JD 80 Port and Polish ???

Alan

Good question. Think of it in terms of 1: a wing on an airplane, and 2: a set of piston rings.

The wing: You've got air flowing thru a constricted port and then suddenly it expands at a 45 degree angle for a tenth of an inch (as in a normal head) then it expands into something the size of outer space when compared to where it came from. Like a wing for a normal airplane has smooth and gentle curves to smoothly duct the air and avoid turbulence - the 3 angle valve grind starts moving the air out at around 30 degrees, then ~45, then ~60 degrees. If the air is allowed to slowly and gently expand in relative terms, there's less of it getting turbulent (like confused air - where do I go now?) and sitting around going "Duh!" while creating an obstacle, actually a barrier, for the air behind it to easily enter. You get better flow into the combustion chamber when the air flows easier; more flow means more oxygen, more oxygen means a bigger explosion. (you can see the same effect on any freeway that goes from one lane to two then back again -- drivers, like air, will sit and go "Duh!")

That's a normal 3 angle grind - next:

2. The rings: Now let's say you want to take full advantage of those 3 surfaces you've cut into the valve seat. So you cut the valve to mate with the seat on three different planes - say 60, 45 and 30 on the valve. You've made the mirror image of the seat/port on the valve side to smooth air flow -- PLUS you've also increased the surface area that the valve has to mate with and seal with the seat. More sealing surface is better than less sealing surface -- in the same way you have two different compression rings on your piston. A tighter seal will hold in more good stuff, so you'll get a better explosion, therefore more power; when the cylinder fires. More power for less work is always better for every living thing -- so a 3 angle valve setup is better; albeit more expensive to do.

Here's another trick I learned in my checkered past and talked about below -- hot hones. You take your cast iron block to a machine shop and they put it on their Sunnen honing machine to make it true - that is to make it mate with the piston rings. You see them bolt on a plate on top to simulate the deforming torque stress that the block has when the head is on. Fine. Makes sense. The better outfits will bolt on a plate at the bottom to simulate the torque stress that's there when the crank is installed. Good stuff, right? Those guys have put stuff on to deform the block in the way it will be when it's actually running. Right? Naaaah. Wrong. They forgot heat. Blocks do get hot. So to get the block the way it's really going to be when it runs you need to add heat. So you get a good propane or electric water heater and pump water thru the block at about 180 degrees, meanwhile you take a torch to the top torque block - the head simulator - until it's about 1400 degrees. Then you hone your block. You put in the right sort of rings and you will get cranking compresion readings you won't believe. Serious! It truly does work.

In that our engines are basically air pumps that create explosions every 4th time around -- the air pump side of things -- the ability to inhale, seal it tight, then exhaust air is at least - if not more important than how much fuel and igntion fire (gas engine) we can add to the mix.

Now down to brass tacks. Have I ever done any of the above to my tractors? No. Have I ever done any of the above to any of my race engines? Yes -- that and more; every darn time. That works out to 6 engines a year over more than 10 years - so let's say 60 times for race engines - but 0 for tractor engine rebuilds. Sixty to 0. The race engines got a whole lot more money and time spent on them than the tractor engines. Then again, I've never caught the bug to go pull tractors in competition.

But in competition - you want to beat some other sob who's just as devious, maybe as smart, and certainly as well financed as you - Or, you just want to go out and till the back 40 with the least amount of hassle? If the later, rather than the former - forget the 3 angle grind.

What's more, if you're 20 and have a lot of testosterone flowing, do the hotrod stuff on your tractor. It's fund and you'll never again be young. If you're pushing 60, like me, you know you're mortal by now and are satisfied to go out in the back 40 with ol' reliable - who's not a screamer, but starts every time and sure does make you happy just to be on it. The race car - or maybe the pulling tractor -- trophies and pictures are on the wall as fond memories of a miss spent -- or maybe a well spent -- (but certainly an expensive) youth.

Hope that not only answers your question, but gives you some perspective into the whole ball of wax as well. Have fun and enjoy -

Steve

I've spent a lot of hours on a flow bench with heads that have 3 angle ginds. It does make a big difference in a race engine -- BUT -- it makes more of a difference the higher you go in RPM, and if the size of the valves, the lift and duration of the cam can take advantage.

Don't know how racy you want to get with the engine, and how much you want to throw at it in the way of cubic dollars. Also, if you're taking the flow work to the Nth degree, be prepared to trash a head because you've cut into the water jacket. All decisions you'll have to make. If you're serious with it, first guy I'd talk to is somebody who has reground cams for an 80 AND has a flow bench around. He'll know where the choke points are getting air into and out of the engine (that includes from the top of the air cleaner to the end of the exhaust pipe), and where to get max gains for minimum effort and expense.

If you're just working the 80, or using it to have fun with; the three angle grind will improve the seal from head to valve. Then I'd get an air gun with a flapper wheel, or even a Dremel; and clean all the crud out of all the ports. Get the exhaust ports looking like mirrors, but remember to leave a coarse finish on the intakes --uh, wait, this is a Diesel -- go ahead and make the intakes look like a mirror as well. For that level, it's about as far as you'd want to go. After that, the curve of effort and expense gets fairly steep.

Will the fact the diesel with no manifold vacuum drive the affect of polishing the intake side?

I guess I was thinking that since the air just tumbles into a diesel, and that the oil bath seems to be the biggest restriction (just unhook the air pipe at the manifold and note that it has less "suction" than you feel over the top air intake). Plus, using a turbo on a two cylinder is prohibitive.

On the exhaust, they have very large valves, and very short exhaust runs within the head. I had thought that if I ever wanted to improve the exhaust side on my '70'D, I'd take my old busted exhaust manifold and cut the two ends off, weld on a 90* and just blow the smoke out to either side.

I guess what I'm saying is that I don't think you would notice porting/polishing work on those slow turning diesels. Fuel work, yes. Cam work, probably.

He's punching out near 80 hp now, stock. I don't see polishing/valve grinding getting you 2 or 3 extra hp. All a guess on my part, but that's not where I'd spend my money.

Anxious to hear from others on this.

Frank

For the time it appears we're bereft of other's thoughts - so I'll add mine.

The polish job is down to the short hairs. The 3 angle valve grind can yield a quarter to half the gains you'd get from a good hot hone and new rings. Less stuff escapes on the compression stroke. That simple - bad valve to seat seals do leak.

In that you're creating less surface turbulance with a smooth surface versus a rough one by polishing, you have marginally improved the ability of the piston to draw in more air. Once when I was a boy racer, we measured the car on a chassis dyno after a race with the ports "dirty" and the valves "burned"; then did a hand valve grind / port cleaning, polishing and measured it again. We picked up 1.5 to 2 hp in the 7500 range. This was on a car weighing about 800lbs. with about 185hp. Scale the percentages and RPM's down to a JD 80 hp range, and it becomes fairly meaningless unless Allen is going to pull competitively and wants every possible advantage. I know those extra couple of ponies let me pass guys down the straight - which is a far safer deal than playing chicken with outbraking games or seeing who's gonna apex first.

In general, even if it is a Diesel - the more O2 you can bring in, the better your bang is going to be. The porting - actually removing material in the port, or in some cases using high temp epoxy to build up other places - to get it to breathe better will make a lot of difference. Example - if we used to get 25 to 35 per cent better flow at 5,000 rpm on a manifold or head ports after really porting (not just polishing) then Allen might get 6 to 10 per cent better flow at 1,000 rpm. Is the cost worth it to him? We don't know - but if he's gonna be a boy racer, or boy puller; if you will - it just might be. Racing is a matter of small differences, and I imagine that the same holds true with tractor pulling.

Interesting deal about the header as well. We used to have a short track header for the 5/8 mile bull ring oval tracks, and a long track header for place like Road America or Road Atlanta with monster size straightaways. The short track setup had smaller diameter and longer length tubes to enhance low end torque, as the engine's job was basically to drag race out of turns 2 and 4. Vice versa on the setup for long straights. Of course, the tube size and length is counter balanced by the cam duration and even the differential in intake versus exhaust valve lash setting (which changes the duration). The short track header also had a "bundle of snakes" equal length header pipe before the conjunction, and the long track header had unequal length tubes before the conjunction for a flatter, less "peaky" torque curve. This was a Cosworth Ford dohc 4 banger, so the measurements would be different than a JD, but I'm guessing the same basic tricks would work to enhance low end torque.

When I was doing this stuff, it was educated guess then trial and error on a flow bench, dyno, and ultimately a track. If anybody is serious about getting the Nth degree in performance now, you can buy what's effectively a dyno in software called Dyno2000. Input all the engine specs and it wil give you a fairly good idea of what will result from changes in cam duration, lift, header pipe diameter, length, intake runner length, etc. Of course, the flow bench stuff is still kinda black magic.

Anyway - we don't know if Allen is gonna compete or just have fun. He's gonna do some kinda valve job anyway, so a 3 angle cut won't cost that much more. As for polishing - heck - there are only 4 ports. Even a Dremel with a flapper wheel should do that job in 30 minutes - and it'll look a lot more sanitary when he gets done. For my money, go ahead and do it.

Steve

I don't disagree that any porting and polishing will make the surfaces slick, and that should let the air slide in more easily. My point is on a two-cylinder, at the relatively low rpm (1,200 max), and the long lag between gulps of air, that by the time the first one comes around for its next gulp of air, that the manifold and intake valve chamber (because there is no throttle plate) is back at atmosphere anyway. As for number two, it's always going to suffer, even if both are ported/polished.

As for the comparison to a racing engine, a 350 Chevy at 7500 rpm, intakes 760 CFM at Standard Temperature and Pressure (STP). The '80' at 470.7 cu.in. and at 1200 RPM will ingest 163 CFM, or roughly 21%. That's not a lot of opportunity to gain air. If lots of work on a flow bench got you 2 or 3 hp at 760 cfm, it's not gonna get him much at 163 cfm. That's my thinking anyway.

The problem I have seen with trying to polish a two cylinder head with a dremel tool and a flapwheel is that it's a long reach down from the head end and up from the valve side. I've done it on a "B" back in the old days and it takes the better grade (read more expensive) spiral wheels on a long shanked air die grinder to really reach the chamber from both ends.

I still think that his money would be better spent on a dry air cleaner element. I think there is far more restriction there than anywhere else on that engine.

The other thing is that I have heard the two-cylinder pullers say that they can get quite an improvement on just upping the fuel, before all they get is more smoke. That tells me that there is already an excess of air. Why bother trying to get more before you burn up what you have?

Frank

Yup - a different stroke for different folk. The JD can't flow as much air as your stock car engine or my formula car engine - but he might be able to flow more air than the other tractors next in line to pull that sled, or whatever. And therein lies the crux of things.

You know they make these Dremels now with remote extension gizmoes which will mount the flap wheel and get down there in those hidden spaces! It's pure magic! I think you can stick that thing down there and have it done quickly and well -- but further debate on this subject will probably end up sounding like one of those spam emails about "up all night" and "bigger is better" and "deeper penetration"- so we probably shouldn't go there.

As to the other stuff: I admit that I don't know where the choke point is on a JD Diesel. That's why I orignially advised getting in touch with a guy who'd ground cams and done flow bench work on these beasts. You may be entirely right - but as they say: "one thing calls for another" so relief in the air cleaner will make something else the next choke point.

Point is -- nobody has all the right answers all the time. That's what makes horse races, makes car races and makes tractor pulls. There are 1000 and 1 different variables and yet the differences, or variables, make very small impacts - yet; if things mesh together, very telling results (telling being relative, as I remember being in races where the first 15 cars qualified within 1 second of one another). One of those things that makes life interesting. Enjoy it.

Steve

God Bless Yall John T

I've never hotrodded a Diesel (as if that weren't apparent from the above talk about what kind of engines I've raced) - but if Alan is going to pull with his JD, or even start racing Semi Diesel trucks (that's gotta be scary) -- two basic principles of motorsport will still hold true:

1. "You can solve any problem with any machine by throwing cubic dollars at it." -- Roger Penske

2. "You can make a small fortune in motorsports; provided you start with a large fortune." -- Briggs Cunningham

If he's gonna complete, he'll likely eventually try anything there is to give him even a half of a percent advantage. Warped wisdom from a guy who's been there, done that, and even got a few T-shirts and trophies left over.

Leaves looking good down there in the hill country by now? Or, are you so swamped by tourists from this part of the state that you can't even get out of your driveway on weekends?

Steve

As far as the 80 goes in farmstock pulls, I'know I'm giving up alot of horsepower to the newer, lighter tractors that pull against me in the same classes, but it's all worth it for the once in a blue moon time when the 80 places against all sorts of turboed, radialed, smoke blowing new tractors. (What I don't tell anyone is that the class had a 4 MPH pace)

Any ways, I think that I will probably end up doing the three angle valve grind and simply cleaning up the ports a little. I definatly am not ready to risk cutting into the water jacket.

Thanks again,

Alan Hughes

Just as a sidenote, A local retired JD diesel mechanic, my brother and I have entertained the idea of turboing a 730 just to see if we could silence all the red guys in the area. We figured the 730 is much more common and lighter and thus would make a better canidate for such butchering. This is just talking out of our a** at this date, though. I've also thought that the belt/gear driven compressor idea might work out better on the 2 cylinder but I have heard of guys using an exhaust driven turbo with limited success.

I like your thinking.

To my understanding, a pull is something like a drag race with a lot of headwind. Torque, not horsepower will punch you through. So I'd study up on all the tricks that can increase the low end torque where the 80 shines, and leave the high rev stuff to the other guys -- like your Oliver. So, for example, heavier instead of lighter flywheels might be called for. All depends on what they do say and what they don't say in the rule book for "stock" class. The secret is to take advantage of what they don't say.

As for the 730 - one thing. Those Farmalls can be had for a LOT less money than a JD (I've got 3 JD's and 1 Farmall, so there's a little experience). Dollar for dollar, you might be better off putting your money on the cheaper initial cost tractor -- just be color blind about that choice -- unless you've won the lottery or made big bucks lately on Chinese internet stocks.

Main thing -- have fun with it,

Steve

Way back when we had a local guy that installed an M&W turbo on his 720D. It did indeed help. When he pulled it also put water in the oil bath to give it extra humidity and make the air cleaner flow more.

What he found though, was that the power pulses hammered the turbo. It would speed up then coast a bit then "PAP!-PAP!" then coast, etc.

After a bit he got nervous and took it off. He found three blades on the turbine cracked and ready to come off. I never heard what the compressor side looked like.

Frank

Just a wild idea, and maybe a worthless aside; but when I was messing with turbo charged race cars -- the big buzz was clam shell size and plenum size. That is, the bigger the clam shell around the vane and the bigger the plenum it was feeding into -- the less "shock" you got from one cylinder firing to another. That was on 4 bangers. Two bangers would require doubling the size of clam shell and plenum, even more so if they fire the way a JD does.

Downside of all that is turbo lag. As a driver it's no fun to hit the throttle on Sunday and get a response on Wednesday. Imagine that making it work on a 2 banger would require huge clam shells, huge plenums -- and throttle lag like crazy -- but so you rev it up beforehand and burn out a clutch on every run at a pull. How big is the payday?

I don't think the lag would be a problem. It's not like a drag race where you need the full output the moment when you punch it. Since you start with the sled weight way back, you have plenty of time after you tighten the chain to push the clutch lever forward all the way, and then push the throttle forward.

Even when I pulled the '70' way back in '70 that was the case. Now whether you had the right drawbar height, ballast ditsribution, or even the right gear didn't usually show up until 70' feet or so down the track.

Dampening that turbo is still the major delemma as I see it. The cycle on the two cylinder is of course kinda herky-jerky, so even the air re-load with a bigger plenum will still be chunky (like all my technical terms?!?). I think a fella would be better off with a gear or belt driven supercharger, and run it through enough gearing so that each step would absorb a bit of the shock.

I don't know. Quite a bit of this has been tried before, and none of it ever seemed to stick. I kind of think that means it didn't work all that well.

What's surprising at the pulls, and I am by no means an expert on this subject, is that so many of the two cylinder Deeres run out of traction before anything else. Might just be odd gearing. But if that's the case, more power won't do any good anyway.

Frank

Fun stuff. I don't see the difference between a supercharger at full tilt versus a turbo charger at full tilt. That is, once the little spinners have gotten up to full chat - inertia takes over and makes one about the same as another. As they say in the travel brochures, though; it's the way you get there that's important. The super on a JD 2 banger should get going faster than a turbo - but can the JD properly use the push in any event?

You probably nailed it in mentioning the way a JD fires at 0, 180, then waits 500 something and completes the cycle every 2x or 720 - chunky, as you say. I like those terms. Anyway, that's surely not smooth. Maybe if we had a turbo or super that would trip a pop off valve relative to that dead space from 180 to 720; and therefore sync to the engine -- maybe then we could file a patent that was hopelessly outdated and useless. Sounds like something do-able with that ol' Motorola HC11 series uP or one of those Siemens uP's with all the A to D ports and a simple 8MHz clock. They're cheap. There's an outfit called NVEC (ticker symbol = NVEC, mucho momo and mojo stock) or Non Volatile Electronics that makes nano tech sensors which would work great for reading the crank degrees and then triggering or locking down the pop-off cycle via the uP ports. All in all, another genius invention the world didn't really need - but actually not too expensive to try given the cost of old HC11 EVA kits and the sensors and electo magnet popoffs involved.

It's always fun to find your name in the PTO (meaning patent and trademark office, not power take off) search index), if nothing else.

Anyway... I'll defer to your expertise in pulling. Closest I've done is a lot of laps on a 15 turn per lap track which means 15 drag races per lap. Have only done 3 or 4 dead stop F1 kinds of starts which would roughly equate to a pull (that kind of start is a real get ur blood flowin' kinda rush, though).

Most important thing, though, is that our 2 bangers have tons of torque compared to the other guys' high rev horsepower. If you run the numbers on the HP and Torque over or times 5252 - there's a heck of an advantage there somewhere. I can see that in my JD 60 versus my Farmall H - or anybody's IH M, or my JD 1020 -- the 60 will initially outpull them all. To make that the case for longer distances, we're into inventing synchro rings in the gearbox of a 50 year old tractor, as well as assuming that the pulling rules allow gear changes - and that it's practical with a hand clutch - or we're into some kind of F1 traction or "launch" control with either brakes or electro-pneumatic gearboxes, and back to digital stuff and software to make it work. Wouldn't that be a kick!

All this is what we used to call "bench racing". I still enjoy it. Thanks for the fun --

Steve

Well, I think that the exhaust driven turbo/compressor unit is so much lighter compared to its Roots equivalent, and with the impulse lag during the 540* "coasting", the turbo will definitely slow down and take punishment from the limited, but powerful impulses that kick it back up to speed. At least the mechanically driven Roots supercharger will have the advantage of operating from the rather constant speed of the main crankshaft.

Even turbo's on slow turning 90* engines like straight 4 cylinders have some fin deflection problems if operated at continous low speeds.

I think the turbo will get its teeth rattled and it might eventually break up.

Well, that's about all I can do in the lab of my mind, and the thread's getting long. Over and out.

Frank

If we'd gotten rid of the Billy Goat and the Bambino curses, we might have spent last night at the local bar and grill watching a fun series game instead.

I'm a Reds fan, but with them at home and living here in Florida, I gotta cheer those Marlins!

F-I-T

Anyway, good luck to your home team. Doubt we'll find many users from NYC here to give you an argument.