Injector timing

[lostagain]

I am doing a tune up on my 6V92 TA.

Took a couple of hours taking half the bus apart to get at the valve covers: removed the exhaust pipe from the right manifold to the turbo, the power steering filler tube, the air intake pipe from turbo to blower, including the horn that fits on top of the blower... etc, etc.

Done the exhaust valves to .016" cold, they were a little loose.

Now the injector heights. My book (Oct '88) is showing 1.464", 1.47", 1.475", dipending where you look.

My injectors are 9B90.

Elsewhere in the manual, it says to adjust all turbo charged engines to 1.484".

The no.1 injector is at about 1.7" before adjustment.

What do you guys think? Maybe the mechanics on the board could give me some guidance.

JC

[lostagain]

Correction: the no. 1 inj. is at about 1.47", not 1.7".

JC

[luvrbus]

JC, 1.470 is a good setting but we need to know what turbo you have on that engine with the A/R numbers   

good luck

[lostagain]

Where is the A/R no. stamped on the turbo? My turbo is hard to look at cause it is burried in things like air cleaner, muffler, and intake and exhaust tubing. I'll need the trouble light and a mirror to find it. It would help if I knew where to look. Thanks.

JC

[Don Fairchild]

JC, Give us the serial number from the engine so I can see what camshafts are in the engine.

My first thought is to change the injectors to 9A90 they are a better injector. The b and c injectors are very heavily retarded inside the injector it's self and they use an 8-0068 tip the A's use a 9-0062 tip they flow at a higher pop pressure and give you a better atomization and a better burn. I would set them at 1.460 If we know what turbo you have we can possably suggest a tighter hot housing for better boost.

I any event If you decide to stay with what you have I would set them at 1.460.


Hope that helps

Don

[lostagain]

Thanks Don, I'm in for lunch after setting my inj. to 1.47"... I could change them to 1.46" this afternoon. I think I have a 1.46" gauge if I remember. I am getting good and fast at this with all this practice, LOL.

I'll go and write down the engine no. in a few minutes.

I still can't find the A/R no. on the turbo. Should I look on the turbine or on the compressor?

Thanks for the suggestion on the 9A90 inj. I'll save that info for next winter's project. I bet, along with a more suited turbo, it wouldn't smoke as much when I put my foot into it.

JC

[lostagain]

Engine no.: 6RF 102452
                8060-7061

While I'm in there, can I set the Jakes a little tighter than specs? (.059").

The piping between turbo and blower has a film of oil inside it. Normal? or not?

JC

[luvrbus]

The A/R for the cold side is stamped on the housing the one for the hot side is inside where it bolts to the exguast .
Most of those 6v92 had a TV7511 turbo with A/R on the cold side of  .75 forgot what the hot side was but will check it out for you and they would boost up to around 25 lbs. with 9A90 injectors when you get ready for a set if Don doesn't have a set I do also have a set of 9G90's  and 9G85's
Check on the center of the turbo you should have a tag and check the valve covers for numbers.
I still like 1.470 for that injector Don.
Better stick with the 0.59 till Don finds out what valves and cams that engine has I have a friend someone told him they read here that 0.55 was better setting on the Jake for a 6v92 he blew his engine in his driveway testing the Jake



good luck

[lostagain]

OK, went for another look. Took the air filter and piping off. I see that the bottom number for the engine is 8060-706L, not 7061 as stated a couple posts above.

Also, I found .95 stamped inside the cold (compressor) housing outlet, near where the pipe to the blower clamps on. Could that be the A/R no.?

What do you think of the oil film inside the cold compressor housing? The wheel has 1/16 to 1/8th play side to side, but spins nice and smooth.

There is some oily gunk on the center of the turbo. I will clean it up to look for a tag.

There are no tags on the valve covers.

JC

[lostagain]

Can't find a tag on the turbo. The A/R no. appears to be .95, if the stamp inside the cold housing is the A/R no. I wiggled the wheel again and the play is really only about a 16th, so I think it is alright.

I left the inj. at 1.47" for now, untill we decide what to do with the turbo, and we'll see what Don says about the camshafts.

JC

[lostagain]

Well, after speaking with Mark at Alberta Engine in Calgary, who have been supplying me with parts and advice for several years, and has been very good and sympathetic (and patient) to a shade tree mechanic like myself, I buttoned up my engine yesterday. I would highly recommend Alberta Engine, (I am just a satisfied customer), to anyone in Southern Alberta. They deal in heavy duty diesels such as Detroits, Cummins, Cats, etc., and are very know-ledgable and helpfull.

He thought that my 9B90 inj. were not the latest and greatest, and that a A or a G would be better, but if the engine has been running good with them, keep them until next tune up.

He thought that 1.470" inj. height was probably good too.

I measured the Jakes specs. and they were at .059", so I left them there.

We talked about the turbo passing some oil. It is not very much. None on the wheel, just inside the pipe to the blower. It may be from idling when I parked it, or from when the air filter was restricted before I fixed it, who knows. I will monitor the situation and fix it when it gets worse. BTW the A/R no. seems to be .95.

Ran the rack too. I'll double check the idle speed and the max no load speed next time I start it, whenever it warms up and I can have the shop door open for a while... Although I remember them being 600 and 2150 rpm.

So that makes me feel good. I learned a lot about my new bus. That's what it is getting for Christmas!

JC