Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Different spark plugs on the same engine problems

Different spark plugs on the same engine problems

Different spark plugs on the same engine problems

Greetings,I need to know what problems can cause the use of different spark plugs on a same Gas Engine. Eg. I have seen the use of Champion RM77N and Champion D14N at the same time on a Waukesha L7042GSI with Altronic III ignition system. I would like to know the consequences of this practice for the ignition system parts and for the cylinder/cylinder head as well...

RE: Different spark plugs on the same engine problems

Ask the engine manufacturer. No one here can answer that without knowing the exact details of the spark plugs and the engine. In general, engine performance, knock sensitivity, and/or spark plug life will be unpredictably and probably negatively impacted if spark plugs other than those recommended by the manufacturer are used. If different plugs are recommended interchangeably, then it is probably fine.

"Schiefgehen will, was schiefgehen kann" - das Murphygesetz

RE: Different spark plugs on the same engine problems

I would think that a decent IC engineering book would discuss this. There's basically gap and position in the cylinder. Unless, the plugs are intended as direct replacements, there will be differences in ignition profile that's different than what the designer intended.

FAQ731-376: Eng-Tips.com Forum Policies

Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers

RE: Different spark plugs on the same engine problems

Thread diameter and reach are the same. The hex diameter is a bit different (it will need a different socket to install/remove). The RM... is a resistor plug, the other one is not (affects electromagnetic interference of nearby electronic equipment).

Only explanation I have is that someone screwed up (or ran out of stock of one and had some of the other on hand). There's no rational explanation that I have for intentionally using different spark plugs in different cylinders of the same engine.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close