656 farmall diesel hard to start

okay I"m looking for advise.
I have a 656 diesel head was redone about 30 hours ago and it was drinking oil. so I rebuilt the engine. new sleeves, pistons, new glow plugs(has the pencil style)new wiring harness, new glow plug switch, new fuel filters. This thing is almost impossible to start even with the last few days in the mid 60"s.I understand these are hard starting engines but this seems terrible. will it get better once i have the engine broke in good? i only have about 3 hours on it mostly just driving up and down the road or idling. haven"t worked it yet. I would appreciate any insight as i don"t think you should have to run 2 brand new batteries down to start it when it"s 65 degrees.also after it"s ran for 10 minutes or so you can shut it down and it will restart great but let it sit about 3 hours and it"s hard to start again.

Just some ideas for you to ponder.

Are you real sure you have that pump timing correct? ONE degree makes all the difference in starting these old pups. Try advancing it ever so slightly.

Does it have a sediment bowl with a plugged screen?

Is the old sis leaking air into the fuel system (this is what it sounds like)?

Are you atually gettin' juice to those glow plugs?

Allan

Are you sure the glow plug is working? You can install a coolant heater on the engine to preheat the engine. That will save your batteries too. Hal

doesn't have a sediment bulb.
getting juice to glow plugs yes.
I didn't mess with the injector timing but which way would i move it to advance it?
not sure what you mean by old sis leaking air into fuel system? how would i check for that as I have thought the same thing that it might be sucking some air?

thanks Ray

bought a heater just like that yesterday. putting it in this afternoon.

How long are you holding the glow plugs? 60 seconds min up to 90 when extremely cold. Since it will start great after it is warmed up I would lean towards it not having fuel, small air leak or glow plugs not heating up. Is the gage working? Before starting it bleed off the fuel filters again to make sure there is not any air. Just a thought.

What did you do to the head when you had it apart? If you had the valves and seats resurfaced without doing anything else you just made any starting problems worse. Those engines are very sensitive to valve recession in the head. The closer you keep the valve heads to .003" recession the better they will start. In most cases when an overhaul is done the seats need to be replaced in the head. By replacing the original valve seats with thicker ones you can often get the correct recession and still use the original valves.

the head was redone prior to me but when i had it apart you could tell they put in new seats

Like Owen has said about the valves and also cranking pressure on the injection pump may be low the injectors may not be cracking or breaking at the proper pressure , injection pump timing may be off . Heck even the new glow plugs may be bad . Just went thru this on a New Holland 665 skid steer . When pre heating you may find that ya need to run the glow plugs for over a min. to get it to start. I can not remember the exact glow plug run time as there was a prescribed time for what the outside temp was .

It's been a million and seventeen years since I did this so am admittedly going by memory. Hope I remember it right.......

Scribe a horizontal line across the pump boss and mounting flange. Loosen the pump and pull the top of the pump 'out' until the pump boss moves the width of that scribe mark.

Makes an absolute world of difference in cold starting. If the engine flares at wide open throttle, you'll want to retard it again next summer when you go to pulling it hard.

As for the air thing, check all the lines for a flare crack under the nut and any fuel hoses for cracks as well. If there is air getting into that system, it is coming from somewhere. Gaskets and seals good on the filter caps/bolts?

Allan

how do you check the cranking pressure on the pump?

On a test stand , at a injection shop . Also just wondering if your starter is cranking as fast as it should . If it is dragging a bit it maybe not turning fast enough . Are your battery's the correct cold cranking amp's are your cables the correct size to carry the amp load ??

I bought a 656 Hydro International (the low profile style) last year and had a devil of a time getting it started until I got an owners manual. This is gonna sound strange, but the IH owners manual says to set the throttle lever at 1/2 to 3/4 open, hold the glow plug button for 1 minute and then start. It works perfectly every time on mine. I just can't get used to starting an engine at 1/2 to 3/4 throttle. I just cringe every time I do that and set it back to idle as quickly as possible. A friend & neighbor who has run 560's (same engine) since the day they were new tractors says that is what he was told to do by the dealer back in the 60's. I do always try to turn the engine over a little bit with the fuel shut-off closed just to get some oil circulating in the engine before starting.

Still having trouble starting the 460 after valve job,injector work,pump work,replacing some glow plugs and both harness,and el fuel pump,i reworked the starter,2 new large battrys whith huge cables,and a block heater! Use the block heater at least 1 hour,use the glow plugs at least i min,turn over a few seconds with the engine stop out/off and it will start and clean up almost immediatley!! Runs like a Railroad Watch after warm but Still A nnalert Poor Starting Engine!!!!!! Most farmers around agree,the 460-560 diesels were the best thing that ever happned to JD!!! Honnest Bud.

I agree with allan, I have had 560's and 706's and every kind of glow plug IH engine made. Twist the pump which is advancing the timing a little bit and your starting problems are over. I very seldom had to use the glow plugs after learning this trick from an old IH mechanic. Unless your pump is getting weak, this will surely help if not solve the problem all together.

I'm not saying that it is your problem, but I'll tell you a little story about Injector pump timing that will make a few guys in the know nod their head.

I have an 806 diesel. I've had it for 5 years and it was always a bear to start at anything below 60 degrees. When I got the tractor, I had to have the roosa master pump rebuilt due to the plastic governor ring inside going bad. A friend with a pump shop did it for me. He told me, "It's all new inside, with all the updated parts available." Well, I timed it as it should be for a d-361, and all was well except having to have ether handy below 60 degrees (or 3 hours of block heater.) Well, fast forward 4 years, and questions on here and to friends more knowledgeable than me. Some said to check your pump timing, it'll make all the difference. I figured, I knew it was right, I did it. And I checked it on a few occasions. Well, I was looking through my service manuals one day (I have the 361 and 407 diesels service manual) and it said that there are different timing specs for d-361 and d-407 diesels, and if d-407 pumps are used on d-361's, to set them at d-407 timing (about 2 degrees advanced IIRC.) Well, I thought, My pump has "All the updated parts", which may include a d-407 advance mechanism, so let's try timing to the d-407 spec. I didn't notice anything different at first, it was summertime. When fall and winter hit, what a difference! It starts much better in the cooler weather (I still plug it in if I know I need it below 45 degrees or so, to plow snow, etc.)

Moral of the story: That 2 degrees made a heck of a difference for starting when I finally figured out that it was the problem. -Andy

Try using a diesel pulse timer for pinpoint setting on the timing, it looks at the fuel pulse to #1 cyl, twist the injection pump as required. Also you said some wiring was done, did you keep the original glow plug harness set up. It should split between the 6 cyls, if you ran it from one end or the other the glow plugs will not heat even. ie if #6 is first in line of the daisy chain it would get the most amps and be hottest and 5 thru 1 would be progressively cooler or not heat up at all in the prescribed 1 min.

I really appreciate all the tips. I"m gonna try some of them this afternoon.
looks like I"ll be re wiring the glow plugs. the harness was missing and with out thinking i wired then in succession so today i"ll go back and split it in the middle like the original would have been. then I"ll slightly advance the timing and hope for some improvements. i hate the thought of ethering a brand new engine.

A timing light that depends on the pulse in the injection line will not work for a 656 because that type of light signals the beginning of injection. The 656 is timed at the end of injection.

Old Mack semi tractors have an AC cord hanging out of the grill for good reason. Some diesels just start hard when cold. Like a woman you got to warm her up for her to love you.