big cube John deere

[DDoubs]

i am looking into building a 1000 plus cube john deere. throwing this out here to see what would b a good tractor to start with G, 70, 720 also who the go to guy's are with cranks blocks and so on. i realize that am going to get a lot of this guy is better than this guy stuff but just let me here it. looking to pull 5000 up 4-8 mph stuff mostly 4mph. thanks for your inputs.

 

[johninmn]

Might be a dumb question but do you really need 1000 cubes to pull 4 mph? Seems kinda high to me but who knows. Just a thought.
John

 

[Mike N Mo]

If you want any chance of making 5000# with moveable weight you'll need to start with a "G". 70's can make 5500#, but not much weight to move. No real advantage to using a 720/730 (heavier) unless that's really what you want to start with. Murphy's is where you want to get the head and block/pistons/rods if you want reliable (round bores and won't leak water) and can provide you with a complete package if you're wanting 1-stop shopping. He can get you close to 1000 cubes. Others suppliers can make the crank, but you're better off having one place do it all to ensure that the entire package will all go together correctly (rod length, crankpin spacing, crankpin/rod/bearing compatibility, etc). My $0.02. Mike
Murphys

 

[DDoubs]

from what i can gather a 10.5 will fit in a 70 and not in a G. also am kicking around the 8in bore have herd some talk that this bore will fit in a 70. but on the same hand i am wanting a tractor that is some what reliable. so ?????????? also the reason for 1000 plus cubes is to run in some 7500 and 8000 4 mph classes. and we run a 6000 lb 8mph class. but i am just trowing this out there to get some feed back as to what works and what will not. keep the posts comming thanks.

 

[2-banger]

iam also looking into building a big g..iam going to have josh blackburn do my crank ..cam..rods..id like to know more about the 8in block ray at extreme makes..i think his 8in block is the way to go and you wont have to cut through side of case cause you can get it without sleeves going into case..then id run a murphys head, duplex manifold with 70 carb. Seems to me if you whent with smaller stroke 9 or 9.25 with big bore it will hold up better. has anyone bought a 8in block from extreme? 8x9 is 905ci

 

[FactoryFarmer]

(quoted from post at 18:15:50 07/16/12) iam also looking into building a big g..iam going to have josh blackburn do my crank ..cam..rods..id like to know more about the 8in block ray at extreme makes..i think his 8in block is the way to go and you wont have to cut through side of case cause you can get it without sleeves going into case..then id run a murphys head, duplex manifold with 70 carb. Seems to me if you whent with smaller stroke 9 or 9.25 with big bore it will hold up better. has anyone bought a 8in block from extreme? 8x9 is 905ci

If your going to have that big of a bore just go with a billet crank. I've talked to a few guys with 7 and 7.5 blocks who used to break a crank a year. To me that does not sound like much fun.

 

[looking also]

When did Murphys start doing their own cranks?

 

[Josh Blackburn]

If they are breaking cranks that often I would recommend a
new crank builder

 

[DDoubs]

Josh how big of a stroke can you swing in a G vs 70. also dose anyone know how much that 8in block is. and also if its a good block or if it will leak water and or go out of round. if i am going to build the tractor i min as well build it to run with the big dogs for a year or two. LOL
thanks for all the replys.

 

[FactoryFarmer]

(quoted from post at 19:22:50 07/16/12) If they are breaking cranks that often I would recommend a
new crank builder

They were using a couple of reliable crank builders, I can't remember their names now but I did recognize them. My tractor also has a crank from the one of the builders and it's been spinning at 1800-2300 for a while.

 

[FactoryFarmer]

(quoted from post at 19:52:28 07/16/12) Josh how big of a stroke can you swing in a G vs 70. also dose anyone know how much that 8in block is. and also if its a good block or if it will leak water and or go out of round. if i am going to build the tractor i min as well build it to run with the big dogs for a year or two. LOL
thanks for all the replys.

http://extremetractorparts.com/index_files/Page375.htm

Looks like 5500. Give Ray a call, he's pretty cool when it comes to throwing around ideas.

919-605-6040

 

[gtx1967jewison]

He doesn't. Cranks are farmed out.

 

[Anonymous-0]

Why limit yourself to 1000 CID.

GROW SOME BALLS AND GO BIGGER!
1200CID sound like a good place to start.

 

[buickanddeere]

Isn't there a point of diminishing returns with increased displacement? The air/fuel mixture is still being flowed in and out of those small ports and valves.
Has anybody put a stock G or 70 head and manifolds on a flow bench and attempted to increase flow?
Cutting the eyebrows off and Extrude Honing the head and manifolds maybe another source of airflow and power worth considering?

 

[RandyB(MI)]

Am I wrong or didn't JD use a center main bearing on some of the newer and larger 2 cyl tractors??? If that is true then how do we get away with the hi comp ratio 9" + stroke hi rpm puller motors with just outside mains?? I realize we aren't farming day after day with them but they wouldn't have done it if they hadn't experienced some problems? Just askin'. And I do value your knowlege over the others. I do watch and listen to your tractors.RB

 

[Little Big B]

(quoted from post at 18:02:13 07/17/12) Isn't there a point of diminishing returns with increased displacement? The air/fuel mixture is still being flowed in and out of those small ports and valves.
Has anybody put a stock G or 70 head and manifolds on a flow bench and attempted to increase flow?
Cutting the eyebrows off and Extrude Honing the head and manifolds maybe another source of airflow and power worth considering?

I've done a dozen or more G's, 70AF, 70 gas heads and about every manifold made for them with the exception of a few. Also with welded chambers and without.. I've also spent alot of time with the A and B heads and manifolds. I've spent countless hours grinding on them trying different idea's on getting the air in and out with the help of my flow bench. I've also done the same with the single barrel carbs. It would take alot to feed a 1000ci G at just 1200rpm, but could definetly be done.
DDoubs, give me a call sometime, 605.929.2797
Derek Holdren

 

[Rwolfejr]

I used Oden Machine in Oden IN and I'm very pleased with their work. Ask for John Jones. 1-812-636-7781

The more radical you go... the less life you'll get out of it. It falls under the laws of physics...

 

[bp4455]

what would a billet crank cost?