myk5rox
1/2 ton status
Agreed
CK5
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why does my 383 suck? >> now a crack??
- Thread starter ashman
- Start date
Agreed
I got out of carbs before I really had to dig into the different cans. I know there are all sorts of different ones available, and that how fast they "drop" based on engine vacuum can be changed, but whether that is practical I don't know...as I recall from my vacuum measurements you'd go from around 19" to 9" with any sort of throttle increase, but if the can operation is linear, than 9" with a 10* can would still be 5*, which could be too high. Not sorry I got out of carbs lol.
EGR, in my setup, showed that timing was less an issue when it was removed, than fueling. There was a pronounced lean spot at cruise that GM had obviously implemented to pull fuel when EGR was active. It may not be the only issue, but at the same time, no setup has the same timing requirements. Whatever the case, slightly richer mix "fixed" the lean cruise spot.
I'd still fix those weights first, it's an obvious problem.
Without knowing any of the pertinent motor specs, pretty hard to guarantee that any one thing is going to fix the problem. Realistically it could be running 10:1+ compression quite easily depending on how it was put together, we just don't know.
That's how mine has been set for about 3 years now and it runs great.
454Sub
5/8 ton status
Really I doubt even gearing is your problem. 1st in that 4500 would more than make up for gears.
Its either timing, or AFR. My bet is all your timing is way off, total timing is way to high, and the vac/mechanical is coming in to early, and to fast.
Its either timing, or AFR. My bet is all your timing is way off, total timing is way to high, and the vac/mechanical is coming in to early, and to fast.
got the new curve kit installed:
one medium spring, one light as suggested.
You can really see how bad the bushings were on the old kit here:
The weights were on sloppy and the springs felt really loose. Bushings were basically nothing.
I had some trouble with my crap ass timing light but I think I got it set right around 34* total timing around 3k rpms. The timing light was giving me fits and I was guessing on the rpms (tach install in the next few days) but it seems much better.
I took it out for a few minutes and got it up to highway speed and tried to recreate the conditions that would make it ping normally. I had to really lug it hard and stomp on it to get any pinging.
Much better!
It always seemed to be worse when the engine was hotter and under more of a load so more testing needed, but so far so good.
Starting it was a touch slow so I may have it advanced a touch too much. What should I be shooting for?
Also while I was at it, I pulled a plug to see how it looked:
Looks pretty good to me.
Gap was about 35. With the coil I have what should it be at? I read somewhere that I should be closer to 45.
one medium spring, one light as suggested.
You can really see how bad the bushings were on the old kit here:
The weights were on sloppy and the springs felt really loose. Bushings were basically nothing.
I had some trouble with my crap ass timing light but I think I got it set right around 34* total timing around 3k rpms. The timing light was giving me fits and I was guessing on the rpms (tach install in the next few days) but it seems much better.
I took it out for a few minutes and got it up to highway speed and tried to recreate the conditions that would make it ping normally. I had to really lug it hard and stomp on it to get any pinging.
Much better! It always seemed to be worse when the engine was hotter and under more of a load so more testing needed, but so far so good.
Starting it was a touch slow so I may have it advanced a touch too much. What should I be shooting for?
Also while I was at it, I pulled a plug to see how it looked:
Looks pretty good to me.
Gap was about 35. With the coil I have what should it be at? I read somewhere that I should be closer to 45.
...hmm
try putting a vacuum on that distributer advance can & see if it works or not...I've seen them go bad.
try putting a vacuum on that distributer advance can & see if it works or not...I've seen them go bad.
The starter kicks it over just fine and it starts within a crank or two but I knew a guy that would set timing then fine tune it by making sure it would kick on instantly. A mistake?
I think so. How the starter works should have nothing to do with the engine. They do making timing retard for high compression engines but you shouldn't have problems. It is just like dirt track guys that mess with timing to cool their engine. Max the hp, fix the cooling system.
will do tonight.
The gearing in LOW has nothing to do with cruising conditions. He is under geared.
Gears are one of the best mods you can do for power.
Martin
My truck has 40s and 4.10s. It is OK on the highway. You actually have a worse tire to gear ratio than I do. If you want to tow at all with it get more gear. You have overdrive so it doesn't really effect your ability to drive it. I would shoot for about 2k at 65mph in od.
454Sub
5/8 ton status
I know his gearing isnt the best, but I ran with 35s, 3.73s, a built 350 and a 700r4 and it did not ping no matter what. Not saying gearing isnt important, just saying even while lugging around, it shouldnt ping like that.
Now that he has fixed part of his timing issue with the new weights and such, it proves it to be a timing/fuel problem, and not a gearing problem. Should he get better gears, well thats a simple yes, but it can poop around with his current gears and be just fine. I am thinking your vac advance is going to high and creating to much total timing. Check the numbers on it like suggested and see whats the up in up. After you get timing locked down and its right, then adjust your carb for your motor. Its not exactly rocket surgery, you just need a vacuum gauge and a good ear. You wont get it perfect without a wideband O2, but a vacuum gauge will get it close enough, and better than the broad spectrum tuning it comes with. Probably pick up some gas mileage as well.
Now that he has fixed part of his timing issue with the new weights and such, it proves it to be a timing/fuel problem, and not a gearing problem. Should he get better gears, well thats a simple yes, but it can poop around with his current gears and be just fine. I am thinking your vac advance is going to high and creating to much total timing. Check the numbers on it like suggested and see whats the up in up. After you get timing locked down and its right, then adjust your carb for your motor. Its not exactly rocket surgery, you just need a vacuum gauge and a good ear. You wont get it perfect without a wideband O2, but a vacuum gauge will get it close enough, and better than the broad spectrum tuning it comes with. Probably pick up some gas mileage as well.
bigred88
1/2 ton status
Generally an HEI should be .045 gap. I doubt there would be a noticable difference from opening them up, but the wider gap should promote a better burn.
That was pretty much my understanding. I want to get the engine squared away, then work on gearing. I'm flirting with 4.56 since I do have OD.
Just so I know what I'm shooting for tonight, with the vacuum canister disconnected, what timing should I be setting?
I've never adjusted a carb before so hopefully you guys can walk me through that as well.
ok, I think that is what I was at last night. I'll double check it and get the vacuum can number.
