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 Post subject: Re: Engine upgrade
 Post Posted: Tue May 01, 2012 10:51 pm 
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WR169 wrote:
Who's dyno?


Lynn Ray of Lynn's Speed and Custom. He's in Midway, near Lexington.

want-a-be wrote:
Chuck,

I always do the initial start up with out water in the engine. On the dyno or between the frame rails. Just long enough to set the initial timing and engine idle.

Don


Is that to help seal the head gaskets or do you have another reason?

So who else has an opinion on breaking it in with the vacuum pump belt off?

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 Post subject: Re: Engine upgrade
 Post Posted: Tue May 01, 2012 11:14 pm 
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I think it's part of it,.... Allows for the engine to heat up pretty quick. Which lets things settle quicker. I like to go through everything while everything cools down. Bolts, lash, anything else that may need checked. Oil pressure.

If anything stupid happens during that initial firing, you don't have to deal with draining the block. Just something I was taught early on by those that mentored me in the old days. It just stuck.

Don

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 Post subject: Re: Engine upgrade
 Post Posted: Wed May 02, 2012 2:22 am 
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Doesnt anyone pull a sparkplug and look and tune anymore on a dyno.


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 Post subject: Re: Engine upgrade
 Post Posted: Wed May 02, 2012 5:10 am 
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shrinker, We know you have dyno'ed a lot of engines in your time so what is your plan of attack on the dyno???

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 Post subject: Re: Engine upgrade
 Post Posted: Wed May 02, 2012 5:45 am 
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I run the rings in and then do a low load pull and read the plugs. Then I creep up to high load pulls by reading the plugs all the time. I do the first series of high load pulls at a static pull RPM fixed mode at a RPM that is in the cam sweet spot but not at the maximum RPM. The pull will usually only be a half a second long or so. I don't ramp the engines until I'm positive the readings are all good and the plugs are correct. I usually back the timing off 2 degrees or so from what I expect will be best based upon how much compression pressure the engine has and how its reading the plugs with the fueling I'm giving it. I can tell what an engines personality is that way.
After a full day on the engine dyno the engine may go in the car and then I start it all over again, I run the rings in if I feel like it because sometimes the engine dyno is not enough to do that. Rings take a LONG time to settle and the combustion gases change over days of tuning. I'm talking about big power engines here, 500hp ones are nothing, stuff thats making over 2hp per cube is fussy.
I take around 3 days on a chassis dyno to get an engine right but its a cracker when I'm finished. Its not 3 days of tuning and changing parts, its 3 days of working out the combustion sequence of the engine and how to redesign the fueling and ignition to optimize it.


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 Post subject: Re: Engine upgrade
 Post Posted: Wed May 02, 2012 5:46 am 
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Notice how many times I read the plugs.


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 Post subject: Re: Engine upgrade
 Post Posted: Wed May 02, 2012 7:49 am 
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Good luck Chuck. I have no advicefor ya. I've only watched one.

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 Post subject: Re: Engine upgrade
 Post Posted: Wed May 02, 2012 10:33 am 
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gearhead1011 wrote:
1. So after I'm done on the dyno I can switch to the synthetic?

2. Got it.

3. & 5. Tim said this should want around 34* of timing so I guess I'll start around 30* then go up a couple * at a time after getting the jetting right.

4. I don't really know what happened to number 4 :-k

5. see number 3.

6. He said he uses EGT and BSFC and has had good results with it. I have a dual wide band monitor on the way but I might have to adapt the connectors for my O2s. What should I shoot for on the AFR? Do you usually have to jet up a little once it's in the car?

7. Got it.

I assumed I would be doing the tuning, he's a Chevy guy and I don't know if he can be trusted with a Ford (J/K). He said it's a D-Pak with a Go Power brake. I will take my weather station with me to verify conditions.

Thanks!

1. You can switch after it all or after 8-10 pulls.
6. EGT and BSFC are neither very useful for determining fuel mixture unless you are dealing with a known engine combo you have worked with many times. You or he won't know what EGT or bsfc to expect with your new engine.

I don't know what data the Depac saves, but if he exports or saves any and all data that he can from the system for all of your runs and you get a copy of the file I might be able to dissect it and get it put into a spreadsheet.

Another thing to remember is to make sure to enter the changes religiously in the dyno to make sure you know what did what later. It can get confusing and you won't have as much time as you'll want to try things.

Rick


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 Post subject: Re: Engine upgrade
 Post Posted: Wed May 02, 2012 9:41 pm 
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rick360 wrote:
6. EGT and BSFC are neither very useful for determining fuel mixture unless you are dealing with a known engine combo you have worked with many times. You or he won't know what EGT or bsfc to expect with your new engine.Rick

Absolutely Correct.
I'm currently running a nascar engine with 8 O2's and 8 egt's. If you were to tune off the EGT's you would be wrong, The WB's show cylinder variation with all the cylinders being a flat AFR all the way up the rev range but the AFR is different on some cylinders. I think there is an issue with the inlet manifold and the way the air turns the corner into the runner. The plenum is not as per original use of the engine either so who knows. The EGT' variation does not match with the O2 data. A hot cylinder EGT is not a lean or a rich cylinder O2 wise, there is no correlation between the 2. The sparkplugs however show correct deposit formation nearly perfectly equal on all cylinders, so I'm not concerned for the engines welfare. It has had 400 US gallons of gasoline put through it so far and its got less than 4% leak on all cylinders.

So I'm saying that observing the signs of an engine with your eyes and ears and a borescope etc is more important than believing meters. Look at the piston tops with a bore scope or even a strong light and just look down the plug hole if you can. These areas are the real areas to look at in an engine, you could be hurting the piston top slowly and an O2 or an EGT wont tell you.
I look at the oxidization of the sparkplug electrodes, this usually correlates with the intensity of color tanning or lack of tanning. Once you know the AFR I expect a certain reaction at the plugs etc, If I dont get it I stop running the engine, try to figure a solution and test that, then after I'm happy or not I continue testing or send the guy home to pull the engine apart. It's pretty tough I know but people always do it and then discover what there missing.

The signals that one can observe of a sparkplug and piston top correlate very very well with the gas species being produced as read by a gas bench. The gas bench is the best tool to have, it reveals all and yet you would struggle to find a dyno operator who has one or even knows how to interpret one correctly and how it relates to combustion issues.


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 Post subject: Re: Engine upgrade
 Post Posted: Fri May 04, 2012 11:56 am 
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OK, I posted this morning but can see there was a board problem and it got lost.

The deal with the O2 monitor fell through so I will have to dyno without that. I do have a borescope so I can inspect the piston tops but I need to know what to look for. I will try reading the plugs so if anyone has any pointers on that I would appreciate it. The main reason for dynoing this was to break it in and get an idea of what kind of power it will make so I can try to set up the rest of the car accordingly. Getting the tune right should have been a bonus. I believe the EGTs will tell me if the tune is far enough off to hurt anything. I figured I would have to fine tune once it's in the car anyway so if I get close it should do. Should I start a little rich and jet down until it makes it's best power? I figured I would leave it a little rich until I got it to the track anyway, thinking that between the movement of the car and the air pushing into the scoop would change things anyway. I have 2 O2s in the car and that will be more realistic anyway. I'm running out of time so if I don't dyno tomorrow I probably won't at all.

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 Post subject: Re: Engine upgrade
 Post Posted: Fri May 04, 2012 8:16 pm 
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An efficiently operating engine will color the plugs in a few seconds. Over time the color will become more dense but the basic color will be there easy to see in a few seconds of load. Light tan is what to aim for. Dark tan is bit excessive it means its a bit too rich. Black is ridiculous. Cold areas like the shell may show black because the heat isnt enough to promote carbon burn. Hydrogen burns first and leaves behind carbon to fend for itself, the conditions have to be right for carbon to burn.
The electrode edge, specifically the corner of the center electrode where the circumference meets the flat, should not burn away. Closely inspect that area with at least a 15x loupe. Its the area where oxygen attacks the metal the most. Its also the area where the electricity prefers to conduct from. If this area is eroding away or melting, the environment is over supplied with oxygen at ignition time (assuming its a cold enough plug).
The strap electrode should gather tan deposits, if the strap is overheated it wont.
The so called "timing line" is incorrect analysis although its touted by people who think they know. The light colored line part way along the strap electrode is actually a metal oxidation point caused by the stressing of the metal and fracturing during the bending process. It has no diagnostic value to the ignition timing decision although it may seem to coincide. It is easier to see the "timing mark" when the vaporization is not optimal. Fix the vaporization, gain power and this "feature" disappears. The "timing line" is able to be moved for instance further down toward the shell by advancing the timing but that's because of the inter-relationship of the timing with the vaporization curve. If you ignite when the vaporization is still accelerating the timing mark is able to be moved by altering timing. If the vaporization is reasonably complete this is not so.
The piston tops should be inspected for burn patterns and checked for aluminum depletion. Piston tops take much longer than plugs to show deposits.


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 Post subject: Re: Engine upgrade
 Post Posted: Sun May 06, 2012 9:40 pm 
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Chuck did you get it on the dyno?

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 Post subject: Re: Engine upgrade
 Post Posted: Sun May 06, 2012 9:50 pm 
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Yeah what's the deal?

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 Post subject: Re: Engine upgrade
 Post Posted: Mon May 07, 2012 12:27 am 
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Been a busy weekend and I hadn't had a chance to post. I didn't get back from the dyno until late Saturday then went to Beech Bend with a friend after church this morning.

I did get it on the dyno and I'm happy with the results. We did get it broke in and the tune about as close as I think it gets until I get it to the track. After a long run in with a light load then setting the valve lash he made a light pull to 5,500 and he said it didn't sound right. I had left the jets way rich from the 370 so we jetted down to 84 & 94 (with power valve) and it ran much better. After several pulls, jet changes, checking spark plugs & the oil filter then one more jet change we made some harder pulls. When we tried to pull it to 7500 something started to malfunction on the brake and it was throwing some sparks. Lynn wasn't too concerned about it at that point because he thought it was just the starter drive bumping the flywheel. After checking a few things he tried another 7500 pull and the same thing happened again. Looked it over and tried it again this time it threw sparks and his tach on the control panel dropped out. He found a loose connector on the RPM sensor and tightened it up then tried one more time with the same result. I pulled the sensor out and found the exciter ring had rubbed a place in it. Then we spotted a badly gouged place in the flywheel ring gear that would indicate something was flexing pretty bad. So not wanting to send parts of his dyno through the building we decided it was in everyone's best interest to stop where we were at. I was disappointed because we never got to pull it past peak and all these pulls were on the renegade 110. I had borrowed some VP 113 from Steve and I didn't get a chance to try that. The good news is it made 800.4 HP @ 7300 and 599.9 ft. lbs. at 6400. I know that sounds a little low but Lynn described his dyno as stingy. He said this depac uses a different (more realistic) correction factor. He said it's about 6% less than what most dynos correct to and said my engine would make 848 HP on most any other dyno. I tried to get the dyno files but we couldn't find a floppy disc, go figure but I did get all of the printouts. I'm going to send him a couple and see if he can get the files to me.

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 Post subject: Re: Engine upgrade
 Post Posted: Mon May 07, 2012 1:41 am 
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shrinker wrote:
gearhead1011 wrote:
Is there a rule of thumb as far as how much less efficient an engine will be for anything over 3.625" stroke? I could see where if you are running a class (ie weight per CI) maximizing the efficiency of a combination would be important but what I'm wanting is the most power per dollar.

Nope no rules of thumb. And you will make more power per dollar with bigger cubes from stroke but it wont be as efficient at fuel conversion and it wont last as long wear wise. Its hard to quantify everything that goes on in regard to this subject because its an idea that forms in your head from experience not something that can be mathematically written down. My experiences tell me one thing but another persons may be something entirely different. It depends on what you value, do you value power per cube without regard to engine wear and vibration or smoothness of rotation? Do you value low down throttle response and linear reaction of throttle to power so that you can maximize the effort of a small tire? You could do a lot of thinking or you can just go and do something. Anything will work, its a matter of realizing what your final goal is.

All forms of motor sport develop a culture of design characteristics over time. In some cases that may be good, in others its a simple monkey see monkey do thing. My work is analyzing other peoples problems, I constantly see, poor vaporization at high RPM, not enough compression, insufficient ignition performance, poor exhaust performance.
One thing leads to another, the things I see occur one after the other in the engines cycle. My opinion is if the heads cant support it dont cam it to trick it, go get better heads. Or dont overstroke it so the heads are an issue.


The vibrations shaking the flywheel are from poor combustion. Ive seen it a few times, engines with poor combustion spark the starters etc on engine dynos.

Your pistons are dished, what that does is the squish action discharges into an open space NOT onto a ramp etc to direct the squish up and around the chamber (thus cleaning it out). I've seen your chamber shape result in very dirty combustion, the engines are not happy at high RPM. You will need to pay critical attention to the fueling and timing at high revs.
If you used a shorter stroke the piston would have a dome and the squish action would be better. However you would have less cubes and probably the same power but a more expensive valve train to run the revs to get the power. Or alternatively you could use a head with a larger CC chamber and then use a dome piston in that.
Thats just how I see it so please dont take offense. I think your engine could be made to be quite good but I fear its going to be a long road of tuning.


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