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With your timing light hooked up your initial timing without vacuum should be 7.5-10* BTDC and should advance if you increase rpm and stop advancing around 4000 +/- RPM. If you connect the vacuum advance to a manifold vacuum port it should advance 15*+. If you don't see any advance in either of these 2 scenario's then you need to troubleshoot accordingly. In your picture above, the plate your finger is on shifts when the RPM increases as the weights deploy. The vacuum advance changes the position of the plate its mounted to as vacuum increase and decreases.
With your timing light hooked up your initial timing without vacuum should be 7.5-10* BTDC and should advance if you increase rpm and stop advancing around 4000 +/- RPM. If you connect the vacuum advance to a manifold vacuum port it should advance 15*+. If you don't see any advance in either of these 2 scenario's then you need to troubleshoot accordingly. In your picture above, the plate your finger is on shifts when the RPM increases as the weights deploy. The vacuum advance changes the position of the plate its mounted to as vacuum increase and decreases.
yeah - I have the initial at 8 degrees - I posted a YouTube video of another mech advance plate being moved so I understand how it works - it won’t budge with my hand and I’ve applied enough force on it where It should - and it does not increase at all under the light - I have new medium springs on it but like I said it wont budge - I haven’t checked vacuum advance under timing light yet - but I will second I get to it again - on another note - I should get my damper bolt tomorrow - but the more I look at it ... I don’t see threads and it it seems shallow? It is possible that It has been missing the entire time I’ve owned the car - Scary thought is ... could It be broken off? Or is there a more likely scenario?
You have find out why its frozen. The bolt bein broken was my initial thought, however its not very long to start with and the crank area in your picture looks really corroded.
You have find out why its frozen. The bolt bein broken was my initial thought, however its not very long to start with and the crank area in your picture looks really corroded.
well I hope the damper bolt part is good news - I’ll keep cleaning the area up in preparation for the bolt - just what I know about the distributor - I put in the new vacuum advance diaphragm - new points and separate condensor - new medium springs - when I break lose the base nut it spins with no problem to set the timing - looking online to see if there’s any good troubleshooting sights for it - thanks!
If it does not look broken off, buy a bottom thread chasing tap and clean up the threads.
thanks for the tip - I have a question - you had replied to a 455 timing thread somewhere (lost where I found it) which coincidently matches exactly where my car is at - .40 plug gap - 30 dwell - 8 degrees btdc - at 1100 rpm - but in all the timing things I see it talks about rpm at (650 I think it was) in drive - if you have a standard do you just ignore that part?
Super tuning = optimizing all timing/ignition events and air/fuel ratio. There is more but let us concentrate on this:
Step zero. Get a bolt on the crank pulley before going any further. As suggested get a thread restoring type of tap. DO NOT use a new thread making tap on existing threads. It will remove too much material. Use plenty of oil on the tap and don't force it. Little in and out at a time cleaning the tap and the hole with compressed air as you go.
Base vacuum and timing should be set at warm curb idle. This is typically anywhere from 500 to 750 rpms. A 68 Toro says 500 rpms is curb idle. Personally, I like 6-650. At 1100 rpms the mechanical timing can start to come in. Also, Id use heavier springs on the weights. All three timings events should come in smoothly at a desired "all-in" rpm, this is preferred. For a stock Olds this is ~3000. The lighter springs will not be optimal. You can mix and match springs to achieve the desired result(e.g. one med one heavy spring).
1. Give the car as much initial timing(base timing) as it will handle without spark knock. Road testing will tell you how much advance the engine can handle before it knocks. 8* is a good start but I'll bet it will handle 12+ all day.
2. Figure out how much more the vacuum advance can pulls in at idle. Usually, 8-10 is good.
3. Mechanical timing. This is a problem for you. If the distributor isn't adding any the car is likely running like a hammer under water. Mechanical should add another 15-20* depending on where the limit stops it. So at about 3000 rpms you should have 38* of total timing plus or minus a few degrees. You need to find out what it likes. The variables are many...timing chain & cam wear, type of fuel, elevation from sea level, your driving characteristics, ambient temp...et al...
Put the engine on TDC of #1 piston. (A remote starter bump switch is useful here) Note the position of the distributor rotor. Mark it. Then yank that distributor out take it apart and see what is frozen. Good time to replace the upper & lower bronze bushings. It's easily rebuildable. Make sure the shaft isn't scored beyond serviceability. You can purchase the parts. Send it out for a rebuild and a recurve(recommended) or buy a new dist.(which will need to be curved as well).
thanks for the tip - I have a question - you had replied to a 455 timing thread somewhere (lost where I found it) which coincidently matches exactly where my car is at - .40 plug gap - 30 dwell - 8 degrees btdc - at 1100 rpm - but in all the timing things I see it talks about rpm at (650 I think it was) in drive - if you have a standard do you just ignore that part?
Spark plug gap should be .030 for points distributors, dwell 30*, timing should be 10* at 1250 rpm, curb idle speed 500 rpm in drive. Is what the manufacturers recommended settings should be. With that said, this is just a guide. Most of us power tune the engine and give it what it likes. I recommend getting it running the way it should with the stock settings and then move on to the performance stuff later.
Thanks both of you! From what I read ... yes... it’s time to pull the distributor and clean it up - l’ll read up on rebuilding it with the bronze bushing thing a ma jigs - I’ll work on bringing the idle down and keep fine tuning it - says 500rpm in drive? How do you test that in a standard manual stick shift?
Also wanted to add - that video of the mechanical advance moving - that isn’t me - I found it online and was just sharing to point out that was what mine was suppose to do - but isn’t - just didn’t want any confusion
I will do - but I still don’t understand how to check a stick shifts rpms in “drive” regardless of the Rpm? Sorry if I’m missing something obvious?
Sorry I was not clear, the 700 rpm is set in neutral. The reason why they suggest setting an automatic in drive is because of the rpm drop going from neutral/park to drive.
Originally Posted by 72442455
Also wanted to add - that video of the mechanical advance moving - that isn’t me - I found it online and was just sharing to point out that was what mine was suppose to do - but isn’t - just didn’t want any confusion
Yes, that's basically what your looking for, the plate moves as the weights extend and moves back as they retract. It may just be as easy as working it and spraying penetrating oil on the mechanism.
On your mechanical advance, if you cannot move the larger plate that the weights set on it may be for a couple of reasons.
1. The plate is frozen and cannot turn. You might be able to free it up by spraying some carb cleaner between the larger plate and the small plate in the center after you remove the cap and rotor, points and condenser.
2. Back in the day, the really good advance recurve kits came with a brass bushing that you would install on the bottom of the larger plate to limit the mechanical advance. This bushing would replace the smaller factory rubber/hard plastic bushing to enable the tuner to completely fine tune adjustment on the timing.
Using a inspection mirror and a flash light, you should be able to inspect that pin and bushing. PS I have seen cases where the factory bushing just wore out causing too much timing.
On your mechanical advance, if you cannot move the larger plate that the weights set on it may be for a couple of reasons.
1. The plate is frozen and cannot turn. You might be able to free it up by spraying some carb cleaner between the larger plate and the small plate in the center after you remove the cap and rotor, points and condenser.
2. Back in the day, the really good advance recurve kits came with a brass bushing that you would install on the bottom of the larger plate to limit the mechanical advance. This bushing would replace the smaller factory rubber/hard plastic bushing to enable the tuner to completely fine tune adjustment on the timing.
Using a inspection mirror and a flash light, you should be able to inspect that pin and bushing. PS I have seen cases where the factory bushing just wore out causing too much timing.
Just to clarify. Limit bushings restrict the total movement of the advance plate. The bronze bushings I am describing are pressed into the distributor body. In which the distributor main shaft rotates off the cam gear. Look for an exploded view of the dist.
Eric, in all my years of tuning I have never heard of a factory timing setting performed (in the real or any world) at anything above curb idle (500-750 max). At 1250 the mechanical could begin to open in which case you're not getting an accurate base timing. It will be less than you think you're getting once down to 500-750. At 1250 your gonna get rubber out of the car shifting in to drive. Teach an old skool tuner something new??
IMO...A good idle for a given old-school street stock V8 should allow the converter on an automatic to not engage (or slip) on the stator. 750-800 max rpm for a stick car. At 1250 (on an auto) your partially on the converter. That means the car will want to drive away and at 1250 that's like standing on the brake at a stop. That will needlessly heat up the trans which isn't desirable either.
Hope I’m not out wearing my welcome with a million questions - but because it’s my crank shaft I’m overly cautious - I received the damper bolt today and it’s perfect - it was simply just missing not broke off or anything - took bolt to hardware store and matched it up best I could with a nut ( 3/4 - 16 pitch sound right?) - I’ve never done a tap or thread restorer before - I asked pep boys - ace - harbor freight - and nobody could help me - i see taps online at amazon but not thread restorers - I really don’t want to spend hundreds of dollars on a kit for one use - any tips or suggestions where I could find a single 3/4 by 16 thread restorer “tap”
Never had a condenser fail and kill engine in 44 years. Module on HEI failed that was only 5 years old, pulled car out of garage and engine died. Had to replace module. If points and condenser are maintained on these lithely used cars the failure rate would be very small if at all.
Years ago I had two bad condensers out of the box new. The car would idle but under load would barely pull itself and pop through the carburetor. Those all in one point and condenser combos like you show in the pic of the distributor, aren’t exactly race parts. Also your advance springs look a little hunky, your weights aren’t pulling back all the way closed. Order a decent set of Mallory 102X points and a new condenser and rotor. Get an advance curve kit and clean and grease those weight pivots and pads. At least you will rule that out and will help your engine run better.
Years ago I had two bad condensers out of the box new. The car would idle but under load would barely pull itself and pop through the carburetor. Those all in one point and condenser combos like you show in the pic of the distributor, aren’t exactly race parts. Also your advance springs look a little hunky, your weights aren’t pulling back all the way closed. Order a decent set of Mallory 102X points and a new condenser and rotor. Get an advance curve kit and clean and grease those weight pivots and pads. At least you will rule that out and will help your engine run better.
thanks for the reply - I have replaced the springs and put in a separate standard blue streak coil and condensor - and a new vacuum canister - there is a little back and forth slop in my distributor and the weights are seized - I’ve been reading trying to find info on how to fix that - so far pulling it and cleaning it up sounds like what I need to do - haven’t been able to find anything about the slop yet though - still searching the Internet on the slop part
Put this in your toolbox. You'll use it quite often
I'd be very careful using a plug tap especially with limited experience with this task. Do you have the proper square drive tap handle or 8 point socket to hold this plug tap? If not you will need that too or you will struggle to get it to work.
The restorers use a standard socket.
Last edited by droldsmorland; May 3rd, 2018 at 08:07 AM.
thanks for the reply - I have replaced the springs and put in a separate standard blue streak coil and condensor - and a new vacuum canister - there is a little back and forth slop in my distributor and the weights are seized - I’ve been reading trying to find info on how to fix that - so far pulling it and cleaning it up sounds like what I need to do - haven’t been able to find anything about the slop yet though - still searching the Internet on the slop part
Eric, Ya that's true didn't catch that little tidbit, doh. Looks like your stuck with a cutting tap. SnapOn nor McMaster Carr offer the 18 thread count. This is a critical operation get it wrong and you will be in a world of....
Eric, Ya that's true didn't catch that little tidbit, doh. Looks like your stuck with a cutting tap. SnapOn nor McMaster Carr offer the 18 thread count. This is a critical operation get it wrong and you will be in a world of....
I erred on the tap and die kit statement... however it did not have a 3/4 tap in any flavor. You stated in post 59 the bolt you received was a 3/4-16 and that's the tap I suggested at Amazon.
I erred on the tap and die kit statement... however it did not have a 3/4 tap in any flavor. You stated in post 59 the bolt you received was a 3/4-16 and that's the tap I suggested at Amazon.
droldsmorland states 18 - but I did order the 16 hopefully a typo - I do have the handle for the tap - borrowing from step dad - I’ll take it very easy - oil the hell out of it and constantly test the bolt to see how it goes
The new to me terms I learn here everyday hehe - I assume the nut I got is a 16 unc - but it doesn’t just spin down this bolt - it fits but feels a little “bindy” if you will - I hope I get this right 😳
I don’t have a tap guide handy but I’m sure that crank bolt is fine thread. The center pole of the distributor between the weights won’t turn much. It is locked to the driven gear and the cam. The plate under the weights which also has the point cam machined on it should rotate about ten degrees and the advance springs should pull it back. If it won’t turn, it is probably just frozen with dried grease or rust. If you pull the distributor out it will be easy to free it up. You may also be able to free it in the car by spraying some penetrating oil around the top center of the weight plate. The best for this is called Kroil, this stuff is amazing. It actually does what is says it does.
Eric, in all my years of tuning I have never heard of a factory timing setting performed (in the real or any world) at anything above curb idle (500-750 max).
It's the way the factory advised to set the timing. The factory tuneup label on my 1970 Supreme showed the initial timing setting of 10º @ 1100 RPM (the one on the 71 was long gone when I got the car, but it is similar). Most all of the literature I have read shows similar initial settings.
Originally Posted by droldsmorland
At 1250 the mechanical could begin to open in which case you're not getting an accurate base timing. It will be less than you think you're getting once down to 500-750. At 1250 your gonna get rubber out of the car shifting in to drive. Teach an old skool tuner something new??
You are right that the mechanical may be coming in above idle speeds - it depends upon the weights and springs in that particular distributor. Doing it the way you posted give the most accurate readings for initial and mechanical, especially for performance tuning. With a stock factory setup the measurements can be made per the tune up label since any early advance has been taken into account by the design engineers.
For absolute clarification, I just pulled the crank bolt out of a virgin 1969, 455 I have on a stand.
IT IS A....3/4" x 16 UNF (or 16 threads per inch or TPI) fine thread with a 1 1/8" 6 point socket head. It is ~1.975" or just under 2" in length.
The thick washer is ~0.380" thick x ~1.90" in diameter
awesome! Thank you for the trouble! I really appreciate it - I get the tap tomorrow - got a busy day tomorrow so I pray I get time to play with my car - I will have everything I need once that tap comes to get it done - need to pick up some Kroil to try and release the mechanical advance mech - then Recheck dwell - timing - a/f and I should be good to go! (As you all know ... good to go = onto the next part of the car I want to work on 😜
I don’t have a tap guide handy but I’m sure that crank bolt is fine thread. The center pole of the distributor between the weights won’t turn much. It is locked to the driven gear and the cam. The plate under the weights which also has the point cam machined on it should rotate about ten degrees and the advance springs should pull it back. If it won’t turn, it is probably just frozen with dried grease or rust. If you pull the distributor out it will be easy to free it up. You may also be able to free it in the car by spraying some penetrating oil around the top center of the weight plate. The best for this is called Kroil, this stuff is amazing. It actually does what is says it does.
thank you for the input - I’m going to try the Kroil with the distributor in the car first - if it doesn’t work I’ll pull it and go all through it - thanks again!
May 1st, 2018, 04:59 AM
