Siromer 304 (Y385T engine) Glow Plug Relay Install

[aesmith]

Here's how I installed a high current feed for the glow plugs on my Siromer 304 (brand sold in the UK, the model is pretty much the same as a Jimna 254 of the same era). I decided to add this as a new post rather than add only my previous thread which started off about decompresser then got a bit side tracked.

This is the relay I used 12V 70A Relay + Base/Holder. Installs nicely at the top and back of the existing fuse and relay board to the rear right of the engine compartment. Conveniently there's a stud which serves both to mount the base and as ground for the coil. Feed to the coil is the green wire that used to go to the glow plug bus bar.

Hot feed wire can be routed inside the existing conduit then exits near the starter. It's the red wire with translucent wrap and yellow crimp...

Other side of the relay heads to the glow plugs (need to get some more of that spiral wrap and tidy the other wiring a little.

And it works! It's above zero C today but the tractor hasn't run for a weeks so starting after only 10 seconds of heat, and not needing a lot of cranking is a definite sign of improvement.

Have to see how it goes in real cold weather. Apart from tidying some of the wiring, I'd also quite like to fit a tell-tale light on the dash, fed from the glow plug bus bar so it shows the plugs actually energised.

 

[coolreinfarm]

So the wire that goes from the starter to the relay is it fused in anyway? I did something similar going from the positive battery post to a 80 amp resettable breaker then to the relay, just in case a glow plug shorted to ground to prevent a fire. I have the 254 Jimna tractor and the 30a preheat fuse is the only protection, my fuse melted so I put in a external fuse.

 

[aesmith]

That's a good point, when I started fitting it out I was set on a fuse right down at the starter protecting everything. However I wasn't able to find a suitable inline fuse holder or work out a sensible place to mount a normal one. So I've ended up mounting a single maxi-blade fuse holder right next to the relay.

 

[mmprestine]

did the same thing, only down side is you cannot tell how hot the glow plugs are getting. the analog gauge was nice for that as the current would decrease as the resistance would change. A simple volt comparator with some op-amps to an led on the front panel would be perfect. would be better to shut the relay off after getting to the specified heat level.

 

[quicksandfarmer]

Thanks for the write-up. This is on my to-do list. Obviously the skinny green wire isn't appropriate for 30 amps. I don't think the switch contacts will stand up to the full current in the long run either. I'm going to try pulling the current from the ammeter feed because I do find it handy to have the meter tell me when the plugs have warmed up. I'll see if that circuit is beefy enough. If not I suppose I could install a voltmeter too.