67 GTX
Well-Known Member
So then that cam stop should be an eaxact swap into the dual point that I've been messing with?
Need Dual Point Assistance
- Thread starter 67 GTX
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So then that cam stop should be an eaxact swap into the dual point that I've been messing with?
The vacuum advance was removed to paint dist, it has an 11 on it, original? Note one light one heavy spring, They look factory to me. A W on top of cam bottom LD not LO. Forgot to pull weights, see if I can do that later or tomorrow. Picture of narrow of cam a little off, you can see in pic .980 peaks 1.030. Have to be an octopus to take picture and measure the cam and get it right. The tag is hard to read, the last 9 wasn't fully stamped the leg of 9 din't imprint. Took a magnifying glass to figure that out. EDIT: corrected the 1.130 to the proper measurement 1.030!
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Forgot to say the cam I believe has never been removed, it took a fairly hard pry to pop it.
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I'm just wondering if you have a defective tach. Double check what lead goes where. I have two dwell meters and one gets hooked up one way and the other the opposite. Negative ground systems get hooked up opposite than the positive ground systems. It's easy to read the instructions wrong. Lay your meter flat and make sure the needle is on zero before hooking anything up. There's a small screw in the center that adjusts the needle. Try another dwell meter for comparison.
There is something wrong with your dual point if the single runs fine. Maybe it's just the point adjustment. You could send it out to someone who has a machine to get it checked over and set it up. @HALIFAXHOPS comes to mind.
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Nothing on weights. Cam slots .390.
miller
Well-Known Member
Which cam stop do you mean? If from the single point distributor, can't tell you. Distributor parts book would, something I don't have.
The cam stop in your dual point 'could' be right as rain. The points gap is the strange part...should be more, based on normal settings.
miller
Well-Known Member
You should NOT have to do that. Consider it all relative. Normally, during engine build, #1 piston TDC, then the drive gear is dropped in place, lining the slot with the camshaft line. End of deal. Does not matter what distributor you put in that slot. Housing gets turned where it needs to be, where rotor points, where #1 plug wire goes on the cap. Done...besides final timing on the light.
Wild shot in the dark, dwell meter off? That would easily explain that.
I have never set dual points out of the given specs, and it run, good anyways.
Looked in 66 parts manual and the part number for Presolite dist cam is 1627261 and single point cam for all single point dist is 2642334. That Presolite P/N is a 50's P/N. MO. My thought is that the cam has to open 2 sets of points is why the peak of cam is higher.
miller
Well-Known Member
Regular parts manual?? Maybe I'll look in my 64 parts manual.
Kinda wondering the same thing.
Yes a factory P/M.
67 GTX
Well-Known Member
The points on your cam definitely look more pronounced than mine
Could be, but I believe I've used two seperate meters in the past and got similar results.
I was referring to the cam from the 62 dual point that I have. If that will be a direct swap into the dual point that I've been messing with all this time.
I had to reindex the gear in order to be able to get enough movement to set the initial timing, and for it to look normal. If would've run the other way, but then the vacuum advance would've been pushing into my radiator hose.
I was thinking the same thing. Must be why is has different point to point readings.
I cant wrap my brain around different cam point heights whether single/dual; the point location on the plate is just slightly staggered, right? No 'halifax' for a couple days(maybe he's figuring the answer right now?). Your point gap so low is really a stumper,everything i look at says .014-.019" single or dual point.
Happen to be fishing through old ebay dist parts and found this. Put under 400% magnification and I think it has an 11 stamped on it. You could contact seller if interested. not mine.https://www.ebay.com/itm/NOS-Mopar-1967-440-HP-Vacuum-Advance/222473364601
Dragon Slayer
Well-Known Member
Let me correct an error
I left out a zero in the pt to pt measurement. The Dual Point cam Point to Point is about 1.025" (Not 1.25"). So yours and Fran show 1.03" which is good, if all the point to points are ok.Frans IBS-4006Z has the LD stamp on his cam stop which is correct for that distributor from the Autolite parts manual. Also notice how the flat on the cam for the rotor is pointing at 2 O'clock, and your cam flat is about 3 O'clock.
My measurements come from actual distributor parts I measured. Single point Prestolite cam have the smaller measurements, and dual points are larger diameter.
That is needed for placement of the points and to allow both to operate in a range to get the correct dwell.
I can't explain why you can't get the gap in spec. Who's points are you using? If the rubbing block is too short that might contribute to the issue.
Did the dual point run fine with vacuum plugged on the road test? Seems it should have.
Dragon Slayer
Well-Known Member
OLDBEE Said: ""I cant wrap my brain around different cam point heights whether single/dual; the point location on the plate is just slightly staggered, right? No 'halifax' for a couple days(maybe he's figuring the answer right now?). Your point gap so low is really a stumper,everything i look at says .014-.019" single or dual point.""
Remember one set of point is opening and closing on one cam lobe and the other set of points is working off a different lobe. The larger the diameter of the circle the longer distance travel for the same amount of time. So the larger cam helps with the dual point operation
Remember one set of point is opening and closing on one cam lobe and the other set of points is working off a different lobe. The larger the diameter of the circle the longer distance travel for the same amount of time. So the larger cam helps with the dual point operation
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Dragon Slayer
Well-Known Member
67GTX, What is the part number of this new 62 distributor? I can tell you what cam designation should be. If a dual point it can fit and work in the first one. Might be more representative of what it should be.
What vacuum reading are you getting on the carburetor fitting at idle?
Your single point is working fine now in the car?
If you have high vacuum at the carb port at idle, you should not at idle. If you do, your either on a manifold fitting, or throttle blades open too much at idle allowing vacuum to come it. If the vacuum cannister of the DP does not have enough spring pressure it is adding timing at idle. Interesting that it would immediately get rough enough car won't run. What does timing do if you can measure it? If you back off initial can the car idle fine with vacuum attached?
If the DP is ok other than vacuum, it should work in the car and run fine even with no vacuum attached. If it doesn't, than maybe too much wear in the distributor, point gap is causing issues, or it looses ground some how at higher rpm and when the plate rotates.
If SP works fine at least we know it is distributor related and not coil, wires, carb, etc... Baffling
What vacuum reading are you getting on the carburetor fitting at idle?
Your single point is working fine now in the car?
If you have high vacuum at the carb port at idle, you should not at idle. If you do, your either on a manifold fitting, or throttle blades open too much at idle allowing vacuum to come it. If the vacuum cannister of the DP does not have enough spring pressure it is adding timing at idle. Interesting that it would immediately get rough enough car won't run. What does timing do if you can measure it? If you back off initial can the car idle fine with vacuum attached?
If the DP is ok other than vacuum, it should work in the car and run fine even with no vacuum attached. If it doesn't, than maybe too much wear in the distributor, point gap is causing issues, or it looses ground some how at higher rpm and when the plate rotates.
If SP works fine at least we know it is distributor related and not coil, wires, carb, etc... Baffling
Just soaking this in a bit. I have some "cam" letters from ones I pulled and rebuilt and slot measurement. Hey here is something none of us touched just had this on a 69 340. The advance plate has ball bearings, well just had one the bearings were worn and the plate was kind of lose so it floated when it advanced on the machine not much but just enough to throw it off., just a thought. I just have to bring my book in from the shop for the measurements no net out there. This is a weird one. I will scan the sun card also no that I have a good number to work with all the settings in one easy to read place. I would kill for a Prestolite reference book on these.
Do me a favor really cant make out the dist numbers
28?????????
IBS 4006Z 47/6?
28?????????
IBS 4006Z 47/6?
miller
Well-Known Member
Just to be clear...are you saying you have two different Prestolite dual point distributors? If so, maybe on swapping the cam and stop plate. Part number to part number, can easily mean slight differences between them. Advance slots the likely.
Don't think distributor #s the same as your's, but from the 64 parts book, just examples...
For the four different dual point RB motor set-ups, one hi-po, one police, I'll add that two didn't list a number for the part.
2448 805 and 1889 709
M That from the FSM or a prestolight book?
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