It finally works

Last summer I retired and on my bucket list was to build an engine dyno for my shop so I bought a pile of parts and have dynoed three engines so far,to get some experience , it is an older 13 inch dynomite by land and sea, with manual load control, which took a learning curve. Today I did the engine for my race car, 540 RB world product block, 4.5 bore, 4.25 stroke, .740 lift Jones cam, pro comp heads Victor Jr copies, I ported and polished, in NSS trim with two 750 AFB's It made 773 ft. lbs torque and 771 horsepower. pretty happy with it. The Engine I blew up last year and windowed the block, took me all summer to get the block fixed and enough money to put together a new short block. Got it together this winter and just been waiting to get the bugs out of the dyno, which is another story.

That’s both impressive and awesome!!! Congrats on achieving that goal. I can imagine the difficulties and issues to work out with a project like that. And nice results with your engine.

Awesome effort and result

Tex

What intake are you running? Single feed or dual feed edelbrocks?

I can't tell due to the light reflection on the screen masking the lower readings, does the HP and torque lines cross at 5200 to 5300 RPM?
The reason I'm asking is they are suppose to according to all the dyno operator, owners say when I have used their dyno

Congratulations! Having my own dyno is also on my bucket list.

Here is my quick fix of his Dyno screen. I darkened out the harsh bright light and then added the 500 RPM jumps at the top and put a line down around the 5200 RPM line.

I am running two 9755S federal mogul AFB's 750 cfm, yes they are converted to dual feed. The needles and seats also have windows cut into them. I also extended the primary boosters as was discussed on a thread a while back. I trimmed the secondary weights down to 102 grams. I used the velocity probe on my flow bench with a brass rod soldered into a jet so I could see what each booster pulled on the bench. With the stock booster they pulled 194 to 198 feet per second at 10 inches of water, with the extended boosters they pulled 220 to 229 feet per second.
The intake is a victor jr. for max wedge ports that I fabricated a top for, and made some dams in the inside. It is 3 tenths faster than a 1964 factory cross ram, with no other changes. Never had the old cross ram on a dyno.

They HP and torque lines on a graph will always cross at 5,250 because that is the constant used to calculate HP The dyno only measures torque, then records the rpm and then calcualtes HP using the formula

(RPM x T)/5252=HP, where RPM is the engine speed, T is the torque, and 5,252 is radians per second.

Nice work! Stock Jetting?

No its got 116 in the primary and 113 in the rear, rods are .054 and .067 steps. Average of the O2's is 12.5 on the one side and 12.65 on the other side. It has always ran a little richer in the one bank, my intake work I am sure. Soon as the tracks open, I will stagger jet it a little to fix it.

Which type of fuel are you using, race or pump?
Have you ran it leaner to find out what is to lean? If not, why not
I know that all systems, O2 and dyno software, are not exactly the same so what I have seen on other motors does not make it the same as yours, and visa versus
I've always went richer first, at the track or a on any type of dyno,chassis or engine, and then went the other way on the tuning and mixtures and I made sure of where the happy spots where on jetting and timing as well as when and where it would start to loose power, up or down

running 110 fuel, I left the engine a little rich, because from my experience while the dyno is a great tool to work out a lot of things, I have never had carb jetting on a dyno be the best at the track, so I leave them a little rich and fine tune at the track. The other reason is my dyno is an older manual load control type, and I don't think I have the skill to find 5 or 10 horsepower changes, to thrash my combination any closer. If I had a dyno with electronic load control, then I would probably fine tune more. Just from the four engines I have dynoed, I can get the torque to repeat really close but the horsepower changes 5 to 10 with most pulls. The reason is with a manual controlled dyno the operator has to twist water flow control valve, listen to the sound of the engine and watch the tach, to keep the acceleration rate the same through the entire pull. That is very hard to do, at least for me. Land and Sea says 800HP is about the limit of my water brake, and my engine is getting close, so it makes it hard to stop the engine from accelerating faster in the last say 1,000rpm, which is where the highest HP numbers normally come from. What I look at is the cylinder temperatures, O2 readings, and plug color to tell me when it as good as its going to get.

At the college where I retired from we had a Mustang eddy curent engine dyno, with electroic load control, and it would repeat within a couple horsepower if you keep an eye on water and oil temperatures for each run. And I could set the ramp rate to what ever I wanted, and by changing the ramp rate you could change the horsepower and torque readings of the same engine with no changes. And the Mustang was rated to 1,500 horsepower. But the unit at school cost $60,000 I got $15,000 in mine. Like I told the girlfriend, the Dyno is something I just always wanted and it is cheaper than a decent used car. Plus I should be able to sell it and get most of my money back one day.

I agree on finishing the tuning in the car at the track
Me too

I sure you know, but the reason the HP and torque change at different ramp rates is because you are using up torque accelerating the metal inside/attached to the engine. One way to get a "true" HP reading is a steady state test. Stopping at each test rpm and take a reading.
About 4 years ago, I was up at Superflow for a class and was complaining about this very issue. Short version is we talked to their engineers and they now have a inertia correction factor. Each engine is different and it's kinda a pain to setup, but when it's set it doesn't matter if the rate is steady state or 100, 300, 600 rpm per sec, the HP and torque give the same results.

Joe

PS so cool you built your own!!!

Thanks for the info. I guess because of the limited number of dynos around, good information on exactly the nuts and bolts on how they work is hard to get. Read a lot about general theory, but not much on actually setting up a dyno and making it work. So if you have a good reading material forward the titles.

The only book i have read on the subject is "Dyno Testing and tuning" by Harold Betts. It's not a bad book.
I can tell you one thing, don't be afraid to believe the data. a lot of times it will be different then "conventional wisdom".



Joe