wornn out big block timing question

My buddy and I spent the better part of toady messing with his beat up old '64 880. Pretty much every part of this car is worn out, beat up, shot or on it's last legs. Regardless, he drives it all the time and it made the 30 + mile trip to my house without incident.

It' got the original 361 with a '65 383 4 barrel intake, 906 heads, stock distributor with a Pertronix module, exhaust manifolds and this weekend we switched out the ancient non-PCV AFB that was on it for a #80457 Holley 600 to gain the PCV. It's a push button auto and highway gears.

So after putting the Holley on, the car would not start/run/accelerate without a ton of ignition advance. We tuned it the shade tree way by ear, twisting the distributor to where it sounded right. Regardless, the distributor was really advanced, seemed like almost 30 degrees initial based on where the vacuum can was pointed. We probably need a limiter plate in the distributor to keep the total down to a reasonable level because it runs real hot now with all the advance.

We had plenty of fuel and the plugs looked somewhat normal - not covered in soot or totally leaned out.

We also fixed all sorts of peripheral stuff including vacuum leaks, ground wires, burned plug wires and throttle rod/linkage adjustments hoping we'd see a major change and not have to run so much advance but nothing made a difference.

So heres the question - why does an ancient, worn out big block with a 4 barrel intake and a Holley 600 need so much timing advance? What could we have missed?

Thanks for any input.

- Greg

I'd guess a vacuum leak between the carb and intake, or something wrong with the carb. Is it new?

Also check/adjust the floats correctly, they could be way high or way low.

Carb is basically brand new. I had it on my truck for maybe an hour of run time and went back to a 750. We had to use an adapter to put the Holley on the old AFB intake. We suspected/found a vacuum leak at one point and fixed it but no significant change in regards to the timing.

Floats are set correctly, trickles out the sight plug when you undo the sight plug. We actually raised them at one point, the fuel would slosh going around a corner and momentarily stall. Raised the float and it was fine. Didn't touch the secondary side.

Forgot to mention, there is a BAD valve tick on the pass. side, not sure which cylinder but it's loud and always present. Definitely mechanical, not an exhaust leak. We had a vacuum gauge on it and it was pretty steady. Has about 13" at idle.

Sounds like you still have a vacuum leak somewhere.

A worn timing chain would throw your timing off.

Timing marks are off? Check it with a vacuum gauge...

With out a timing light you have no idea where the timing is. Being It's been apart who knows if the distributor was put back in the original location? Does it crank slow? If it's really has 30 degrees initial I would expect it to crank slow. Nobody has a timing light?
Doug

Why would one have to even mess with the timing if all you did was a carb swap?

Shouldn't have needed to and any running difference would be slight, assuming nothing else wrong.

The AFB should have had PCV provisions, since it didn't it had the wrong carb on to begin with.

PCV leans out the mixture unless tuned for it, which this Holley carb should have been close.

Does putting the old carb back on fix the issue?

Get a timing light.

Does this 880 have solid throttle linkage that pushes forward instead of pulling back.

That 64 engine with 906 head is giving away lots of compression, does it have blue feel pro head gaskets also?

13 seems low for a basic stock engine.

Everything Supercuda said; turn the dampener till the marks are at 15 BTDC. turn the housing till the magnet is dead even with the tooth and the rotor is under the #1 or #6 plug wire cap terminal (depends on if you are on #1 or #6 compression). pull/check the plugs (they might just be fouled from all this). See if it will start/run with the Holley. If not then clamp the PCV hose & retry. if no go then put the old carb back on & then see if it will run. If no run right then something got bumped/altered cuz it ran with the AFB before. If it runs good then try swapping back to the Holley carb again. Keep us posted. EDIT missed that you had the P ign, get its trigger lined up to fire just like the OE electronic ign.

Sounds to me as well, that the carb has possibly a mismatched base gasket-manifold issue. If it ran decent before you pulled the old carter off, then the distrib may not be the culprit. Over advancing ign timing can mask some lean issues.

Thanks for the replies. We did get it running OK eventually for him to drive it back to his place, about 30 miles and he said it ran as well as it ever did but just got really hot from all the advance. It just took hours of fiddling. Couple answers to some questions below.

I know this will sound stupid but I have two perfectly good, working timing lights, one normal and one dial back plus one of the old Snap On advance meters. In doing all this fiddling to get it to run right, we tried the timing 17 ways to Sunday; retarded, advanced, in the middle, no difference no matter where it was. It would crank fine but it was hard/no starting and popping out the carb. The popping made me think one of two things - it was lean or the noisy valve is really bad and the miss is affecting the overall low speed operation.

Before we got it running OK, it would pop out the carb and had no power under load. We kept driving around the block to see if what we did worked. At that point I made big swings with the timing just to see if there was an effect one way or another. The only way it would start easily and stay running was with the advance cranked way clockwise.

After a couple hours of this, we tried advancing it farther than I thought would be normal, thinking it would fire/run, then back it down a little to a normal level to see if it was OK. It started right up though and stayed running so we said OK, that's what it needs. We were just happy to get it to stay running and drive sort of normally. It was raining, he had to get back home, took way longer than anticipated. I meant to go back and check the timing, just didn't. I fully knew there was too much advance regardless of what the actual number is. Yes, it's half a$$ed. What can you do.

The old AFB had no PCV, it was from a '62 413. I did not think the PCV leaned it out but I guess it is more air into the mixture. Kind of a catch 22 there? Smokes out the breathers without it.

Throttle linkage is indeed the solid rod type that pushes forward. It needed adjusting because the AFB throttle lever put the end of the rod in a different spot than the Holley. Just a minor move was all it took to get it right but it was double checked with the lever on the trans to make sure the kickdown was correct.

I don't believe there is still a vacuum leak, unless it is somewhere other than where we checked which is entirely possible given the overall poor condition of the car. We checked it with carb cleaner all around the carb base to see if the rpm changed and it was good after we fixed it. The adapter is a PITA, would rather not have to use it.

There's nothing obvious (to me) that points to why it needs so much timing, just looking for clues beyond what we did. Again, I know we need to check the timing accurately but we know it is way too far advanced and will not run with less timing.

Put the light on it & see what you have. any possibility it jumped a tooth? You might check exact TDC. Holler how it turns out

X2 on the cam timing jumping a tooth. I would look there first.

Maybe with all the popping and such with the Holley it did jump a tooth. That could explain explain the need for so much timing, and running hot and no power with retarded cam timing.

I appreciate the suggestions on the timing chain and it makes sense but there is no way I am getting involved in that job with this P.O.S. death trap. I have actually advised my friend several times not to keep sinking money into it but he has some sort of strange attachment to it. (like me and my truck but that's a different story) I get into these exercises for my own fun and to hang out with him but I hate to say I'm not fully engaged in it like with my own projects.

Maybe there is something to the chain being off in this situation though. When I was a tech, I remember doing a timing belt one time and ended up off a tooth. On the road test it was real sluggish like described above, foot to the floor, no power. Brought it back in, re-installed the belt in the correct spot and it was back to normal. Didn't make time on that one but learned a good lesson.

Again though, I'm not digging into it here to figure it out.

What about having HIM! do some quick checks in that regard? He could (carefully/slowly) hand turn/bump the crank (CW) with a 1&1/4 socket/breaker bar till the reluctor wheel is dead centered for the dist to fire on either #1 or #6 cyl and see where the marks are at on the dampener. On a SB one tooth off is a 15.6 deg difference (23/46 teeth on SB crank/cam sprocket(s), 360 div by 23 = 15.6). not sure on a BB (BB newbie here)

It may be an old car but it didn't jump timing when it got to your house!If you just installed the Pertronix module,you are off on timing to begin with,the Pertronix can re phase the timing as much as 5/10 degrees before or after TDC.

HIM! is a total rookie who can barely boil water. I always (regrettably) offer 'help' which invariably turns into an adventure with this car.

It's all in good fun though. I've learned a lot about the older stuff, it's cool.

We are planning to reconvene in a week or two to further the tuning process.

I agree that it's probably not the timing but it might be something to consider. Again, I'm not taking the thing apart to check it, no way, no how so even if it is jumped, it ain't gettin' fixed, at least not by me in my driveway.

I did not know that about the Pertronix, I am going to look into that further. That would explain a lot actually, thanks for the insight.

The Petronius was already there and running, the problems started with the Holley.

The problems started when my friend bought this stupid car and I offered to work on it with him. But I digress...

I just read through an older thread about how retrofitting the Pertronix module into an old points distributor can present rotor phasing problems. Pertronix rotor phasing.

We had a similar experience as the OP but we just twisted the distributor until it fired. The content of that thread sort of explains why in our case we seemingly need an unusually large amount of advance, because the rotor phasing may have been off by 20 degrees! I can't check it now because I don't have the car but I will look into this when he comes back.

If this is the case here which it very well could be, then it would also be compounded by the fact that the rubbing block in his old points distributor is worn to the point of being round. Funny, I told him he needs a new distributor for that reason because the parts in the old one are so worn out but no because I thought it was causing a rotor phasing issue.

I have to say, this explanation probably makes the most sense so far. If the timing chain jumped a tooth, I would think it would have presented differently, more like a bad miss/popping everywhere. I don't have any experience with an older engine that jumped timing so I have no frame of reference for that scenario but the rotor phasing makes more sense here.

I don't remember "all that advance" causing an engine to run hot. If it isn't the cooling system, retarded spark is the primary culprit for running hot. After that would come too lean fuel mixture or perhaps too rich.

It sounds very much like you need to find TDC of the #1 cylinder and start from there. I'm betting you are still retarded on the ignition.

Also, a stock 361 should be running at least 18" vacuum at idle, even with the 906 heads lowering compression.

IMHO it's in the ignition. That's where I'd start.

R.

If the timing chain has never been changed on that engine, it could be part of the problem. The factory used a plastic or fiber toothed gear on the camshaft. I have seen them run with missing teeth, but your timing will be off. Doesn't always change the timing enough to pop or miss. If nothing else the timing chain itself could have stretched enough to retard the cam timing, in which case it may cause the need for advancing the ignition timing to help offset it. Swapping the timing chain on a big block is very simple. Pop off the fan and water pump housing, pull the crank pulley and balancer, take off the timing cover, remove the chain and gears, then line up the dots on the new chain and gears and button it back up. I can do the job from start to finish in about an hour, but then, I've done dozens of them. Also, if the engine backfired or popped at all after swapping carbs, that is enough to make it jump time with a worn out timing set.

Easy check for bad cam timing gear/ and or chain stretch-
Pull off the distributor cover, watch the rotor, grasp the fan belt and pull in opposte direction of engine's normal rotation. See how much crank rotation you have before rotor moves. Any slack (cam retardation)will cause untold timing problems. Try the test at different crank positions. That'll show missing teeth.
After losing a 383 and a 318 to this cancer, any Mopar I pick up and give half a s@ about, first thing I replace- timing set. Cheap, and easy peasy.

So just to update this thread here. Turns out the issue was a crack in the distributor cap and some burned plug wires. I did not figure this out myself. After we finished two Sundays ago my buddy drove the car home from my place back to NYC. He parked it that night and had to move it for alternate side of the street parking the next day. He went to start it and it was dead. He got it jumped, drove it a few blocks and it dies again so he got it towed to a shop he uses.

I did not mention this in any previous posts but the alternator was charging at over 14.6 volts at idle which I thought was high. Thought maybe he had a bad diode in the alternator but nope. The dash lights pulse too but that could be the misfire/tick. In addition, this thing has a history of eating voltage regulators since there were 3-4 old ones in the trunk when he got the car.

The crack in the cap has me a little perplexed as far as it being an explanation of the car being dead the next day, dying again after being jumped and then becoming a no start. The symptoms all pointed to the charging system but apparently a new cap and some replacement wires was all it took to get it back up and running and evidently the charging system is working properly. The advance was backed down to a somewhat normal level by his guy though I don't know exactly where.

I don't know where the crack in the cap was. His guy said it was minor. When he brought the car to my house, we actually fixed the #1 plug wire because it was burned through the insulation. I didn't bother to check the others but I remember thinking in the back of my head there were probably more. Note to self - next time there is one burned wire, check for more. I put the wires on myself two years ago and made every effort to keep them neat and off the manifolds. When I popped the hood, all the looms were gone, the wires were flopping around loose and were covered in oil/grime. Yeah, less than two years old but looked like they'd been there since 1977.

Again, this thing has a bad tick and is very loud (glass packs, no mufflers) so it's a little tricky to identify a different miss beyond he obvious one. Guess it was there but it seemed to be running OK for this car so I didn't really think to look into it.

In any event, this stupid saga is done for now, thanks for the replies.