Frustrated

[Wrongway]

So the hold down was tight guys. I didn't check the resistance between the hold down and the distributor shaft. Its a really tight fit but it was between 00.4 and 00.6 depending on how and where the probes touch. I rechecked the ground strap that I just scraped the paint off of and it was 00.1- 00.3. I tried the one on the back of the motor the I couldn't get off to clean and couldn't get the probe on the block. There's just not enough room.

[64 kiwi boni]

On 4/7/2021 at 5:55 PM, Wrongway said:

I may sound ignorant Two Lane but I did not know that the distributor hold down grounded the distributor. I'll check it tomorrow bro, thanks. 

all sound good to me mate 👍

[Fitzy]

Can I just say that I just got back from work and am now catching up and I have read most of Wrongway's saga. The depth of assistance, knowledge, experience and willingness to help is inspiring. I've seen chat on lesser forums where trashing each other seems more important than anything constructive. Wrongway, despite what you're enduring, you are a lucky man to have such friends to help out.

I'd like to chime in with a similar story (I'll keep it as short as possible - am conscious of hijacking these days!) I used to have a 1964 EH Holden which had a following almost as popular as your 57 Chev. It was a handsome, capable car and was ideal for Australia back in the early 60s. Anyway, I had some headers fitted. When I got the car back, it wouldn't idle properly and would almost die then inexplicably rev to about 2k all by itself then almost die again before repeating. I didn't have a clue! One day, I'm staring at that engine doing it's thing and it was like my hand was guided by a superior entity: I reached under the inlet manifold (it was a 6 cylinder) and there was a huge square hole! THEN I realised what had happened: the exhaust shop had removed the old exhaust manifold that was bolted to the underside of the inlet manifold and had acted as a heat riser but nobody realised there was a hole underneath. Anyway, I replaced the manifold with a later one and a 2 barrel carby and she ran sweet ever after. I have been relentless about vacuum leaks ever since! Attached is a file photo of an EH.

Compared to poor Wrongway, mine was an easy fix. Good luck, mate.

[Wrongway]

Yeah Fitzy, your 100% right brother. I looked at some other forums before joining this one. I had never been on a forum and stayed away because of the trash taking and lack of respect. I would look for answers but that was it. I actually looked back on this site at some older posts and the comments people had trying to help each other. I watched new posts and member interaction for a couple of weeks before finally joining and speaking. I guess I was just nervous asking strangers for help after seeing all the bull crap on other sites. I'm glad I joined (still the only forum Iv been on). The level of knowledge, skill, and dedication by the people on this site is truly inspiring. Ringo did a great thing here and yeah buddy were all very lucky to have Forever Pontiacs and the friends that go with it. 

Thank you again everybody!

[BearGFR]

Wrongway, have you been over to gtoforum.com?  I think folks over there tend to be pretty helpful also.

 

Bear

[Fitzy]

On 11/20/2020 at 2:16 PM, 64 kiwi boni said:

i found this via nastyz28 and its from hot rod forum. enjoy the read....

 

 

This is a great article!!!!I had my vacuum advance hooked up to the ported vacuum port after reading this article I hooked it up to full manifold vacuum adjusted the idle rpm.The car has so much more power now.



As many of you are aware, timing and vacuum advance is one of my favorite subjects, as I was involved in the development of some of those systems in my GM days and I understand it. Many people don't, as there has been very little written about it anywhere that makes sense, and as a result, a lot of folks are under the misunderstanding that vacuum advance somehow compromises performance. Nothing could be further from the truth. I finally sat down the other day and wrote up a primer on the subject, with the objective of helping more folks to understand vacuum advance and how it works together with initial timing and centrifugal advance to optimize all-around operation and performance. I have this as a Word document if anyone wants it sent to them - I've cut-and-pasted it here; it's long, but hopefully it's also informative.

TIMING AND VACUUM ADVANCE 101

The most important concept to understand is that lean mixtures, such as at idle and steady highway cruise, take longer to burn than rich mixtures; idle in particular, as idle mixture is affected by exhaust gas dilution. This requires that lean mixtures have "the fire lit" earlier in the compression cycle (spark timing advanced), allowing more burn time so that peak cylinder pressure is reached just after TDC for peak efficiency and reduced exhaust gas temperature (wasted combustion energy). Rich mixtures, on the other hand, burn faster than lean mixtures, so they need to have "the fire lit" later in the compression cycle (spark timing retarded slightly) so maximum cylinder pressure is still achieved at the same point after TDC as with the lean mixture, for maximum efficiency.

The centrifugal advance system in a distributor advances spark timing purely as a function of engine rpm (irrespective of engine load or operating conditions), with the amount of advance and the rate at which it comes in determined by the weights and springs on top of the autocam mechanism. The amount of advance added by the distributor, combined with initial static timing, is "total timing" (i.e., the 34-36 degrees at high rpm that most SBC's like). Vacuum advance has absolutely nothing to do with total timing or performance, as when the throttle is opened, manifold vacuum drops essentially to zero, and the vacuum advance drops out entirely; it has no part in the "total timing" equation.

At idle, the engine needs additional spark advance in order to fire that lean, diluted mixture earlier in order to develop maximum cylinder pressure at the proper point, so the vacuum advance can (connected to manifold vacuum, not "ported" vacuum - more on that aberration later) is activated by the high manifold vacuum, and adds about 15 degrees of spark advance, on top of the initial static timing setting (i.e., if your static timing is at 10 degrees, at idle it's actually around 25 degrees with the vacuum advance connected). The same thing occurs at steady-state highway cruise; the mixture is lean, takes longer to burn, the load on the engine is low, the manifold vacuum is high, so the vacuum advance is again deployed, and if you had a timing light set up so you could see the balancer as you were going down the highway, you'd see about 50 degrees advance (10 degrees initial, 20-25 degrees from the centrifugal advance, and 15 degrees from the vacuum advance) at steady-state cruise (it only takes about 40 horsepower to cruise at 50mph).

When you accelerate, the mixture is instantly enriched (by the accelerator pump, power valve, etc.), burns faster, doesn't need the additional spark advance, and when the throttle plates open, manifold vacuum drops, and the vacuum advance can returns to zero, retarding the spark timing back to what is provided by the initial static timing plus the centrifugal advance provided by the distributor at that engine rpm; the vacuum advance doesn't come back into play until you back off the gas and manifold vacuum increases again as you return to steady-state cruise, when the mixture again becomes lean.

The key difference is that centrifugal advance (in the distributor autocam via weights and springs) is purely rpm-sensitive; nothing changes it except changes in rpm. Vacuum advance, on the other hand, responds to engine load and rapidly-changing operating conditions, providing the correct degree of spark advance at any point in time based on engine load, to deal with both lean and rich mixture conditions. By today's terms, this was a relatively crude mechanical system, but it did a good job of optimizing engine efficiency, throttle response, fuel economy, and idle cooling, with absolutely ZERO effect on wide-open throttle performance, as vacuum advance is inoperative under wide-open throttle conditions. In modern cars with computerized engine controllers, all those sensors and the controller change both mixture and spark timing 50 to 100 times per second, and we don't even HAVE a distributor any more - it's all electronic.

Now, to the widely-misunderstood manifold-vs.-ported vacuum aberration. After 30-40 years of controlling vacuum advance with full manifold vacuum, along came emissions requirements, years before catalytic converter technology had been developed, and all manner of crude band-aid systems were developed to try and reduce hydrocarbons and oxides of nitrogen in the exhaust stream. One of these band-aids was "ported spark", which moved the vacuum pickup orifice in the carburetor venturi from below the throttle plate (where it was exposed to full manifold vacuum at idle) to above the throttle plate, where it saw no manifold vacuum at all at idle. This meant the vacuum advance was inoperative at idle (retarding spark timing from its optimum value), and these applications also had VERY low initial static timing (usually 4 degrees or less, and some actually were set at 2 degrees AFTER TDC). This was done in order to increase exhaust gas temperature (due to "lighting the fire late") to improve the effectiveness of the "afterburning" of hydrocarbons by the air injected into the exhaust manifolds by the A.I.R. system; as a result, these engines ran like crap, and an enormous amount of wasted heat energy was transferred through the exhaust port walls into the coolant, causing them to run hot at idle - cylinder pressure fell off, engine temperatures went up, combustion efficiency went down the drain, and fuel economy went down with it.

If you look at the centrifugal advance calibrations for these "ported spark, late-timed" engines, you'll see that instead of having 20 degrees of advance, they had up to 34 degrees of advance in the distributor, in order to get back to the 34-36 degrees "total timing" at high rpm wide-open throttle to get some of the performance back. The vacuum advance still worked at steady-state highway cruise (lean mixture = low emissions), but it was inoperative at idle, which caused all manner of problems - "ported vacuum" was strictly an early, pre-converter crude emissions strategy, and nothing more.

What about the Harry high-school non-vacuum advance polished billet "whizbang" distributors you see in the Summit and Jeg's catalogs? They're JUNK on a street-driven car, but some people keep buying them because they're "race car" parts, so they must be "good for my car" - they're NOT. "Race cars" run at wide-open throttle, rich mixture, full load, and high rpm all the time, so they don't need a system (vacuum advance) to deal with the full range of driving conditions encountered in street operation. Anyone driving a street-driven car without manifold-connected vacuum advance is sacrificing idle cooling, throttle response, engine efficiency, and fuel economy, probably because they don't understand what vacuum advance is, how it works, and what it's for - there are lots of long-time experienced "mechanics" who don't understand the principles and operation of vacuum advance either, so they're not alone.

Vacuum advance calibrations are different between stock engines and modified engines, especially if you have a lot of cam and have relatively low manifold vacuum at idle. Most stock vacuum advance cans aren’t fully-deployed until they see about 15” Hg. Manifold vacuum, so those cans don’t work very well on a modified engine; with less than 15” Hg. at a rough idle, the stock can will “dither” in and out in response to the rapidly-changing manifold vacuum, constantly varying the amount of vacuum advance, which creates an unstable idle. Modified engines with more cam that generate less than 15” Hg. of vacuum at idle need a vacuum advance can that’s fully-deployed at least 1”, preferably 2” of vacuum less than idle vacuum level so idle advance is solid and stable; the Echlin #VC-1810 advance can (about $10 at NAPA) provides the same amount of advance as the stock can (15 degrees), but is fully-deployed at only 8” of vacuum, so there is no variation in idle timing even with a stout cam.

For peak engine performance, driveability, idle cooling and efficiency in a street-driven car, you need vacuum advance, connected to full manifold vacuum. Absolutely. Positively. Don't ask Summit or Jeg's about it – they don’t understand it, they're on commission, and they want to sell "race car" parts.

Did everybody read this? I took the time to carefully read it and it's GOLD. If you haven't run out to the garage and made sure this is happening on your engine, shame on you!

Go on, I don't care if you have Krusty The Klown pyjamas on - go out there right now and make sure you are taking advantage of full manifold vacuum by porting the vacuum advance BELOW the throttle plate, not above it. I once experimented with my old 1968 302 Fairlane and disconnected the vacuum advance and played with the timing and went for a long drive. The thing drank so much fuel that I reversed everything I had done when I got to my destination and cruised home with the sort of efficiency I should have had all along.

Wrongway, since you're up to your neck in car parts, nuts, bolts and grease, you might as well do this as well. We can all rejoice as we smoke our tyres up and down the street impressing the neighbours.

[Wrongway]

No Bear, I haven't bro. Most of the trash I found was while helping a friend try to get his Chevy running. I had pretty much given up on forums until I came across this one. I may go peak in the windows over there and see what's going on since you suggested them.

I did move the GP yesterday! I didn't take her down the road due the the pouring down rain but I did back her down the drive and pull her back up a couple of hours later. Fired up the first shot both times!

[Wrongway]

Fitzy, very interesting read. I read it, thought about it and just reread it. I'll switch ports and see what happens but if I have to make any changes then I'll have to wait until I figure out why a timing light wont work. Thanks for the article and I'll let you know what happens. 

[JUSTA6]

19 minutes ago, Wrongway said:

Fitzy, very interesting read. I read it, thought about it and just reread it. I'll switch ports and see what happens but if I have to make any changes then I'll have to wait until I figure out why a timing light wont work. Thanks for the article and I'll let you know what happens. 

They are talking about early smog attempts at lowering emissions.  Mid 70's N up, and guessing stock carbs.  If your ports are in the baseplate I take it your OK.  Doesn't sound like anything aftermarket would do.  Holley ect. 

[Fitzy]

Hey Wrongway, this is off topic but I wanted to ask you about your Torq Thrust fitment. Did you use hub rings to get a snug fit? It looks like my new wheels will have a hub bore diameter of about 83mm but the GP has about a 70mm diameter. Is yours the same?

[Wrongway]

Hey bud, nope no ring or spacers. I made a tool that's shaped like a T with sliders, It slides against the drum so I could spin the drum and get the measurements I needed. I can send you the sizes, measurements or model numbers later today bro.

[Fitzy]

Yeah, thanks. I had a think about it last night and it seems natural that the hub should fit within the wheel's centre bore neatly, but of course that has never applied to the rears, where there is no protruding hub. Does anyone know about this? Perhaps a neatly secured front wheel steers better or has some positive effect on the geometry, or I've had too much coffee and am overthinking it. And, come to think of it, my old VW Beetle had those factory pressed rims with widely spaced lug holes and no question of any centre bore fitment.

On 4/13/2021 at 2:36 AM, Wrongway said:

Fitzy, very interesting read. I read it, thought about it and just reread it. I'll switch ports and see what happens but if I have to make any changes then I'll have to wait until I figure out why a timing light wont work. Thanks for the article and I'll let you know what happens. 

We need to thank Kiwi for the article - I just pushed the barrow a bit harder!

And I've hijacked your thread. Apologies.

[64 kiwi boni]

2 hours ago, Fitzy said:

or I've had too much coffee and am overthinking it

yip, a case of tooo much coffee .... 8 luggers are the same as vw too, dont think it matters too much fitzy.

2 hours ago, Fitzy said:

We need to thank Kiwi for the article - I just pushed the barrow a bit harder!

yeah, i found it via nastyz28 website, which i have been a member of since first buying the camaro way back... its a very full-on site, but they have some very cleaver guys on there too,

justA bout as cleaver as some here!!... well justA bout 

[Wrongway]

No apologies needed bro. Not sure if you still need to know now or not but on my 17 inch rims the bore size is 83.06 according to American Racing. Hope it helps 

[64 kiwi boni]

hay wrongway, it must be getting warmer where your are, as its getting bloody cold where i am now. whats your plans for the 63 ?

[Wrongway]

Well bro, as soon as I get this guys paint finished and bike gone I'm going to change out the vent window frames so I can hang the new door panels. Then I think I'm ready to start the body work and hopefully get her in paint by the end of the summer, as long as there's no issues when I do start driving her.

[64 kiwi boni]

1 hour ago, Wrongway said:

Well bro, as soon as I get this guys paint finished and bike gone I'm going to change out the vent window frames so I can hang the new door panels. Then I think I'm ready to start the body work and hopefully get her in paint by the end of the summer, as long as there's no issues when I do start driving her.

way cool mate, sound like you have a plan, what colour ?

[Wrongway]

Originally it was a paint called Magnetic, Its basically dark charcoal that I added more black to darken it up. Its got ground up course and medium aluminum chunks with finely ground silver dollars. Its an amazing color bro. I cant wait to send y'all pictures when its done! 

[64 kiwi boni]

6 minutes ago, Wrongway said:

Originally it was a paint called Magnetic, Its basically dark charcoal that I added more black to darken it up. Its got ground up course and medium aluminum chunks with finely ground silver dollars. Its an amazing color bro. I cant wait to send y'all pictures when its done! 

now thats a way cool trick paint job 

Are you painting it your self ?

Edited April 16, 2021 by 64 kiwi boni

[Wrongway]

Yeah bro I am. I've also got an idea about putting a rose in metal flake behind the doors on bottom justa head of the rear tire. Since they don't make a stencil and it would have to be air brushed and I'm not much of a hand at air brushing I don't know if that'll make it on her. 

[BearGFR]

6 minutes ago, Wrongway said:

Yeah bro I am. I've also got an idea about putting a rose in metal flake behind the doors on bottom justa head of the rear tire. Since they don't make a stencil and it would have to be air brushed and I'm not much of a hand at air brushing I don't know if that'll make it on her. 

Wrong way, I'm olde and senile, but occasionally a couple synapses will sputter...

Are you a paint and body guy, have some skill there?

 

Bear

[Wrongway]

I've done paint and body off and on since I was about 17. I'm doing a metal flake and glow n dark paint job on a bike right now. That what's holding up progress on the GP currently. It was more or less what I always fell back on when I needed money or was looking for work in my younger days.

[BearGFR]

Cool! I may need some guidance! I'm in the process of refinishing my hood. I've got it painted and cleared, color sanding right now.  I did sort of a test 'cut and buff' on part of it a few days ago and was surprised to see some small scratches show up that didn't show at all until the gloss started coming up. It's  PPG DBC9700 black with Southern Polyurethanes Universal Clear.  

I can keep sanding/buffing/sanding/buffing until I get it right, but I'm hoping there's a way to tell when it's really ready to cut without having to do all that trial and error. 

 

Bear

[Wrongway]

Anything I can do to help I'm happy to bro. DBC is good stuff bro. Its put out by PPG. That's normally all I use. I'm a big fan of their 2000 paint system. As far you scratches go, what was the final grit you did on your color sanding? You did wet sand not dry sand?

[BearGFR]

Yes, I did everything wet. After the clear I used 1000 Trizact to get rid of any peel, then 1500, 3000, and 5000 foam pads wet. All done with a Dynabrade 6" 3/32 stroke random orbital palm sander.  It all looked flat after sanding and I couldn't see any scratches, but when the gloss came up buffing, there they were. 

 

I'm hoping that there's some way to see them without having to buff?

 

 

 

 

Edited April 19, 2021 by BearGFR