After rebuild, how much time on a dyno ?

I have a similar question. When I finish my 70 Diesel, I intend to run it a bit, look for and repair leaks, fuss with it here and there, and listen to it run. Problem is, other than driving it around the pasture, or pulling an almost meaningless implement, the old girl will not ever see much of a load.

I thought it would be a good idea to take it to my dealer who has a dyno, and let it spend some time running under load.

Question is, how much time is enough ? And how long do you let it just run in on it's own in your driveway before committing it to the dyno ? While on the dyno, what do you look for ? I supppose the usual: steady oil pressure, no leaks, good exhaust, no odd smells, bad noises, etc.

I'd really value some input here.

Oh, and BTW, it's gonna be 80 degrees here on Sunday.....

Frank-in-Tallahassee
70D // 855

First of all shame you're not in VA. I'd invite you right over.

There is a correct way to break-in engines on a dyno. John Deere has a specific way for each tractor(even ones sold today, must be dynoed before delivery!!!) I do it the following way. Please use this as a guide and ask your JD dealer for there recommended way.

Basically what I do is divide the advertised HP by 4 and come up with a factor - lets use 20HP. Start engine and for first 15 minutes run at 1/4 load (20 HP). Remember set high idle speed at exact rpm before loading on dyno to get accurate govenor operation. Then after 15 minutes remove load let run at High idle no load, then increase load gradually until next 1/4 (40 HP). Continue this process for a total of one hour (e.g. 60 HP 3rd 1/4 and max/full load at 540 rpm should come out at 80 HP, hopefully! Maybe more!!).

As you run the tractor you will notice the engine will pick up RPM's Just remember keep your HP Settings - Factor consistant. Don't try to increase load until the appropriate time.

Biggest key is pay attention to the gaugesmake sure the engine radiator is clean and allowing full air flow. MOST IF NOT ALL BLOW UPS ON A DYNO COME FROM LACK OF AIR FLOW TO KEEP RADIATOR AND ENGINE WATER COOL.

Any questions e-mail me.....

Tony - JD 630

Tony

Now, Tony, How long can I just mess around with it before I need to be serious about getting it on the dyno. I mean, in engine hours, if I have it around the place, run it, drive it, check it all out, it might get a bit of time on it before I get to the dealer, and since they're 25 miles away, I wanted everything to be in good, dependable, and safe operating shape before I take off on a trek like that.

I know some folks say that if you sissy them around you can glaze them up, but I've never seen that happen, but I've always been able to put an engine I've rebuilt to work...even a garden tractor Kohler.

So, say this 70D is rated at 52 hp (I think that's a good guess). Then 1/4 of that is 13 hp. So 15 min @ 13hp, 15 @ 26, 15@ 39, and finish it up at 52, or whatever is can hit while maintaining rated speed, right ?

Thanks for the info. We had our 4020 dynoed once, but I didn't have a chance to watch the procedure.

Frank-in-Tallahassee
70D // 855

I asked the dealer if they had a dyno, and could I get an hour or so on it, and they said "Sure !".

The parts guys are all pretty young, and truth be known, I think they really do want to see an old one huffing on the dyno. You know, after they help you track down parts from all over, they feel a bit connected to it, too. One of them said, "Does that tractor have a PTO ? You need one for the dyno..."

I'll check with them and let you know. For now, I think Tony630 has me on the right track.

Frank-in-Tallahassee
70D // 855

I asked the dealer if they had a dyno, and could I get an hour or so on it, and they said "Sure !".

The parts guys are all pretty young, and truth be known, I think they really do want to see an old one huffing on the dyno. You know, after they help you track down parts from all over, they feel a bit connected to it, too. One of them said, "Does that tractor have a PTO ? You need one for the dyno..."

I'll check with them and let you know. For now, I think Tony630 has me on the right track.

Frank-in-Tallahassee
70D // 855

The guys at this shop are so new at it, I don't think they would have even considered that condition !

I really think that this will be the first two cylinder one that thay will have seen. Each time I worked my way through a major system, I took a few parts for show and tell. They were shocked at the size of the pony heads, then shocked more by the pistons and rods.

I'll let you know how it works out.

Frank