Upgrading glow plugs

[srjones]

I have an older tractors where the manufacturer charges an *obscene* amount of money for the glow plug. And, unfortunatly, I haven't been able to find an after market match. So, here's my thought, find a more standard Bosch glow plug available at NAPA, and then get threaded reducer so that this smaller plug can fit in the larger hole.

Does anybody see any potential issues with doing that? If not, what type threaded reducer material would be appropriate for that part of the engine? Stainless steel? Brass?

I don't even want to think about the damage I'm doing to it every time I use starter fluid to get it going.

Thanks in advance,

-Steve

 

[markct]

well without knowing more details its hard to say, theres alot of different shapes of glow plugs, they usualy seal on a seat tho nearer the end, not on the threads. i recently had a problem finding glow plugs for an IH TD9 dozer and was almost ready to machine up a few adaptor sleeves for ford 7.3 glow plugs which use the same thread but a different length on the seat but luckly ebay came thru with a set of brand new ones for about what a set of 7.3 ones would cost

 

[AndyMA]

Steve

I don't see a problem with this as long as nothing protrudes farther than the original glow plugs into the cylinder. I would use stainless due to the high pressure and temp.

Andy

 

[srjones]

Thanks for the advice...here's a picture of the actual dead glow plug.

From what I can measure, it fits the metric thread of 1.5 and the housing fits closest into the 18 mm hole. As you can tell from the picture, it's about 70mm long with the exposed glowtube about 20 mm.

Does anybody know of online resources/catalogs that have exact dimensions of various plugs?

 

[CurlyDave]

I don't know what an obscene amount of money is, but i bet you are going to come pretty close to it by the time you buy a different glow plug and then get someone to make up the reducer for you.

I would avoid stainless -- instead try to match the material of the threaded portion of the glow plug itself. You already had a cast iron head, and a steel plug, adding a third material is just asking for trouble IMHO.

When you assemble this be sure to use a good high-temperature anti-sieze. You want to guarantee you can get it apart easily in case something goes wrong.

 

[PineRidge]

I agree with CurlyDave as I've seen to many problems with galling when using stainless on threaded connections. I would also use the original glow-plugs if they are still available. When you think about it, even if the initial cost is high, they really don't go bad that often to warrant changing the style.

 

[RobJ]

I don't see a problem either as long as it doesn't leak. But maybe time for a top end overhaul to avoid using the ether. The older the engine the harder it is on the engine IMO. You should never have to use ether.

Good Luck,
Rob

 

[normde2001]

Run your glowplug's part # by NAPA or Advance Autoparts and see what comes up.

 

[srjones]

$120 for a glowplug seems obscene to me and in the $5-15 range of replacement plugs, I'm sure I could figure something out for the other $100.

And at this point, it's a matter of principle.

Thanks everyone for the advice!

 

[schmism]

Stainless is VERY hard to machine.

Id stick with Brass or bronse reducers if you go that route