injector and compression question

[GeorgiaDave]

I'm slowly bring a mid-70's MF300 loader back to life. Motor is a Perkins AD4.203. I pulled the injectors, there are dust seals at the top, but no sealing washer in the bore - is this typical, or am I just not able to see the washer?

Also question about testing compression - since the injectors are not threaded, is there an adapter tool that I can use to measure compression?

Thanks!

 

[Dieseltech]

There SHOULD be a copper sealing washer to seal the compression, the upper rubber dust seal hopefully keeps dirt from packing the injector tight over time. As an OLD MF/PERKINS mechanic I've never seen that lower copper gasket missing on ANY Perkins engine. I have a few injector bodies that are modified for compression testing, hopefully it will have 350/450 PSI if in good shape. A GAS tester won't do the job.

 

[GeorgiaDave]

I have some old injectors here I'll modify, just curious is there was something off the shelf.

When I pulled the injectors, there was no crush washer in the bore, which I found very odd. I'm planning on adding them, just wanting to know if anyone else has seen this.

 

[Dieseltech]

I have some old injectors here I'll modify, just curious is there was something off the shelf.

When I pulled the injectors, there was no crush washer in the bore, which I found very odd. I'm planning on adding them, just wanting to know if anyone else has seen this.

You better LOOK AGAIN, scratch the surface with something sharp and see if it's copper. I use a long 7/16 NF bolt thread to remove old washers stuck in the head by pushing down on the bolt head while turning clockwise to thread the bolt into the copper washer. Never had a problem getting them out this way. The bolt won't thread into the cast head but will break the washer loose so it can be pulled out. USUALLY those washers stay on the injectors, but not always. If those washers are missing, I'm surprised the injectors were not carbon soot stuck tight in the head. Those gaskets are needed to prevent compression leaks past the injector.

 

[GeorgiaDave]

Those injectors were a nightmare to remove! Took me the better part of a day to coax them out. I'll try the bolt idea, but I did scratch the bottom of the bore with a screwdriver, and it definitely does not appear to be copper.

 

[Dieseltech]

Those injectors were a nightmare to remove! Took me the better part of a day to coax them out. I'll try the bolt idea, but I did scratch the bottom of the bore with a screwdriver, and it definitely does not appear to be copper.

No copper gaskets is just asking for trouble, and why they came out so hard. Makes me wonder what other short cuts Bubba did on that machine in the past.

 

[Powered By IH]

Those injectors were a nightmare to remove! Took me the better part of a day to coax them out. I'll try the bolt idea, but I did scratch the bottom of the bore with a screwdriver, and it definitely does not appear to be copper.

Make sure to clear out the injector bores too when re-assembling.