Couple of questions Timing and Carb

[rat roaster]

Engine is a 511 b engine, Muscle motors short block
Cam is 284 @.50 630 lift
Heads Indy Alum with Max wedge ports
Indy tunnel ram
Pro Systems 780 double pumpers
MSD 6AL box and billet mechanical advance dist

First the carb(S) problem. These carbs have the idle adjuster screw on the primary and secondary. I called Pro Systems after I broke the motor in to ask about the float height. We talked about adjusting the idle and four corner mixture.. The guy never said any thing about adjusting the idle screw on the secondary. Of course with no instructions. I am tired of calling them.

I know I do not have the idle set right because when adjust the idle mixture screw nothing happens. What is the proper procedure for adjusting the idle?

Second I called muscle motors before I broke the motor in or cam in. I asked about timing. There dyno guy told me that with the tunnel ram and motor specs that the tunnel ram would like it if I pulled the dist locked the mechanical advance and set total timing at 34 deg. Which I have done. It is a bear to start most of the time.
What should I set my initial and total timing to? How soon should I have the advance come in?

Car will never be drag raced. Maybe occasional street race,,,lol
Thanks
Duane

 

[dvw]

Should start at 34. Mine starts 14.8-1. Make sure all cables and connections are up to snuff. I found 32 degrees ran as good as 34 34 in my Indy headed motor. Flat top piston, a domed piston may like more. All 8 mixture screws should be turned the same amount. Turn each one in counting the turns until bottomed to see where they are at now. Start at 1 turn out and then adjust from there. My bet is you'll end up at 1 1/2- 2 1/2 turns out. The speed screws (throttle blade) should only need a turn or two from being fully backed out.
Doug

 

[lewtot184]

all of the idle mix screws will need to be adjusted. if starting problems become too big of a headache just attach a start retard.

 

[Mike Gaines]

Why in the world would you want to lock the timing in at 34 degrees, or any degrees locked.
Doesn't make sense to me. With that cam you may have trouble with the motor not wanting to turn over when trying to start it.
Put the springs and bushing back in it. Set the "total" timing to around 34 and have it "all in" by around 3000. Look at the MSD chart to figure how much "initial" timing and how much "total" then put the appropriate springs and bushing back in the MSD Dist. You wont be fighting the kickback with too much timing to get it started.
My opinion is to just give all 8 idle adjustment screws about 1 1/2 turns out, then adjust the primary and secondary throttle blades (idle screws) (on both carbs) to get the RPM that you want at idle. You gotta get the "idle" set before you can do anything....If after this procedure you like the quality and speed of the idle and if it doesn't "bog" when you launch it from idle..then you are set.
If you like the idle but it "bogs" at launch then you gotta get serious about transfer slot settings (which is controlled by the throttle blade (idle speed screws) and pump cams, etc, etc, etc,
But try the simple method first and see if you can live with it.

 

[Tempest 455]

Should not be that much of an issue having timing locked with that duration cam. Locked usually helps it idle better with large duration roller cams.

If the idle mixture does nothing, you are past the idle circuit. The throttle blades are open too far. You need to fix that 1st once you have timing set.

 

[IQ52]

What does "bear to start" mean? Kicks back against the starter or rotates over and doesn't start for awhile? That cam should like starting and idling at 34 degrees.

 

[Tempest 455]

Forgot to mention. With a T-ram and (2) Holleys, you are going to need to get a decent amount of fuel into the intake before you try and start. On mine, I would turn on the fuel pump, pump the throttle a good 4-5 times (or more depending on temp) and then try firing it up.

It's not like starting a stock or small plenum intake. You need the appropriate amount of fuel for the plenum volume.

 

[IQ52]

Still, the same questions................

What does "bear to start" mean? Kicks back against the starter or rotates over and doesn't start for awhile? That cam should like starting and idling at 34 degrees.

 

[rat roaster]

Thanks
Bear to start means.. From cold motor. I usually pump the pedal four or five times.
Then have to pump it while it is cranking over to get it to run.
Usually it will back fire out the carbs and die.

I know how to adjust all 8 mixture screws. My problem is when I try to adjust them nothing happens. I think the butterflies must be to open and they are above the idle circuit..
Should I pull the carbs off and adjust the idle speed screw on the primary's so that an equal square is visible on the idle circuit? Then adjust the idle speed with the idle screw on the secondary?

 

[Tempest 455]

Should not be that much of an issue having timing locked with that duration cam. Locked usually helps it idle better with large duration roller cams.

If the idle mixture does nothing, you are past the idle circuit. The throttle blades are open too far. You need to fix that 1st once you have timing set.

Yes your primary throttle blades are open. You can adjust a DP so the secondary side opens for more idle. Pull the carbs off and look for a small screw near the secondary throttle blade shaft. Open them up and close primary a bit. You will need to play with them, every car is different.

 

[Mike Gaines]

You are on the right track saying taking off the carbs and setting the transfer slots (both primary and secondary) to be a "small square".
You do this, of course, by screwing the idle speed screws in or out.
Do that first and remember how many turns the idle screws are "out" so you dont have to take the carbs off each time to see where transfer slots are adjusted.

 

[ozymaxwedge]

I have just fitted a Indy tunnel on my 528 wedge (285@50 727 lift roller) with 950 cfm TRE carbs so interested in this thread. It is starting OK, not perfect and I too have had the odd back fire ect but I guess you have to learn what it likes, 4-5 pumps would be a huge amount of juice but Ill try it. My MSD is locked up 34 deg but I have a start retard. When it is warmed it will idle no problem and that will do me until I go to the dyno .

I agree, take the carbs off and get them slots right and start again but a trip to the dyno for A/F is a must.

What jets you got in them ? Mine have 88's all round :icon_eek:

- - - Updated - - -

Try ONE big pump to the floor before turning the key and just cracked while first spinning, 4-5 pumps is too much, don't forget you have 2 carbs with 4 pumps !!

 

[rat roaster]

I have just fitted a Indy tunnel on my 528 wedge (285@50 727 lift roller) with 950 cfm TRE carbs so interested in this thread. It is starting OK, not perfect and I too have had the odd back fire ect but I guess you have to learn what it likes, 4-5 pumps would be a huge amount of juice but Ill try it. My MSD is locked up 34 deg but I have a start retard. When it is warmed it will idle no problem and that will do me until I go to the dyno .

I agree, take the carbs off and get them slots right and start again but a trip to the dyno for A/F is a must.

What jets you got in them ? Mine have 88's all round :icon_eek:

- - - Updated - - -

Try ONE big pump to the floor before turning the key and just cracked while first spinning, 4-5 pumps is too much, don't forget you have 2 carbs with 4 pumps !!

Not sure on the jets. can not find my spec sheet. Yes I need to call around and find a chassis dyno. I know there is a shop not to far from here. Larson Racing, he has the fastest street driven car.

 

[Tempest 455]

I have just fitted a Indy tunnel on my 528 wedge (285@50 727 lift roller) with 950 cfm TRE carbs so interested in this thread. It is starting OK, not perfect and I too have had the odd back fire ect but I guess you have to learn what it likes, 4-5 pumps would be a huge amount of juice but Ill try it. My MSD is locked up 34 deg but I have a start retard. When it is warmed it will idle no problem and that will do me until I go to the dyno .

I agree, take the carbs off and get them slots right and start again but a trip to the dyno for A/F is a must.

What jets you got in them ? Mine have 88's all round :icon_eek:

- - - Updated - - -

Try ONE big pump to the floor before turning the key and just cracked while first spinning, 4-5 pumps is too much, don't forget you have 2 carbs with 4 pumps !!

You need to find out what the motor wants. That's what mine needed. Every motor is different.

 

[dvw]

Thanks
Bear to start means.. From cold motor. I usually pump the pedal four or five times.
Then have to pump it while it is cranking over to get it to run.
Usually it will back fire out the carbs and die.

I know how to adjust all 8 mixture screws. My problem is when I try to adjust them nothing happens. I think the butterflies must be to open and they are above the idle circuit..
Should I pull the carbs off and adjust the idle speed screw on the primary's so that an equal square is visible on the idle circuit? Then adjust the idle speed with the idle screw on the secondary?

My big plenum Indy cross ram like 3 pumps, then let it set 30 seconds. Then 1 pump, starts right up. If it doesn't start due to setting a long time or cooler weather, repeat the process. When it's really cold (less than 45 degrees) I throw a cloth fender cover over the carbs. That way I can hold the corner of the cover sitting in the car and yank it off once it's running. Without the fender cover cold it WILL NOT start. Once warm I just open the throttle 1/2 way, less than 1 revolution it will start.
Doug