Rebuilt 3.0 engine issue, Hi temps on one side Options

[gereed75]

Agree with all -you need correctly timed spark, fuel and compression

my logic is that if the ignition/timing is correct to run cylinders 1/2/3 there is nothing intrinsic to the system that wouldn’t run 4/5/6 (assuming plug wires are correct).

So then there is fuel , hence my thought about fuel level, or some other aspect of the non running 4/5/6 carb. Could be fuel delivery to that carb but we were told pressure there was fine.

Could be valve timing on 4/5/6 but that seems unlikely because the builder appears to have gotten 1/2/3 bank right. Nothing to suggest that 4/5/6 isn’t correct, but the easiest way to know would be a compression check.

My bet is fuel.

[930cabman]

Agree with all -you need correctly timed spark, fuel and compression

my logic is that if the ignition/timing is correct to run cylinders 1/2/3 there is nothing intrinsic to the system that wouldn’t run 4/5/6 (assuming plug wires are correct).

So then there is fuel , hence my thought about fuel level, or some other aspect of the non running 4/5/6 carb. Could be fuel delivery to that carb but we were told pressure there was fine.

Could be valve timing on 4/5/6 but that seems unlikely because the builder appears to have gotten 1/2/3 bank right. Nothing to suggest that 4/5/6 isn’t correct, but the easiest way to know would be a compression check.

My bet is fuel.

given the information (IMG:style_emoticons/default/agree.gif)

[Retroracer]

Joining this a little late, some good recommendations from the tribal elders to check here in the thread; but one item to consider from the initial post:

"...sprayed points on the throttle shaft on 1,2,3 there was a noticeable change in idle"

That is going to be a problem. There should be no leakage in the throttle shafts, so whether this is the sole issue for your temp mismatch (doubtful), it will be a neccessary item to address to get to a decent (predictable) tune, unfortunately.

- Tony

[Retroracer]

And:

"...would a bad MSD unit cause one bank to not get spark?"

Highly unlikely. The MSD has no idea which spark plug the disty + rotor is pointing at so it doesn't care about banks or individual cylinders. It just goes full on when the points are opened.

- Tony

[scrz914]

Joining this a little late, some good recommendations from the tribal elders to check here in the thread; but one item to consider from the initial post:

"...sprayed points on the throttle shaft on 1,2,3 there was a noticeable change in idle"

That is going to be a problem. There should be no leakage in the throttle shafts, so whether this is the sole issue for your temp mismatch (doubtful), it will be a neccessary item to address to get to a decent (predictable) tune, unfortunately.

- Tony

Yep. It’ll be a cause for frustration. I’ve already contacted some shops. Waiting to hear back.

[scrz914]

I did have some progress today. Needless to say, getting the spark plug wires oriented correctly made a difference. No more backfires or spitting out the carbs. I was able to get the timing done at 5 BTDC @ 900 rpm without stalling. Did a float level check one the 123 bank and it’s set too high. So I will make that adjustment next. Floats too high mean a thicker shim, correct?
Interesting though. I’m getting better temp readings on the exhaust ports averaging around 500 degrees EXCEPT 2 and 6! They are around 150 degrees. I’m wondering if the plug wires aren’t seating properly in the distributor cap. I’ll take a closer look at that.

[Root_Werks]

Sounds like you are getting closer to a solution. So cool you have an engine stand to sort all this out before the engine goes in the car.

(IMG:style_emoticons/default/driving.gif)

[scrz914]

Sounds like you are getting closer to a solution. So cool you have an engine stand to sort all this out before the engine goes in the car.

(IMG:style_emoticons/default/driving.gif)

Yeah the stand is making things easier. Especially since I’m learning as I go. I learned a lot about the wiring harness (shout out to Perry Kiehl) and gauges just mocking things up for the test stand console. I wanted to get the engine sorted as best I can before installation.