Posted October 25, 2023 Electronic ignition makes less than zero difference in the timing needed. One possibility is that the ring on the harmonic balancer has slipped, and TDC is not really TDC. That can be checked with a positive stop in CYL #1. With all plugs out, battery disconnected, you crank by hand with a wrench until the piston stops against the stop, make a mark, and then go the opposite direction until it stops and make another mark. TDC is halfway between the two marks. Another good possibility is that the advance mechanism in the distributor, mechanical or vacuum or both, is not working as designed. 3 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted October 25, 2023 Author Share Posted October 25, 2023 Yes, I had the vacuum disconnected when setting timing. I set the carb per the book which indicates it's set at 450 rpm and I try to dial it down some since I don't have an rpm meter. The low rpm setting in the book seems to indicate it's to disengage the distributor vacuum advance so with it physically disconnected anyway does it really have to be at 200-300 rpm exactly? I had put a new vacuum control unit on the distributor when I rebuilt the engine. How do I validate the distributor doesn't have a vacuum or mechanical issue? Per NC-car-guy, wouldn't a 14 degree difference with the Pertronix have a bearing on timing marks/scale since it only goes to 7 1/2? Link to comment Share on other sites More sharing options...
NC-car-guy Posted October 25, 2023 Share Posted October 25, 2023 12 hours ago, Bloo said: Electronic ignition makes less than zero difference in the timing needed. One possibility is that the ring on the harmonic balancer has slipped, and TDC is not really TDC. That can be checked with a positive stop in CYL #1. With all plugs out, battery disconnected, you crank by hand with a wrench until the piston stops against the stop, make a mark, and then go the opposite direction until it stops and make another mark. TDC is halfway between the two marks. Another good possibility is that the advance mechanism in the distributor, mechanical or vacuum or both, is not working as designed. The martins at centerville are the ones the told me to do 14 degrees after I had them rebuild my distributor with the pertronix in it. 1 Link to comment Share on other sites More sharing options...
old-tank Posted October 25, 2023 Share Posted October 25, 2023 1 hour ago, buickbrothers said: does it really have to be at 200-300 rpm exactly? No, just slow as possible so that the mechanical advance is not in play and contributing to any timing observed with the light. I don't see how a 55 balancer can "slip". It may be the camshaft if replaced, so forget about the timing light and set with a vacuum gauge. 3 Link to comment Share on other sites More sharing options...
Smartin Posted October 25, 2023 Share Posted October 25, 2023 How much is way off? 10 degrees? 40 degrees? You're hooked up to the first cylinder on the right side of the engine, correct? (sorry, elementary question, but I like to cover basics). 2 Link to comment Share on other sites More sharing options...
Bloo Posted October 25, 2023 Share Posted October 25, 2023 6 hours ago, NC-car-guy said: The martins at centerville are the ones the told me to do 14 degrees after I had them rebuild my distributor with the pertronix in it. Is it possible they also changed the curve? I don't doubt their advice. All a Pertronix does though is replace a mechanical switch with a transistor. That by itself won't change the engine's timing needs. 2 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted October 25, 2023 Author Share Posted October 25, 2023 This car just keeps giving and giving. So bought a vacuum gauge today and started checking things out. When I set the distributor per the vacuum gauge, I no longer see the timing line on the balancer (it's somewhere on the driver's side) and I reached a point I couldn't turn the distributor any further to increase optimal vacuum setting. I set the carb as well and in I'm in the 21 range on the gauge. Still not quite there on smoothing out the engine. I pulled plug number 1 and rotated balancer until I had compression at 1 (finger check and blew my finger back). My timing line and scale showed between 5 and 7.5 degree's on the compression check to plug 1, but the rotor seems slightly passed the TDC on the distributor cap position. So, is this telling me my distributor is not performing as it should? Link to comment Share on other sites More sharing options...
NTX5467 Posted October 25, 2023 Share Posted October 25, 2023 Interesting comments about fuel octanes from various prior times. INCLUDING that the way of talking about octane levels has also changed. ALL of the octanes mentioned in the upper item are RESEARCH octane. By 1957, "Ethyl" or "Premium" was 97 Research octane, plus or minus 1 octane number. Regular was usually 94 Research octane. Then, when the "sub-Regular" grades (as Gulf's Gulftane) appeared they were about 91 Research Octane. By the time that low-lead/unleaded gasolines happened in the early 1970s, the newly mandated "consumer-oriented" PUMP Octane numbers appeared. An average of the fuel's octane level, posted as an average of the Research (the number everybody was used to seeing and talking about) and the Motor method (which was a more severe test and yielded lower octane numbers). As a general rule, you can add about "4" to the pump octane number to get "Researchj Octane" numbers. So that makes the current "Regular" 87 octane fuel basically equal the earlier sub-Regular gas of the 1966 times. The "Mid-Grade" 89 pump octane fuel pretty much the old "Regular" gas from the 1966 time. With 93 pump octane"Super Unleaded" being close to the old "Ethyl" of 97 Research octane. But the earlier 91 pump octane "Super Unleaded" closer to the old "Regular" of 1966. In 1966, "Regular Fuel" would take care of an engine with 9.0 compression ratio nicely. "Ethyl" or "Premium" did the 10.0 compression ratio engines. Just wanted to mention these things for a better understanding of current numbers. Enjoy! NTX5467 1 Link to comment Share on other sites More sharing options...
NTX5467 Posted October 25, 2023 Share Posted October 25, 2023 As to hot idle rpm and distributor advance, just as in later years, the centrifugal advance usually does not start until about 1000rpm. Vac advance needs about 9" Hg to start, which is why they used ported vacuum to keep the distributor from adding advance (for the base timing), so it can be set accurately and consistently with the vac advance unhooked and plugged. As far as what you are getting in initial timing settings . . . as long as the engine does not ping/clatter under light acceleration, you're fine with the fuel currently in the car. Should the engine clatter on hard acceleration, then back it up until it doesn't. Enjoy! NTX5467 Link to comment Share on other sites More sharing options...
EmTee Posted October 26, 2023 Share Posted October 26, 2023 43 minutes ago, buickbrothers said: My timing line and scale showed between 5 and 7.5 degree's on the compression check to plug 1, but the rotor seems slightly passed the TDC on the distributor cap position. So, is this telling me my distributor is not performing as it should? Ugh, lots going on here... I guess I'd like to just check that i understand what you have done and what you observed. First, as Adam noted, you're referring to the forward cylinder on the passenger side as #1, correct? (Most other GM cars, except Cadillac, called the first cylinder on the driver's side #1.) If that's correct, then I suggest doing as Bloo suggested and rig a piston stop in the #1 spark plug hole to facilitate verification of the TDC mark on your crank shaft balancer. Now, with TDC verified, you can check that both valves are closed at TDC on the compression stroke. Your observation about 'running out of adjustment' (my interpretation) when trying to set the timing by the vacuum method, and your comment about the rotor not quite lining-up with the #1 tower on the distributor cap makes me think that the distributor may be installed 1-tooth off. With #1 piston at TDC on the compression stroke, you should be able to remove the distributor, align the vacuum advance where it 'belongs' and index the rotor so that it aligns with the #1 tower on the cap when the distributor drops back into place. The rotor will turn slightly as the distributor gear engages the cam gear, so you have to account for that - which may explain how it wound-up one tooth off the last time it was installed. Sorry for the long dissertation, but hopefully you can help clarify what you are seeing and we can help you figure this out... 1 Link to comment Share on other sites More sharing options...
Smartin Posted October 26, 2023 Share Posted October 26, 2023 Could be off a tooth 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted October 26, 2023 Author Share Posted October 26, 2023 Yes, EmTee, first cylinder on passenger side for #1. FYI - I'm running the original cam and crank just so you know - they were polished. I did go to 4.25 pistons. I did pull the distributor earlier this week to realign. I set the balancer timing mark on 5 degree's and I reinstalled the distributor vs. 0 degree per the book. After all this discussion on the Petronix being 14 degree's out, I'm wondering if I should have aligned on 0. Now the balancer timing mark is out of sight. Using the vacuum gauge, I've turned the distributor counterclockwise to obtain the best vacuum pressure and smoothness, but it stops where I cannot turn it any further. My distributor cap clips are almost parallel to the carburetor if that gives you a reference on the distributor position. This is crazy. I don't know if the distributor is an issue, the carb or the pertronix. 1 Link to comment Share on other sites More sharing options...
old-tank Posted October 26, 2023 Share Posted October 26, 2023 1 hour ago, Smartin said: Could be off a tooth Hopefully it's just the distributor installed one tooth off; if the timing chain was installed one tooth off there's a lot of disassembly. 1 Link to comment Share on other sites More sharing options...
NTX5467 Posted October 26, 2023 Share Posted October 26, 2023 In another forum, there was mention of a whistle which screws into the spark plug hole. As the piston moves up on compression, it whistles. When the piston heads down, no whistle. Quite simple and accurate enough. Seems that normally, the cap retention clips are parallel with the back of the block, one at 3:00pm and the other one at 9:00pm. That way, greatest accessibility to remove the cap. For other references, you can find spark plug wiring images in a service manual or online. Worst case scenario, pull the engine and take it apart enough to see where everything is. Might beat leaning over the fender or grille! Enjoy! NTX5467 Link to comment Share on other sites More sharing options...
old-tank Posted October 26, 2023 Share Posted October 26, 2023 34 minutes ago, NTX5467 said: Worst case scenario, pull the engine Sounds easy if you say it real fast... 1 Link to comment Share on other sites More sharing options...
NTX5467 Posted October 26, 2023 Share Posted October 26, 2023 8 hours ago, old-tank said: Sounds easy if you say it real fast... This is very true, although leaning over a fender can be part of a "lower back stretching exercise" some might find uncomfortable these days. 30 years ago, less much. Point is that looking at some of the issues can be better done with the engine on an engine stand rather than in the car. The narrow engine bay might be better for lifting heavier engine parts over the fenders, but also tighter to get down and dirty to look at things, it seems to me. My earlier point was that although many like to "do things by the numbers", as to timing and such, as long as the engine makes no unusual sounds other than "quietness" during normal driving under acceleration or going up a hill in "passing gear", just drive it and enjoy it as it is. ALSO, ensure it does not run hotter than normal, too. "No clatters" and "no higher operating temperatures" (when cruising down the Interstate), all should be fine. Trust what the engine and car are telling you rather than being a slave "to numbers". Numbers can be important, but can also be a baseline from which to possibly improve things. In using a vac gauge to set timing, find the max vac at idle and then back it down a bit from there, for good measure. Being a bit conservative might cost a little bit of fuel economy, but be better in the long run, by observation. THEN ask Santa Claus for a dial-back timing light and dwell tach for Christmas. Timing lights and dwell tachs can generate "better numbers" than a vac gauge ever could, from my experiences. Plus not being affected by altitude! Enjoy! NTX5467 1 Link to comment Share on other sites More sharing options...
EmTee Posted October 26, 2023 Share Posted October 26, 2023 21 hours ago, buickbrothers said: FYI - I'm running the original cam and crank just so you know - they were polished. I did go to 4.25 pistons. I did pull the distributor earlier this week to realign. So, this engine has been rebuilt, or at least significantly disassembled and reassembled? That opens other possibilities WRT things that should be checked to verify proper installation/alignment... 1 Link to comment Share on other sites More sharing options...
buickbrothers Posted October 31, 2023 Author Share Posted October 31, 2023 Sorry for the delayed update. I tried a variety of things last week including moving the distributor and swapping between two carbs. I bought a vacuum gauge, pulled and reset the distributor per vacuum and adjusted the carb per vacuum. It's running pretty smooth; however, I'm getting occasional burb's/fluctuations which you can see in the vacuum gauge. So, I think I know what the problem is and I'm providing some history for reference. When I did the first engine start after the rebuild, my timing marks were visible, and all was well. Engine ran great on several break in runs. Once I installed the engine in the car and integrated to all the other parts, and wiring, plus did additional engine starts/runs to test all the integration, that's when the rod issue showed up. Some followers may remember I had a rocker arm break off and I found a bent rod. Discovered it was due to the after-market rods being slightly thicker than the original rods and in "some" rod holes it could rub on the under-side of the rod against the head casting due to clearance issues. It was not visible/obvious during engine assembly. After finding this, I discovered a Mudbone video on this rod clearance problem which requires boring out the rod holes. Since it was not possible to bore the holes at this stage without either pulling the engine or taking the heads off (didn't want to risk metal shavings going everywhere and, in the engine), I decided to swap some of the after-market rods on some valves/rockers that showed clearance problems with my best original rods. No, I didn't really want to do this. However, I needed to confirm it was the rod clearance that was the problem and not sticking valves per all the forum member inputs. The valve job was done by the machine shop - I did all the rest of the engine work and reassembly. So, my mind was constantly going to concerns if they did the valve job correctly. I thought the hydraulic lifters would compensate for any variation between old/new rods. But now, I believe it's been the source of my timing mark movement and the burb's/vacuum variation showing on the gauge leading me to equate all this to slight valve timing differences due to the rod mix. So, I plan to pull the heads, bore the rod holes and go back to one set of after-market rods vs the mix. Don't beat me up for the approach I took. Am I accurate in thinking the rod mix is behind the timing mark/vacuum variations? I've provided a video for reference: https://youtu.be/56RpExX-uIc Link to comment Share on other sites More sharing options...
old-tank Posted October 31, 2023 Share Posted October 31, 2023 20 minutes ago, buickbrothers said: Am I accurate in thinking the rod mix is behind the timing mark/vacuum variations? I've provided a video for reference: I don't think so. Before you start tearing into the engine, try pouring some lubricant down the carb like Marvel mystery oil. Machine shops will sometimes set the valve to guide clearance too tight like the chevy engines they are used to. Did it ever run with the pertronix before the rebuild? 1 Link to comment Share on other sites More sharing options...
old-tank Posted October 31, 2023 Share Posted October 31, 2023 Looking at the video again I noticed the position of the distributor. All of my nailheads with a properly installed, timed and adjusted distributor the vacuum advance is pointing to the inside corner of the valve cover. When I had pertronix installed in order to get it to run and timed correctly the vacuum advance was pointing toward the fender. Also the terminals inside the distributor which usually have a spark sweep across the whole terminal with pertronics it was only at one corner of the terminal. Your vacuum advance is pointing toward the fender. My suggestion is to install a distributor with the original points and condenser and see how it works out. Easier and cheaper than removing cylinder heads and buy another gasket set. 1 Link to comment Share on other sites More sharing options...
EmTee Posted October 31, 2023 Share Posted October 31, 2023 9 hours ago, buickbrothers said: I'm getting occasional burb's/fluctuations which you can see in the vacuum gauge. 8 hours ago, old-tank said: Machine shops will sometimes set the valve to guide clearance too tight like the chevy engines they are used to. Sticky valve(s)? 6 hours ago, old-tank said: My suggestion is to install a distributor with the original points and condenser and see how it works out. I concur. Timing offset due to the Pertronix seems plausible and a test using breaker points would either confirm or refute the theory. Link to comment Share on other sites More sharing options...
buickbrothers Posted November 5, 2023 Author Share Posted November 5, 2023 Final update. I've switched to points, original coil, reconnected the ballast resistor. Added Mavel Oil to the carb to loosen valves which helped a lot! My timing marks are back/visible on the balancer. Set at 5 degree's when I dropped in the distributor. I set the distributor timing and carb using a vacuum gauge which still ends up putting the balancer timing mark passed the scale. Dwell is set at 30. Engine is running really good although it still has a very slight/random burp - not a misfire but very slight occasional delay on a valve open/closing. I have about two hours of total run time on this engine so I'm thinking once the valves have more run time this will subside. A second big milestone is that I hooked up the fuel line to the gas tank. I'd was operating off a 5-gallon gas can up to now. Gauge works and had no issues/leaks drawing gas supply from the tank. Third milestone, I drove the car just long enough to back it out of the driveway, turn it around and reposition in the driveway. This was a first move of the car using the engine and the rebuilt transmission. Performed great accept the brakes need some tuning. The brake pedal is very slow to come back up after pressing the pedal. All the brakes have been redone as well - new shoes, turned drums, new brake cylinders, etc. I rebuilt the booster as well. I'm thinking there may be air in the brake line and I'll need to bleed the brakes again. This was a first test of the brake system with vacuum coming from the engine. Overall, big steps forward! Thanks for all the help. 4 Link to comment Share on other sites More sharing options...
old-tank Posted November 5, 2023 Share Posted November 5, 2023 1 hour ago, buickbrothers said: The brake pedal is very slow to come back up after pressing the pedal. Check that the spring is in place, then try it with the boot loose from the booster. Report back. Link to comment Share on other sites More sharing options...
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