Hi everyone,
I need some help or guidance. I am a rookie, so I might be missing something obvious. I have a 1969 455 that I swapped into my 442. The engine is original from a delta 88, I cleaned it up, rebuild the carb (rochester 4bbl original to the 88), replaced everything in the ignition system (points ignition). I fired it up for the first time several months ago. It has always run smooth since the first time I hit the key. Currently the engine starts right up. Idles smooth and if I hit the gas it sounds great past 3k rpms. When I put it in gear, it idles down and still sounds great. Good down the road until I either try to get into it, or once I get to about 45 mph. (sorry I didn't think to look at rpms) If I am really soft with the throttle it feels like I could get up to full speed, but if I give it just a bit more pedal it starts to sputter. I dont know if I can tell the difference in engine sounds from timing, to lean, too rich but my gut seems to point to either the secondaries are not opening, or my fuel system is not delivering enough fuel. But as I said, that is just a guess and I am not even certain it is a fuel problem. I did make some serious swings in timing and tried it out, but it still did the same thing. Anyone have any suggestions on troubleshooting or things I should consider?

Thank you,
Bob

 

Bob, have you got a vacum gauge? I'd start there. Basically you'll need to re cover all the things you've done so far...like making sure the distributor cap is tight and correctly seated...no pinched wires etc.

Might be a float issue...If you were to take the top of the carb off I'd be looking that over. Idiot (me) has gotten that top gasket to interfere with the primary rods/power piston before, causing problems.

 

What is your dwell and timing set to? With the engine off, look down into the primaries and secondaries (you may have to prop the butterfies open on top) and see if your throttle is opening all the way with a helper pushing down on the gas pedal. Make sure you have no vacuum leaks and the choke is opening up all the way. Also make sure that when you operate the throttle looking into the carb that there is 2 goo solid streams of fuel spraying.

What do the spark plugs look like?

 

Make sure the choke pull off is holding vacuum properly. It could be the secondary carb air door is setp too loose, most are.

 

Big question, did you replace the timing chain before you installed the motor, the original timing chains gears are nylon coated and can break leaving excessive clearance (see photo). Also, can you post pictures of the engine with the air cleaner removed. Maybe someone will spot something obvious. Cheap points will bounce causing trouble. I always use Accell 32oz. points, very good quality. There are youtube videos for checking coils. Make sure the distributor shaft doesn't have side to side slop. I hope you find the trouble.

 

Sorry I took so long to get back on. I took some pictures of the engine and carb, maybe someone will notice something I screwed up.

I will try to answer all the questions. I have a vaccum gauge from my brake bleeding kit, not sire if that will work. If not I can go get one. What would I look for with it?

I did not change the timing chain. Eventually I plan to have the engine built, but it was a good runner in the donor, so I wanted to enjoy it for a summer first.

I originally tried to set the timing at 12 initial. I tried both around 20 max timing and 34 max on friday, neither seemed to change the problem, although it popped a bit at 20. I dont have a dial back, so paint marks on the flywheel may not be that accurate. I can get the engine to run crappy with the timing, but it seems to have no effect on the pedal down problem.

I also cannot open the secondaries by hand and I fear maybe I put it together wrong? Or is it normal for them to be shut when the car is off?



Thanks everyone,
Bob

 

This could be fuel or it could be ignition. My money is on the latter. I've had a similar situation where a bad coil started breaking down at higher RPMs and the car just wouldn't run.

 

I do have a couple old coils. Seems an easy thing to try. Thanks Joe

 

Take a quick look at the points and make sure they haven't cratered or pitted. They can cause the engine to sputter when pressure is applied. It is still a points car isn't it?..... Tedd

 

There is a lockout tab for the air door on the se secondaries, the air door won’t open if the choke is on. It’s to prevent the secondaries from opening until the engine is warm. If the air door won’t open with the engine warm, that could be you poor higher rpm performance issue.

Check the fuel lines, any rust holes? Kinks? Collapsed hoses? Fuel filter?

 

Check the above post.
Also if screw is too loose, they'll stick open

 

Whats your dwell?

 

FYI, years ago I deliberately blocked the secondaries from opening and while it decreased power, the engine ran smoothly up through the RPM range. Kinda like a 2bbl engine instead of a 4bbl engine. No sputtering or inability to rev.

I agree that it sounds like it may be an ignition issue. Burned points, low coil voltage, bad coil, etc can cause issues that show up under load or higher RPM and result in sputtering and/or popping.

 

This morning I rechecked initial timing. Tried 8, 10 and 12 initial. No change in the problem. I swapped coils, no change. I also noticed that its worse the harder or quicker I hit the throttle. I bought a fuel pressure gauge thinking maybe the fuel pump is bad. I figured I would check on it.

I checked points. They still look brand new. I do not have a dwell meter so cannot check that. I have considered going to hei. At this point would that be a better or more sure option? If not I will order a dwell meter and keep trying. Its the first beautiful day this year, and its getting frustrating. Might be time to drink a beer and turn on the Brewers game.

I thought I smelled fuel once or twice when i was trying to get it to open up. Maybe its flooding?

Bob

 

Changing to HEI won't fix anything unless your current ignition system is totally FUBAR. You can find used tach/swell units cheap, since most people get rid of points. Have you tried changing the coil? What is the state of the Qjet? How is the secondary air valve spring adjusted? Does the dashpot on the secondary air valve work, or can the air valve open too soon? How is the accelerator pump function and timing? DO NOT simply throw parts at this unless you know something is bad or if you have money to burn.

 

I think I should have said electronic ignition. Figured that would at least eliminate dwell being the issue. The carb was rebuilt, although by me. I only had a few parts left over, haha.
I tried a second coil. No change.

I am not that knowledgeable with engines, but it seems logical to me that if it was a timing or ignition issue, then all the changes I made to gap and timing that something should have at least effected the problem in some way.

Could a vacuum problem cause this? Like if I connected hoses wrong?

Thanks and happy easter
Bob

 

What is the point gap setting?

 

Short answer - Yes.
I don't recall if you have a CSM - I hope you do. In this order:
(1) Ensure all your vacuum hoses are in good condition & solidly connected to the correct ports - ported and/or manifold;
(2) Tune your engine in this sequence following the CSM - exactly in this order (I believe you said you have contact points/condenser): Dwell (#1 cylinder @ TDC)>Timing>Carburetor [Dwell=30*; timing=12*BTDC @ 1100RPM];
(3) You must have a vacuum gauge (or one you can borrow). Pay careful attention to remove the distributor vacuum advance line and plug it when setting timing (critical);
(4) Measure your vacuum. You should achieve between roughly 17" Hg to 21" Hg. The reading should be "steady". Adjust your A/F mixture needles (both LH & RH at base of carburetor) to achieve the highest steady vacuum pressure possible.

 

No, hoses connected wrong for the distributor will not cause this issue.

 

Agree, hoses connected wrong for the distributor will not cause this issue (which is not what I said). However, hoses connected incorrectly for many other boss ports (both ported and/or manifold) including any emissions ports, might cause the engine to stumble (e.g. brake booster plugged into the carburetor port, unused open manifold &/or ported vacuum, ATM modulator plugged into the carburetor, emissions canister plugged into a manifold port) there are several scenarios where incorrectly configured vacuum lines could cause engine stumbling. Is the car equipped w/ a DVS, is it plugged, is it open, is half of it plugged, the other half open, the ported carburetor port open/closed, the DVS vacuum plugged into the choke? I can think of several scenarios where a vacuum could effect the overall condition of the engine's operation.

 

Since you recently built the carb, I'd bet that is the cause. Try operating the secondary air valve by hand. Observe the hanger in the center of the two air valve doors. You should see the hanger lifting the two secondary rods towards the front of the secondaries. If those rods are not hooked up properly and don't lift, then the air valve will open allowing air into the engine, but no additional fuel will flow (thats what the rods do) and the engine will bog and not accelerate.

Did you have a kit with instructions on how to adjust everything? One important adjustment that could cause issues, is adjusting the air valve wrap (tightness of coil spring that holds the air valve closed).

If the rods are fine, I had a similar problem, with a built engine. I hooked up a fuel pressure gauge that was visible when I drove (removed the hood centerline trim and bolted it through the holes in the hood. I used rubber washers to ensure I didn't ruin the paint). I found that the fuel pressure was dropping too low at high load. An electric fuel pump replacing the supposed high volume mechanical pump solved the problem.

 

Thanks everyone who chimed in so far. I haven't got much accomplished. I tested a few things and more importantly, grabbed a trio of things that I am sure will get my problem solved. And guidance or tips on how to best use any of them will be greatly appreciated. If not I am sure youtube has a 35 minute instructional that will cover the 3 minutes of instruction I need.

I did play with the idle screws on the carb, got it to run worse at least. Now that I have a gauge, i should be able to get them dialed in. Hopefully I can get back in the garage on Thursday.

 

The Oreo's ought to help a lot.

 

x2

 

Well when your trying to teach yourself how timing, carburation and vaccum work on an engine, you need something to help maintain sanity. I find double stuffs do just that.

 

Heck yes.

 

And, just to repeat, in hopes to helping you remember to keep things simple - the sequence is always this.

(1) Dwell
(2) Timing
(3) Carburetion

Dwell effects timing - timing does not effect dwell. KISS

 

Thanks Chief, I will troubleshoot/start over in that order.

 

What were the results of your fuel pressure tests? Did you replace the fuel filter when you rebuilt the carb? It sounds like you have a plugged filter and running out of fuel as your engine climbs in RPM or fuel needs. Your engine will run fine until it begins to starve for fuel. Obviously everything else needs to be in proper working order as well, but if the ignition system is "close enough", the engine will run well enough but best to make sure. Set the dwell, timing, and idle carb settings with the proper tools. If the problem persists after that, change your fuel filter. It's easy on a Q-Jet. Also make sure all your rubber fuel lines are in good shape. If they get too old they can collapse under the suction of the fuel pump if they have some kind of obstruction in the tank for instance. You have had plenty of good advice on ignition tune-up but don't forget your fuel system.

 

Get a dwell meter to set the points. You can't set them accurately any other way. HEI may eliminate the points, but I am not convinced its any better than points. You have some very good suggestions on here to get to the bottom of your problem. Be patient and you'll get it figured out. Good luck.

 

This morning I set the dwell, 30.1 is as close as I could get it.

I hooked an inline fuel gauge up also. It bounces between 6 and 8. Settles in at 6 when I open the throttle.

Then I disconnected the vaccum and hooked up my new gauge to the manifold. Set initial timing to 12, then, adjusted my idle jets and got 21 on my vaccuum at idle.

When I hooked the vaccum back to the distributor, i am all in at about 35* at about 2900.

Still no change in the problem. Runs smooth up and down the rpm range, but if I open it fast, or try down the road it pops and sputters.

I checked the rods on the secondaries. They are moving up and down, but if I open the secondaries wide open by hand while running should my engine get fuel? Nothing changes, so I am wondering if my secondaries are not getting any fuel. Seems like it would make sense if all I am running in is idle and primaries.

Love to hear your thoughts.

 

If you are opening the air doors only, that pulls the rods up, but there is no air flow (because the throttle plates are still closed) so fuel will not flow out of the secondary fuel ports.

 

QUESTION: Do your secondary air doors have GOOD tension on them? They are NOT supposed to lay flippy-floppy - they are supposed to have GOOD tension on them. If they don't have GOOD tension on them, the doors will open & they will 'flutter' - the carburetor will 'flutter' and the car feels like it's chugging and not lurching forward with a solid snap. Check your secondary air doors for GOOD tension.

 

If you really want to learn the mechanics of how the secondaries operate on a Quadrajet carburetor, in very easy layman terms with excellent visualization of the secondaries, I'd strongly suggest you watch Tyler's YouTube video of
Tyler might not be the fastest at explaining some things, but he's funnier than bat **** & seriously knows how the Quadrajet is put together - check him out.

Here is a quickie YouTube video regarding that flutter I was referring to and why it's important to have good tension on the secondary air horn plates>>>

 

^^x2^^ on what Kenneth said w/ my own elaborated explanation.

The air horn doors (plates) on the top (air horn) side of the carburetor move the secondary metering rods up & down when the air horn doors open & close. But, the air horn doors only open & close when the base plate carburetor throttle plates are moved to the open & closed positions via manifold vacuum - thereby applying manifold vacuum (and a decrease in vacuum pressure) to open the air horn doors.

 

They open with, believe it or not, exactly what I would describe as GOOD tension.

 

How do I check that my secondaries are functioning? Should I just go back through the carb and see if I missed something on the rebuild?

Bob

 

Remove the air cleaner and look straight down the carb. As you manually pull the throttle you see the larger primaries open. After that, continue throttle and you see the mechanical secondaries open.

 

Well, you can check the manual aspects by moving the throttle arm on the drivers side of the carb to the fully backwards position (wide open throttle) and see if the secondary throttle plates are moving from horizontal to vertical (90º) position. You'll need to open the secondary air doors to look into the rear bores to view the throttle plates.

I really doubt this the issue, though. If the secondaries weren't opening properly, the engine would still run but with reduced power, similar to a 2bbl setup.

 

Leaning out would be dangerous to the engine, careful!