400 Pontiac

[scca_stang]

Hey Guys.

I know this is a Ford site, but I was at my friend's house tonight and he has a 70 GTO with a 400 Pontiac motor.

we checked firing order (18436572, counter clockwise)... correct

I know he had the cam out and the distributor out... and I was not there when he dropped it all in. but what I do know is that his number 1 wire on the distributor faces the firewall... not sure this is correct.

he gets it to start up occationally, but it is definately NOT firing on the back cylinder's 7&8 (cold header primaries).

Oh, and he called me after I left and he was telling me that he ran it for almost 15 minuits and his middle primaries were steaming hot while the back primaries are still coldish... and the front primaries are only mild to hot, so now I am not convinces that he is getting hits on the fronts as much as the middles either.

Carburator is a Edelbrock 4 barrel on a Edelbrock aluminum airgap intake.
Heads are Edelbrock aluminum heads
Hooker Headers
Accel HEI distributor
Comp Cams Cam, Hydraulic lifters

anyone got any suggestions.

Click to read more...

 

[Aron]

Distributor 180* off?

 

[scca_stang]

Distributor 180* off?

I don't think it would really run as good as it does being that far out???

 

[Aron]

You never know. Did you double check that all the plug wires were routed properly?

 

[Dana]

did he fill/soak the lifters before he installed them if they are new?

maybe the distributor is one or two teeth off? bring the timing marks to TDC and see where the rotor is pointing. It should be pointing at either the first cylinder in the firing order or the fifth cylinder on the dist cap.


or the cam gear is one tooth off.

locate the number one cylinder, remove the spark plug and the valve cover and bring the piston to TDC. Both valves should be closed, if not rotate the crank 360* and see if that closes both valves when the piston is again at TDC.
If both valves on cyl #1 aren't closed at one of these two times, you have the timing chain in wrong/miss timed.

Double check the firing order.

Is this an HEI ignition? does it have points? recheck the gap/dwell if it does.

 

[batman]

sounds like a lifter problem...valves arn't opening

 

[scca_stang]

did he fill/soak the lifters before he installed them if they are new?

don't know... will ask

maybe the distributor is one or two teeth off? bring the timing marks to TDC and see where the rotor is pointing. It should be pointing at either the first cylinder in the firing order or the fifth cylinder on the dist cap.

I asked him that and he stated that he is certain that it is perfectly on

or the cam gear is one tooth off.

I will ask him to recheck it

locate the number one cylinder, remove the spark plug and the valve cover and bring the piston to TDC. Both valves should be closed, if not rotate the crank 360* and see if that closes both valves when the piston is again at TDC.
If both valves on cyl #1 aren't closed at one of these two times, you have the timing chain in wrong/miss timed.

Double check the firing order.

done, done again, done again... done by me like 4 times too

Is this an HEI ignition? does it have points? recheck the gap/dwell if it does.

[/quote]
as stated in original post it is HEI... no dwell or gaps to check
HEI... FTMFW

 

[scca_stang]

Fixed... and running, we took it for a spin today...

turns out that it was all because neither of us had ever tuned a edelbrock carb... both Ken and I had alway's messed with Holley or Demon carbs and the edelbrock carb runs so lean compared to it that we simply had to richen up the mixture... once we did that it fired right up and runs pretty damn good.

Thanks for all the suggestions.