Injector Timing Pump Question

[greg_g]

</font><font color="blue" class="small">( Hey guys.. I saw the last post for the drip timming tool.. That may well be an answer but $80 for a 1 time use thing is a tough bullet to bite though )</font>
You misread. The $100 Harbor Freight injection system test kit is on sale right now for $80. Apparently you missed the link to the Harbor Freight online catalog. The drip timing device in the photo is a $25 Mercedes part.

My Jinma book specifies for the Y385
"Advance angle of supply fuel supply/speed (before TDC)
10 (+/-1) @ 3000 rpm
18 (+/-1) @ 2800 rpm
16 (+/-1) @ 2600 rpm
15 (+/-1) @ 2400 rpm"

That's RPMs, not static.

Consider that this Y385 motor is put in a number of tractors of varying horsepower. It's rated to put out from 19.2 KW (25.7 HP) to 24 KW (32.2 HP) between 2400 and 3000 RPM. To me, that equates to the three cylinder versions of the JM25x, the JM28x, the JM30x, and the JM35x.

So as you can see, the HP generated is pretty much dependant upon the governor setting; same engine - more RPMs, more HP. To determine which timing point is appropriate for your tractor, consider your governed RPMs. First place I'd look is for a red line on your tach.

Oh, and that the 3000 RPM timing number might be a misprint in the manual. Simple linear progression suggests that the timing mark should be 20 degrees BTDC, rather than the stated 10 degrees.

//greg//

 

[SevenCorners]

Greg,
I really like the drip concept. I assume it works something like this, attach to #1. Start engine, start stopwatch for 10 seconds, count drops, divide by 10. ****** or advance to get desired number timing point X.
Problems:
Since timing is a static RPM reading does the engine need to be running at recommended RPM to properly set timing?
How do we determine the X in the equation? Meaning is it .5 drops per second or 1 drop per second.

On a side note, I am thinking to heed Harry's advice to go ahead and change the thermostat. Does anyone know the crossreferrence numbers? Also what would happen if I removed the Thermostat? Would the engine just never obtain operating temp? Or would it overheat because all the thermal capacity or the cooling liquid is reduced?

 

[Harrygoodwrench]

The drip method I'm sure is with engine off. Just using the primer pump. At least thats how I did it on other type engines.
Without thermostat engine will never reach full operating temperture and will result in lower HP/performance. There are crossover #'s for thermostat, etc here.

http://www.capital.net/~disc1/Filter%20-%20Spare%20Parts.htm

 

[SevenCorners]

I just bookmarked the website. Good stuff! Thanks Harry

 

[bluechip]

I must be missing something here with this drip method...maybe someone can help me, but I cannot see how the number of drips will tell you when the injector pump is pumping, only how much it is pumping per revolution?
I would think you would somehow have to monitor crankshaft position.

If it is done with the engine positioned at the desired crankshaft position, how does the pump pump.

Keep in mind that the body of the pump is not rotated, the location of the timing gear is adjusted.

By the way, we had to replace the three washers on the bolts that hold the gear to the hub, those slots take a toll evertime they are tightened.

What we need is a way to trigger our timing lights on the pulse of the fuel through the hard line. Any of you electronic gurus got a way to do this? perhaps by microphone listening to the injector "fire"?

 

[Harrygoodwrench]

Bluechip, I must admit I've never had to time one of these Jinma's. I've done probobly a hundred or so other diesels, GM's, Mack, Cummins, Perkins, etc. Mack did years ago use the drip method. Crank was locked at a partucular degree and pump rotated until a specific # of drops were observed in 10 seconds or so from gooseneck pipe. But thats water under bridge.
If I understand what you are saying is,,,,,,the pump cannot be rotated from outside??????? The pump mounting holes are slotted and would allow it to be rotated from exterior. Maybe you're correct as I've stated I've never done a Jinma. Others do it that way though. Please explain as I would like to know.
I've used Kent Moore "Tach n Time" timing tool on GM diesels before and know they are pretty accurate. Here is a link with a diesel timing tool. Don't know much about the quality.

http://www.toolsource.com/ost/product.asp?sourceid=&dept%5Fid=500&pf%5Fid=58061&mscssid=7W4Q8C1E7GHA9PEGA97JUSRHFTNK1LN5

Whoops, /forums/images/graemlins/blush.gif had to edit this........that is a diesel tach for about 200 bucks. The Kent Moore Tach n time is about 900 bucks. Unless you had a shop and did many it is a pretty pricey investment.

 

[SevenCorners]

Guys,
I hate to ask but in process of getting new thermostat I failed to add new gasket, yep it's leaking.... Does anyone have cross numbers for all gaskets, I will just save it away for future use.

THanks

 

[Harrygoodwrench]

Seven corners, sorry about that but don't have a thermostat gasket part #. I'm sure if ya take housing to any big parts store you can find an equivilent. I've matched up misc gaskets like that many times. They usually have a rack of hundreds. You could try the silicone method or make your own but don't recommend it. Hey, when you do find one, post the gasket part # and from where for us guys if you don't mind.

 

[greg_g]

The drip method is definitely with the engine RUNNING. I only described the IP timing method for my Mercedes 5 cylinder turbo-diesel; once engine timing (BTDC) is confirmed correct, rotate injection pump with engine running till drip tool indicates a consistent 1 drop per second. The concept should be similar for the Y385, I just don't know if it's IDENTICAL.

Seven - cut your own thermostat gasket. Run down to the local NAPA and buy a roll of composite gasket material. That, a scissors, and a hole punch - and you're in business.

//greg//

 

[SevenCorners]

Well I got the new grade 8 washers, I would recommend to anyone doing the same repair skip the factory washers and buy new ones, at least grade 5.
I redid the whole procedure, starting with #1 @ TDC look for fuel to well..... Timing was as I expected off, It was advanced too far. Reset timing to specs Greg posted. Started it up, it was slightly retarded, bumped it up and wow runs like a champ!! I am totally amazed that I did this repair myself, well with your help, thanks to all that contributed to my post, Greg, Harry, and Chip special thanks..... could not have done it without you's....