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270 spark plug question

T

TerryGerm

Member
Spark plug for 270?


A 1982 crusader 270 spark plug question. I have twin 270's one is a long block replacement not up and running yet. I ordered spark plug kits on line for a ridiculous price, but they said these are genuine crusader parts (RP030010). The plugs I received are acdelco 41-101 #12568387 iridium with a preset gap of .060. From what I have read is the plugs come preset so do not change the gap. Well, I put a set in my port engine which had been running somewhat ok. It fired right up and ran good, I let it run a half hour or so then shut it down and then restarted it several times. It started right up each time. I shut it down for about 45 minutes and tried to restart it, would not start. It would pop a little, maybe try to fire back into itself.


The ignition was converted in a yard a couple of years ago to electronic and had run okay but I think the wrong plugs have been in it since that time. The timing has not been fooled with (yet) so that should not be an issue. So I am wondering about the gap issue and not getting complete engine combustion when trying to start.


Any thoughts welcome.
Terry
 
You really don't need the iridium plugs in that engine...they would be happy with MR43Ts. Yes, they are preset and you don't want to mess with the gap.

Depending on what went into the conversion, I'd be a little leery about using a gap of 0.060"...I'd also verify the advance mechanism is free and working properly.Finally, make sure the cap and rotor are good and that each plug wire is functional and properly seated...
 
http://www.marineengine.com/boat-forum/showthread.php?415924-Correct-spark-plugs&p=461023#post461023

What happened to this post, my post? and another members post here? I asked why Champion spark plugs were recommended, only because I am a fan of Champion, & there are a lot of Champion naysayers out there!

Yes, I do like the AC MR43T plugs very much too, I have used them in my boats, & cars, they have a very beefy center electrode, plus they are alloy, and don't rust!

By the way, your original ignition system was not made for firing across a .060" gap, but I see you have upgraded to electronic ignition afterward, what type? Pertronics? But was the coil changed? If not, it still doesn't have the power to fire across an .060 gap! If you just install the AC MR43T plugs, and set them at the stock recommended 1982 ignition spark plug gap specs, I think you'll be Very Happy!
 
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When the ignition was converted a pertronix, Flame Thrower, ignitor II was installed which should do the job that is required. I was just concerned about these plugs which are provided as genuine Crusader parts and the .060 gap.

Thanks
 
What are the spark plug gap specs for the original spark plugs? Or, what was the original gap of the plugs you took out? If it was .035", to .045", in 1982, then you could set the new plugs at that, But, You Cannot Do That With Iridium Plugs, they are too brittle, and the electrode Will Break Off! Just get a version of the AC MR43T plugs,,, You must check though if you need the std. length or long thread version?
 
Terry hi, I have crusader 270hp as well. I was having trouble with my distributer and my mechanic in my yard replaced my distributer with a Pertronix Flame thrower distributer also. I do not like it. I can not find caps or rotor for this easily. Were can I get them ? Thaks Mike
 
Mike, just Google, sierra 18-5266 and you will find many suppliers, I had to call and talk with a sierra tech to find the correct one, I hope.

My old plugs were set at .035, Champion RV9YC, which I was told is not correct for this application. I looked at a AC MR43T today and it is a little shorter than the Champion, but both of those are about 3/8" shorter than the iridium which were marked genuine crusader parts. So I am still researching.

Terry
 
Maybe you need the MR43TS a longer thread version of the same plug. Spark plugs usually are either a 3/8" thread, or 3/4" thread. That's what I was trying to tell you, but got tired of typing.
 
Terry:

whoever sold you the iridium plugs made a mistake. the original crusader number (33311) now maps to champion's RV8C, which cross to MR-43T and BR6FS.

Whenever in doubt, it's best to check the spark plug maker's application data, especially for older engines...just my two cents.
 
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