Looking for Fuel Leak into Oil

[chessie4905]

Don't assume more than one is loose. Probably just that one. I'd recheck after fixing that one, and if no more leaks, leave the rest alone.

[Fred Mc]

I have 4 that I think are leaking so I will do the first one and if it corrects the problem on that one I will then tackle the other 3.

Regards

Fred

[chessie4905]

Wow, if you have that many leaking, the set must have not been rebuilt properly in the past. Better do them all then. Course, you could upgrade one injector size for more power.

[Fred Mc]

Dunno. Ive had the bus for 30 years and haven't done anything to it.
What are the downsides to increasing injector size? Dioes it involve any other adjustments.Timing etc.?

Fred

[Geoff]

Geoff back--. The reason you have N60's is because your engine came with standard timing in the gear train.  If you put N65's your engine will start smoking under load.  You need to advance the timing for bigger injectors, and that is a big job.  Just try to tighten up one injector body and if that doesn't stop the leak then get a rebuilt set of injectors.  You can change them without removing the rack, you just have to wiggle them out and back in.  Then you can have everything adjusted when you find a 2-stroke Detroit mechanic.

[Fred Mc]

Thanks Geoff. Thats what I figured.

[chessie4905]

Just need to use an injector with the advance timing built in to it. 7c65 or something like that. This was discussed some time back.If you've been happy with it for that long, then just fix what you have.

[luvrbus]

You can upgrade to 7G65 injectors without A timing on a 8v71 I do it all the time and people love it.Talk to Don and have him build a set of low calibration 7G65, the atomization is so much better than the N series and spray pattern is better so you get more HP from the cleaner burn it dosen't add much of any heat increase or smoke from the higher HP .He can use the 7E65 also without A timing,but I prefer the 7G65   

[Geoff]

I talked to my injector rebuilder and he said 7G65 injectors won't work without updating the cams.  I know the later 8V71's used the newer injectors but they also used the smog cams with different timing built in.  So I don't know what to say other than the old school of thought.

Geoff

[luvrbus]

I don't know what to tell you but I have a engineering bulletin that say different Don Fairchild and my self have been doing it for years I just done Tom's old dry block 8v71 and he is very happy,then TomC has 7G85's in his 8v71 non A timed turbo engine but Fred can use what he likes if he wants to stay with the C-60's it ok by me   

[Geoff]

Cliff-- you are braver than me.  I might try it on a new style block but not a dry block.  I didn't think there were even any dry blocks left!  They crack at the lower bore from heat, while the new style blocks have coolant around the lower bore. (This is not news to Cliff, but for the other people on this board).

[luvrbus]

That is what he wanted Geoff so I did it his is defiantly a old dry block 8v71 lol I see quite a few of those blocks still running in 4106 GM buses.I had to remove a set of 7G65's a bus guy installed in place of N65's on A timed engine it was a dog with the 7G65's 

[Geoff]

CA  EPA used to put 7G75's in the 277HP 6V92TA transit engines, for what it's worth.

[Fred Mc]

Sio I remnoved the first injecotr and tested it on the bench for leaks and it definetely leaks around the o-ring. Tommorrow I will get the proper socket and re-torque it. Is replacing the o-ring doable or will all the parts fly all over the place if I remove it to replace the o-ring? The cam follower shows little wear.

[Taibob]

Fred,
I had these people install my Jakes. 8N70S injectors (aug.2011)
24V Jake Soleniods,Buffer switch , Run rack and tune up.
Very good mechanic and high on details.
Cost at time OK. Would use again if needed. No problems to date.

Gary Woods Pres.
K.N.W. Diesel Inc.
Unit C-1 19325 94 Ave
Surrey BC  604-888-3440