Just cant get it tuned right 440

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hemijosh426

hemijosh426

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Ive got a steel crank 440, fresh rebuild, .030 over 10-1 comp.
1.5 roller rockers
.557 purple shaft Solid
906 heads ported
mopar alum intake dual plane
hooker super comps
750 demon
Spring kit in dizzy
MSD 6al

I have tried numerous things to tune the motor to no avail. It seems like it surges when im cruising, and when above 3500 rpm it feels like it falls on its face. I have adjusted the timing all the way to where it gets hard to start, then backed it off a little.

My 440 source fluid balancer is a POS and has the wrong timing marks on it, so im unsure of my exact timing, need to buy a good timing tape to know exactly.

I have tried numerous jetting combinations and power valves, and still just doesnt seem like im headed in right direction.

Is there anyone out there running a speed demon 750 on their 440? What jet sizes do you use, and which power valve?

Also, When I installed the spring kit in the dizzy, the factory springs were set up with one really strong spring, and one spring about half the strength. The new springs arent much, so I used one factory smaller spring and one of the spring kit springs. I tried using both of the spring kit springs, but I could spin the dizzy with my hand and it looked as if they opened too easily. Can someone tell me if i should be running both spring kit springs or If running one and a stock one is ok? I can almost feel the timing kick in at about 2500 rpm
 
i don't know anything about the carb. get yourself a positive tdc stop, the one that screws into the #1 hole. now turn the motor over buy hand(with all the plugs out, it's easier, lol) until it stops. mark it on the damper under the pointer on the timing cover. turn it over in the opposite direction until it stops. make it again. your tdc is halfway between those marks. now measure to the right 1 3/8" and that is 38 degrees. each 1/16" is 1 degree. you don't need no stinkin timing tape, they just fly off anyway. 2500 rpm isn't too bad, try leaving out the little kit spring and see how that goes.
 
I recently had a similar problem. Timing was all over the place, and I was chasing my tail with the carb. After a year of that I decided that I wanted more cam any way. While putting it back together I a friend of mine (who is an engine builder) picked up the timing chain, and was looking at it. What he discovered is that the chain did not fit the sprocket, the tooth spacing and the chain were different. The timing set was a Comp piece that was only a year old with only about 600 miles on it, so I know that it was not stretched or worn. Long story story short the engine was literally hunting for correct timing as the chain would grab whatever teeth it could as it turned. I replaced the Comp POS with a piece from PBM, degree'd the new stick and went back to to basics with the carb to start over, and now that thing is a monster. As for the timing mark bOb is right. Timing tape just flies off. I made a sheet metal tab and tacked it to the timing cover once true TDC was determined, and a good digital advance timing light will show you where your timing is at.
 
Great idea. I will find exact tdc and put a mark on balancer at 38. I have a comp double roller chain in mine too. I thought about degreeing the cam so I know its right. What is the deal with the PBM design, havent heard too much about them locally
 
Nothing real special about the PBM (I think that they were formerly Erson) It is just where my engine builder friend buys from and he gave a smoking deal on it. It is just like the 9 position Cloyes unit, definetly should look into one if you will be degreeing your cam. PBM Performance is what they are under, google it and they are under
"timing sets" they are $89. Let us know what you find out that was causing the problems.

PBM8607
BB 383-440 billet single bolt w/torrington 9 keyway$89.54
 
I just realized that your cam is a three bolt set up, but PBM lists one for that also.

After looking at your first post again you said that it falls flat about 3500? If so I'm NO expert but I can see a couple of things that may be contributing to your woes. First thing that cam likes ALOT of compression, you are most likely bleeding off a ton of cylinder pressure with only 10:1. Second is that cam doesn't really start making power until around 3000 rpm, and most dual plane intakes I know of run out of steam around 5-5500. Next thing is your carb may too small. I was running a Holley 750 dp mech. secondaries with a much smaller cam and it wasn't enough. I have since up graded to a Quick Fuel 850 cfm mech secondaries carb, and now things are moving in the right direction.

What is the primary use of your car? Is it a street car or a race car? What rear gear do you have and is it a 4 spd or an automatic? What stall do you have if it is an auto? these all play into the big picture.

Hope this helps, I just went through alot of your experiencing.
 
check your valve seat pressure, you mite have to much spring pressure when cam is open and closing your valves, this will eventually wipe your cam out, but it'll also not let your vavles open and close properly!!!!! to fast to slow not good!!!!!! runs like crap
 
Gear and stall converter very important to make good power You have to match your power band got it.Think of it if you cam starts @ 3000 you need intake,gear,convertor,all to start at the same time,I have seen it to often guys stick in a big cam that starts around 3 grand and wonder why she is a dog off the line with stock stall convertor.got to get thoesssss revs working just at the right time.
 
Get the timing issues figured out first. Mark TDC on balancer and run about 20* initial to start and around 36 total all in by 2500.

That cam should idle at 900 rpm

Reset the carb to the factory setting, jetting/power valve. If it has the idle ease set up, that will help, but, start with it closed off.

Bob, you sure on your 1 3/8" is 38*. Each degree is about 1/16, so he needs 2 3/8". I'm thinking a fat finger deal... :)

I like to mark my balancers at 15 and 30BTDC. You can usually get any timing event up to 40btdc using factory timing marks.
 
Well I have got the timing right for the most part, will be looking into a good adjustable advance timing light to properly set the timing.

You all will never guess what fixed it for the most part, a set of 8.5 MSD wires...
I popped the hood at night and could see all kinds of arcing going on from my 4 year old Moroso 8mm wires. Did not expect a set of decent wires to take a crap that quick. I kept feeling the car have a miss, which made me pop the hood to fiugre it out.

I also changed the alternator to a 120 amp unit off a imperial, $79 at advance auto. Kind of big, but it lines up and works. I am powering an electric fan, MSD 6AL, aeromotive fuel pump, as well as lights at night time. I noticed the 60 amp alternator was not keeping up with the amp draw.

Next step is the jet the carb a little bigger( I bought a jet kit) and go from there. I think its starving for fuel. Seems to me like its running lean.

When I bought the cam, I had the valve springs matched up for that cam, and its within the allowed specs, but that would have been a good thing to check.
 
BEFORE you make changes to the jets/ carb read your plugs! That's the best way to find out what the engine is asking for.
 
Don't forget to put a heavier wire from the alt to the battery

When I put my stereo amps in I seen good advice about using a 8 gauge or larger cable from the alt to the battery. * gauge was bare min and look whats on there now. I left the factory wire and just added an 8 gauge wire and extra ground wires. It made that wimpy 60 amp alt seem more powerful

Spark wires need to be handle with care and the heat - vibration do break them down. Solid wire was the cure but that can mess up computers so we got thin wound wire that breaks more easily

New wires each season might be over kill but I try to do every 3 years
 
I put dielectric grease in every boot of my ignition system. Stuff really helps prevent any spark scatter.
 
crackedback said:
Get the timing issues figured out first. Mark TDC on balancer and run about 20* initial to start and around 36 total all in by 2500.

That cam should idle at 900 rpm

Reset the carb to the factory setting, jetting/power valve. If it has the idle ease set up, that will help, but, start with it closed off.

Bob, you sure on your 1 3/8" is 38*. Each degree is about 1/16, so he needs 2 3/8". I'm thinking a fat finger deal... :)

I like to mark my balancers at 15 and 30BTDC. You can usually get any timing event up to 40btdc using factory timing marks.
Click to expand...

:eek:ops:
you are correct, dare i say it was a typo? it's 2 3/8" for sure.
 
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