timing mark at 30 adv.

[tom55]

 :shruggy:i have 69 charger that i put a  77, 440 motor that I rebuilt... put a 270 comp cam ,new timing chain ect... the engine runs good, sounds good, starts good , but I'm not inpressed with the power I thought I  would have once I took it for a spin... The main question I have is that when I checked the timing with the timing light its way over on the left side of the tab about 30 in advance...with the vacuum advance plugged while checking it...  I did degree the  cam with a degree wheel ect... the proper way and mounted the harmonic balancer line right on the ZERO on the timing tab.
Even before I put the comp cam in ... the stock cam gave the same reading with it running it did the same thing with the timing light . I thought maybe my timing light was bad but I checked it on another car and it worked fine is this a mopar thing ANY advise out there on this   

[firefighter3931]

Tom, first off welcome to the site. 

When you rebuilt the motor did you swap out the pistons ? Did you check the indexing on the balancer ?

A couple of comments ;

The stock compression of a late model 440 is very anemic...in the 7.8:1 range so getting some snap out of the engine can be difficult. Generally speaking, BB Mopars like lots of spark lead at idle and around 38* total timing all in by 2500-2800 rpm. Low compression motors can tolerate even more total advance....in the 40*-42* range.

At this point, further gains will be realized through tuning and specificly the advance curve on your ignition. For sure 30* total is nowhere near enough timing.




Ron

[tom55]

thanks Ron, I should have made 2 seperate post so before I worry about the power that I thought the 440 should of made that will be the next advise i'll need...let me try to get a answer on the main subject which I don't understand.....
When I checked the timing, with the timing light at idle the index mark is somewhere over to the left at about 30 in advance, if I try to turn the distributor to get the mark within the tab marks it will not run , shounld'nt it be somewhere between the timing tab at idle... NOTE...BEFORE STARTING AFTER REBUILDING MOTOR I put the harmoic balancer line at 0 on the tab with the no.1 piston at TDC, turned the rotor to no.1 on the cap before starting it and this was where it runs at about 30 in advance   
quick review on what I did....I did not change pistons I put new rings ,had heads rebuilt , even before I put the 270 comp cam in i had it running with the stock cam and the timing was at 30 in advance at idle ...I thought I messed something up so I tore it down and put a 270 comp cam with timing chain, got a cam degree wheel did the works eveything lined up perfectly , The homonic balancer went on with the line pointing at the 0 degree mark on the timing tag , So I knew then that the harmonic balancer didnt slip, and wasnt at fault...any help on this

[firefighter3931]

Tom, i think you need to check the indexing on your balancer....something isn't right. 

I haven't seen a BB mopar that wanted 30* of spark lead at idle. Heres a link to checking the indexing in case you're unfamiliar with the procedure.

http://1970chargerregistry.com/70messageboard/viewtopic.php?t=1885



Ron

[tom55]

Ron,I did that during the process when I degreed the cam , I used a piston stop and rotated the cranks both ways and determined that the hormonic balancer was dead on at the line for zero (on the line), I know it doesnt make much since but thats the mystery i have tryed to figure out...with the engine static timed, with a standard timing light the line shows up at about 30 or degrees from where the zero mark on the timing tab is at idle...  i thought  this might have been a mopar thing , Like when I put the timing cam on the cam gear dot  was at the 12 o'clock position and the crank gear was at the 12 o'clock position on the no.1 tdc ,.... chevy has the cam gear dot at the 6 o'oclock postion with the dots next to each other i had to find this out when I was degreeing the cam in other wise the 440 mopar would have been on the no.6 tdc...Well if theres anything else that could help please let me know 

[firefighter3931]

Ron,I did that during the process when I degreed the cam , I used a piston stop and rotated the cranks both ways and determined that the hormonic balancer was dead on at the line for zero (on the line), I know it doesnt make much since but thats the mystery i have tryed to figure out...with the engine static timed, with a standard timing light the line shows up at about 30 or degrees from where the zero mark on the timing tab is at idle...  i thought  this might have been a mopar thing , Like when I put the timing cam on the cam gear dot  was at the 12 o'clock position and the crank gear was at the 12 o'clock position on the no.1 tdc ,.... chevy has the cam gear dot at the 6 o'oclock postion with the dots next to each other i had to find this out when I was degreeing the cam in other wise the 440 mopar would have been on the no.6 tdc...Well if theres anything else that could help please let me know 

Tom, just a question : when you used the piston stop to measure tdc were the heads on the engine ? Was it disassembled on a stand ?

I would try again with the engine in the car...install the piston stop in #1 and rotate both ways until it hits and mark the balancer at zero on the timing cover for clockwise & counterclockwise rotation and measure halfway between the 2 reference points. My guess is that you did something wrong during the indexing check. I've found it more difficult to check for true TDC and balancer index with the engine apart (heads off, no timing cover or dampner). The piston will dwell for several degrees of crank rotation at TDC and this can complicate things. Using a piston stop with the engine assembled and having the timing cover & balancer installed makes things easier.

Give it a try and see what you come up with. 

Do you have a dialback timing light ? Does the balancer have timing tape on it ?


Ron


Ps. You will still be able to tune it but knowing where TDC is makes it much easier to dial in the ignition curve.

[tom55]

yes , I degeed it with the engine assembled in the car and thats what I came up with piston stop rotating the engine had to take the radiator out ect...so I could get to it , I don't have the degree tape on the hormoic balancer and dont have a dial timing light ...once it warms up here, I will put the car in the garage and borrow a dial timing light and go from there I will let you know then if I find anything else out , thanks for your input as it is well respected

[firefighter3931]

Tom, there are a few other possibilities as to why you're getting such a high advance at idle :

** If the vac advance is plumbed into the wrong port on the carb it will actually retard the timing when you step on the throttle.

** What port are you using ?

**what carb ? CFM ?


Fwiw....I allways tune w/o vac advance.....i disable it. Makes life much easier. 

This motor can still be tuned even if we can't figure out the timing mark mystery. I would get some timing tape on the balancer for the future and we can tune it for max vacuum at idle and then adjust the rate of advance as well as limiting the mechanical advance. A combo like yours (low compression/healthy cam) will want ~20* advance at idle so we need to limit the mechanical to 18-19* for a total in th 38-40* ballpark all in by 2600-2800 rpm. The timing tape will help by giving us a reference point to start with and the ability to measure the total spark lead.

If you don't have a vacuum guage and a tachometer I would suggest you get one. There are a few good dial back timing lights that come with a built in tach....these come in very handy.


More details about the car will help too :

converter stall speed/rear end gearing/tire diameter etc...



Ron

[tom55]

Yea I have the vacuumed plugged, ....heres what I have in my charger... a 1977 440 rv motor, block is standard , 270 comp cam, timing chain,lifters,(cca-sk21-306-4), comp springs (cca-911-16), rebuilt 452 heads,elderbock 440 performer dual plane intake#2102? /holley 670 avenger carb/headers (hedmann?)/ dual exaust with flowmaster 40 mufflers , accel coil/accel wires/stock distributor (points)/727 trans /with stock rv converter/ 8 3/4 with posi 3:55/ 295 50/15 tires. I did try to put a elctronic distributor and it did the same thing with the timing issue ... (had problems with the alt not charging or something didnt work right), so I put the point system back in ...NOTE another thing this 77 motor came with a dist that had a lean setting???,(I cant remember) also had the probe deal by the timing tag ,I did away with all that and got a standard point distributor at autozone.So thats what I have for now...

[tom55]

Ron,also do you know why the hormonic balancer has 3 lines on it ,I know I have it on the right one, lined up on no.1 tdc , because I painted it when I degreed the cam... but was just wandering

[firefighter3931]

Yea I have the vacuumed plugged, ....heres what I have in my charger... a 1977 440 rv motor, block is standard , 270 comp cam, timing chain,lifters,(cca-sk21-306-4), comp springs (cca-911-16), rebuilt 452 heads,elderbock 440 performer dual plane intake#2102? /holley 670 avenger carb/headers (hedmann?)/ dual exaust with flowmaster 40 mufflers , accel coil/accel wires/stock distributor (points)/727 trans /with stock rv converter/ 8 3/4 with posi 3:55/ 295 50/15 tires. I did try to put a elctronic distributor and it did the same thing with the timing issue ... (had problems with the alt not charging or something didnt work right), so I put the point system back in ...NOTE another thing this 77 motor came with a dist that had a lean setting???,(I cant remember) also had the probe deal by the timing tag ,I did away with all that and got a standard point distributor at autozone.So thats what I have for now...

Tom, the most glaring problem with your build is the lack of compression. The 270 H cam is descent but it is designed for a motor with more compression than yours has. The 7.8:1 comp ratio is really hurting you....and that cam is really to big for the compression you currently have.

There are ways to work around it ; more stall, more gear and playing with the advance curve on your ignition. By dialing in more base timing you will wake it up and you want the timing curve to come in as soon as possible. This is a bandaid approach to mask for a low compression build that is overcammed. The carb is definately too small as well....it should have a 750cfm carb minumum. Another common carb issue is throttle adjustment....make sure you are getting full throttle when the pedal is on the mat. There is a Mopar specific throttle adapter that must be used with a holley carb. PN 20-7 (Holley)

I would start by retiming the engine and keep advancing it until it the engine speed stops increasing....then back it down a hair. Readjust your idle speed/mixture as needed. Have the timing tape installed and with the light on, map out the timing curve and note how many degrees it advanced before it stops and at what rpm it stops advancing. This will tell us how much mechanical advance is built into the distributor and how fast that advance is coming in. The rate of advance is adjusted with the springs on the advance plate mechanism. The mechanical advance is adjusted by the length of the slots in the advance plate mechanism. The newer MP electronic distributors have adjustable slots in the advance plate so this makes dialing in the mechanical advance much easier. The old points style distributors need the holes in the plate welded up to limit mechanical advance.

How old is your MP distributor. If it's fairly new it should have the adjustable advance mechanism allready installed.



Ron



Ps. I'm not sure why your dampner has 3 marks....they usually only come with one mark from the factory. Perhaps the outer ring has slipped in the past and it was re-indexed by a previous owner 

[tom55]

I bought the point distributor at auto zone recently, I will get some degree tape on the hormonic balancer, Ron I read one of your other post about spark plugs, what would you recommend for my application and plug gap...(low compression 440 /point dist.)

[firefighter3931]

I bought the point distributor at auto zone recently, I will get some degree tape on the hormonic balancer, Ron I read one of your other post about spark plugs, what would you recommend for my application and plug gap...(low compression 440 /point dist.)

NGK XR5's gapped at .035 


Ron