Loose Spark Plugs.

[Superjet3]

I have been having a problem with my spark plugs coming loose causing a hesitation. Does anyone have an Idea as to what might be causing this? I have tried several sets of plugs and multiple torque amounts.

 

[the only couch rider]

dumb thought but are the threads worn on the head? other than that i am at a loss.

 

[SuperJETT]

I have been having a problem with my spark plugs coming loose causing a hesitation. Does anyone have an Idea as to what might be causing this? I have tried several sets of plugs and multiple torque amounts.

Detonation creates high frequency vibration which can loosen plugs no matter how tight you get them.

I'd look at your overall state of tune, timing, compression, etc.

The next level will be the ceramic on the plugs cracking.

 

[Superjet3]

ADA Domes were new at the beginning of the season when I bought the rest of the parts for the motor.

 

[SuperJETT]

Here is what it can do.
http://www.x-h2o.com/threads/3189

 

[Superjet3]

Well, The motor is tuned perfect as far as air/fuel ratio. I think my compression might be a bit high though. My snap-on gauge said 225psi but I figured it was broken. No signs of detionation on the plugs. Maybe I will have Chuckie machine me a new set of domes.

 

[Watty]

The first thing I would do here is check the squish. Is your bore size noticeably different to your dome size? My deto sensors would be going off inside my head!!

Note your settings and then give it a bit more juice on the high speed's and see if ti makes any difference. Even using pyro sensors on my engine, I'll see big differences in temp from one day to the next, even if the water and air temp are only slightly different.

 

[bad93blaster]

did you ever figure out the problem? my plugs are doing the same domes are pretty new less than 3 hours on them

 

[njfl]

Paul,

I have a Snap On gauge if you want to swing by during the next couple of days. 225 does sound a little high if you aren't using race gas.


Paul and bad93blaster, First of all, determine if your plugs are loosening or are the domes loosening. This will tell you whether the problem is something with the thread/plug interface or the dome/sleeve interface (or dropping sleeve).

 

[bad93blaster]

the plugs are loosening can almost spin them out by hand after every race

 

[njfl]

the plugs are loosening can almost spin them out by hand after every race

And you have replaced them with new ones and they still come loose?

 

[bad93blaster]

And you have replaced them with new ones and they still come loose?

yes they been swapped out a couple of times. i could see a bad plug or a bad dome but it happens on both cylinders and it looks like paul has the same problem

 

[njfl]

yes they been swapped out a couple of times. i could see a bad plug or a bad dome but it happens on both cylinders and it looks like paul has the same problem

Call ADA and speak to Brooks about it to see if he has seen it before. I've had tons of ADA heads (well realistically five) and never seen such a thing.

 

[Superjet3]

I spoke with Chuck and he felt it is due to the high compression. I am gona have the domes cut back a bit to bring it down some.. Or loc-tite the plugs in.. She rips with the high compression!!! Also squish is perfect. I checked that right after building the motor.

 

[bad93blaster]

never thought about locktite on plugs
i might have a different problem if its compression as im at 175psi