I have a 68 chevelle with a 350 in it. I just bought a brand new hei distributor for it and it still does not want to run good at all. Timing is still at 35 degrees advanced at idle. I have double checked and triple checked everything. The wires are in the right spot. Didn't miss a tooth on the dis. gear ir timing gear. When I give it any gas at an idle it just wants to sputter out the exhaust and die. I have a summit cam witha 500 lift and an edelbrock 750 on it. It's running a 9.5.1 compression. I have headers and an aluminum intake as well. Please let me know of something I can do. I have been trying to fix this for 5 months now. It's my daily driver and nothing seems to be working on it. Everything on this motor is new now. Cam, dis, carb, intake, petjackson gear drive, but I am still lost! Thanks

Vhaun. Has the motor run ok at ANY time since the cam/gear drive change?

Unless you've locked the centrifugal advance on the distributor, 35º initial is way to much. Typically, centrifugal will add about 15º-25º, resulting in the engine trying to run backwards once that advance arrives. If the engine won't idle at a more reasonable initial (like 15º-20º), I'd look elsewhere for the problem (cam phasing? valve adjustment?, etc.?). It would be helpful if you provided more info. Cam lift isn't nearly as relevant to your problem as is duration. "Hei" covers a lot of territory. Is it a GM HEI or another electronic ignition? What is it's curve? What rpm do you idle at?

The motor truely only ran good once, after I messed with the timing but it started running bad again by the time I could get it home. The duration I believe is at 238 at .050". And to be honest I don't know what the centrifugal advance is. What would be the best proper way to adjust the valve with a hydralic lift cam, should the engine be running or not. It is a gm hei as well. But even a little bit of gas right now will make the thing want to die. I'm just out of ideas.

I am having a running problem with my BB I currently have a post in the performace section titled I am starting to wonder why I did it. Read it,, lots of good info there, just some things I might suggest, I take your base timing at 35 is with the vaccum advanced hooked up correct ? if not it is way to high, Mine didnt idle for crap when I 1st started mine engine the valves were way to tight the only way I could dial it in was to loosen all rocker nuts and slowly do a running valve adjustment, put a vaccum gauge on it and see how it reads it should be steady and around 14hg for what I am told, but check out my post hopefully it will help you to.

Don't know if you ever read my post on a similar subject a couple of months ago but I had a similar problem that took way too long to figure out.
Car would run & idle fine and I could drive it around but when I put it to the floor it would die. The cam sounded way more radical than it should have and it had a "glasspack" sound to the exhaust when you would rev it up in neutral. (I have UltraFlows)
I changed the distributer, fuel pump, wires, plugs, fuel filter, fuel line, vac advance, jets in the carb,re-set the lifters 3 times, Adjusted the timing about a dozen times, Ect. messed around for 2 months and finally figured it out.
When I built the motor 10 years ago (never fired it) I mis-read the lower timing gear. I used the 0 that is above the keyway to line up to the upper gear instead of the 0 that is 2.5 teeth counter clockwise to the keyway. It was not stamped very deep and I missed it. I put it all back together and proceded to lay 20' of posi in front of my driveway! (wife was even happy I finally got it running right)
I just finally decided to tear into it as I thought it was either the gear or the cam and I was going to fix it either way, Turns out it only took a couple of hours to fix and I had probabally had 40 into it up to that point.
Just somthing to consider.

LK

thanks I may just try that tonight.

The only difference is that I can floor it in the later rpm and it seems to do fine with no pinging or backfiring, it's just in the early rpm. And now it won't run at all even though it was running fine before I put the new distributor in there. Well it kinda runs but just even worse than it did.

Try this: Pull the valve cover off the drivers side. Disconnect the dist. so it can't start. Have someone bump the engine around till you see #1 cylinder intake open. Now bump it till you see #7 exhaust open. Check the dist. rotor. The rotor should be pointed near #1 plug wire. If not pull the dist. and turn it around so it does.
I don't know why it possible but you can drive a car with the dist 180* out. I have actually done that a very long time ago, runs like crap, but it will run.

I have never seen any car that would start with the distributor 180° out.

Timing should be between 8 and 16 at idle with the vacuum advance disconnected and plugged. Is this how you are checking it? (The exact amount you need depends on the carb, cam and heads you are running. Try shooting for 12 at first to see how it does.)

You either have too much timing or your accelerator pump on the carb is not working or both. Get the timing set correctly and if that doesn't fix the off-idle performance, check to make sure the accelerator pump is set up and working correctly.

My car seems to run great in the low rpm when the car is advanced beyond recognition. It is at about 45 degress advanced at idle. Runs great though, but pops in the high rpm. Is there anything that I can do?

What is the initial timing? (At idle, vacuum advance disconnected and plugged.)

Slightly off topic, but based on Brains post... I never heard of a Chevy engine running @ 180* off either, although a friend of mine who has worked on Chevy engines his entire lifetime said that when he obtained a job to work on a young kid's camaro, the timing was 180* off and it still ran. I did not believe him, I did not see the car, however he swears that it ran (like cr@p though). That has me dumbfounded and confused! I'm more inclined to go along with Dean's post.

The engine is fireing on the down stroke rather than the up stroke. If he increases his timing to say at least 60* and the idle goes up and it starts running even better and stops backfireing then we know whats wrong. If he increases it to 60* and it runs worse, if not shuts off all together then we can say the dist. is in correctly.
I wouldn't believe it myself that they will run but they can. They are very hard to get them to start from the beggining. VHAUN was the car hard to get running when you put the new dist. in?

Vhaun, I agree with Rich-L79, it sounds like either an accelerator pump problem inside of the carb, or the distributor is installed incorrectly. There's no way you should be running 45* (or more) timing at idle. In fact, Chevy engines love to run at 35-37* TOTAL advance (initial timing at distributor + vacuum advance + centrifugal advance), and this would be at the upper RPM ranges ONLY. You don't need (or want) all that advance at idle, because your engine will start pinging like hell once you stomp on it. If you try to think about it logically, the whole purpose of advanced spark timing is nothing more than a mechanical attempt by your distributor to compensate for the engine's higher and higher RPM's as it accelerates. The faster your engine is spinning, the sooner you want that spark and whole combustion process to take place so there's adequate "burn time" for the spark to do its stuff on the air/fuel mixture inside the cylinder heads. As engine RPM steadily increases, you want the plugs to fire earlier and earlier, while the pistons are still on their upward compression stroke, or BEFORE they actually reach TDC (Top Dead Center); hence the term BTDC (Before or Below Top Dead Center).

Regardless of whether you installed your cam advanced, retarded, or "straight up", your engine should fire up. If you're positive you're getting fuel flow through the carburetor, leave the carb alone for right now. The first thing you need to do is make sure you have the distributor installed correctly and that it is firing based on the position of the #1 cylinder. If you're not sure how to do this, let me know and I'll walk you through it step-by-step. Whether you're using HEI or points, it doesn't matter. It's a piece of cake. I can either post the info on here, or e-mail it to you directly, but I think there are probably others out there who would benefit from being walked through a distributor installation if they've never done one before.

A dynamic (running) valve lash is best for hydraulic lifters once the engine is up to temp, but you're gonna' have to get that puppy fired up and idling relatively smoothly before I walk you through that one. Start with the distributor first.

:thumbsup:

Slightly off topic, but based on Brains post... I never heard of a Chevy engine running @ 180* off either, although a friend of mine who has worked on Chevy engines his entire lifetime said that when he obtained a job to work on a young kid's camaro, the timing was 180* off and it still ran. I did not believe him, I did not see the car, however he swears that it ran (like cr@p though). That has me dumbfounded and confused! I'm more inclined to go along with Dean's post.

It's possible to install the distributor in any position, including 180º off, and still have correct timing as long as the wire/rotor/cam relationship is correct. The main problem when the distributor isn't installed in the correct position is the timing adjustment range will be limited due to the vacuum canister hitting something (intake runner, coil). It could also be a problem with points distributors if the window isn't accessible. If timing has been checked with a light and it's ok, distributor position isn't the problem. If proper timing can't be achieved due to the vacuum canister hitting something, distributor position (or the distributor drive gear position) is the problem. In some cases the drive gear was removed and reinstalled, it could be reinstalled 180º off. It fits just fine in either position but the #1 position of the distributor could be 17.5º off, creating clearance problems when setting timing. There is a dimple on the gear that should face towards the rotor contact, not away from it.

In fact, Chevy engines love to run at 35-37* TOTAL advance (initial timing at distributor + vacuum advance + centrifugal advance), and this would be at the upper RPM ranges ONLY. :

Gotta disagree with that statement. While 35º-37º is usually near optimum total, total does not include vacuum advance. A typical vacuum advance adds about 16º under light load conditions so a typical total + vacuum advance would be around 52º. High compression, crappy gas, etc., may not handle that well so vacuum advance needs to be reduced. In any case, if you set total to 36º with the vacuum advance connected, you'll wind up with a total that's way below optimum. If it's got a really mild cam, it might even run :).

So, the question still stands, where is your initial timing set with the vacuum advance disconnected and plugged?

My car is at 45 to 55 degrees advanced right now, at idle, with the vacume advance disconected and pluged off. It runs great in the low rpm but bad in the top. But when I retard it, it runs good in the top but not the bottom. Isn't that the complete opposite of what it's supposed to do, any sugestions? I'm getting close I at least got to drive it today.

I have never seen any car that would start with the distributor 180° out.

me either.

I'm tellin ya' - It's more serious than adjusting the timing. (Cam gear)

Did you put the cam in the motor?

LK

Set the initial timing to 16 degrees BTDC. If it won't run well at that setting there is something wrong in the crank/cam timing. Either the lower gear was installed wrong (most have multiple keyways) or the timing marks were not lined up or the timing set was manufactured wrong. Regardless, you likely have a serious cam/crank timing maladjustment which you need to fix before you bang a piston into a valve and seriously break things.

Before you dig into the engine, however, I need to ask one obvious question: are you checking the timing using the #1 cylinder? This would be the cylinder which is on the driver's side front of the engine.

He could have a balancer that slipped too.
You might want to buy one of the screw in TDC tools

He could have a balancer that slipped too.
You might want to buy one of the screw in TDC tools

Good point.

There was only one keyway on this and it is pointing at 2 o'clock like its supposed to be. The ballancer is right on, We checked tdc by pulling out the sparkplug and the line marks up just fine. It's a solid gear drive from peet jackson. I put the cam in but the marks on the gears are poionting directly at eachother. It was at top dead center like that. Some people are saying it shouldn't be but most people I know do it that way and are having no problems. While it was on top dead center I droped the distributor in and the rotor was pointing at the number one plug. This was also a crate motor from hi-tech. Should the firing order be from the year of the motor or the distributor? I'm down to where I will try everything.

yes the marks should line up so you can verify the cam timing, I may be wrong but I think when the marks are together that the engine is on # 6 cyl compression stroke? leave #1 plug out and have a partner bump the engine over while you hold a finger over the plug hole till you know it is coming up on the compression stroke. Line up the timing marks , pull the dist cap and verify that its pointing to #1 wire..

that is exactly how i did it. My dad would put his hand over the hole an we woul make sure it was on the compression stroke.

I have a 68 chevelle with a 350 in it. I just bought a brand new hei distributor for it and it still does not want to run good at all. Thanks

Did you replace a points distributor? If so, did you remove the resistor wire when you hooked up the HEI?

Hook it up with a heavy gauge wire directly to the firewall connection block or wire it to the fuse panel. Get all the resistor wire out of the car.

~Scotch~

There was only one keyway on this and it is pointing at 2 o'clock like its supposed to be. The ballancer is right on, We checked tdc by pulling out the sparkplug and the line marks up just fine. It's a solid gear drive from peet jackson. I put the cam in but the marks on the gears are poionting directly at eachother. It was at top dead center like that. Some people are saying it shouldn't be but most people I know do it that way and are having no problems. While it was on top dead center I droped the distributor in and the rotor was pointing at the number one plug. This was also a crate motor from hi-tech. Should the firing order be from the year of the motor or the distributor? I'm down to where I will try everything.

Vhaun, the firing order for a Chevy engine is always the same, regardless of whether you're using an HEI or a points-type distributor, or different year motors. The correct order is 1-8-4-3-6-5-7-2, so make sure that whatever tower on the distributor cap you choose as #1, that you run your spark plug wires in a CLOCKWISE direction when looking down at the distributor from the front of the vehicle. Choose your #1 wire location on the cap and mark it. Then transfer this mark to the distributor body just below the #1 tower you just chose on the cap. This will give you a reference for #1 when the distributor is in the engine but the cap is off. This mark will allow you to see the relationship of the rotor with respect to the #1 location in the cap once you go to insert the distributor into the block. Also, remember that the helical-cut gear on the end of the distributor shaft will cause the rotor/shaft to rotate slightly when the distributor shaft gear engages with the cam shaft gear. You'll need to compensate for this slight rotation through a little trial and error when you go to install the distributor and are attempting to get the rotor to point towards your #1 mark on the body of the distributor.

Most people pick the foremost tower on the cap closest to the front of the vehicle; this would be the one just above the adjustment window if you were using an old points-type distributor, but it doesn't really matter, as long as you complete the firing order sequence of -8-4-3-6-5-7-2 after you've selected #1. Make sure that the next wire immediately to the left of that #1 wire is #8, then #4, then #3, and so on around the cap. Route the wires one at a time from the cap to each plug. The cylinders/plugs on a Chevy engine run 1-3-5-7 from front-of-engine to back-of-engine on the driver's side, and 2-4-6-8 from front-of-engine to back-of-engine on the passenger's side of the vehicle.

Once you have the #1 piston at TDC on its compression stroke, the distributor installed and the rotor pointing towards your #1 location on the distributor body, install the cap, turn your harmonic balancer a few degrees into the BTDC (Below Top Dead Center) range, and fire up your car. Once you get your car to fire up, go ahead and set your timing at the harmonic balancer with your light while your vacuum advance hose running from the carb to the distributor vacuum advance canister is still plugged. (Remember, you're plugging up the end of the vacuum hose, NOT the little opening in the end of the vacuum advance canister on the distributor).

The main reason for going through all of the above girations is that you're attempting to recreate the condition of the engine which exists when the #1 cylinder is just about to fire towards the end of its compression stroke.

The other thing you may want to check is that your vacuum advance hose is connected to a "ported" or variable source of vacuum on your carb (any port on the carb ABOVE the throttle plates), not a source of constant manifold vacuum, otherwise your timing will be advanced all of the time at idle/off idle, instead of allowing it to vary as your engine vacuum fluctuates.

Give this a try so we can eliminate the distributor as the source of your problems and move on to something else.

I've gotta ask, did you attempt to back the timing down and see how it runs? What happened?

I put the cam in but the marks on the gears are pointing directly at each other. It was at top dead center like that. While it was on top dead center I droped the distributor in and the rotor was pointing at the number one plug.

Still wanna tell me it not 180 out?
If you lived close, I would come over and give you a hand.