Its me again lol

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Okay, so at low rpm test at 20* the stuttering still occurs. I couldn't take it higher than 20* as I lose function of my idle set screw and my driver side idle mixture screw doesnt function iether. I have backed the motor down to 16* for now, as a safety thing so as to not hurt the motor. Not sure if it will but I tend to error on the side of caution. I'm going to pull the carb once it cools down enough for me to handle it, and take a look at how my primary blades are sitting. Just making sure the transfer slots are what they are supposed to be. I'll take pictures as soon as I get it off the motor.
 
Did the 20* test improve or lessen the hesitation?
Sometimes the fix will be a combination of two or more things, such as more timing + more fuel.

But, yes, remove the carb to check where the T slots are. Here is a trick to check the T slot position without removing the carb every time:
- adjust idle screw so that 0.020" slot is showing. Note where the slot on the screw head is and measure with a caliper from the screw head to the screw mounting boss.
- repeat procedure with 0.060" slot showing.
- record the measurements
- 020-060 are your limits, with 020 preferred. Having it at 020 allows more sweep of the T slot for transition to the main cct.
- people are harping on about centri curves, springs. Forget about that. You have a low speed, off idle problem.
- the 1406 carb has leaner jetting than the 1405. I would rejet to the 1405 specs.
- to determine optimum idle timing is very simple: engine idling, in gear if auto, slowly turn dist to advance timing until you have the highest rpm, by sound & feel. Idle will also be smoother. Toggle dist to make sure the rpm is at max. Now check the timing. If, as an example, it is 28*, you can use vac adv connected to manifold vacuum to achieve this. This is covered in the Edel instruction book. Use an adj VA unit. Using the 28* example, you could use 12* + 16* added with MVA. You will need to fabricate a stop for the VA plunger to limit to 16*. It is all about tuning the combo!!
- once you have idle timing sorted, if too much T slot is still exposed at idle you then need to drill a small 3/32" hole in each pri t/blade & re-test idle speed/T slot position. Keep enlarging the holes in 1/64" increments until the T slot position is correct.
- with T slot & idle timing correct, check for the flat spot. 1405 jetting might correct the problem if it is still there
- once the idle/hesitation is fixed, then you can modify the centri curve & dial in the total timing at WOT. VA goes to zero @ WOT so it is out of the picture.
- report back.
 
TT5.9mag said:
Like we talked about in your other thread, you might need more initial timing (to bring the idle speed up and be able to close down the throttle blades and square up the transfer slots) but you can’t do that yet because the mechanical advance brings in too much timing and it rattles. This is all part of tuning. You need to limit the mechanical advance in the distributor and bump the initial up a few degrees. Then test, and do it all over again.
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Well, he can do it to see if it will solve the crappy idle issue. At least then he'll know what it needs. Sounds like it's getting too much too soon. Sometimes heavier spring(s) will solve it by themselves. Sometimes. lol
 
R3N0 said:
Okay, so at low rpm test at 20* the stuttering still occurs. I couldn't take it higher than 20* as I lose function of my idle set screw and my driver side idle mixture screw doesnt function iether. I have backed the motor down to 16* for now, as a safety thing so as to not hurt the motor. Not sure if it will but I tend to error on the side of caution. I'm going to pull the carb once it cools down enough for me to handle it, and take a look at how my primary blades are sitting. Just making sure the transfer slots are what they are supposed to be. I'll take pictures as soon as I get it off the motor.
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Ok, so it's possibly not timing related. Look at the accelerator pump arm. There should be three holes in it. Which hole is the rod in that comes from the throttle lever? If it's not in the hole closest to the carburetor, try putting it there. This increases the pump shot and may clear it up.
 
my 2 cents. 900 rpm in p/n with that cam, something is wrong. It should idle easily at 750-800 maybe less with 14-16* of timing.

IMO, you need to get the idle down first. Post 26 makes no sense, more timing means the throttle blades should be closed more, creating greater control by the mixture screws.
 
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Post #20 [ my post makes 1000000% sense ] in conjunction with post #13 that I linked to it. That course of action [ more idle timing] does get the idle speed down [ slightly ] & also gets the most efficient idle for the combination. You get the idle speed down by doing idle timing first, not the other way around.
There can be a host of reasons why the idle speed is 900 rpm & idle vac 14-15". Cam installed in a retarded position &/or low comp ratio are two that come to mind.
The OP sounds like he wants to tune the engine as best he can without pulling it apart....
 
Ok, I'm gonna try to answer all the questions here and maybe give a better overall picture.
1: the cam ( XE256H) is installed straight up. It has 4* of crank ground in.
2: the pump was started at the top hole an now in middle, still had hesitation issue. I'll move it to 3rd hole and try cause that's super quick test. Middle is usual spot I put it in.
3: the 900 rpm is my personal setting, i put it there cause the transmission brings idle to 700 when in drive. But I have been considering making it 700 and letting drive drop it 500 rpm.
4: no the 20* made it a little worse, felt like it fell flat faster.
5: compression is 9:5.1 (.030 bored w/ 91' 308 swirl port heads ported and polished) comp spring, hydraulic lifters and comp rods. Hyperueretic pistons.
6: VA is adj. But is not hooked up as I was fixing the timing issue, with lots of help from yall. Also the edelbrock air gap intake blocks my access to the VA, thinking about takin a saw and cutting a 1/4 piece off the VA tube so I can at least put a tube to it.

First thing I'll start with will be the 3rd hole on pump. Easy to eliminate. I'll pull the carb after that if it doesnt work and checking the transfer slots as I did chem dip the carb after it sat for almost a year. I want to make sure I put the blades back on correctly. If all else fails, I guess I'm drilling.
 
R3N0 said:
Ok, I'm gonna try to answer all the questions here and maybe give a better overall picture.
1: the cam ( XE256H) is installed straight up. It has 4* of crank ground in.
2: the pump was started at the top hole an now in middle, still had hesitation issue. I'll move it to 3rd hole and try cause that's super quick test. Middle is usual spot I put it in.
3: the 900 rpm is my personal setting, i put it there cause the transmission brings idle to 700 when in drive. But I have been considering making it 700 and letting drive drop it 500 rpm.
4: no the 20* made it a little worse, felt like it fell flat faster.
5: compression is 9:5.1 (.030 bored w/ 91' 308 swirl port heads ported and polished) comp spring, hydraulic lifters and comp rods. Hyperueretic pistons.
6: VA is adj. But is not hooked up as I was fixing the timing issue, with lots of help from yall. Also the edelbrock air gap intake blocks my access to the VA, thinking about takin a saw and cutting a 1/4 piece off the VA tube so I can at least put a tube to it.

First thing I'll start with will be the 3rd hole on pump. Easy to eliminate. I'll pull the carb after that if it doesnt work and checking the transfer slots as I did chem dip the carb after it sat for almost a year. I want to make sure I put the blades back on correctly. If all else fails, I guess I'm drilling.
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Did you put a degree wheel on it?
 
I dont have the info for the 1405 set up, but I'll look it up. I have a rod spring and jet kit, so I'll see if I have the parts to do it.
 
Did you CC the Combustion chambers? What thickness Gaskets are ya running? All this matters for actuall CR... not picking on Ya Dude, just curious....
 
For instance, I'm Running 10 or 10.5:1 old Trw Slugs....with (if I recall correctly) 72cc chambers and the thick blue Felpro gasket. It's NOT 10:1....and I Should HAVE bumped the .484 MP cam in w/ a wheel to 4° advanced, I belive.. or left the solid in. IT AINT a Dog or slow... but maybe could have git that Lil 10th of a few HP more...
 
I did cc the chambers bit dont remember what it was. I was using math done by Pete's garage, I have all written done somewhere. But I'd be lying if I said I knew where. As for the thickness of the gasket that I dont remember. It came with the whole engine gasket kit. Probably a standard mopar 360 head gaskets.
 
I built this motor almost 8 years ago and then sat it down in a crate as I had kids and had other financial obligations at that point. No it's in the truck and idles great, sounds great. @ idle lol top end screams now but I'm getting hesitation on the idle to light throttle.
 
As a matter of fact if I remember correctly I didnt really touch the bowl too much other than to clean them up. I didnt cut all that much out just cleaning edges and obvious cast defects. I cut and polished the walls leaving the swirl wall alone other than cleaning and polishing. So the bowls are probably pretty close to the stock cc with maybe +1 or +2 cc over
 
R3N0 said:
As a matter of fact if I remember correctly I didnt really touch the bowl too much other than to clean them up. I didnt cut all that much out just cleaning edges and obvious cast defects. I cut and polished the walls leaving the swirl wall alone other than cleaning and polishing. So the bowls are probably pretty close to the stock cc with maybe +1 or +2 cc over
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Nice Man! It sounds like you did alot of your own work, that's a good Thang! There is alot of Great Guys here that are willing to help. I Can say, once 50 ideas start flying in, Be careful, change 1 thing at a time. I've also seen cases where sometimes the person try to take you on the slow and stable track will get upset because 80 other people are posting on the thread at the same time, when they just want a Baseline.... and I dig that man that's like finding the center of a giant building and pulling all your layout for your framing on it... if the framer the electrician and the plumber don't use the same Baseline and all the pipes are ran underground in the wrong place and then you come in and build your walls somebody's going to be cutting a lot of concrete to make up for that one.....
 
I did, it was fun. I love this motor... now I just got to convince her to love me back lol
 
Ironracer said:
Nice Man! It sounds like you did alot of your own work, that's a good Thang! There is alot of Great Guys here that are willing to help. I Can say, once 50 ideas start flying in, Be careful, change 1 thing at a time. I've also seen cases where sometimes the person try to take you on the slow and stable track will get upset because 80 other people are posting on the thread at the same time, when they just want a Baseline.... and I dig that man that's like finding the center of a giant building and pulling all your layout for your framing on it... if the framer the electrician and the plumber don't use the same Baseline and all the pipes are ran underground in the wrong place and then you come in and build your walls somebody's going to be cutting a lot of concrete to make up for that one.....
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Yeah just taking it one step at a time. I know the motor is strong, I can hear it... it's got heart. But I gave it a tall task ... pushing a 8.5k pound 88' w250 hd around. It used to belong to the forestry department.
 
Now that I think more about it, I remember getting the 9:5.1 cc and thinking this cant be right. If I remember correctly the original heads where 62cc and the motor had an 8:5.1 cc at that time. If these heads are 57cc and I'm using a stock gasket... I might just be barely hitting the 62cc mark again. I wish I could find the paperwork so I could have someone double check my math.
 
Have you checked the timing with it in gear after the RPM drop? That's a bunch of drop for a small cam and strong vacuum.

Try setting the idle at 650 with timing set the same as now and see what reading you get.
 
R3N0 said:
Yeah just taking it one step at a time. I know the motor is strong, I can hear it... it's got heart. But I gave it a tall task ... pushing a 8.5k pound 88' w250 hd around. It used to belong to the forestry department.
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We Have a Forestry Driver on Board here!
 
R3N0 said:
Now that I think more about it, I remember getting the 9:5.1 cc and thinking this cant be right. If I remember correctly the original heads where 62cc and the motor had an 8:5.1 cc at that time. If these heads are 57cc and I'm using a stock gasket... I might just be barely hitting the 62cc mark again. I wish I could find the paperwork so I could have someone double check my math.
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My Brain works great, but add another 12 Years? Wow Man, uhhhh....Duh... um.. yep. Where's my Notebook? Arrgh
 
R3N0 said:
Yeah just taking it one step at a time. I know the motor is strong, I can hear it... it's got heart. But I gave it a tall task ... pushing a 8.5k pound 88' w250 hd around. It used to belong to the forestry department.
Click to expand...
Lots O' Truck Brother!
 
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