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Need help with 440-3 cutting out on heavy acceleration. Solved!

Nismobishi

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Hi guys,
I have a 1965 Satellite with a 440-3 out of a 1974 motorhome. it has the 213 heads that take the 5/8" peanut spark plugs.
I have been having an ongoing problem for as long as I can remember where the car idles great, sounds great, drives great, but when accelerating heavy or WOT is sputters and jerks then it will eventually clear up and take off.
here are the specs:

440-3

MSD 6al with pro billet distributor with 1 silver spring, 1 blue spring, and the black bushing with initial timing at 18* for a total of 36* all in around 2000 to 2500 rpm, MSD Blaster coil, Taylor 10mm wires, and NGK UR5 spark plugs. (have tried ngk, champion, autolite, and bosh plugs with no change in acceleration).

A&A transmissions brand cross ram manifold (426 Super Stock tribute) http://www.aandatrans.com/Products/...ake-Manifold-(As-Cast-Port)__RMWACRIM-14.aspx

2 Edelbrock 500 cfm manual choke carbs (have tried all 3 accelerator pump positions)

Lunati cam lift .465"/.465" advertised duration 285*/300* duration at .050 tappet lift 228*/235* https://www.jegs.com/i/Lunati/638/33702/10002/-1

213 heads surfaced and shaved

timing gear drive

bored .060 over

compression 9.25:1

Napa brand flat top pistons

hardened valve seats and high pressure valve springs

30/30 crank grind

Hedman headers

I cant seem to find the happy place for timing or maybe this is not a timing problem at all? Maybe too much carburation for this engine? Exhaust smell at idle is a real eye burner even though it idles great.

Any help would be greatly appreciated. I might be able to get a video of the problem tomorrow if it would help.
 
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Have the carbs been on there a long time? I just rebuilt my 800 avs with an edelbrock kit and carb cleaner and it has cleared up my lean idle problems (smelly). It had a lot of varnish and crud in the idle circuit and air bleeds from sitting in fuel for long periods in storage. I would take them off and clean them, blow out the passages and idle screws with carb cleaner. The rebuild kit is useful but not absolutely necessary, can probably just get one for the both in case some of the gaskets are destroyed.

If you are having a stumble, probably too lean as well. But I would just clean them first before making any big changes, see if that helps.
 
It has been like this since the carbs were new. Also, it was never quite right even with the single Edelbrock 550 or the Demon 800 I had on it with a different manifold.
 
fuel dripping in from boosters? Too much fuel pressure. Seen a lot of ede/carter carbs have an issue with this.

That timing you should be able to clean up the idle.
 
Sometimes it runs great like a race car but most of the time its a dud! Possibly temperature related.
 
fuel dripping in from boosters? Too much fuel pressure. Seen a lot of ede/carter carbs have an issue with this.

That timing you should be able to clean up the idle.

Thats what I thought but it was like this even with a single carb. Edelbrock and a Demon.

This is why i think its a timing problem, but everyone swears by the blue/silver/black spring and bushing combo of the msd set at 18* initial which is what I have set up so I'm at a loss now.

Now that I think about it it was not this bad with a single carb. Now its kind of like the stumbling doubled since changed it to 2 carbs.
 
Thats what I thought but it was like this even with a single carb. Edelbrock and a Demon.

This is why i think its a timing problem, but everyone swears by the blue/silver/black spring and bushing combo of the msd set at 18* initial which is what I have set up so I'm at a loss now.

Now that I think about it it was not this bad with a single carb. Now its kind of like the stumbling doubled since changed it to 2 carbs.

What about changing the metering rods? that was my next thought.
Also, Does this cam sound ok for this build. Is it a good match?
 
I have no experience with a crossram or dual quads but it should be able to be fixed. Hot rod has some avs tuning guides. Main thing I would check is step up springs, try to target 1/2 your idle vacuum, so an orange 5" spring for 10" vac. Try adding more fuel for the transition to full throttle by putting in metering rods with smaller numbers for last two digits. If you have 7052 rods, try 7049, 7047. You can also upgrade the acc pump squirters or spring to add more fuel. Assuming the bog is from a lean condition.
 
I have no experience with a crossram or dual quads but it should be able to be fixed. Hot rod has some avs tuning guides. Main thing I would check is step up springs, try to target 1/2 your idle vacuum, so an orange 5" spring for 10" vac. Try adding more fuel for the transition to full throttle by putting in metering rods with smaller numbers for last two digits. If you have 7052 rods, try 7049, 7047. You can also upgrade the acc pump squirters or spring to add more fuel. Assuming the bog is from a lean condition.

Thanks for the advice! It looks like I will be ordering some metering rods and step up springs.
 
Do you have a carb throat vacuum gauge? I think they are called a uni-syn. Essential for tuning dual carb applications.

Also, it could be that your mechanical advance is sticking. Try locking out the vacuum advance (if you have one) and put it under load and see what it does.

Other than timing adjustment I wouldn’t mess with the cam just yet. Even if it’s mismatched to your combo it should still run smooth under acceleration, you just won’t make decent power.
 
Have you thought about installing a O2 sensor?

Is it worth hooking one up through an exhaust cutout? I know they recommend being further up the head pipe. I’d like to rig up something inexpensive and non-permanent to get my new carb dialed in. I’ve seen guys use a multimeter instead of a fancy gauge.
 
I had this problem, started, revved ok, but with throttle under load would stumble.

What I found was not getting 12+ volts to coil. Now using relay to get full voltage to coil.
 
I got it running like it's never ran before! I put on a set of MSD street fire spark plug wires and reset the carbs back to all factory settings. I then slowly adjusted both carbs equally using the idle mixture screws. Ended up at 1.5 turns out. I then set the idle with the primary idle screws. I also found that my number 6 plug wire had a loose terminal at the plug end and I thought I had the blue and silver springs in the distributor but I actually had the light silver and heavy silver. I switched to the light silver and light blue and double checked that my initial timing was at 18*.

Now it runs like a race car! I couldn't be happier. I will still get the carb synchronizer to fine tune it though.

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