Strokes 440 diesels after long drive and warm up

[saludora]

Hey all I recently rebuilt my 440 6 pack and dropped a 512 striker aluminum heads and solid roller tuned it to what the cam said and after running it on a long drive it diesels when shutting off... is this a timing issue? Any help or direction is appreciated. Also I was told to adjust the timing to max vacuumed with a gauge instead of using cam card spec thanks again all the desiring is bad

 

[saludora]

Hey all I recently rebuilt my 440 6 pack and dropped a 512 striker aluminum heads and solid roller tuned it to what the cam said and after running it on a long drive it diesels when shutting off... is this a timing issue? Any help or direction is appreciated. Also I was told to adjust the timing to max vacuumed with a gauge instead of using cam card spec thanks again all the desiring is bad

View attachment 426127

 

[saludora]

Also it is a mechanical advance

 

[mopar 3 B]

You did all your tuning with the engine at running temp?

 

[saludora]

Set timing to card spec at temp

 

[saludora]

Should I do a vacume tune at temp or will it matter with a mechanical advance msd

 

[mopar 3 B]

Bad gas
Leaking carb
Throttle plate not closing
Idle set to high
What does it do if shut down in gear?

 

[mopar 3 B]

Should I do a vacume tune at temp or will it matter with a mechanical advance msd

Why would you want to tune a cold engine? It is not going to go down the road cold.

 

[saludora]

Bad gas
Leaking carb
Throttle plate not closing
Idle set to high
What does it do if shut down in gear?

Haven't tried in gear idle is set at about 5-700

 

[saludora]

Why would you want to tune a cold engine? It is not going to go down the road cold.

True

 

[Rick62]

Is you car equipped with an idle solenoid? I think the factory cars came with one specifically to prevent this problem.

 

[Hemirunner]

What cam, what head, what compression ratio, what fuel? I've never seen a cam card have timing specs so what are we setting the distributor to? Are you setting timing at idle or at full advance? How much advance is in the distributor?

 

[PurpleBeeper]

Bad gas
Leaking carb
Throttle plate not closing
Idle set to high
What does it do if shut down in gear?

Most of the time, "dieseling" is due to the center carb (or all three) not being closed off enough at idle. You say your idle rpm is 500-700 rpm (very low for a six pack) which is a little confusing.

Is it possible that you've got the idle screw opened quite a bit just to keep the car running with a big cam? If so, the idle solenoid should do the trick. You set the carb's idle screw all the way closed & let the idle solenoid set your idle. When you turn off the key, the carbs close completely (solenoid turns off).

Another possibility, from my experience, is your total spark advance being set too high. After it's warmed up, does it have a hard time re-starting? (turns over slow)

 

[moper]

Need more specs on what's in that engine and the current timing and carb (internal) setups. As was said - dieseling is the carb too far open. That could be for a variety of other issues.

 

[440fish]

Dealt with this for 2 years....

Try this test. Add 3 gallons of 110 to the tank and report back if it still does it.

 

[saludora]

Motor is 70 440 block 35 overbore forged and balanced 512 stroker 10.5/1 compression with aluminum heads comp cams 577/588 solid mechanical roller, 1.6 roller rockers and roller lifters. Msd mechanical advance with original springs as recommended by msd and msd 6al2 ignition system and components. Edelbrock 6 pack manifold and Holley carbs. Timing is set at 38 degrees all in as recommended by comp cams

 

[MW 413]

If your curb idle is not adjusted to high it sounds like it needs more octane. Like 440fish said, add a couple gallons of 110 octane racing gas and see how it does. My MW440 does the same thing when its on straight pump 93 octane gas. Not bad but just post idles for a second or 2 when shutting off at op temp on a hot summer day. Restarts fine. No slow turn over on hot restart.

 

[moper]

What is the timing curve? Or do you mean the timing is locked at 38*?

 

[saludora]

What should idle be 1k or less?

 

[saludora]

I'll try some aviation fuel and see how it likes it it is sposes to run off non octane premium fine but I can see it being an issue