Fuel Injection Pump Timing Question

[Tinkerer]

The engine is a Case 301B. I recently had the injection pump rebuilt.Before I removed it I used a cold chisel to mark the precise position of the pump on the engine. I replaced it today in the exact position it was in. The factory timing marks are in the proper position for the injection pump crankshaft. I then set #1 cylinder at 0 degrees top dead center. Next I reinstalled the drive gear on the injection pump. I was very careful to not disturb any of the alignment marks.
I started the engine and bled out all of the injector lines at the injectors. It runs like a sick pig. Lots of white smoke,sounds like it is misfiring and a lot of noise in the exhaust similar to small explosions. I have the genuine case shop manual for it. It tells in great detail how to do the R&R. It also says to look on the valve cover for a sticker that has the correct degrees for the injection pump timing in relation to the engine crankshaft. There is no sticker to be found on a 30 year old machine. Is 0 degrees TDC to late for the timing ??

 

[CumminsTD]

Yes 0 deg is too late. I don't know what the correct number is for these machines but I do have some knowlege on other diesels. I'd guess that somewhere around 12-13 degress is more in the ball park. Although if your pump has the ability for some dynamic timing adjustment (advances with RPM) it may be a bit lower.

This is just for information, don't go setting your timing to my numbers, wait till you find the right number.

Mike

 

[thepumpguysc]

I TRIED TO TELL YOU>> to time it before you took it off..LOL
WE"LL figure it out.. Did you see the timing plate and timing mark on the front drive hub??
I'll check the specs and be intouch..

 

[Goose]

What machine is the engine in? I have a book that tells all of the machine and timing spec by machine model that I use when the sticker on the engine is gone.

 

[Tinkerer]

The machine is a Case 680C serial #9111325. Welcome aboard pumpguysc ! I know/I know ! I was toooo lazy to line up the pump timing marks and then checking the degrees on crankshaft damper before pulling the pump. I just didn't realize the degree setting for the crankshaft damper wasn't in my shop manual. It was bad judgment that the technical writer didn't include the degree setting in Step #19 . I am including a copy of one of the pages in my shop manual.

 

[Goose]

The static timing for a 680C is 31 degrees BTDC. Hope that gets you going.

 

[CumminsTD]

The static timing for a 680C is 31 degrees BTDC. Hope that gets you going.

Wow, 31 degress seams like alot (not questioning you or your book, just making an observation).

The 680 engines are essentially a B series Cummins engine aren't they? In the picture it looks like a piston type injection pump (Bosch P series?) To set the timing do you use dial indicator to set the pump plunger lift on #1 then set the engine to TDC and lock the gears or is there a different method for these?

 

[Goose]

The engine in a 680C was a 301 Case engine. They didnt start using the B series engines until the 680K series

 

[CumminsTD]

The engine in a 680C was a 301 Case engine. They didnt start using the B series engines until the 680K series

Cool! Thanks for the info.

 

[thepumpguysc]

CUMMINSTD, You are partially correct, its a Bosch "A" pump..{removable side cover}
Some[most] of these units DO NOT have timing marks on the drivehub and you use a SPECIAL LIFT GUAGE to "set the lift" [beginning of injection] on #1 cyl.
Thats why ITS SO IMPORTANT for anyone taking the "A" style pump off, to time it first..

 

[thepumpguysc]

Tinkerer, Is the drive gear on the pump "helical" or "straight" tooth??
If it helical, its going to "ROLL" when you put the pump in and the timing marks will no longer be lined up..
IF its straight, then you dont have much to worry about...
I guess the BIG QUESTION WAS what engine degrees its supposed to be at..

 

[Tinkerer]

Pumpguysc, The gear is a helical. I was pretty sure the timing marks were still lined up on the pump hub. BUT you have me thinking maybe the hub may have rolled with the gear. Goose says it should be 31 degrees. That, I think is why I am getting all the white smoke and loud popping sounds in the exhaust (unburned fuel). Today is Sunday so the old girl won't be getting any attention from me today.

 

[willie59]

Hi guys, following this with interest. :yup

Goose said the static timing was 31 degrees. Is that the crank at 31 degrees BTDC? If so, makes sense to me, because with the pump on it's marks, the helical gear would turn the pump shaft and put the shaft in a position to agree with the 31 deg crank position. Is that pretty much the way it works?

 

[Tinkerer]

ATCOEQUIP, Yes that is my take on it. I'll find out when I redo the timing. Before attempting to start the engine I will have all three of the timing marks dead on target. It has been an interesting situation for me. I have set the timing in many,many gas engines but never a diesel.

 

[Goose]

With the engine on 31 degrees BTDC installe the pumpwithe the marks line up. The line may be off a little from the helical gear and then rotate the pump on the bolts. You must have the lines lined up and the engine at 31 BTDC with the pump mounted.

 

[Tinkerer]

Thanks Goose, That is exactly what I will do.

 

[Tinkerer]

Today I reset the timing on the crankshaft to 31 degrees. Then pulled the drive gear on the fuel injection pump and reset the timing marks on it. The engine started up and runs better than I have ever seen it run.
To my dismay though I found that the engine compression is really low when I was turning it by hand. I knew I was getting a lot of blowby but didn't know if it were the valve guides or the piston rings. I left the valve cover off until I was sure the timing was correct . That also gave me the opportunity to see that the blowby is coming up out of the crankcase. It seems repairs never end.

 

[willie59]

Good to hear ya got her sorted out tinker. If she started up promptly, I woulnd't worry too much about the blowby, she'll probably run for many more years with a little wear on her innards. If you have to wake it up with a good dose of starting fluid, well, that's a different matter. Let's hope your Ok.

 

[Tinkerer]

Thanks ATCOEQUIP, Yes it does take a pretty good sniff of either to get it started. The motor does have 42 lbs of oil pressure when warm at idle speed. So that is a positive. I do have new valves,guides,seats,springs and retaining clips in a box in the garage. I will probably do the rebuild on the heads (it has two) this coming winter. I just don't know about the engine rebuild. I should do it then but it takes a lot of money for a rebuild kit plus any machine work the crankshaft may need. Any opinions on the total rebuild would be appreciated.

 

[willie59]

Sounds like the compression may be a little low Tinkerer, not unusual to need a little starting fluid. If it runs good once it gets going, and doesn't smoke like the woods are on fire, and doesn't drink oil excessively, wouldn't worry too much. Phil might have an idea of about how much it would take to rebuild that engine.