Ed's 77 Terex 72-41

[mountainguyed67]

Everything looked like it went up and down. I turned the key, I didn’t have a wrench with enough leverage to turn it over by hand. And not a big enough cheater. Two cylinders had a little slack in the rockers, two were tight.

 

[Birken Vogt]

Two cylinders had slack in which rockers? The injectors are not supposed to have slack, they get preloaded.

 

[mountainguyed67]

I forget which ones.

 

[mountainguyed67]

Both rockers had about the same slack, on two cylinders.

 

[56wrench]

the centre rocker lever of each group of 3 is the injector. also check for cracked injector lines. they usually crack around the flair under the nut. usually caused by overtightening which may cause eventual failure. were you able to tell which cylinder is running cold?

 

[mountainguyed67]

I looked at the lines, but not thoroughly. And not by the flare. Wouldn’t a cracked injector line add diesel to the engine oil? There’s no evidence of that. The cylinder closest to the bell housing is the one running cold.

 

[mountainguyed67]

I had to block the steering tank up to get the valve cover out.

 

[mountainguyed67]

the centre rocker lever of each group of 3 is the injector.

I didn’t check the middle one. Next time up I’ll know more what to look for, and put more time on it.

 

[56wrench]

as far as leaking a lot of fuel into the crankcase, it would depend on how long you ran it after it started missing. also check for a bent injector push rod on the bad cylinder. i think i had that happen once in a 4-71 but that was 40+ yrs ago and my memory isn't as good as it used to be

 

[mountainguyed67]

If the push rod was bent enough to be a problem, wouldn’t it be obvious? They all looked even, to the eye anyway. I’m thinking I need to switch two injectors now. I haven’t looked that up in the manual yet. I should be able to go back up in a few days.

 

[56wrench]

they are such a short pushrod you have to look very closely

 

[mountainguyed67]

It looks the same as this.

 

[mountainguyed67]

Delo 100 is a CF-2 .

Also Rotella T1.

 

[mountainguyed67]

I haven’t looked. I assumed the nut would be captured in there, and so I didn’t look at it. Looking at it afterwards I think it’s an oversized square nut.

It was a standard 1/4-20 with 7/16” hex. I had two in my nuts and bolts collection.

 

[mountainguyed67]

Id think you will see the problem by popping off the valve cover. Ive had injectors stick before.

I really didn’t pay attention to the injectors, and ran out of time. I will look next time, and try to talk my son into going to help. Otherwise it’ll be tough to turn the engine over by hand, and look at what’s going on at the same time.

 

[mountainguyed67]

Someone said to switch two injectors to see if the problem goes with the injector or stays with the cylinder, good idea?

 

[56wrench]

Well, yours is not quite the same. Yours has a 4 valve head and the rigid levers on the rack control tube. The 6V71 in the video has 2 valve heads and the newer style spring-loaded rack control levers. The governor setting procedure may also be different depending on what governor yours has

 

[56wrench]

You could swap injectors but be aware that when you do that you will have to set the injector timing with the special timing pin and adjust the rack control levers on both the injectors you swapped

 

[kshansen]

You really need to come up with something to let you turn the engine over by hand so you can stop it while the two outer rockers on the cylinder in question are all the way down on the valve bridges. Then check to see that there is no gap under the rocker for the injector where the red arrow is pointing in the picture.

Also I would suggest removing the pin in the linkage where the yellow arrow is pointing, be very careful to not drop cotter or the pin it's holding in! Then work that tube by hand to see that all the rods coming out of the injectors that the levers work and coming in and out nice and free on all the injectors. Forget how much they move seems like it's about 1/2 to 3/4 in travel. Main thing is that tube that work the injectors works very free.

 

[mountainguyed67]