Timing issues

[themons]

Hello:

After recommissioning my port 454 straight drive, I encountered a popping noise on cylinder 6. The popping noise stops if I disconnect the spark plug wire.

According to the breakerless Prestolite distributor wiring configuration it is a RH rotation with 1, 2, etc. firing order.

The Crusader manual says 10 BTDC on idle, but the Prestolite chart says 0. I am not sure which is correct.

The timing is set at 10 BTDC according to the timing plate with my digital light. This is on the port side of the 0 mark. Is this correct for a RH rotation or do I have a LH timing plate and my timing is way off?

Also does it matter which connections the spark plug wires are on the distributor as long as I preserve the correct firing order? In otherwords, does cylinder 1 have to be on a specific connection on the distributor as long as the rest of the wires are in the correct sequence?

Thanks.

 

[themons]

Could this be a stuck intake valve issue?

 

[RicardoMarine]

.......................

After recommissioning my port 454 straight drive, I encountered a popping noise on cylinder 6. The popping noise stops if I disconnect the spark plug wire.
The #6 intake valve may not be fully seating.

According to the breakerless Prestolite distributor wiring configuration it is a RH rotation with 1, 2, etc. firing order.
Port engines with straight drives are typically standard LH rotation.
Engine rotation is determined while viewing from the flywheel end!

Since the oil pump rotation is not changed with either LH or RH engines, the ignition distributor rotation remains standard CW.


The Crusader manual says 10 BTDC on idle, but the Prestolite chart says 0. I am not sure which is correct.
A mechanically advancing ignition system will spec out a BASE or Initial advance.
However, the more important aspect of ignition timing will be the progressive and TA (total advance).

The timing is set at 10 BTDC according to the timing plate with my digital light. This is on the port side of the 0 mark. Is this correct for a RH rotation or do I have a LH timing plate and my timing is way off?

If you are refering the timing tab marks... here's one for a Std LH engine.
These are rather useless for TA work since they are limited to only 16 degrees.

Your more useful markings will be on the harmonic balancer.
These will be read against the ZERO/TDC notch of the tab.
(standard LH rotation engine shown)

If this is a Standard LH rotation engine with straight drives, the progressive markings on the harmonic balancer will be to the Port side of the tab's ZERO/TDC notch.... as shown above.

Conversely, for a Reverse RH engine, the progressive markings on the harmonic balancer will be to the Stbd side of the tab's ZERO/TDC notch.


Also does it matter which connections the spark plug wires are on the distributor as long as I preserve the correct firing order? In otherwords, does cylinder 1 have to be on a specific connection on the distributor as long as the rest of the wires are in the correct sequence?
With any "even fire" engine, you are correct.
As long as the firing order is observed, the distributor and engine won't know the difference.

 

[themons]

Thanks for the input Rick.

The firing sequence of 1-2 etc versus 1-8-etc would make it look like a RH rotation. So, it may be an oddball deal with a RH in on the port side.

I'm going to take off the valve cover and see if the intake valve is stuck open or partially open next.

 

[makomark]

A RH on the port would be appropriate if you have the "oddball" 1.88:1 or 1.91:1 gear behind it...you can tell by the model number on the gear.

The pic of the timing tab is for a LH engine...if it is used on a RH engine, the "before" and "after" would be "backwards"...I read the explanation a coule times and think the port and starboard references have been swapped....

If you have a digital advance light, you can verify the "sense" of the "before" direction....

If you haven't started on the rocker, you may find a compression gauge easier to assess if the valves in #6 are seated.

 

[RicardoMarine]

1.... The firing sequence of 1-2 etc versus 1-8-etc would make it look like a RH rotation. So, it may be an oddball deal with a RH in on the port side.

2.... I'm going to take off the valve cover and see if the intake valve is stuck open or partially open next.

1.... Keep in mind that with either rotation engine, the distributor rotates CW.

The Std LH engine firing sequence of 1-8-4-3-6-5-7-2 will be from the from the #1 cap tower in clockwise direction.
Likewise, the Rev RH engine firing sequence of 1-2-7-5-6-3-4-8 will be from the from the #1 cap tower in clockwise direction.
(see image below)

2.... I'd go with Mark's suggestion.
If an intake valve is not quite closing, and is causing this popping, you won't be able to see it with your eyes.

 

[themons]

The port engine definitely counter rotates on this model boat. Turns out the problem was indeed a stuck open intake valve on cylinder 6. Almost have the valve working normally. I picked up an Indemar shop manual for the 454 at the local used book shop for $8. It is actually better than the Crusader shop manual for some things.