Timing for 440 with mild cam

[CjVan]

I have a 440 v8 in my 67 belvedere. When I bought it, nothing was known about the cam size and brand, I was told it's mild but damn does it rumble, it's my first bb engine vehicle so not sure what the timing should be set to. Any advice short of removing the cam to measure it would be welcome.

 

[CjVan]

ok from what i've read I found that 12 degrees advanced is a stock setting, does anyone know if 12 degrees is a good setting for my 440?


FYI its a stock 440 engine aside from the mild cam installed and its got electronic petronix points and a holly 650 double pumper.


Reason I ask is because once Im at about 35 mph and I lightly press the gas, i think i hear a knocking coming from a connecting rod or two and Im praying to all the Gods that the timing is the issue since the previous owner told me they hadnt set the timing, they just did it on the fly and did it by ear, just to start the engine after the resent install of the 440 engine.

 

[HitIt]

Hi -I'd try knocking it down to 10 degrees and see if it helps. What type of distributor are you running?

 

[CjVan]

Well that im not sure of, I'm very new to Mopar, until now i've been driving 67 mustangs with 289 and 302 small blocks... if itll help heres a picture of the engine before it was installed on the car. If memory serves me right, the distributor came from the original 383 engine that came with this engine.

Also, from looking at the picture below of my 440 engine.... can anyone tell me what year or models this 440 is usually seen in?

 

[68ChargerAG]

Have you already tried using higher octane fuel? Also, make sure the carb has the right jets so you are not running lean. Are your RPM high or low when this occurs? It sounds more like a lean running condition to me. Cams with longer than stock duration generally require an increase in timing advance, so if stock is 12 BTDC and you are running 12 BTDC I would say timing is not the problem. I think that 10 - 12 BTDC is about what is correct for cams with mild duration, 220 and under.

 

[CjVan]

the knocking occurs during low RPM and goes away when I accelerate or when theres more load on the engine. Im worried the engine does have a rod knock.

 

[Meep-Meep]

Yeah, I'll agree with 68AG. I typically ran as much as 15 I on my 383 with a mild cam.

If it's a rod knock you should be able to hear it in the driveway while slightly revving the engine.

By the way, I'm a big small block Ford fan too! Had a 68 Mustang J code GT 4 spd.

 

[CjVan]

Well i havent noticed any knocking while lightly pressing the gas with transmission in park. Ill try it again today to see if I hear it. Nice! i had 2 67 mustangs, both coupes, first one was stock, the other one had a 68 CS trunk lid spoiler and 67 gt500 tail panel and eleanor front end. cool little cars, i thought it was a decent first car

 

[MarPar]

Well i havent noticed any knocking while lightly pressing the gas with transmission in park. Ill try it again today to see if I hear it. Nice! i had 2 67 mustangs, both coupes, first one was stock, the other one had a 68 CS trunk lid spoiler and 67 gt500 tail panel and eleanor front end. cool little cars, i thought it was a decent first car

Well, i'm glad you came to your senses and bought a MoPar!!! LOL :tongueflap:

 

[CjVan]

lol thanks one thing kept me from going mopar was (since i watch alot of TV) that Dodge and Mopars always reminded me of Al Bundy and his Duster and the Viper he almost won. Theres a mopar website (forgot which one) that has a picture that says "Legends of Mopar"... it has a transparent image of a man that looks like Al Bundy, same hair line and all.... im 27 so hopefully you can understand the error of my ways

 

[69 Runner]

The best timing for your engine is what works best for it, no matter what a book might tell you.

As far as the pinging goes, you need to work on the advance curve in your distributor and slow it down

 

[68ChargerAG]

Maybe it would be worth disconnecting the vacuum advance as a test (and plugging the vac line) to see if the noise goes away... then at least you would know if this is causing it to advance too much, or too fast... then go from there???

 

[CjVan]

Ill try disconnecting the vacuum advance today and update later

 

[CjVan]

ok, checked and reset the timing... With V.A. disconnected and plugged i was getting 1 degree btdc and i set it to 10 degrees btdc and with v.a. hooked up the timing moves to 8 degrees btdc... feels nicer and the knock went away. thanks for the help guys.

 

[Meep-Meep]

Am I reading this correctly, or is it so late that my brain has turned in to a pumpkin? 10 BTDC with no vac advance and 8 deg with it hooked up? If the vac advance is hooked up to the ported port on the carb, and the primary throttle blades have not uncovered the port, then you shouldn't get any timing change (not to mention retarding the timing) when you hook it up.

 

[CjVan]

Well, Ill explain what I did word for word, i know sometimes my typing can get dyslexic at times.

Ok, I hooked the timing light to cylindar #1, drivers front cylindar.

- loosened bolt that hold dist from rotating
- hooked up timing light positive and negative leads of the battery
- disconnected dist vac advance & plugged line with a screw
- start engine
- while engine is idling, I see im getting about dead on 1 degree BTDC
- rotated dist slowly clockwise till I hit 10 degrees BTDC
- tightened bolt that locks dist in place
- hooked up vacuum line back into dist vac advance
- As I plugged in the vacuum line the timing changed from 10 BTDC to 8 BTDC during idle



When I turned the timing clockwise to get back to 10 BTDC the idle did raise slightly and I didnt tune it down before rechecking the timing and locking it in. At the time I was in a pinch and had to hurry so i didnt lower the idle after words but it sounds like it only went up 300 rpms or so.

Based on what I did, Is there anything you all can see I did completely wrong?

 

[Meep-Meep]

Your timing setting method seems fine. My question is why the vacuum advance seems to retard the timing when it's hooked up (10 deg BTC - 8 deg BTC when it should be 10 deg - 12 deg). When you slowly rev the engine (with or without the vac advance hooked up) the timing should advance. Note which way the mark goes. The only explanation I can think of is you are 10 deg AFTER TDC and hooking up the vac advance brings the timing closer to 0, or TDC. Also having a vacuum signal present at the ported port would indicate too much throttle opening to keep the engine running in the retarded timing state. I almost need to go out and look at my 66 to make sure I have this right.

 

[CjVan]

Well based on what the timing marks say, 10 BTDC is on the far left (facing front of engine) and 10 ATDC is on the far left of the timing marker.

Without the vacuum advance plugged, im at 10 BTDC and when i unplug the advance, the marker moves to the right Or clockwise direction (while facing the front of the engine).

Anything out of the ordinary with that?


Pretty accurate depiction below of what Im looking at when standing infront of the engine while looking at the timing marks over the crank.
|-----------|-----------|
10before___0_________10after

 

[68ChargerAG]

When you plug the vac advance tube with a screw does the engine RPM go up slightly?

It sounds to me like with the vac advance plugged the engine must rev up slightly causing the mechanical advance in the distributor to advance a bit, then when it is unplugged or plugged into the distributor it is seeing a vacuum leak that is dropping the RPM back down and retarding the timing.

Are you doing this check below 1000 RPM? I think that as long as you are below 1000 RPM there shouldn't be any mechanical advance taking place. I think that you should be somewhere between 600 - 650 RPM when doing this check. You might want to verify this... as well as a possible vacuum leak in the distributor vac advance plunger if you are seeing what I am describing. Just some ideas... because I agree that the results that you are getting are very out of the ordinary. If anything, when things are working properly and you hook the hose up to the vac advance on the distributor you should get a slight increase in timing as Meep said.

 

[CjVan]

could be that the idle was too high, I'll have to check it during my lunch break. ill let you all know.