jd 730 diesel

[want2pull]

Ive done some messuring and it looks like i can put 830 valves in my 730 d . im taking it to the valve shop and was wondering if anybody has done this.thanks

 

[Drew]

Like I told you when you asked the same thing 2 weeks ago, unless you have done a lot of other things to the engine(work on intake ports/manifold, adding a couple hundred CI, etc), you are wasting the machine shop's time and your money to put huge valves in. If the valves arent the bottleneck in the intake airstream, bigger valves will do absolutly nothing.

 

[want2pull]

you might be right ,but ive got to have the head redone anyways, since im goin threw the tractor from front to back to restore it ,i might as well put the bigger valves in it while im having it worked on.it could come in usefull in the future

 

[want2pull]

Drew , im guessing you pull these tractors ,and im sure you know more about them then me.why is it that i can add lots more fuel to the tractor but i dont have the air to burn the fuel up .it just seems that bigger valves is the way to go.

 

[Mike Aylward]

Drew may have already told you but sometimes adding a bigger valve in these tractors can actually hurt your air flow. If the valve is too close the the cylinder wall it effectively blocks off that side of the valve from introducing air into the cylinder. Mike

 

[want2pull]

mike , maybe im asking the wrong question,then.i add fuel to the tractor and it just smokes more,since its not burning the fuel.if valves arent the solution what is.

 

[buickanddeere]

Bore size on the 730 and 830 is the same.

 

[Drew]

But are the intake valves in a 730 the same distance from the bore centerline as an 830? Or are the 830 valves closer to the bore center to accomadate the larger head?

 

[Anonymous-0]

Drew could you explain in steps what needs to be done to a 730d to make it pull. Please completly explain as i dont know pulling terminology.

 

[wilamayb]

The limiting factor is usually the air cleaner. Replacing with a dry filter element may make a difference especially if your original screen is plugged with dirty grease.

If you want to keep your original you can remove the canister and soak in slovent.

 

[730Jim]

If you open the rack up, they still smoke with NO air cleaner.

 

[2 color green]

I have a 70D i pull. 730 pumps, extensive head work, dry air cleaner, 830 valves, rack @ 16, smokes no more than a working tractor.

 

[gpuller]

820/30 intake valves are the same length and stem diameter. The head is .125 bigger in diameter. As I recall, the 720/30 intake valve is 2.50 dia and the 820/30 are 2.625.
The exhaust valves are about .25 bigger in dia.
I've been looking into this also, not much more room to squeeze a bigger intake valve into the bore.

 

[730Jim]

Well there's his answer then. The headwork and 830 valves allows enough air for the increased fuel. All the 720/730's around me are stock (head, stroke, bore, etc.) but have had their fuel systems rebuilt and the racks opened. Lots of smoke then. We looked at the head, but were afraid of opening it up too much. Does your tractor still have good torque? Any dyno numbers?

 

[2 color green]

Lugs ok to about 850RPM. Pto clutch started slipping at abouy 70HP. Have PTO out of it now. I don't like to run over 1500RPM, but have been up to 1700. Crank is balanced.

 

[buickanddeere]

What rpm were you reading "70HP" at?

 

[want2pull]

hey guys thanks for the advice,im going through this tractor completely,ijust want a strong running tractor,when im threw.i dont mind the money side of it.the block is being bored .125 over when i get it back ill do some measuring to see how close 830 valves will be to the walls.thanks

 

[730Jim]

Now that you say that, I learned my tractor's pto slipped when we put it on the dyno the first time. It's been awhile, but I think we had around 65hp at 540. Bone stock with fuel system rebuilt to specs and rack opened.

 

[buickanddeere]

How much extra airflow are you planning on gaing with a 125 thou over bore?
You would have been money and airflow/HP ahead having the head and manifold Extrude Honed. And install a Berry Cam.
Now the block has no more room for boring.

 

[want2pull]

i had to have it bored out it already had .090 over pistons in it and the bores were out of spec.ive got the cam off and plan to send it somewhere.I own a mashine shop and i did work to the manifold myself and hope the guys that do the head work can give me some advice on how much i can grind out of the head,thanks

 

[Anonymous-0]

I put mine on a dyno and at 1150it was 68 1050 it 71 950 it was 74

 

[buickanddeere]

Check again. You are reading torque rise but did not calculation for the drop in rpms.

HP = Torque X RPM / 5252