ih td340 crawler with 166 diesel engine glow plug.problem

[farmall help]

We have a Ih TD340 with a 166 diesel engine. We put new
glow.plugs in and only pushed switch for few.seconds and it
mushroomed the glow plug tips. Does this circuit need.a
resistor before the glow plugs? How are the glow plugs
supposed.to be wired.or.hooked up? Got as a project and
wont start without the glow plugs working properly. Any
ideas?
 

[pete 23]

No resistor on those engines and they are hooked in parallel. In other words, hooking one directly to a 12 volt battery would not hurt it. However, high voltage like having a booster charger on it will fry them in seconds. Never exceed normal regulated voltage which would be about 14.5 volts. Even that high is not good. What I do on all those style glow plug engines is keep them on while cranking and after starting but do not let go of them and then reapply. The original generators did not have enough output to raise voltage to regulated voltage while holding glow plugs but once you let go then the voltage will rise. With an alternator you could very well reach regulated voltage even with glow plugs on. So, if you have correct plugs, only high voltage would blow them.
 

[farmall help]

Thankyou pete. The booster may have done it.
 

[farmall help]

Thankyou pete. The booster may have done it.
 

[mkirsch]

You sure you got the correct plugs?

AFAIK some are series, some are parallel.

If you got the series plugs, they'd go *PIFF* if you hooked them directly to 12V.