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TOPIC: Timing adjustment

Timing adjustment 3 years 1 month ago #114546

Hi Everyone,
Slowly fixing up my Dad's Bearcat 55. I installed the Pertronix Ignitor II #91545 (with adjustable dwell), with their Flame-Thrower II coil, and Flame-Thrower carbon core suppression spark plug wires. Then tried to set the timing at 8 BDC but it varied quiet a bit. Some flashes showed 8 degrees, some at TDC, and some at a greater advance. All I could do was try to get an average at 8 degrees. I'm new to using a timing light, but from what I gather there shouldn't be this type of variation. Am I good, or is there a problem? The timing mark on the flywheel didn't line up with the one on the crankshaft, so I drew new marks on the flywheel edge based on the crankshaft mark. It idols a bit fast at about 900 rpm (intermittantly drops down to about 600; may be a carb issue), and doesn't advance all the way to 43 degrees at 4200 rpm. Any advice? Thanks.

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1970 Boston Whaler Sakonnet w/ Bearcat 55
1960 Chris Craft Continental w/ 283 ci V8

Re:Timing adjustment 3 years 1 month ago #114550

Just talked with the owner of the timing light I borrowed and we decided I might have been getting aberrant firing of the light due to closed proximity of the other spark plug wires to the pickup on the #1 wire. I'll repeat and try to isolate the #1 plug wire better.

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___________________
1970 Boston Whaler Sakonnet w/ Bearcat 55
1960 Chris Craft Continental w/ 283 ci V8

Re:Timing adjustment 3 years 1 month ago #114684

You probably won't get it to run well with the carbon core wires. The screw in style connectors in the cap are designed to pierce copper core wires. Unless you are running a stereo while the motor is running, you do not need suppression ignition wires, or resistor plugs. Here are the wires I am running, and they work great:

smile.amazon.com/gp/product/B00NB657NK?psc=1&redirect=true&ref_=oh_aui_detailpage_o03_s00

What I did to set the timing on mine, was to get it on the water with the cowl off, have the screw on the front of the distributor clamp loose, have someone pilot the boat up to full throttle, and then I advanced the timing until I achieved the highest RPM. It isn't too important what the advance is at idle, so long as the engine doesn't diesel on when you turn it off. The high RPM advance is what's critical in achieving full hp.

Dave

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Re:Timing adjustment 3 years 1 month ago #114723

Thanks for the info Dave. So, are you running the Pertronix Ignitor, or the Ignitor II? Asking because the instructions for the II specifically say it has electronic parts that are sensitive to electromagnetic interference that require suppression wires. But if you are running a II and getting away with solid core, then I might try switching my wires.
Jon

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___________________
1970 Boston Whaler Sakonnet w/ Bearcat 55
1960 Chris Craft Continental w/ 283 ci V8

Re:Timing adjustment 3 years 1 month ago #114901

I'm running the Ignitor, not the two. You just moved past my level of expertise.... So I'm going to guess that you would use cut to length wires. Once you have wires pressed onto the barbs in the cap, make sure you fill the air space under the cap lid with di-electric grease to prevent any possibility of moisture arcing.

I'm not sure I wouldn't bail on the Ignitor II and get a Ignitor I. Carbon suppression wires don't like shock and vibration, an tend not to last as long in the kind of environment that a marine outboard runs in.

Dave

This is from Magnacor's FAQ page:

CARBON (SUPPRESSION) CONDUCTORS

Carbon conductors are used in original equipment ignition wires by most vehicle manufacturers, and in the majority of stock replacement wires. This style of ignition wire is cheap to manufacture and generally provides good suppression for both RFI (radio frequency interference) and EMI (electromagnetic interference). Conductor usually consists of a substrate of fiberglass and/or Kevlar over which high-resistance conductive latex or silicone is coated, and functions by reducing spark current (by resistance) to provide suppression — a job it does well while the conductor lasts. Vehicle manufacturers treat ignition wires as service items to be replaced regularly, and limited life is never an issue. This type of conductor quickly fails (burns out) if a high-powered aftermarket ignition system is used.

EMI (electromagnetic interference)

EMI from spark plug wires can cause erroneous signals to be sent to engine management systems and other on-board electronic devices used on both racing and production vehicles in the same manner as RFI (radio frequency interference) can cause unwanted signals to be heard on a radio receiver. Engine running problems ranging from intermittent misses to a dramatic loss of power can result when engine management computers receive signals from sensors that have been altered by EMI emitted from spark plug wires. This problem is most noticeable on modern production vehicles used for commuting where virtually every function of the vehicle's drive train is managed by a computer. For many reasons, the effect of EMI on engine management computers is never predicable, and problems do become worse on production vehicles as sensors, connectors and wiring deteriorate and corrosion occurs. The problem is often exacerbated by replacing the original ignition system with a high-output system.

SOLID CORE CONDUCTOR WIRES

Solid metal (copper, tin-plated copper and/or stainless steel) conductor wires are still used in racing on carbureted engines, but can cause all sorts of running problems if used on vehicles with electronic ignition, fuel injection and engine management systems, particularly if vehicle is driven on the street — and damage to some original equipment and modern aftermarket electronic ignition and engine management systems can occur. Solid metal conductor wires cannot be suppressed to overcome EMI or RFI without the addition of current-reducing resistors at both ends of wires.

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Re:Timing adjustment 3 years 1 month ago #114922

I thought I would get the latest and greatest Ingitor II because it features adaptive dwell (hope that wasn't a mistake), but you can't use solid core wires with the II. I talked to pertronix, and they assured me their MAG suppression wires would work with the barb/bayonnet style distributor cap, so I went with the II and MAG wires. I bought cut to length MAG wires, installed, and filled under the cap lid with dielectric grease as you mentioned. After my second post I re-checked the timing with better isolation of the timing light pickup on the #1 wire, away from the other spark plub wires, and got nice steady readings, adjusted to 8 degrees BDC. It runs fine in the water barrel. I'll adjust the timing at wide open throttle on the lake as you suggest when I get a chance.

So I think I am good with the ignition system at this point. The question will be the durability of the MAG wires compared to solid core, as you indicate. If there is a long term problem, I'll have to move back to an Ignitor 1 and solid core wires. Here is a nice description of the available types of spark plug wires that I found very helpful: www.auroraelectronics.com/Understanding%20Spark%20Plug%20Wires.htm It indicates that the carbon core suppression wires aren't very durable, as you mention. It doesn't really comment on durability of the newer MAG type suppression wires such as the Pertronix Flame Thrower wires that I installed. I guess time will tell.

Perhaps I am the first guinea pig to try the Ignitor II and non-solid core wires on a Bearcat? I don't know how long the II has been available. Anyone else out there running this setup?

It still idols a bit fast at 900 rpm, but I need to rebuild the carbs and hopefully that and carb adjustment will yield a slower idol.

Thanks for your info and insight. Jon

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___________________
1970 Boston Whaler Sakonnet w/ Bearcat 55
1960 Chris Craft Continental w/ 283 ci V8

Re:Timing adjustment 3 years 1 month ago #115001

Many things on these old engines come down to trial and error :)

900 RPM idle sounds good, the manual states 1000 idle rpm, but I like the slightly slower speed, it's easier on the transmission going into and out of gear.

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