Billet alum head for diesel tractor puller?
Billet alum head for diesel tractor puller?
(OP)
Would be interested in opinions on whether a solid billet aluminum head would live on a John Deere diesel puller engine. The pull lasts about 40 to 50 sec.Occasionally they have to rerun in a "pull off" tie breaker
They now run a ported stock cast iron head that has the water jackets filled solid with block filler (grout)and don't seem to have much trouble. These are serious pull only engines with 120+lbs manifold pressure, 5000 rpm,roller cam, etc.
The head is approx 48"x8"x6"
They now run a ported stock cast iron head that has the water jackets filled solid with block filler (grout)and don't seem to have much trouble. These are serious pull only engines with 120+lbs manifold pressure, 5000 rpm,roller cam, etc.
The head is approx 48"x8"x6"





RE: Billet alum head for diesel tractor puller?
RE: Billet alum head for diesel tractor puller?
RE: Billet alum head for diesel tractor puller?
You may have some trouble with distortion as you machine the part and relieve stresses that were locked into the billet. One way to deal with that is to finish the head bolt holes early, and lock the workpiece down to a strongback, or fixture and machine it cylinder by cylinder.
It's really a joy to machine 2024-Tx; it produces beautiful curled chips, and you can run most tools as fast as your spindle will go. It's very strong, too
Mike Halloran
Pembroke Pines, FL, USA
RE: Billet alum head for diesel tractor puller?
Mike Halloran
Pembroke Pines, FL, USA
RE: Billet alum head for diesel tractor puller?
RE: Billet alum head for diesel tractor puller?
RE: Billet alum head for diesel tractor puller?
Stout1 is correct in that the overall weight may not be a concern but where it is placed is important...so lighter parts allow more flexibility in weight placement how ever that is not my main issue I just am not thrilled about carving a complete cyl head out of steel
They tell me their ex temp is usually around 1800* I don't really see seat retention as a problem if the interference is correct I have seen computer traces from Top Fuel cars that have temps approaching this range (run time much shorter) How close would egt reflect in cyl temps?
RE: Billet alum head for diesel tractor puller?
RE: Billet alum head for diesel tractor puller?
Valve seats do sink back into aluminium heads under the seat pressures you need for high rpm blown alcohol motors (9000 rpm, 40# boost SBC at 1500 HP with over 300# on the seat).
I don't know what seat pressures they run on diesels, but I would think cylinder pressures and temperatures are higher than alcohol motors.
I think tractor pull motors run really high boost, so spring pressures might be high despite relatively low rpm.
The valve seat problems occur if the inside rad of the port is to close to the valve seat and so reduces support, and if the heads have started to go soft. The extra heat in a diesel motor might send the heads soft earlier.
For thermal stability you might need a T6 grade of aluminium as lesser heat treated grades shrink on repeated thermal cycling. I think the Si level also impacts on thermal stability.
Of course even mild steel will be more stable.
Another problem with aluminium is that it expands more than steel or iron and therefore does not have a good consistent grip on the gasket and is more inclined to pull studs. Having said that, many people successfully run aluminium heads.
If I went aluminium heads, I would "o" ring the heads with receiver groves in the block.
When I raced air cooled VWs I actually used thiner head studs with bigger threads so they stretched a little when stressed by expansion. This overcame the stud pulling problem that was very common with high output VWs.
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RE: Billet alum head for diesel tractor puller?
Is that a 2-valve or 4-valve configuration? I would think a 4-valve would be harder to make but better at taking a beating.
It sounds doable. But I would be in great fear of running it for too long though. Having a bulk of the initial heat coming from high EGT should keep the seats tight. But heating up the head and then putting around could go the other way. Also the head will loose strength as it gets hot. A second or third run in a short period of time might waste everything.
You might also consider having a very simple new iron head with your name on it poured somewhere.
RE: Billet alum head for diesel tractor puller?
Pat is correct that high spring pressures are needed however the cyl.bore size is 5.120" so this allows me room for seat inserts with a beefy o.d. and still have the needed valve size
The cast iron idea is interesting but I don't know anything about designing a casting Is cast iron billet available this large? or at that point would it just be better to use mild steel?
brngrhd, not really into pulling just engine building and machining but it's good to know someone has done it
Thanks guys,
Tom
RE: Billet alum head for diesel tractor puller?
"rectangular log" of gray iron. On the high end of tech, you could have a styrofoam pattern CNC machined and the foundry could make a "lost foam casting". Between these two extremes would be having wood patterns made with varying levels of complexity and cost.
RE: Billet alum head for diesel tractor puller?
I did not look it up but I seem to remember 2024 had stability problems over 300* F.
If you do use Aluminum I would start with a 356 T7 cast and try to get a foundry to double the silicone and 4% cooper.
Matl Gurus please keep me honest.
But if you are going to cast I would suggest Meehanite or CGI casting.
A simple pattern could be made to give you all the spring pockets and cover lip and combustion chamber rough in.
I think you could do all of those without cores which is the most expensive in pattern making.
Just bring the pattern maker the head and tell him the material you want to cast it out of, and that you do not want any cores.
He will calculate the shrink, and cast the part so that you can finish machine it or CNC complete.
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Cheers
Cheers
I don't know anything but the people that do.
RE: Billet alum head for diesel tractor puller?
RE: Billet alum head for diesel tractor puller?
Tom
RE: Billet alum head for diesel tractor puller?
Also, is there an alcohol head available? Maybe you could get them to make a version with a flat combustion surface and a different material. Not the best option, but may be an option.
ICZ