rebuilding after the crash

We got the car fired on gas/efi late today. It didn't go with out a little issue. For some reason the starter went bad over winter. I use a dodge 318 Dakota starter. The local auto parts store didn't have one in stock but told me the warehouse in Milwaukee did. That wasted two hours. Back home we got it all back together and it fired up. A timing adjustment was needed to stop the flames from coming out of the pipes. The oil pressure gauge was pegged and there were no leaks. We ran it until the heads got hot were it had to shut off. There is no water in it right now. We ran out of time today for running nitro through it. Sunday is a new day so it will happen then. I will also have video.

 

The nitro start up went great. It ran on the bottle but not on the pump. I dove into my archives to locate the pump directions. Since I took the pump off the dual drive i had a suspicion that the rotation needed to be changed. After changing to a clockwise direction it's all good. The second video called first start up shows too much flames. It's running lean do to the big increase in timing.
the first video labeled second start up shows less flames and it's running right. The barrel valve leak was increased from 67 percent to 85 percent. That's a big jump. That shows how much timing effects a nitro engine. I'm looking into the pipes to make sure the bv changes are not making them wet.
Excuse the quality. It's hard to hold the phone and tune the car.
We ran it inside the shop with head phones and respirators. The whole shop turned a cool yellowish haze. Smelled great to.
I cannot get the videos on this site no matter what I tried. They can be found on YouTube under kohlmann 2019 nitro start up. If some one can post them here I would appreciate it.

 

https:/

 

i wasnt right clicking to get the drop down box. i might be able to get it next time. thanks for posting for me.

 

That is one ANGRY hemi!

 

For how wicked this thing is, it starts easy and idles well. Sounds deceptively tame at idle.


Sent from my iPad using The H.A.M.B. mobile app

 

It starts very easy. It's hard to hear in the video whats going on. The car is being started on efi/gas. Once it's running the nitro is turned on along with the mag. The efi is then shut off. It all happens quickly. Normally to start a nitro engine on 50 degrees of lead it takes a 36 or 48 volt starter. I'm using the running engine to get it going on nitro. My starter is 498 cubes of hemi power. We just solved the problem by thinking a little bit outside the box. After it was done running we had the feeling of wow that crazy idea really did work. A dedicated race car would not have the second fuel system so they cant pull off what we are doing. I'm glad it worked as planned. It's a big relief.

 

Always enjoy your posts about your awsome car! Thanks for taking us along on your build, and best of luck on Drag week.

 

Brian. So this is similar to starting a nitro engine on alky and then make the switch to nitro, but you are doing this on gas. I guess with a smaller load of nitro the engine does not have to be rolled back after shut down?

 

If I squirted alchohol or gas in the engine then hit the starter it wouldn't start using a 12 volt starter. I'm actually starting the engine with the efi system first. Then I pull the fuel lever and turn on the mag. Then turn off the efi. The running engine is the starter for the nitro.
We do roll the engine back after its run on nitro. Really bad things can happen if you dont. On drag week I put the turn down bar in the car with me so I can roll it back before driving back to the pits after a run.

 

Brian I hope that your saying the turn down bar is secured in the car on drag week? I know your a mad scientist and all so assume you thought that scenario through.


Sent from my iPhone using The H.A.M.B. mobile app

 

I think he's up on the dangers of loose stuff in a race car...from the beginning of this thread.

 

The bar is placed inside the passenger's seat. It fits tightly between the seat and padding. If it comes out I have waaaayyyy bigger issues going on.

 

Is it possible to switch it back to EFI/gas from mag/nitro before shutting it down and save having to roll it back?

 

I dont see why not. I plan on doing just that on the street. On the track i shut it off at the end of the pass. The engine is off before I make the turn off.

 

Ahhhh, reminds me of the old days, starting up the Farmall TD18 on gasoline, then switching it over to diesel. Well, sorta........ hahahaha! Wow, what an amazing piece of engineering this car is!

 

yup, just like that TD-9 I had.

 

I have pondered this, in regards to this subject.. I want to make a 331 run hard when I need it to.

So, I am not crazy after all! Cool!

Sent from my Moto Z (2) using The H.A.M.B. mobile app

 

To make things regarding the start up more clear the video shows it starting up without priming the engine with a squirt bottle. There is no need to prime it because it's already running on gas.

 

When I posted earlier that the pump rotation was backwards I confirmed it with the directions supplied with the pump. I needed clockwise rotation. As seen in the photo I had counter clockwise rotation. I will show the directions for not only the pump I'm using that being the twin gear but also the more common enderle pumps. These directions can come in handy depending on how you want to drive the pump.
The pump can be mounted on the cam cover driven by the cam. It can be reversed to be driven by a belt. It can be run off a adapter that's connected to the mag using a cable for remote mounting. It can be run off a dual drive in either location. Every setup requires the correct rotation. I hope this helps someone out some day.

 

Just one ask the professor question. In the video where you say it is running good now, every once in awhile you see a puff of "Exhaust" or whatever come out one of the pipes for just a second or two. Then another pipe does the same thing a bit later but in no pattern of occurrence. What does that?

 

for a nitro engine to run right it needs to burn a lot of fuel. the fuel burns very slow that's why they need so much advance. The combustion process needs to start earlier. do to the slow burn as the exhaust valve opens some of the fuel is still burning resulting in flames coming out of the pipes. the cam centerline usually 112-114 degrees favors the exhaust with a faster opening. this acts as a safety valve to release the pressure. both valves cant be closed a bdc with the fuel still expanding something would break. The engines are very loud do to the cam timing and still burning fuel. The nitro engine makes its power through big fuel volume. A gas engine cant run big volume. Because of the big nitro load not all of the fuel gets burned every time the plug fires. The extra fuel gets blown out of the pipe. The fuel can ignite on the next cycle or so resulting in a flame out of that pipe.
Some intermittent flames are ok. Steady big flames while impressive are not good for making power. Ever notice how sickly a cackle car sounds but looks cool?
There is a happy medium on the idle set up. Looking at or as they say reading the pipes tells the tale.
Extremely rich: has raw fuel flying out of the pipes.
Rich: the pipes look wet inside all the way to the end.
Close: pipe ends dry several inches into the pipe.
Lean: completely dry pipes
Dangerously lean; glowing red dry pipes.
I hope this helps. If it still doesn't make sense or you have other questions feel free to ask.

 

That answers the question just fine professor.

 

I should have put a disclaimer on my last post. your results may vary. there are many ways to tune one of these engines and more that one way to build them. some builders like high compression some low. some big inches some small. the possibilities are endless. the way I do things is the way I was taught. the last race of the year I had everything were I wanted. now we added 12 degrees of timing and the engine was lean on the start up. so you can see how one change can effect the whole combination. its easy to see how some teams get lost on their tune up. it would be interesting to hear how others do things. nitro engines are like no other. roo do you have any comments?

 

Somewhere around here I have a book that goes into building/tuning Harley Sportsters for various uses. There's a chapter on running nitro and the author asked the 'expert' guy what the difference is between gas and nitro. I've never forgotten the answer...

'Running gas is like making a phone call in a booth; open the door, go in, call.
Nitro is open the door, throw in a hand grenade, then make the call...'

 

its very well documented the damage on a almost biblical scale nitro can cause when things are not set up correctly. if you think you are going to tame the beast with a iron fist it wont go well. tune slow or you will either end up broke: in a burn unit: dead or all the above.

 

To back up what Brian posted, it is easy to get lost on the tune up. When the engine is loaded during a run it behaves way differently to what it does in the pits. The engine has to be loaded to burn all of the fuel, even in what is basically a "mild" combination like Brian's. With a "big show" car having a fuel pump that can deliver 110 gallons per minute the ragged edge is a lot closer. Even a slight amount too much tire slippage or a bit too little clutch load will put cylinders out and then the whole engine gets screwy as the rest of the cylinders are carrying more of the load and that can make them too lean. With a fuel pump restricted to 21 gpm the nostalgia funny cars have to get the rpm's up before they shift (they run a two speed trans). If the shift is made at too low rpm's the fuel pump does not have enough volume at that point and when the engine is tugged down by the shift it needs more fuel to handle the load. The consequences are usually backsided pistons or in the worst case a backfire that launches the body as seen on several runs at Bakersfield this past weekend.

Roo

 

Love the nitro info in this thread!