Coil question
08-12-2019 | 09:15 PM
#11
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Joined: Jul 2011
Posts: 9,594
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From: Ft. Worth TX
6.2 EFI as mentioned used T bolt ignition on many Merc engines. And for the record the OIL filled coil is not oil filled anymore. I have had issues with the current coil. I went back to an oil filled coil that I sourced out and have not looked back. This also includes the HP 500 carb engine T bolt ignition coil... Giving the heads up about this one..
MerCruiser MX 6.2L MPI Bravo Distributor & Ignition Components Parts
MerCruiser MX 6.2L MPI Bravo Distributor & Ignition Components Parts
Last edited by BUP; 08-12-2019 at 10:09 PM.
08-12-2019 | 09:40 PM
#12
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Joined: Jul 2011
Posts: 9,594
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From: Ft. Worth TX
The TBIV and V ignitions (most carb engines) use a coil that , if I remember correctly, has .6ohm resistance. If you use a coil with different resistance you run a chance at frying the Thunderbolt timing module/amplifier. The OE coil does not use a resistor to step down the voltage. Just the old points type did.
98% of the computer controlled Merc engines used the ACDelco EST coil. Only a few used the Thunderbolt style. These will fire a SC engine with 7pounds boost and 5k+ rpms. It. also, is plenty fine for most marine engines that use this style coil.
The Thunderbolt V differentiates itself from the IV by using a knock sensor and a timing strategy (Mean Best Timing) in the module, vs a fixed 'curve' in the IV's module. Yes, a few V's did not use a knock sensor.
98% of the computer controlled Merc engines used the ACDelco EST coil. Only a few used the Thunderbolt style. These will fire a SC engine with 7pounds boost and 5k+ rpms. It. also, is plenty fine for most marine engines that use this style coil.
The Thunderbolt V differentiates itself from the IV by using a knock sensor and a timing strategy (Mean Best Timing) in the module, vs a fixed 'curve' in the IV's module. Yes, a few V's did not use a knock sensor.
. T bolt V used the added ICM. Also It had knock sensors --- even for carb engines, the T bolt V -- 5.7 350 CID had a knock sensor . T bolt V had MBT and ASA and ISSC and REV limiter -- some called it Over Speed control as well..
. T bolt 4 was in carb engines and T bolt V was in both carb and EFI engines.
Last edited by BUP; 08-12-2019 at 10:21 PM.
08-13-2019 | 04:31 AM
#13
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Joined: Dec 2013
Posts: 527
Likes: 52
From: Greenfield, Me.
Interesting...
Pertronix does sell a .6 ohm coil.
I was initially concerned about the engines poor starting (it just kind of started by catching on a couple of cylinders then everything would start firing) but after my wife caught glimpse of the giant spark arching across the high output and the primary negative, I knew what part of the problem was. Of course not before I had to do the float of shame from the dock to the trailer because it decided it had had enough.
Pertronix does sell a .6 ohm coil.
I was initially concerned about the engines poor starting (it just kind of started by catching on a couple of cylinders then everything would start firing) but after my wife caught glimpse of the giant spark arching across the high output and the primary negative, I knew what part of the problem was. Of course not before I had to do the float of shame from the dock to the trailer because it decided it had had enough.
There's a good chance ya need a coil wire, or cap, 'n rotor, or plug wires, or spark plugs, as there's extra resistance down stream of the coil which caused the problem in the 1st place,....
You'll also need the new coil, as once it does what it's doin', it'll continue after you fix the initial problem,....
08-13-2019 | 01:35 PM
#15
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Joined: Jul 2012
Posts: 206
Likes: 22
From: Fort Worth TX
6.2 EFI as mentioned used T bolt ignition on many Merc engines. And for the record the OIL filled coil is not oil filled anymore. I have had issues with the current coil. I went back to an oil filled coil that I sourced out and have not looked back. This also includes the HP 500 carb engine T bolt ignition coil... Giving the heads up about this one..
MerCruiser MX 6.2L MPI Bravo Distributor & Ignition Components Parts
MerCruiser MX 6.2L MPI Bravo Distributor & Ignition Components Parts
What is wrong with the new style coil? I just bought a new OE 300-8M0079202 one to replace the 20 year old on my HP500, now I'm questioning that decision.
08-13-2019 | 08:19 PM
#16
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Joined: Jul 2011
Posts: 9,594
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From: Ft. Worth TX
Shake the coil and see if you have the oil in it ? they went to an epoxy fill no more oil. engine miss fires after it gets hot. Keep in mind I quit buying them since last year and went to a sourced out oil filled coil. The quality oil filled coils lasted a long time. You have that proof as well 20 years correct . Only mount oil filled coils perfectly vertical
08-13-2019 | 08:21 PM
#17
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Joined: Jul 2011
Posts: 9,594
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From: Ft. Worth TX
Test it and see --- Who knows you might have a good one or the issues were taken care of by now with the coils. I do not care I went and sourced my own instead of the average quality China sourced ones. The box will say China on it correct ??
With all that said even a broken clock WORKS GREAT TWICE A DAY.
With all that said even a broken clock WORKS GREAT TWICE A DAY.
Last edited by BUP; 08-13-2019 at 08:25 PM.
08-13-2019 | 11:52 PM
#18
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Joined: Nov 2004
Posts: 14,105
Likes: 3,692
From: On A Dirt Floor
Andover Coils by any chance ?
edit in: according to their Facebook page they went out of business several years ago and building torndown. Supposedly bought by Engineered Performance Ignition Co. but I see nothing on that. Bummer. Andover was where a lot of the good coils came from.
edit in: according to their Facebook page they went out of business several years ago and building torndown. Supposedly bought by Engineered Performance Ignition Co. but I see nothing on that. Bummer. Andover was where a lot of the good coils came from.
Last edited by SB; 08-14-2019 at 12:10 AM.
