With or Without CAP?

[SF-66TC]

Can anyone tell me the meaning between the two descriptions below

Don't know what Without CAP / With CAP is referring to -

5 - Without CAP (cleaner air package) 12.5 degrees BTDC


7- With CAP (cleaner airpackage). 5 degrees ATC

I have a stock '66 383-2 that was upgraded to a 4-bbl and need to know correct timing spec. I assume the carb shouldn't make a difference so need to know meaning of With CAP or Without CAP

Info taken from http://www.tpocr.com/Chry1.html

 

[commando1]

so need to know meaning of With CAP or Without CAP

Are you asking what the differences are between the two?

 

[SF-66TC]

Yes Commando1 - I don't know what that means... what is the CAP that's being referred to?

Are you asking what the differences are between the two?

 

[300rag]

My best guess is the California vs. the 49 state emission version.

 

[69CoronetRT]

...what is the CAP that's being referred to?

I have the full TSB if you are interested

 

[MrMoparCHP]

If your car was originally a California car it would have a 1 under the E on the data plate.
If it has the 1 under the E (not e) then it has CAP.

Even us here is California don't follow that, we tune for optimum performance or mileage your choice.

Since we no longer need to worry about smog checks on these car I set it where I want, even when they reset it to do the check Iwould set it back to where I wanted it.


Alan

 

[SF-66TC]

65CoronetRT, YES I am interested in the complete TSB!

I'm getting pinging/knocking in the engine no matter what I set the timing to and am now thinking this new found information is shedding light to the puzzle. The TSB states the three special components of the CAP were a redesigned 2bbl carb and dizzy and the addition of the VCV.

Back in the '70's my pops upgraded the stock 2bbl with a 4bbl but left the VCV attached to the dizzy. With my pops upgrading the carb it threw a wrench into the equation which is probably why the car isn't running as well as it should.

What I've done -

Thinking the pinging had something to do with the vacuum advance I disconnected the VCV from it so I'm essentially running the dizzy as a mechanical advance unit. With the vacuum advance line disconnected and plugged I had set the timing to 12.5 BTDC, but the engine still pinged. I retarded the timing to 10, then to 7.5 then to 5 with no change. I then set the timing back to 12.5 and using a variable timing light checked to see what my total advance was - it showed the dizzy is giving me about 30 degrees of total advance or 17.5 degrees at the dizzy itself. The question is, "what should it be?"

Since the dizzy was also part of the redesign it's internal components ie: weights, springs would be different throwing another wrench into the mix!

With the engine still pinging at various settings I began thinking the pinging could be gas, I drained out as much as I could (needle was at E) then I put about 2.5 gals of premium (91) and drove the car about 70 miles. After 70 miles the needle was just about E so I added in 6 more gals of premium (91) and drove the car 20 miles to get some 100 octane race fuel. I added 5 gals of (100) to the mix which I figured was now diluted down to about (94). The engine still pinged under load, but not as bad before adding the race fuel.


What say you? Since I live in California and the car is CA smog exempt, I can disco the VCV. Since it has a different carb that should take care of that, but what do I do about the dizzy? Would it be best to get a non Calif one or a Mopar EI unit from Summit?

I have the full TSB if you are interested

 

[SF-66TC]

Alan,

Yes it is a CA car and has a CAP



I'm also in California, SF to be exact. How are you running the vacuum advance? You're not running through the VCV are you? Are you using the stock dizzy?

Steven

If your car was originally a California car it would have a 1 under the E on the data plate.
If it has the 1 under the E (not e) then it has CAP.

Even us here is California don't follow that, we tune for optimum performance or mileage your choice.

Since we no longer need to worry about smog checks on these car I set it where I want, even when they reset it to do the check Iwould set it back to where I wanted it.


Alan

 

[MrMoparCHP]

I just go down to Autozone/RockAuto etc and get a distributor for an application with electronic ignition, don't recall there being any listed for CA/Non CA

I then get a Mopar electronic ignition module and pigtail and wire it up.

The vacuum advance is run like non CA cars, carburator to distributor. On my Barracuda which I still have the vcv on for show just has a vacuum line looped around itself to look like it is hooked up (an old smog check trick, loop them around the carb and plug into itself same with the EGR and NOX devices). I actualy had to track down a VCV for my Barracuda when I did the restoration although it isn't used.

So yes not having to do smog checks you have some freedom, plug the port on the manifold and toss the valve in the tool box.


Alan

 

[shooter65]

Thanks Everyone!

This is why I joined this forum. Excellent tech resource!

 

[70bigblockdodge]

If you are pinging at 7.5 and 10 btdc with 91 on a low compression 2 bbl engine, either you have some massive carbon build up or your TDC mark is not accurate. You can check TDC with a positive piston stop tool. Then you can truly set the timing.

 

[SF-66TC]

Thanks 70bigblockdodge, I was also thinking my TDC mark was not accurate and what you suggested will be my next step before changing any other parts.

A couple of questions:

1. regarding the piston stop tool, what length should the stop itself be for determining true TDC. I've looked online to see what the tool actually was and it appears the stop itself can be adjusted either up/down. Unless the stop is adjusted to stop the piston at the very top of the stroke, true TDC will not be achieved. That said, it does matter what length the stop itself is, doesn't it?

I saw on YouTube one can be easily be made with a spark plug and a 1.5" x 1/4" 20 head bolt and nut which is what I'll do.

2. What size is the bolt head that securing the harmonic balancer to the crankshaft? With the deep dish of the pully mounted in front of the harmonic balancer it's difficult to get a socket and rachet/flex bar in there as there's not much room due to the radiator being so close. Is it a 32mm?

If you are pinging at 7.5 and 10 btdc with 91 on a low compression 2 bbl engine, either you have some massive carbon build up or your TDC mark is not accurate. You can check TDC with a positive piston stop tool. Then you can truly set the timing.

 

[70bigblockdodge]

Dampener bolt is 1 1/4socket, short extention works. Set the depth so that it stops the piston about 10-15° btdc mark dampener at the zero mark then rotate ccw until it stops again make another mark on dampener at zero, halfway between the short distance of these two marks is true tdc and if all is right corsponds with groove on dampener. Sometimes it is a little hard to feel when the piston hits in a big block because of the angle that the spark plugs go in at. Before you do this check you rotor phase with plug wires on cap they might be one tower off especially if this was changed last by previous owner.

 

[SF-66TC]

hmmmm..... sorry, still a little confused. If the dampener position is wrong to begin with, wouldn't using 10-15° btdc as the initial stop point be off as well? OR it doesn't matter because 10-15° would just be a mark as a point of reference? I'll try and check this out tomorrow.

Dampener bolt is 1 1/4socket, short extention works. Set the depth so that it stops the piston about 10-15° btdc mark dampener at the zero mark then rotate ccw until it stops again make another mark on dampener at zero, halfway between the short distance of these two marks is true tdc and if all is right corsponds with groove on dampener. Sometimes it is a little hard to feel when the piston hits in a big block because of the angle that the spark plugs go in at. Before you do this check you rotor phase with plug wires on cap they might be one tower off especially if this was changed last by previous owner.

 

[70bigblockdodge]

Its just a reference, if the groove is not acurate it will not be halfway between your marks. First thing is check your dist cap/wires. Put engine on TDC and make sure rotor is pointing at 1 or 6 doesn't really matter which just so it is aligned with either

 

[SF-66TC]

Used the piston stop and my TDC is correct...

With the CAP, timing setting is 5d ATC. Since I was trying to go through the process of elimination and take the VCV out of the equation I disconnected it from the dizzy vac adv and plugged it off, set timing at 12.5 (as Without CAP) and the engine still pinged.

Retarded timing to 10, 7.5, then 5 and engine still pinged.

I checked for TRUE TDC using a Piston Stop Tool as 70bigblockdodge suggested and TDC is set correctly.

Next I will completely bypass the VCV and hook ported carb vacuum directly to the dizzy vac adv and check if pinging still present.

If pinging still present I will need to check if my vac adv is possibly leaking. I tried the "suck on the hose" method, but I'm getting constant air so I'm thinking maybe my vac adv diaphragm is leaking... may not be an accurate test? I'll get a pressure pump to test for more accuracy.

So it looks like I'm down to my pinging either being a bad VA diaphragm or the dizzy's curve advance is incorrect due to the dizzy's redesign for CA smog emissions as stated in 65cornonetRT's TSB.

If the VA diaphragm is good - rather than find a shop to recurve it, it might be best to just swap over to a complete electronic setup (dizzy, harness, control unit). I do have a Pertronix Igniter II that I was going to install, but if the actual curve is incorrect then the Pertronix won't really do me any good.

Anyone have any experience with either of the two units?

Proforms 66993 unit - http://www.summitracing.com/parts/pro-66993
Summits Mopar 850004 unit - http://www.summitracing.com/parts/sum-850004

The Proform 66993 unit says it's "bluprinted and features a factory-set performance advance curve" Whereas Summits 85004 says it's "equipped with a Performance Advance Curve"

Since my 383 is a stock 270hp engine, would Summits unit work ok?

Well, those are my next steps. Please feel free to chime in with your experience, suggestions and/or opinions - thanks

Its just a reference, if the groove is not acurate it will not be halfway between your marks. First thing is check your dist cap/wires. Put engine on TDC and make sure rotor is pointing at 1 or 6 doesn't really matter which just so it is aligned with either