potterc32

iTrader: (1)

Sbc 350, q-jet carb, rpm intake. Just installed new cam, 490 lift, 110 LSA and about 234 actual duration.

Trying to start it up to break in the cam, but i can't get it to idle at all. I know it has to do with spark timing. How do i set timing after distributor is installed? It will run fine at about 1500 rpm, but when i let it drop to idle it dies. I have watched some videos in how to time a small block, but they are all vacuum advance, mine is not vacuum. It is an HEI though. Any help on a how to time and what degree seeing has worked best for you guys, would be appreciated. Thanks!!

92Formula94

I would pull distributor out because you probably didn't drop it in in the same place that you pulled it out. Manually crank motor by hand at the harmonic balancer until the hask mark comes around. Line it up with zero. While your doing this you or a buddy can have a finger in the number one spark plug hole and if your feel air you are in the right spot. If you dont, go around another rotation. Put the distributor in facing the number one spark plug. than time the car with a timing light to 6*

92Formula94

Pull your est connector after you fire the car up, set timing. shut car off. Tighten distributor. plug connector back in, unplug battery to clear est code. oh, your looking for 6* retarded

potterc32

iTrader: (1)

I got it to idle okay for the most part, still kind of rough. Without removing any connectors, it seems to run best with timing at 56*.... No joke. Ammeter is on the right plug, seems to run fine over 1000 rpm.

I know i payed close attention to it during installation, but it's it possible the timing chain is off by one tooth or something? If spark and valvetrain are in time with each other,but crankshaft is off, i would think it wouldn't want to run hardly at all.

Also, when installing the double roller chain, i noticed it had some play in it, compared to the single that was on it (tight As hell) . is that normal?

potterc32

iTrader: (1)

Bump

potterc32

iTrader: (1)

Still Having problems getting this thing to run right. Drove it yesterday and it acted okay, other than the rough idle, until I got about a mile and a half down the road. When letting off the gas, it seemed to want to die on me... kinda started jerked back and forth.

I did find out that when I rebuilt my carb (well over 8 months ago, installed on engine before the camshaft install, ran just fine then) I forgot to put the little green rod in on top of the TPS. Installed it, and it seemed to start up much better, and allowed me to adjust timing to around 45 degrees advanced.

If I go any less than 40 degrees advanced, it won't run at all, regardless of whether or not the EST connector is plugged in. I looked at a new harmonic balancer, and it looks like to the timing mark on mine is in the correct place.

Does anyone have any ideas???!!!!!????

Formula 305

You said you put the timing light on the RIGHT side?? The timing light should read off the #1 cylinder, which would be front DRIVER SIDE cylinder, which would be the left side of the engine. May be why your timing numbers are weird.

Night rider327

iTrader: (13)

Just something to throw out there...

Most RPM intakes are square bore flange. The Qjet carb is a spread bore. Is your carb sealing to intake?

FRMULA88

WRONG..

base timing is "0" from the factory if you bother to read the label under the hood of any 3rd gen.

Better performance can be had by ADVANCING base timing 4 to 6 degrees from "0"

How do you find "0" ? In simple terms with EST unplugged you want to see 16 - 19 degrees of initial (base) timing at idle. You adjust the dial on the timing light to that amount, say 18 degrees, when you aim it at the balancer this will show up as "0" on the timing tab you may have to rotate the distributor to get this right.

Since total timing is controlled by the computer (timing tables) whatever you add to your base timing will increase total timing. Typically a small block chevy does not need more than 36 degrees total timing for optimum performance at WOT.

At light engine loads total timing can be advance by the computer to 40+ degrees to improve emissions and fuel economy.

timing should be read from the #1 spark plug..

potterc32

iTrader: (1)

I got the RPM Q-Jet intake. It is spread bore. And yes, my ammeter is on the correct plug wire.

FRMULA88 I have never heard of that process before... Just curious as to where you came up with that. If that's the case, it makes me feel a whole lot better about my car running best at about 40 something degrees advanced.

Formula 305

You shouldn't feel good about 40 degrees of base timing. If your unplugging the EST wire it shouldn't be anywhere near 40, I believe either you are doing something incorrectly or your timing gun is defective.

How exactly are you reading 40 degrees? The timing marks on my car only go to about 12 degrees advanced and 8 retarded if I remember correctly.

potterc32

iTrader: (1)

I was using a Snap On timing light, and I just kept "upping" the timing setting on the light, and when it reads 46 degrees, the timing mark lines up with "0" on the timing tab.

Formula 305

With the brown single wire connector unplugged?

potterc32

iTrader: (1)

left that one plugged in, unplugged the 4 wire connector going to distributor. And I suspected an issue with the timing light, I have used 3 different lights, all of them are within the same range. All 3 different brands. I have a hard time believing the problem is the lights. I think either I am the issue, or there is something wrong with the car. I first suspected the harmonic balancer to have worn the rubber and the outside portion to have slipped, causing the timing mark to be in the incorrect place. But I looked at an illustration online, and it seems to be in the correct place in relation to the keyway.

Formula 305

Hmmm... something definitely seems fishy

potterc32

iTrader: (1)

I thought the brown wire was for the tach... I'm not supposed to unplug that am I?

RamIt

I believe there are different ways of setting timing between injected cars and carbed cars.

FRMULA88

Sorry I mis-read your post, is this a carbureted engine with HEI and no computer control for the spark advance?

the timing process is the same just simpler with a carb.

AT IDLE you should NOT have 40 degrees of timing.

You only need 12 to 19 degrees of initial ( base) timing at idle. carb or efi.. does not matter. This is just enough initial timing to start the car and maintain a nice smooth idle.

another issue is a cam that big will need more curb idle speed.. it will not idle at 700 RPM like a stock cam..

my engine idles at 900-1000 RPM because of the camshaft.

sounds like you have other issues to check before you ruin a cam & set of lifters..

Idle speed
Idle mixture

get the car started and hold the idle at 2000 RPM for 20 minutes. to break in the cam (follow the break in instructions that came with the cam.. you DID read those right)

once you have the cam broken in, then you can play with timing etc. to fine tune it..

FRMULA88

potterc32

iTrader: (1)

Already broke in the cam for 30 minutes at 2400 rpm. I read the instructions thoroughly!! My car is carbed, with computer controlled advance.

I did not adjust anything on the carb related to fuel mixture.

FRMULA88

OK then you have way too much initial timing.. with 40 degrees of timing at idle the spark plugs are firing way too soon..

disconnect the ESC wire from the distributor, (it's tan or tan with black stripe or white stripe) it has a quick connect fitting shoots right to the firewall (towards the ECM under the dash) if your car has A/C this wire normally runs along the top if the blower motor box..
Set your base timing (initial timing) between 12-16 degrees. loosen the dist. hold down bolt and turn the dist. clockwise.. this will retard the timing... do that until you can "0" between 12 - 16 degrees.. with your timing light. as you retard the timing the idle speed may increase.. you can fine tune that later.

then reconnect the ECS wire, it's that simple.

then adjust idle speed and idle mixture for best vacuum reading at idle in gear. Idle speed should be around 800 RPM in gear. a little higher RPM in neutral.

A cam like that you may only get 8-10" of vacuum at idle.. so power brakes will be another issue.

potterc32

iTrader: (1)

That's the 4 pin connector isn't it? If I remember correctly, and if I'm reading the diagrams correctly, there's only the red wire for power, brown for tach, and the 4 pin EST connector.

And my Brakes seem to work just fine, so I think vacuum is okay. I'll see if I can borrow a vacuum gauge and timing light again, and see where things go.

FRMULA88

fyi

FRMULA88

just remember with ESC the computer handles the total timing and timing advance.

The only this you can adjust is the initial timing.. the computer simply add to that...

you can check total timing when you are done and if you want more, just advance the distributor a few degrees.. but most SBCs with a cam like 16-19 degrees of initial timing.
work out to 36... total it can be more with al low loads..

FRMULA88

The only way your timing can be that far off is if you installed the distributor incorrectly in relation #1 piston being at TDC. OR you installed the spark plug wires in the wrong firing order.

Make sure #1 is at TDC on the compression stroke, when it is the rotor should be aligned with the #1 terminal on the distributor cap.

Firing order is 1 8 4 3 6 5 7 2

Drivers side are odd,, #1 is at the front of the engine.

Passenger side are even #2 is at the front

Check these two things first...

otherwise the only other problem could be if you rotated then engine (moved crankshaft) after you removed the camshaft. hopefully you installed the new cam and timing in the same position the original one was in and not rotated the crankshaft. Ideally you lined up the timing marks "dot to do"t removed the old cam etc. then reinstalled the new "dot to dot".

FRMULA88

watch and understand...

potterc32

iTrader: (1)

I get all that. And no, I turned everything without the cam installed to make things easier when installing the new springs. I did get the cam and crank timing together correctly, that much I know.

I even tried to degree the cam, thinking maybe I had the crank gear in the wrong place. I tried advancing the cam, (which would pre-advance the distributor in relation to the stroke of the piston). But it didn't seem to change anything but made it idle rough. Since then I have reinstalled it back to 0* .

It will run smooth and not misfire (so I know the plug wires are in the right place) and it really doesn't matter how you install the distributor, you can turn the cap to any position you want to make it run (third gens of course lack the room to do that), but I can turn it close to 50* either way while adjusting timing, it runs anywhere from 35*-65* before it dies, runs best around 45*. All of this check at idle (around 800 rpm) with the 4 pin connector unplugged at the distributor.

Could anything like vacuum leaks, faulty sensors (tps), or air fuel mixture, or anything of that nature, cause an engine to run so advanced? Doesn't have as much power as I expected (maybe that's just my expectations). Could low compression, bent/burnt/leaking valves cause a scenario like this?

FRMULA88

If you "got all that" then you would understand that is actually does matter how you install the distributor, because the distributor runs off the camshaft.

Whoever said "you can turn the cap to any position to make it run" is misleading you

You have to install the distributor correctly with #1 piston at TDC.

My guess is because you rotated the engine prior to reinstalling the distributor you installed the it incorrectly in relation to the camshaft / #1 piston @ TDC
Your timing light says 40 something degrees at idle because you installed the distributor off by over 20 degrees.

remove the spark plugs and turn the engine by hand until #1 is at TDC on the compression stroke.. then check the position of the rotor... my guess it is not even close to #1 terminal on the dist cap

reinstall the distributor correctly.

potterc32

iTrader: (1)

I have done that on many engines. It doesn't matter where the rotor is pointed when installing the distributor, as long as the cap is installed in relation to the distributor itself. Some plug wire lengths will not allow you turn the cap far enough of course, but this is irrelevant in this case, I'm not trying to start a pissing match.

Regardless of that matter, the distributor is installed with rotor pointing at the #1 cylinder, with #1 ATD on compression stroke.

FRMULA88

That may be true but how many cams have you swapped?

Obviously something is screwed up.
trying to reach out over the airwaves to help you diagnose & fix your car is impossible, but we can try.

Did you check the timing mark on the balancer with #1 piston at TDC? The mark should line up with "0" at the timing tab.
if not simply draw new mark with a sharpie and check the timing in relation to your new "0".

You may have installed the balancer,timing chain, or even the camshaft with #1 not at TDC so the factory mark on the balancer is wrong.

potterc32

iTrader: (1)

I do appreciate the help and ideas, that's why I love this forum, people seem to be more than willing to spend their time helping others!!

I'm going to check my balancer this weekend again, just make darn sure the rubber didn't fail, allowing the outside to slip (moving my timing mark). Really didn't want to have to drain coolant again, but it looks like I have no choice!

Thanks again folks, especially FRMULA88, all of your input is greatly appreciated!!

potterc32

iTrader: (1)

I have only swapped a 2 cams before this one, both of which went smoothly. I know I had to have messed something up... I did not think to check the location of timing mark with #1 ATDC!!! That will make like much easier than pulling the D*** thing off.


Good idea!!

FRMULA88

it is quite possible you installed the balancer out of sync with #1 @ TDC so your timing reading completely off. If you installed it correctly the factory mark on the balancer should fall on "0" on the timing tab with #1 at TDC.

If it is way off make yourself a new mark at "0" and then check your timing based on your new mark. you will have to remember to use your mark, not the factory one, if you don't want to remove and reinstall the balancer.

Good luck

Formula 305

Do the older Carbed cars have a 4 pin connector for the ESC where the newer EFI cars have a 1 pin??

potterc32

iTrader: (1)

Mine sure does!! Has the single connectors (red for power and brown for tach), and the (3?) pin connector which all go to the cap, and then the 4 pin harness that goes to the distributor base.

Mine is computer controlled (electronic spark control, and computer controlled carburetor.) No vacuum advance or mechanical advance, all done by module.