Macadoo

Yeah, that's a head-scratcher. My old tiny nothing radiator did fine as long as I was moving, It was sitting that was the problem; even with all the goodies in place.

Firewalker

Just sitting or moving slowly is usually a not enough air flow problem, though a slowed water pump could cause it. Trapped air, or to much antifreeze, or partially plugged cores can contribute. My ride having is small engine compartment with a 455 it was especially touchy when it got close to 100 in town in summer.

With the radiator less than an inch from the water pump pulley bolts a regular fan or shroud were out. A Hayden 14 inch reversible fan mounted in front in pusher mode kept it cool. Cruising above 40 no problem with no fan on, and the same on long highway trips until I slowed for towns. But everything had to be right in massive heat going slow.
A switch to a 2 row aluminum radiator with a little more surface area was the best thing I ever did, and better than the 4 row brass radiators I had built and tried.

RetroRanger

Ill try a new cap,
ive been driving it like this for ~1000 miles i dont think there would be air trapped in it ?
I also have a coolant recovery tank on it, level rises when hot and drops to the same level when cold
No issues w the same rad when i had an SBO in it.
I just figured cuz its only at highway not idle or 50mph or less cruising that the rad just didnt shed enough heat ?

Firewalker

An old radiator that was used for years on the 350 may not have good thermal transfer now, and or water flow like when it was new. With the 350 no problem with the old radiator, but with the 455 needs more and it can provide.

You can have air trapped in air pockets in the heads and the like that never travels to the radiator normally. There are varies ways to try and bleed any out, but one thing I did with mine was drive it on a hot day till hot and the thermostat would be open, and drive up a very very steep driveway a few times, on the day that business would be closed. This put my radiator way higher than normal and my engine, and slanted the engine up so trapped air would head that way to the nose and the radiator. Once there then the air can bleed out entirely into the reserve.

My guess is your old radiator is not not adequate, and a new aluminum 2 core for a few hundred or less will fix that like a champ. Just my views

Macadoo

Okay fellas, I'm having trouble nailing down my tune for this 461. Seems like I get it close and then I lose it. I think a lot of it is the 110 LSA on the cam. I can get it to cruise very smooth and to break loose at the 2-3 shift but it pings at WOT. So I dial it back just a little and it becomes a turd. It likes a quick timing curve but the mark bounces around at idle (800 rpm in park). So I put in stiffer springs (two medium) and it becomes a turd at part throttle. (HEI)
Today I tried limiting the mechanical advance to about 12* and bumping up the initial to 21* and it runs "okay" but I know there is more power there. I realize that's only 33* total so I need to trim my mechanical limiter a little. And it's a little hard to start when hot with 21* initial. No kickback, just a little slow turning over (Summit mini starter).
I'm still dialing in the Q-jet's APT but I've got it close. No stumble and good cruise mileage (18 mpg - ish with my 200-4r and 3.73s). That's using Cliff's tip-in method at 2200 rpm. But I can still pull the AC vacuum hose and increase the idle (manifold vacuum).
Idle tubes are at .038
Down channels .055
Idle bypass air is at .120
Jets: Cliff's 73
Metering Rods: Cliff's 44
Mixture screws are 3 turns out giving me a steady 14 inches of merc
I do have a 1" spacer under the carb for clearance reasons. That may be part of my low part throttle power issue. I could probably get away with a 3/4" but not much less.
Engine runs strong and pulls HARD but only if I push the timing past the safe zone.
Thoughts?

VinMichael

BangScreech4-4-2

Forgive my ignorance, but what do they do?

VinMichael

olds 307 and 403

I had the same issue with my 9.6 to 1 350 but it had a too small 204/214 cam. Are you running manifold vacuum advance and how much? Add 2 degrees of mechanical advance, it might help. Unfortunately, pinging on a high compression, old iron head engine is an issue with any sort of aggressive advance curve is a issue. Iron head Olds V8 like an aggressive curve for a crisp part throttle response, in my experience's.

BangScreech4-4-2

Thanks!

Macadoo

Yeah man, I recently learned about these, also. Seems like a good move. But no, don't have one yet. Probably need two and switch to read one, then the other.

I wouldn't say my cam is too small at 227/233 and .512 lift in and out, lol. Need to find that Goldilocks cam!
So this is interesting; my timing mark that is jumping around? I used my old non-dial-back timing light, and although I couldn't see my timing mark, the nicks and other marks on the balancer were rock solid! No jumping at all. I think I gave $60 or $70 for this POS dial back.
Yes, I've limited the vac can to 11* which might not be enough for this BB, and I'm hooked to manifold.

It almost wouldn't start today after a good hot drive so I have to back off the initial a little, maybe 2* and add another 4 or 5* to the mechanical.

olds 307 and 403

That sounds like a good plan and your mileage is very good for a 455.

coppercutlass

Its gonna be the carb. I have ran many 110 cams with more duration and overlap and it kept its tune very well . My last sbo had more cam and a 750 holley DP. It never changed. No vac. adv. I have had the same issue fiddling with bad carbs or carbs that where way too finicky. I normally run 14 to 16 initial with a really fast ramp on the curve so right off idle it comes up fast all in by 2500.

VinMichael

Macadoo

I dunno' fellas, this is all above my pay grade. I can't say why, but Cliff Ruggles says that, although a tight LSA works well in a small block, they can be tricky in a big block. But I think he's mostly referring to idle quality. Copper, the Holley had the same rough idle. If I set the *park* idle to about 800 it will idle fine, lopey and mean sounding, but fine. If I drop it into gear that will drop to 500 or under and wants to die. So I set the *park* idle at 1000 and I do okay but I may not be totally on the idle circuit of the carb at that rpm. I'm really starting to think that the torque converter may be part of the problem. It's a 2500 but it came from Midwest Converters in Rockford (came with the trans).
Today I'm going to get a timing tape put on the balancer, check that TDC matches the balancer mark. When that's done I'll increase the timing at the dizzy and back off the initial.
Is there a big difference between 92 and 93 octane? I usually run 93 but the Shell I was yesterday only had 92 as their V-power. Weird, my local Shell has 93 V-power.

coppercutlass

That cam should act smaller in a big block. I think the rough idle is a vacuum leak. I once had a vacuum leak I always though it was just the cam. I plugged the bolt holes on the carb pad not being used and it idled like a stock engine lol. You might wanna check for that too. I have seen edelbrock intakes where the bolt holes go into the intake plenum and don't bottom out. As for the car dieing in gear it sounds like your converter. I had the same issues with my trans when I went to EFI except the EFI didn't like to recover from a 250 + rpm drop. You can try to fatten up the idle it helped me when I had the carb still with the same issues.

Macadoo

I've had multiple problems with this used intake. I wouldn't be surprised if it's warped or cracked somewhere. The only bolt holes are for a quadrajet, it doesn't have 8 holes, just the four, but they go all the way through into the plenum. Maybe I should try some thread sealer on the bolts. I should probably replace it this winter with a new one. I think it's time to start looking elsewhere since three different carbs all have poor acceleration and idle quality.
I'll try turning the mixture screws out a little more. Can I let it idle for while and check the plugs for color, like after a cruise but for idle rich/lean?

Firewalker

Richer on idle is the natural path. get best vacuum and turn out a quarter or half a turn richer on most carbs/engines.. Idle rich is not favored by OEM/EPA.

In normal running we idle little.

coppercutlass

A bad tq. converter will give poor acceleration if its not stalling ( flashing properly ) I went through the same crap with the th350 in my Pontiac. swapped trans it was a totally different car. I chased my tail tuning it., I went EFI and it didn't change and not long after that swap I lost 1st gear and reverse. Put in the new trans it was golden. For a 4k lb pig with a sbo and 3.08 gear it will lay some rubber down.

RetroRanger

Macadoo

Yes sir, the mixture screws are responsive but only to a point. After about three turns there is no vacuum difference. I went about another 1/2 turn after the vac topped out.

Yeah man, I'm sure this 200-4r isn't helping but I DO like the mileage. When I get this tune figured out, I'll pull the governor and do the mods to improve the shift points.

Some guys tap one of the extra holes not used by the rotor and adapt a screw head. If it were me, I'd make the head eccentric. But I worried the screw would loosen during testing so I just pressed in a roll pin and shaved it down until I got the degree of advance that I wanted. Right now I'm at 19* initial and 17 mechanical for a total of 36*.
Adding the timing tape to the balancer worked great. I can't believe all this time I've been changing springs in the dizzy thinking they were bouncing the weights around and it turned out to be the dial-back light. And it was jumping a good 10 degrees.
Lastly, when I check the all-in advance by throttling the carb, the curve is nice and smooth right up to 36* but the marks start jumping around after that. Can't say the exact rpm as I can't see the tach, it's in the car. But I would guess the marks start to jump around 4000 rpm.

Macadoo

Update: above I said the timing curve is smooth up to 36*. I was wrong. Actually, the advance starts about 1300 and quickly rises from the 18* initial to 28*. But then the curve slows a lot all the way until it stops advancing at 36*. Certainly NOT a smooth timing curve. What could be causing this? I have MSD weights, center plate, and a light - medium spring combo.

sysmg

I usually set the mixture screws via a tach. First I turn each screw in and count the turns (in units of 1/8th turn), then I average the two counts and turn them both out the same amount (that average you took). With a tach on at idle speed (about 600rpm) turn both screws out 1/4 of a turn, the idle should increase. Once it stops increasing, I turn the screws in a 1/4 turn. Reset the idle speed.

As for the marks jumping around, that could be your points bouncing at high rpm. Either get a pertronix or get heavy duty Standard or Accel points with a stronger spring.

Macadoo

I should have mentioned that this is an HEI system, and I'm pretty sure it'd a POS. I tested the actual curve yesterday and with the stiffer springs, although the advance doesn't come in at 1000 rpm park idle, it doesn't start to advance until 1300 or 1400, jumps up 9 degrees quickly, and then very s l o w l y advances another 6 or 8 degrees. And wasn't all-in until about 4000-4500.

Today, I put in lighter springs. The curve is much smoother all the way until it's all-in, at about 3500. Still a little late but....
With these lighter springs, I've had to drop the park idle down to 800 to keep the mechanical from advancing at idle. Advance starts right off idle and has a smooth curve but at 800 park idle, drop it in gear and the idle drops to 600 and really struggles, engine dancing in the bay, wants to die at stop signs (but has't yet), and just sounds kinda' bad.
All my light and medium springs have been through the ringer, installed and uninstalled several times. I think I need a new set of springs.
My vac advance I had limited to 11 degrees when I had the small block and left it there for this BB. Today, I cut some off the limiter and it's up to about 15. Didn't change much.
Is there an HEI unit that has an electronic version of the curve? Something adjustable without pulling the cap and springs every time?

Fun71

Advance coming in at low RPM (as in at idle speed) and RPM dropping when I put it in gear and/or turn on the AC is what prompted me to investigate a higher initial setting. I had started back in the 80s with a factory 1979 403 HEI distributor and a Moroso advance curve kit to replicate the 24º mechanical advance that my points distributor had, which let me set the initial in the 10-12º range. Jump forward twenty-some years and I started experimenting with increasing the initial and decreasing the mechanical and after much experimenting, I discovered that the original GM weights and center bar that came in the distributor actually gave me what I was looking for: 18º initial and about 18º mechanical. All I had to do was choose the correct springs to get the advance to come in at the right RPM.

Oh yeah, I also switched the vacuum advance to manifold vacuum and made a stop to limit it to ~12º and that really helped with the low RPM, with increased vacuum and a lot smoother idle.

So I dunno if your engine can tolerate a higher initial, but it's something to think about.

Firewalker

I know the difference in Vacuum, weight springs and initial, but with that said, that's why I look at the initial timing of the initial plus the vacuum off of the manifold vacuum, as the actual initial for a running engine. Sometimes the weights are beginning to add more as well at idle depending on springs, weights, and rpms of the idle. Its the balance.

RetroRanger

Re electronic curve,

I saw a Mallory dist in a ford a few years back, it had two clickers to adjust vac and mech advances.

Never saw one for olds tho plus IIRC it was $400+ although after a few weight n spring changes $400 starts to look not so bad

Firewalker

I have used a Mallory variable timing **** under my dash, for a few decades, and actually noticed once maybe 40 years ago for an easy fine tune for conditions.

My setup is a points distributor, with a Mallory unilite points conversion, aftermarkets weights and spring kit, with a Promaster coil, plus BlueMax 8mm spiral core plug wires, and accel or NAPA rotor and cap. I then added an MSD6 analog, and Mallory timing control years later.

Macadoo

Actually Retro, I was looking at that $400+ price tag and thinking a few more spring changes doesn't seem so bad, lol.
Ken, That's exactly where I am now; 18 initial, 18 mechanical. But to get my idle up to 900-1000, I have to use stiffer springs and they didn't play nice with my weights. I may go back to the stock weights and see what they do with the stiffer springs.
I'd love sitting in the front seat with a laptop tuning my curve but that $400 would be a good start towards an EFI