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jwhobbs 01-22-2012 02:06 PM

Chevy C6500 truck with 454 engine install distributor with cam sensor
How to install distribuotr with cam sensor into 454 Chevy engine to be in time with crank sensor?

LATECH 01-22-2012 04:30 PM

Is that the plastic distributor, with the hold down that only allows the distributor to go in one posistion?

jwhobbs 01-22-2012 05:16 PM

Chevy C6500 truck with 454 engine install distributor with cam sensor
The only thing this unit does is drive the oil pump and send signal to computer where cam is located.

LATECH 01-22-2012 05:51 PM

IIRC there are no timing marks on the balancer, just 3 or 4 little cuts in the front edge.
What you need to do is turn the engine by hand with a socket wrench on the crank bolt, untill you get tdc #1 compression stroke.
Being there is no timing marks you have to rely on your expertise to gauge TDC through the spark plug hole.Then if you can put on a timing tape, back it up to 14 degrees BTDC.
At that point you are ready for the dizzy.If you look real close at the dizzy, where the cap touches the edge at the place it mounts, there is a number 8.
You want to drop the dizzy in the hole and end up with the rotor aiming at that number.
Now the 14 degrees BTDC may be hard to get to, but one of the little cuts in the balancer should be at the bottom where you can see it.I think that is 14 degrees when it is straight up and down, IIRC. Been several months since I did the last dizzy gear change and set one up.
Now when you get done, If it throws a code p1345, then you need to re learn the cam/crank angle. If the data stream shows that you are 7-13 degrees BTDC on the cam sync pulse timing then it is timed correctly and all you need to do is perform the relearn according to the scanner instructions.

jwhobbs 01-22-2012 07:09 PM

Chevy C6500 truck with 454 engine.......
Thanks I will try this. Does the number 8 on the rotor need to match number 8 on the body of the dizzy?

LATECH 01-22-2012 07:14 PM

No. Put the rotor at the little number 8 on the dizzy housing. Dont pay any attention to the firing order.Be sure when it is tightened down the rotor points at that little number 8. The 8 is to reference the dizzy as used in the 8 cylinder. Some of those dizzys had a 6 and an 8, and could be used in either a 6 or 8 cylinder, and were marked for reference accordingly.

jwhobbs 01-23-2012 09:08 PM

Chevy C6500 truck with 454.....
At what point on the rotor is considered the pointer that needs to be aligned with the #8 on the dizzy housing? My counterblancer does have degree marks.

austinv 10-18-2015 09:04 PM

yes, I would like to know the answer to that question also.

austinv 10-18-2015 09:48 PM

454 dizzy number 8 ???
guys, There is no rotor on this distributor. how the hell can you put or point an invisible, non existent rotor at anything? There's no contacts on these. its electronic. This is an incomplete forum.
SO, the real question is, after the number 1 piston is on the exhaust stroke, backed up to 14 degrees btdc, Where does the number 8 on the dizzy, (metal top of distributor), go, or point to? before i put the flat plastic top cap on. there are no wires to this, This engine has coils on each cylinder.
Please inform me im sure its stupid obvious. Thanks

LATECH 10-19-2015 06:18 PM

what year make and model do you have. It must be newer than the OPs .
More info needed

austinv 10-19-2015 07:26 PM

454 big block timing cap confusion continue
yes, its a 1999 gmc topkick total nightmare. i've just finished a complete removal and rebuild, its all back in, and i'm having trouble even getting spark, compression is only 45 lbs. everything has been torqued to specs and new bearings, rings, gaskets throughout and rebuilt heads. I did it rite, Now I am going to freak out unless this thing comes alive. help

austinv 10-21-2015 06:48 PM

its a 1999 gmc C6500 top kick fresh rebuild, no spark, and I meant to say, (on the compression stroke in my previous forum script. Man, anyone help me get spark?

LATECH 10-21-2015 07:29 PM

Compression is only 45 PSI. It will never run.
You must have the cam/crank timing off, or the valves are to tight.
If the cam/crank timing is off, you cannot successfully time the distributor on this engine to make it run. It simply wont fire the ignition because it (The ECM)knows the crank timing is wrong.
Get to the bottom of the compression problem first, then go back to the timing sequence as outlined.
The distributor housing willonly allow the holdown to hold the dizzy when the housing is in one spot, so getting the rotor to aim at the correct place (that little number 8 on the housing with crank at TDC number 1 cylinder compression stroke) will be key.
If you have had the bottom gear off the dizzy and don't have it on correctly (180 out) it will also not run and can cause engine damage.

waynep712 10-21-2015 09:33 PM

for this topkick motor.. you need a VORTEC rotor to align the shaft when installing the distributor.. . it can be an old one.. it can be a new one..

if you look carefully.. there are 2 screws holding a cover on the top of the housing.. where the distributor cap would normally be.. under that is a conventional Vortec distributor shaft.. its probably drilled and tapped for a conventional vortec rotor..

you may now proceed as a normal vortec distributor installation.. getting the rotor to point at the \8/ in the inside of the lip of the housing..

warning... if with the crank at TDC with compression at #1.. if you cannot get the shaft to align perfectly.. DO NOT MODIFY the hold down clamp..

remove the distributor.. mark the gear on the same side as the rotor tip is installed on the top of the shaft... drive the roll pin out.. do not remove the gear.. rotate it 1/2 turn and install the roll pin.. the mark you made on the distributor gear should now be pointing the other direction..

when you install it this time.. once you get the distributor to engage the oil pump shaft and the rotor pointing in the proper direction. you should have the tip pointing directly at the \8/ on V8 models or the \6/ on V6 models..

if you have NO compression.. something else may be wrong.

if you have NO spark... something else may be wrong..

the crank sensor sends the PCM crank position signal..

the cam sensor sends the pcm cam signal to allow it to figure out which of the coils to fire... also which of the injectors to fire..

a question.. did all the ground wires get hooked up to the engine.. there are usually some along the back of the cylinder heads... those are the PCM Negative connections.. no hook up there. the PCM won't get any electrons to operate the computer.

Hogg 10-22-2015 09:07 AM

To help any people working on the Vortec L21 BBC in the future, this is Austin's original post before this 3 year old post was dug up.


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