Perkins 2666108 Intake Heater

[StoneCrab]

My Perkins 4.108 has one of these intake heaters in the intake throat but it has never been put in service. My engine is a hard start, so I was considering a remote ether injection but then remembered that this heater was already in place.

I removed the heater to figure out how it worked. It is plumbed to the top of the fuel filter housing, so when the motor is turning over, it will get low pressure fuel flowing to the heater.

There are stab connectors for the 12 volt power and a heating coil built in but no evidence of a valve to control fuel flow. This seems like a fire risk to me... spraying fuel onto a hot coil. Also, once the engine starts, what turns this system off? or stops the flow of fuel through it?

Is the 12 volt supplied from the starting solenoid, or from a separate glow plug push button, so that it is only engaged at or prior to startup? Does providing power to this unit also control the fuel flow through it?

I'd like to know from someone who has this Perkins 2666108 intake heater how it works, how it is wired and plumbed in, and how well it works.

This link goes to an Amazon page listing the heater. https://www.amazon.com/2666108-Genui...07VC9NM34?th=1

[skipperpete]

That heater on the 4-108 intake is a masterpiece of ingenuity........the quantity of fuel was originally limited to the volume of a little tank fed by the fuel return line and when you operate the key switch heat function , a coil around a brass sleeve heats up and the sleeve expands. Inside the sleeve is a metal rod with a thread on one end and a flat on the other. The flat end of this little steel rod presses on a steel ball that sits on the fuel drilling and as the coil expands the outer sleeve the rod moves very slightly and allows the fuel to leak in and catch fire on the glowing wire coil. A forum member posted that his heater could be leaking and I cut one open to see if it could harm the engine or waste fuel if it leaked continuously into the intake unrequested........ it can.... but only if the little rod and ball is out of adjustment or the keyswitch fails in a way that keeps the coil hot. I took some pics of the dissected heater plug but since I moved to using the mobile version of the forum I need to relearn posting photos and links, it was easy on the app.

[skipperpete]

In answer to your original question ...... yes it works quite well but can billow smoke and flame into your engine room if you stop cranking while heating.

[StoneCrab]

How long should the heating coil be energized before cranking?

If I understand this, there is no fuel available to the heater until the starter is engaged. The rotation of the engine activates the lift pump supplying fuel pressure at the heater which only opens when the coil is hot enough....since the engine is cranking, the fuel and flame is drawn into the cylinders, providing a measure of safety.

If the engine doesn't start, I suppose fuel could still burn in the intake for a period of time.

Thanks for the answers. I'd love to see your pictures of the dissected heater.

[skipperpete]

The best way to get a feel for how long the preheat should take is to get an assistant to do the preheat while you observe the action at the intake manifold. There are several variations on how the preheat is activated and supplied, one version has a little dedicated tank with maybe 150ml , another has a tube directly to the return fitting on the CAV filter head. Some have a preheat position on the keyswitch , others have a button that allows cranking and heating simultaneously.
One thing is certain , if the little threaded adjustable pin that holds the ball on the seat is loose for any reason you will lose return line fuel into the intake. I’m still in the dark about how to post pics on the forum after the loss of my beloved CF app so you’ll have to google the Perkins pdf or images for the workings of the nifty but messy heater.

[GordMay]

Perkins air intake [flame] heater [2666108], also known as a grid or manifold heaters, are used to pre-heat the combustion air, to the required temperature, to aid cold starting. Used as an alternative to glow plugs, to provide quick starting in cold weather. Also, can be used to reduce white smoke [cold emissions], engine wear, and battery/fuel consumption during start-up
Turn ignition key ‘on’ [or ‘pre-heat’], for at least 15 seconds [watch for a puff of white smoke], prior to attempting a ‘start’ [cranking].
See #2666108 ➥ https://shop.perkins.com/parts/elect...nd-spark-plugs

See also:
“Perkins cold start aid wiring” ➥ https://www.cruisersforum.com/forums...ng-196958.html
And:
“Cold Start Heater on Perkins 4-108" ➥ https://www.cruisersforum.com/forums...08-a-7203.html