Flutter below 2k rpm

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No, I'm saying it has long slow acceleration ramps, that make it harder to tune, like a big cam, yet has the power of a 223/230 cam.
I'm not a fan of roller cams and especially not one like this. That is my opinion. But that doesn't make the cam crappy. At your stated pressures it should pull like a freight-train, and idle pretty wicked.
 
AJ/FormS said:
No, I'm saying it has long slow acceleration ramps, that make it harder to tune, like a big cam, yet has the power of a 223/230 cam.
I'm not a fan of roller cams and especially not one like this. That is my opinion. But that doesn't make the cam crappy. At your stated pressures it should pull like a freight-train, and idle pretty wicked.
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I was bustin your chops ... lol

Frankly I am a bit disappointed with the overall performance of the engine. It runs good but doesnt shine anywhere. Its pretty torquey but doesnt boil the skins off yet it lacks a high end. I am assuming I can tune it into better shape but not to the level of what I expected.
 
what step up springs are in it? I run a stock 68-69 340 intake with the divider cut down to about 1/2”. At the problem rpm you could be “floating” the step up springs.
 
mbaird said:
I have spent much time trying to get my 360 to run crisper below 2k. It is what I would call a flutter.
Engine is a 5.9 with EQ IMM heads (9.7:1)
222/229 @ .050. And .509 lift on 112 cam
Airgap with an AVS2 650
Dougs headers
Timing at 19* mech adv of 14* starting around 1000 and all in by 3000.
17* of Vac adv starting @ 12” and all in by 18”
Idles at 800 rpm with 14” in nuetral/12.5 in drive.
AFR is around 13.5 at idle and 14.5 at light cruise.
Cranking compression is 168-175 psi

I have tried both HEI and mopar electronic.
Orange and chrome boxes. 3 different distributors and installed new plug wires/ gapped the plugs to .034

Maybe I am just imagining this and its just the way it will run ?

Any thoughts?
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What do the plugs look like?
Where is the timing mark on the plug ground strap?
 
furrystump said:
what step up springs are in it? I run a stock 68-69 340 intake with the divider cut down to about 1/2”. At the problem rpm you could be “floating” the step up springs.
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Stock Orange spring. I can try a lighter spring.

512Stroker said:
What do the plugs look like?
Where is the timing mark on the plug ground strap?
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With the ethanol in fuel now its hard to read plugs... they always look white.

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i would play with the step up. See if it changes.
 
mbaird said:
Stock Orange spring. I can try a lighter spring.


With the ethanol in fuel now its hard to read plugs... they always look white.

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Judging buy you're pic's you are way too LEAN.
From what I can see of the ground strap the timing mark looks low(towards the threads) this I believe means you are running to much advance.
Research threads on reading timing marks on plugs.
How many miles on the plugs in your pic's?
 
I am somewhat familiar with plug reading but its kind of an art .
There are about 1000 miles on the plugs.
As far as running lean my Wideband show me between 12.5 and 15.5 at the leanest. Most low speed cruising is around 13.5

The QF 750 VS I was running had it so rich I had to wipe down the rear bumper !
 
mbaird said:
I am somewhat familiar with plug reading but its kind of an art .
There are about 1000 miles on the plugs.
As far as running lean my Wideband show me between 12.5 and 15.5 at the leanest. Most low speed cruising is around 13.5

The QF 750 VS I was running had it so rich I had to wipe down the rear bumper !
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I dont care what your meter say's or what your bumper looks like those plugs are way lean for my taste.
Again research plug reading and see for your self.
I know when I got it right the plugs are a light toasty brown, timing mark is toward the bend of the strap.
And yes a lean condition can cause a miss as you describe.
I just went thru all this with my built 340.
 
I have been down this road of reading plugs while running ethanol. I kept fattening the jetting and the plugs were still white .
I am sure an experienced tuner with a plug reader can do it.
How do you explain raw fuel out the tail pipe and black exhaust tips ? Not to mention 8 mpg on a 260 mile road trip...
 
mbaird said:
So are you saying I have a crappy cam ?
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He says everybody has a crappy cam. Long ramps make it harder to tune? Hogwash. That's the biggest bunch of nonsense I've heard in a long time.
 
mbaird said:
I have been down this road of reading plugs while running ethanol. I kept fattening the jetting and the plugs were still white .
I am sure an experienced tuner with a plug reader can do it.
How do you explain raw fuel out the tail pipe and black exhaust tips ? Not to mention 8 mpg on a 260 mile road trip...
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Some where I missed you were running ethanol. That is a hole different tuning game,one I cant help you with.
I know a few boys around here that tried running E85 they all ended up going back to premium gasoline.
What % ?
Why would you want to run ethanol on the street?
The only alcohol I am familiar with comes from Kentucky
 
mbaird said:
I was bustin your chops ... lol

Frankly I am a bit disappointed with the overall performance of the engine. It runs good but doesnt shine anywhere. Its pretty torquey but doesnt boil the skins off yet it lacks a high end. I am assuming I can tune it into better shape but not to the level of what I expected.
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This with the other data you supplied, speaks directly to the 168 to 175 pressure reading you obtained.I'm kinda thinking the gauge you were using is extremely optimistic.
If the Scr truly is 9.7,
and your elevation truly is ~2500feet, then
then the pressure would be waaay down from those numbers.
 
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I missed alcohol too
but it wouldn't significantly change anything I said, in regards to mechanical things.

I have not tuned anything beyond E10,
but one thing I know is that alcohol likes Scr, lots and lots of it; 9.7 will not be enough for a 274 cam, especially not a 274 with those long slow ramps.
Also all the timing and carb stuff I spouted is in regards to regular pump-gas, and including E10.
 
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Not E85. Just 10%.

My gauge is a Snapon not a cheapie...

My expections might be too high .
 
I will try each of the tuning procedures recommended and see which one works best.
It will be fun experiment.
 
I don't pay a whole lot of attention to my AFR gauge at idle and low-RPM cruise; I tried tuning those with the gauge and it ended up being too lean. Didn't have "flutter" but wasn't responsive and would stumble when opening the throttle slightly. With a carburetor and a cam with any kind of overlap the low-speed AFR readings aren't accurate. I have a 360 with a 222/226 @.050" hyd roller cam and only 9:1 static comp with aluminum heads running at 5000' above sea level. I don't notice any "fluttering" below 2000 RPM but because of the cheap loose 2600-stall torque converter it doesn't spend much time at those speeds unless I'm basically coasting down a flat road barely touching the gas pedal. However I'm running a 750 cfm Street Demon which is a bit different than an AVS.

At this point I would ignore the AFR gauge and just tune the carb so it runs the best. Mine now says I'm running 12:1 AFR at low-speed light-throttle cruise but my spark plugs say otherwise, I just ignore the gauge now unless I'm getting on it hard. That gauge will drive you nuts if you try to get it to read perfectly at all loads and speeds; it's just not possible with a carburetor. EFI, yes.
 
mbaird said:
Not E85. Just 10%.

My gauge is a Snapon not a cheapie...

My expections might be too high .
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Dude I doubt 10% is going to make a huge difference.
Those plugs still look lean to me
 
I understand what you guys are saying about 02 gauges and plug reading . I use the gauge as a guide only and understand the pitfalls.

The plugs are darker than the pics show. Kinda like a lightly roasted marshmellow.
But when my eyes are stinging from the fumes and there is a layer of suit in the exhaust tip I can tell you its not running way lean.
 
mbaird said:
I understand what you guys are saying about 02 gauges and plug reading . I use the gauge as a guide only and understand the pitfalls.

The plugs are darker than the pics show. Kinda like a lightly roasted marshmellow.
But when my eyes are stinging from the fumes and there is a layer of suit in the exhaust tip I can tell you its not running way lean.
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Welcome to the world of Hot Rodding
In all the built up cars I have owned over the past 40 some years I cant remember one the did not burn your eyes and gas you out of garage, even when tuned correctly.
Good Luck
I'm out
 
mbaird said:
Not E85. Just 10%.

My gauge is a Snapon not a cheapie...

My expections might be too high .
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Not at all; I currently run an 11/1, 367 at 177psi with a 276/286/110 Hughes cam,(230/[email protected]) on 87E10; and it spins hardened 295s to whenever ; with 3.55s no less. It will break them loose at 50 in second gear, without the help of a convertor. It did the very same with the earlier cam, a Hughes 270/276/110 (223/[email protected]) but with a lil more pressure.
I expect at 168/175psi, yours should too.
I'm wondering now, if the 9.7Scr is the error. With 360cubes, you would need a total chamber volume of 84.77cc. With a zero-deck and flat-tops I don't see how that's possible.
But with 10.7Scr the total chamber volume rises to 76cc, very doable.

Both of these cams were , and continue to be, a blast, with no, NO disappointment, and the 93mph Eighth-Mile trapspeed proves it. I think Rumble is running a similar combo, and I've never heard him lament either.

mbaird said:
How do you explain raw fuel out the tail pipe and black exhaust tips ? Not to mention 8 mpg on a 260 mile road trip...
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Yeah I feel for ya man; what's your cruise rpm?
My cam is hard on gas too,but not at all like yours. I run a GVod with 3.55s so my cruise rpm is 65=2240, and my pipes are clean. The 230*cam vacuum peaks at ~2100, so I'm right on the edge. I run a cruise timing of over 52* tho. With your cam, you're gonna have to start the fire real early to cruise with clean pipes. And here's why;
working off the advertised numbers your power cycle ends at 103* ATDC. But off the .002 spec, the valve is already opening at 93* ATDC. In other words the piston is around half way to the bottom when the exhaust valve opens. There is no way, on the mechanical timing, that the A/F charge has finished burning at cruise rpm. So it will continue to burn in the pipe at a drastically reduced pressure, and soot, and 8mpg, is the proof. You may never get enough timing with the factory-type D and factory Vcan. I had to get me a stand-alone, dash-mounted, dial-back timing box, to make up the difference. At 2240 cruise rpm my combo was wanting up to 60* advance, with aluminum heads and running 207*F minimum cooling temperature.I settled on 56*.
How are you gonna get there?
Now, once the timing is there, you will find that you can lean it way way out, because the pressure spike is now occurring when it should, making way more cruise torque; and all the gas is now burning.

With my 367 I have run just about every rear end ratio Mopar ever made for an 8.75 from 2.76s to 5.38s, at one time or another. And I gotta tell ya, the right 222type cam is IMHO the best street cam for a high compression360 making mountains of torque, a solid mid-range, and while a little short on the top, it will still pull hard deep into the 6000s. All you gotta do with that combo is gear it right for the job and it's a funtastic combo.

By the way my Hughes HE2430AL Flat-Tappet Hydraulic, 270/276/110 and 223/[email protected], and .538/.549 lifts w/1.6arms;
went 106 in the quarter with 3.55s, no tuning.
had mega torque, 440 magnum-like torque to 3500rpm or so.
pulled fuel mileage even carb'd 4-bangers would envy
and ran clean out the TPs.
Yeah,OK the tuner mighta had something to do with that, but the basic package was very simple; like yours; just a near-zero deck short with 63cc aluminum heads and all the typical bolt-ons, I used a750DP for everything except hiway. For that I prepped and dedicated a 600VS Holley. I mean the thing practically fell together just short of 11/1.
Your cam will not like the cruise rpm that I ran with the 223* cam; lol. The gearing was A833od box with the GVod behind it for 7 useable gears. 65 was less than 1500. We cruised with the traffic at up to 85=1900, but mostly at 75=1700. I could tell you in point to point we hit over 30mpgs US, but I haven't met anyone yet that doesn't poo-poo that. It is what it is, and I really miss that cam. I urge you to get the timing right.
 
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I just swapped in a 2.76 pig for a road trip to Sun Valley to watch Supercars run flat out.

As far as compression ... I have a stock 5.9 short block that I refreshed with new bearings / rings / linehone / square decked block etc. .028 head gasket for good Squish
The heads are (IMM) Brians EQ magnums with 2.02s / 1.6s , cut guides , springs and his valve job . Supposed to flow 270ish @ .550
 
Recurved the dist today.
14* initial and 18* mechanical ....17* vacuum coming in around 12”
Set idle to 650
I havent messed with the jetting yet but the flutter seems to be almost gone.
A side benefit is the car seems quieter.

I will mess with the idle adjustment tomorrow before work. Then the jetting when I have more time.
 
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