65-440
Well-Known Member
3/32 Allen.... I don't see why I wouldn't be able to use it, my engine pulls decent vacuum. The part I'll need to play with is when to have it start advancing...
Constant or Ported Vacuum Source for Distributors? ...AGAIN!
- Thread starter cuda66273
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MOPAROFFICIAL
Oogliboogli
LoL
I had mine set to only add 12 degrees, when it came in...is when the throttle blades were closed enough to signal the orifice and pull on the canister!
Boy that article misinforms people....
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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If you have a clutch you pretty much have to go ported, and the higher your cylinder pressure, and the slower you want to operate her at, the more important it is to soften the pressure pulses, and that can only be done by retarding the timing.Then you just speed up the rate to catch up; I just don't get the the big deal.
I have tuned a few big-cammed-for-street, SBMs. One my own;at one time, a 292/292/108cammed, 11.3 Eddie headed 367; to run, down at under 10*idle-timing,with a 750DP/A-Gap, and slug away at 600rpm pulling itself with 3.55s, and 27s.I didn't think any of them were a big deal.
But,if you have a low-compression slug with an automatic,I guess she'll need all the help she can get.
You guys with your 8.00Scr teeners running 268* cams,and 124psi cylinder pressure,and automatics; I guess you have to keep them running somehow. But don't blame anything but that lousy cylinder pressure, for your sluggish take off with the factory TCs.You can't fix that with timing! It's hard enough with a TC in the upper 2xxxs. I just don't get it; you'd rather crank the timing up and put a big TC in there,and probably throw some gears at her; ......than a decent set of pistons, a tight-Q, and and a synchronized Dcr.
What's the installed cost of high-compression pistons? Compare that to a big-TC and a set of gears also installed? I know which I'd rather have. I'm not saying that once you get the pressure up, that you might not still want a bit more TC and more gear than 2.76s for sure,lol, but now it's an option, not a prerequisite.
Get the pressure up and put the timing where the engine needs it to be ....not where you think it should be. And if it idles a lil lumpy, well; half you guys put that stinking cam in there just for that, IMO, silly reason, in the first place.Let it lope;what's the big deal;it's an automatic with a high-stall. They don't much care about low-rpm timing, 'til it hits stall-rpm.
And besides all that rant; To get your T-port synced,and run a PCV, you just can't put a buncha timing in it anyway,and still have a slow enough idle speed, with any carb I have seen. You can M-A-K-E it idle, but then when you put it in gear, uglychithappens......especially if the Vcan is hooked to manifold vacuum, and the timing falls out as the vacuum drops. Now everything is all messed up. The idle-timing may be insufficient, the sync is off, the PV may open/or the M-rods jump up, air flow takes a dive, and the engine floods and crashes to a stop. You can fix all those things.......But why? That just creates new problems. Back off the idle-timing,sync the T-port,fix the rate of advance,put the can on the Spark-Port,and all thebadchit goes away.
I have tuned a few big-cammed-for-street, SBMs. One my own;at one time, a 292/292/108cammed, 11.3 Eddie headed 367; to run, down at under 10*idle-timing,with a 750DP/A-Gap, and slug away at 600rpm pulling itself with 3.55s, and 27s.I didn't think any of them were a big deal.
But,if you have a low-compression slug with an automatic,I guess she'll need all the help she can get.
You guys with your 8.00Scr teeners running 268* cams,and 124psi cylinder pressure,and automatics; I guess you have to keep them running somehow. But don't blame anything but that lousy cylinder pressure, for your sluggish take off with the factory TCs.You can't fix that with timing! It's hard enough with a TC in the upper 2xxxs. I just don't get it; you'd rather crank the timing up and put a big TC in there,and probably throw some gears at her; ......than a decent set of pistons, a tight-Q, and and a synchronized Dcr.
What's the installed cost of high-compression pistons? Compare that to a big-TC and a set of gears also installed? I know which I'd rather have. I'm not saying that once you get the pressure up, that you might not still want a bit more TC and more gear than 2.76s for sure,lol, but now it's an option, not a prerequisite.
Get the pressure up and put the timing where the engine needs it to be ....not where you think it should be. And if it idles a lil lumpy, well; half you guys put that stinking cam in there just for that, IMO, silly reason, in the first place.Let it lope;what's the big deal;it's an automatic with a high-stall. They don't much care about low-rpm timing, 'til it hits stall-rpm.
And besides all that rant; To get your T-port synced,and run a PCV, you just can't put a buncha timing in it anyway,and still have a slow enough idle speed, with any carb I have seen. You can M-A-K-E it idle, but then when you put it in gear, uglychithappens......especially if the Vcan is hooked to manifold vacuum, and the timing falls out as the vacuum drops. Now everything is all messed up. The idle-timing may be insufficient, the sync is off, the PV may open/or the M-rods jump up, air flow takes a dive, and the engine floods and crashes to a stop. You can fix all those things.......But why? That just creates new problems. Back off the idle-timing,sync the T-port,fix the rate of advance,put the can on the Spark-Port,and all thebadchit goes away.
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Actually I would not have guessed that. LOL. I just assume that there's a certain percentage of speculative "what if" threads.
I think we talked about this in the last few posts (other thread). If you want a good comparison, start with the same vacuum advance. The only change to make is use the ported source, unless that takes away too much timing at idle.
Since the vac pod is leaking, if weather and time permits, plug the vacum line and just experiment with the intial and mechanical. See how it will run with no vacuum advance at idle. That's what's going to happen anyway when you go ported. Its also what you'll need to do anyway to measure out the mechanical advance curve.
65-440
Well-Known Member
I did just that last weekend, that's when I also took my cruising RPM's and vacuum readings. Car ran just fine at idle, still smooth on take off too. My total mechanical is set at 36 degrees at 3k. I think my initial was somewhere around 16 ... I'd have to double check that though !
65-440
Well-Known Member
well ****, so much for that. The 2 advance cans that came in were wrong, the only other one is obsolete. Looks like I'm outta luck on this. Mechanical advance only for me ...... unless i look at different a distributor
What distributor? Mfc., & P/N if you have it.
65-440
Well-Known Member
It's a reman unit. Box is long gone. For a B engine ... here's a pic of the can....i cannot find one with the same arm, they either bend the other way or pin is on the other side
BillGrissom
Well-Known Member
I agree. The various vacuum cans are confusing and poorly documented. Guys who fool with their engines would be better served with an electronic spark controller, then they could tweak spark timing vs (rpm & MAP) to their hearts content. There was one named RapidGator which came and went. I expect the developer got a busier day job. I recall Kit was also working on one. One can do so with a Holley Commander 950, and perhaps others fuel injection controllers, if you use a GM 8-pin HEI module. A bit clumsy if not using the EFI part, but you can find the controller alone cheap on ebay, and could wire your own cable w/ just the wires needed for spark control. Can also add feedback O2 (wideband is best).
@65-440
The one in the pictures is the correct one, right?
The ones with the pin the other way are for A & LA.
The one with the bend that's off may be a flavor for /6, but I think rotate the same direction as small blocks. However /6 Dan has noted they don't all interchange.
If youre gettin' frustrated hunting - see if Ray (Halifaxhops) or Tony who used to sell a lot of parts here (but was starting a shop) has one to sell you.
ps. No prob about the p/n, especially with a reman.
I still think you should measure the advance curve - its not a straight line.
The one in the pictures is the correct one, right?
The ones with the pin the other way are for A & LA.
The one with the bend that's off may be a flavor for /6, but I think rotate the same direction as small blocks. However /6 Dan has noted they don't all interchange.
If youre gettin' frustrated hunting - see if Ray (Halifaxhops) or Tony who used to sell a lot of parts here (but was starting a shop) has one to sell you.
ps. No prob about the p/n, especially with a reman.
I still think you should measure the advance curve - its not a straight line.
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65-440
Well-Known Member
Yes, that is the one I need . Frustrated? Try beyond frustrated ! I went through this 2yrs ago with the factory distributor, found the can only to find out it was obsolete. Bought this reman one, can failed and as life would have it.... it's the same can that I Needed 2yrs ago ! I will not pay for an NOS unit, too much $$ just to have that fail as well because it's ancient!
I'll send you a PM so the thread doesn't go too far off track.
I believe the OP is Don.
KitCarlson
Well-Known Member
I completed my prototype, it works great. Coil near plug, multi-spark, full electronice advance, tune real time, real time timing readout, data logging, interfaces with smart phones tablets and notebooks.
The greatest problem, was revision of starter, and alternator power circuits, for clean ECU feed. That work while not difficult, or expensive, would be a show stopper. There are perhaps a hundred + posts about alternator issues, where bad grounds, poor bulkhead connectors .... they go on for pages. Steering people to fix, is well beyond my patience.
Then the major tuning leap, there are those that think no advance, like a lawn mower is the key to drag racing. Vacuum advance, not requried, or only manifold source. Much it is about knowing what is wrong, when timing is off... Leaving off +, - , things like difficult starting, poor throttle response, pinging, idle speed runaway, poor economy, over heating, stinky .... herky jerky coast down. Thinking running like a beast, is a beast... A well tuned car is smooth, reponsive, economical, yet max power, optimal perfomance, for all RPM, and load conditions.
They are becoming a issue for me also, NOS mopar are to much to have on the shelf, seem the straight arm is 440 points, but it is also on some 383? Confusing as hell to figure out in a listing.
Hey Hoppy, I was looking in the '67 books at single point BB distributors. There was one non-CAP 440, high performance distributor with single points. Most of the others are Prestolite dual-points as you'ld expect.
FWIW, there's five 383 single point distributors and three different vacuum cans. I assume these were all the stamped metal style like you picture. Wouldn't be too hard to make any that fit work for hot rod..
Not usually, most interchange only difference is the advance plate easy change if needed. I wish I had a book on just the vac advance applications, no way I am looking them all up in the fsm's. Biggest thing as you know is the amount of vac advance, just because it fits.......
In your situation, that would be best - an old SMP, Echilin or similar catalog with interchange numbers maybe. With the FSM as you know its a multi-step look up so making your own list would take just a day less than forever. lol hey a puzzle for the kids....
Right, I am already trying to make a list of advance cams in prestolight dual points from when I work on them, of course no part numbers on them either.
Remember I get cores, some are virgin, some have been into before. I use the numbers on the sun cards they seem to be the best so far compared to the FSM, have not found a mistake on them yet.
I have a 70's Delco book that is pretty good and also a Filko one that has some of it.In your situation, that would be best - an old SMP, Echilin or similar catalog with interchange numbers maybe. With the FSM as you know its a multi-step look up so making your own list would take just a day less than forever. lol hey a puzzle for the kids....
65-440
Well-Known Member
The first picture, can on the left is what need ! Do you have any good replacements availiable ?On my oem distributor the arm is stamped 13L ....
Let me look send me a pm to keep track of it. Possibly those are the ones that are a PIA to find.
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