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Engine Masters rod ratio test results

General engine tech -- Drag Racing to Circle Track

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Re: Engine Masters rod ratio test results

Post by Tuner » Thu Mar 12, 2020 4:58 pm

David Redszus wrote:
Tue Mar 10, 2020 5:49 pm
"I have yet to meet the racer (or engine builder) who knows the actual timing curve of his engine while on the track."
I have confidence the curve seen on a distributor machine and confirmed in the engine, on a dyno or not, is what you get on the track.
You're kidding, right?

For vintage ignitions tuned on a distributor machine, track results are very often affected by shaft end play,
point bounce and jitter, coil over heating, loose electrical connections, cylinder pressure and temperature variations and a whole bunch more.

For electronic ignitions we have measured ignition lag due to switching delays, heat buildup of coil and ignition box and a whole bunch more.

For mapped ignitions, we have measured variances from the map due to input errors, sensor errors and incorrect mapping. With multiple inputs used to drive ignition maps, it is often not possible to accurately predict actual curves.

The cool thing about ECUs and data loggers is that you can see and measure invisible variables.
The sad thing about ECUs and data loggers is that you can see and measure invisible variables.
I have confidence the curve seen on a distributor machine and confirmed in the engine, on a dyno or not, is what you get on the track.
You're kidding, right?
No, are you?

Do you own a distributor machine? How much actual experience do you have repairing distributors and using distributor machines to calibrate advance curves, hours, days, years, decades?

Have you ever gathered timing information on a dyno in 500 or 1000 RPM steps through an engine's full RPM range to maximum engine speed, used a distributor machine to apply that information and confirmed the results on the dyno?

You present a good argument that a vintage mechanical distributor can be a more accurate ignition timing device than an ECU. What do you consider a good vintage?

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Re: Engine Masters rod ratio test results

Post by Tuner » Thu Mar 12, 2020 5:01 pm

maxracesoftware wrote:
Tue Mar 10, 2020 12:58 pm
Stan Weiss wrote:
Mon Mar 09, 2020 12:35 am
Where are these dyno sheets at ?

If you have accurate dyno room weather data (BP, VP, TEMP), fuel lbs/hr and A/F ratio. SCFM can be calculated.

Stan
i'm likewise wondering :
Where are these dyno sheets at ???

anyone have a web Link to these Dyno Sheets ??
Don't want to lose track of the subject of this thread, comparing the rod lengths.

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Re: Engine Masters rod ratio test results

Post by David Redszus » Fri Mar 13, 2020 12:48 am

Do you own a distributor machine?
Yes, it has been modified to accept electronic distributors as well as points, centrifugal types. It has a the ability to fire 8 spark plugs which can be observed with a magnifier and a variable pressure chamber with primary and secondary traces visible on a scope.
How much actual experience do you have repairing distributors and using distributor machines to calibrate advance curves, hours, days, years, decades?
Over 45 years of restoring (never merely repairing), recurving advance curves, removing bounce and jitter at high rpms, and indexing the proper firing interval between cylinders.
Also graphing the advance curves so the distributor can be correctly installed in the engine.
Have you ever gathered timing information on a dyno in 500 or 1000 RPM steps through an engine's full RPM range to maximum engine speed, used a distributor machine to apply that information and confirmed the results on the dyno?
No. We gather engine data using high speed logging directly from the engine while it is on the race track. Data in rpm steps is bogus. A higher sampling rate will produce smooth data curves that can be fed into engine simulations.
Dyno tuning is only a beginning step toward track winning performance.

We sell and service engine management systems (MoTec), and perform the ignition and fuel mapping as well. Our history includes vintage high pressure fuel injection systems as well.
You present a good argument that a vintage mechanical distributor can be a more accurate ignition timing device than an ECU.
Forty to fifty years ago, even Formula One engines used mechanical distributors, (sometimes more than one), quite successfully. Then we went through a series of changes including: magnetic triggers, optical triggers, Hall Effect triggers, transistor switch boxes, CDI boxes, hybrid systems, individual coils per cylinder, etc. Did I mention knock retard system ignitions? While the management of the systems improved, not much has changed in the plug gap.

Whatever the device, if it misfires or does not have the proper interval and curve, it is not a performance part.
What do you consider a good vintage?
I will admit my bias. Since we have worked with Bosch for so many years and received so much technical assistance from them (still do), they are my vintage preference.
With regard to current technology, either the MoTec or factory systems with reprogramming, and linked to a quality
data logger is my choice (requirement).

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Re: Engine Masters rod ratio test results

Post by maxracesoftware » Fri Mar 13, 2020 3:08 am

Over 45 years of restoring (never merely repairing), recurving advance curves, removing bounce and jitter at high rpms, and indexing the proper firing interval between cylinders.
Also graphing the advance curves so the distributor can be correctly installed in the engine.
48 years :D
my Marquette Distributor Machine ( purchased 1972 ) ... made my own Spark Plug load bar w/adjustable Plug Gaps
what i did was experiment with 5 or so Distributors that would start missing at certain RPMs
adjusted Plug Gaps until Distributor Machine should same RPM as Race Car or Dyno
and its worked great all these years with that Gap ... and correlates within +- 100 RPMs on Dyno
this Pic in 1980's
still works in 2020 ... moved it into Dyno Engine Room years ago .
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Re: Engine Masters rod ratio test results

Post by David Redszus » Fri Mar 13, 2020 2:36 pm

maxracesoftware wrote:
Fri Mar 13, 2020 3:08 am
Over 45 years of restoring (never merely repairing), recurving advance curves, removing bounce and jitter at high rpms, and indexing the proper firing interval between cylinders.
Also graphing the advance curves so the distributor can be correctly installed in the engine.
48 years :D
my Marquette Distributor Machine ( purchased 1972 ) ... made my own Spark Plug load bar w/adjustable Plug Gaps
what i did was experiment with 5 or so Distributors that would start missing at certain RPMs
adjusted Plug Gaps until Distributor Machine should same RPM as Race Car or Dyno
and its worked great all these years with that Gap ... and correlates within +- 100 RPMs on Dyno
this Pic in 1980's
still works in 2020 ... moved it into Dyno Engine Room years ago .
Nice set up, looks somewhat similar to mine.

I have noticed a considerable difference in required firing voltage when firing plugs into a pressure
chamber compared to free air. As the pressure goes up, the voltage requirement does as well and the
spark duration diminishes until misfires occur.

Combining a scope with the distributor machine results in one of the most useful tools in the shop.

With a multi channel scope, various spark plug secondary wires can be tested as well. Some name brands
are not much (if at all) better than OEM wires.

Run the test bench with the shop lights turned off and watch the light show. All that is missing is a guitar. 8)

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Re: Engine Masters rod ratio test results

Post by maxracesoftware » Fri Mar 13, 2020 4:31 pm

David Redszus wrote:
Fri Mar 13, 2020 2:36 pm
maxracesoftware wrote:
Fri Mar 13, 2020 3:08 am
Over 45 years of restoring (never merely repairing), recurving advance curves, removing bounce and jitter at high rpms, and indexing the proper firing interval between cylinders.
Also graphing the advance curves so the distributor can be correctly installed in the engine.
48 years :D
my Marquette Distributor Machine ( purchased 1972 ) ... made my own Spark Plug load bar w/adjustable Plug Gaps
what i did was experiment with 5 or so Distributors that would start missing at certain RPMs
adjusted Plug Gaps until Distributor Machine should same RPM as Race Car or Dyno
and its worked great all these years with that Gap ... and correlates within +- 100 RPMs on Dyno
this Pic in 1980's
still works in 2020 ... moved it into Dyno Engine Room years ago .
Nice set up, looks somewhat similar to mine.

I have noticed a considerable difference in required firing voltage when firing plugs into a pressure
chamber compared to free air. As the pressure goes up, the voltage requirement does as well and the
spark duration diminishes until misfires occur.

Combining a scope with the distributor machine results in one of the most useful tools in the shop.

With a multi channel scope, various spark plug secondary wires can be tested as well. Some name brands
are not much (if at all) better than OEM wires.

Run the test bench with the shop lights turned off and watch the light show. All that is missing is a guitar. 8)
i also had the Marquette Oscilloscope hooked a few times with Distributor Machine as well as a few times on the Dyno
i wish i would have not sold the Marquette Oscilloscope to a friend :(

i also back-to-back old Champion Spark Plug checker w/Air pressure Psi -vs- what i was seeing on Dyno + Distributor Machine
played around with modififying Plug ground straps to J-style and J-style pointed end-shapes in 1970's
modified many Distributor single point-plates to for 32oz ? Accel dual-points
used clear distributor caps for more testing
really cool at nite to turn lights off in the Shop and spin a Distributor hooked up to my Spark Plug Load-Board
and watch + hear MSD fire multiple sparks at low to mid RPM then change to lesser multiple sparks at highr RPMs
could spin a Magneto to 9500 RPM , and normal distributors to 11,000 RPMs easily , optional higher HP electric motor
... also cool was smell of Ozone from MSD sparks

i'll Post a Pic of my Marquette Oscilloscope later today or tonite :)
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http://www.maxracesoftwares.com
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Re: Engine Masters rod ratio test results

Post by Tuner » Sat Mar 14, 2020 12:22 am

You guys are "bringing a tear to me one good eye." :D I have the same rigging and been doing the same spark gap and oscilloscope games since the early '70s. What a long strange trip it's been. First played with a couple of my father's friends' distributor machines in the 50s in grade school, used the same machines with purpose in high school, got serious with borrowed machines in the mid 60s and got my first machine in 1972, oscilloscope in '75 and still use a DM every few days, plan to tomorrow or Sunday.

Have you fired an ignition on your spark rack or a plug gap and blown on the gap with a shop air nozzle or your breath and watched the arc move out of the gap to the plug shell? If you use a rubber vacuum line to blow on the gap with your mouth, be aware the hose will conduct electricity. High resistance, but none the less a conductor with the moisture of your breath.

In this forum a few times I have mentioned high RPM advance curves and posted a recipe for HEI distributors to make a curve that advances about 1 degree per 1000 from 3000 to 8000 + . Have either of you calibrated distributors with high RPM curves such as this, HEI or otherwise?

Have you noticed it seems the "short rod" engines benefit more dramatically from the correct high RPM curve?

Mr. Redszus, amongst all the files and data logs you have accumulated in Motec and dyno results isn't there a means to ascertain a trend relating spark advance to this short vs. long rod issue?

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Re: Engine Masters rod ratio test results

Post by ClassAct » Sat Mar 14, 2020 12:37 pm

Tuner wrote:
Sat Mar 14, 2020 12:22 am
You guys are "bringing a tear to me one good eye." :D I have the same rigging and been doing the same spark gap and oscilloscope games since the early '70s. What a long strange trip it's been. First played with a couple of my father's friends' distributor machines in the 50s in grade school, used the same machines with purpose in high school, got serious with borrowed machines in the mid 60s and got my first machine in 1972, oscilloscope in '75 and still use a DM every few days, plan to tomorrow or Sunday.

Have you fired an ignition on your spark rack or a plug gap and blown on the gap with a shop air nozzle or your breath and watched the arc move out of the gap to the plug shell? If you use a rubber vacuum line to blow on the gap with your mouth, be aware the hose will conduct electricity. High resistance, but none the less a conductor with the moisture of your breath.

In this forum a few times I have mentioned high RPM advance curves and posted a recipe for HEI distributors to make a curve that advances about 1 degree per 1000 from 3000 to 8000 + . Have either of you calibrated distributors with high RPM curves such as this, HEI or otherwise?

Have you noticed it seems the "short rod" engines benefit more dramatically from the correct high RPM curve?

Mr. Redszus, amongst all the files and data logs you have accumulated in Motec and dyno results isn't there a means to ascertain a trend relating spark advance to this short vs. long rod issue?


Exellent post Tuner, but I have some questions.

How do you change the gap on your spark rack.

And about paragraph two...do you know this as an old wives tale, or have you experienced being shocked while blowing on a runner hose to watch the spark moving across the gap?

TIA

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Re: Engine Masters rod ratio test results

Post by swampbuggy » Sat Mar 14, 2020 11:39 pm

In a high performance engine, especially a high RPM/ race engine, the longer connecting rod has more points scored in the plus column than shorter rod setup. This is MPO. Now that the train is back on the tracks, LOL Mark H.

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Re: Engine Masters rod ratio test results

Post by treyrags » Sun Mar 15, 2020 3:01 pm

The race engine builders I have seen are more concerned with getting the deck as low as possible to straighten out the intake track as much as they can. Whatever rod length that requires is what they end up with, within reason.

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Re: Engine Masters rod ratio test results

Post by Walter R. Malik » Sun Mar 15, 2020 4:04 pm

treyrags wrote:
Sun Mar 15, 2020 3:01 pm
The race engine builders I have seen are more concerned with getting the deck as low as possible to straighten out the intake track as much as they can. Whatever rod length that requires is what they end up with, within reason.
That sure is one reason ...
Back in the 90's when stock deck height was required for Trans Am racing, we used a 6.300" length rod with a 3" stroke in the 18 degree, 309 Chevys, simply to get the piston a lot lighter. That reciprocating weight was a whole lot more important than whatever the rod length needed to be.
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Re: Engine Masters rod ratio test results

Post by Little Mouse » Sun Mar 15, 2020 4:09 pm

So what if sbc, you used a 3.00 stroke 6.50 length rod and 1.00 CH piston. 2.16 rod ratio
The piston would be light and with that short stroke and really long rod there would be little side loading on the rings and piston. Would it be dud performance wise compared to using a shorter rod, or no difference in a negative way. Howard's has a steel I beam rod 6.50 a bit heavy at 680 grams. Callies has a 6.30 rod 620 grams. These rods are in my affordable range $800.00 Howard's, $650.00 callies.
Last edited by Little Mouse on Sun Mar 15, 2020 4:23 pm, edited 2 times in total.

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Re: Engine Masters rod ratio test results

Post by Little Mouse » Sun Mar 15, 2020 4:20 pm

Walter R. What type and size 18 degree head was used on the 309 cu.

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Re: Engine Masters rod ratio test results

Post by gmrocket » Sun Mar 15, 2020 4:20 pm

Tuner wrote:
Sat Mar 14, 2020 12:22 am
You guys are "bringing a tear to me one good eye." :D I have the same rigging and been doing the same spark gap and oscilloscope games since the early '70s. What a long strange trip it's been. First played with a couple of my father's friends' distributor machines in the 50s in grade school, used the same machines with purpose in high school, got serious with borrowed machines in the mid 60s and got my first machine in 1972, oscilloscope in '75 and still use a DM every few days, plan to tomorrow or Sunday.

Have you fired an ignition on your spark rack or a plug gap and blown on the gap with a shop air nozzle or your breath and watched the arc move out of the gap to the plug shell? If you use a rubber vacuum line to blow on the gap with your mouth, be aware the hose will conduct electricity. High resistance, but none the less a conductor with the moisture of your breath.

In this forum a few times I have mentioned high RPM advance curves and posted a recipe for HEI distributors to make a curve that advances about 1 degree per 1000 from 3000 to 8000 + . Have either of you calibrated distributors with high RPM curves such as this, HEI or otherwise?

Have you noticed it seems the "short rod" engines benefit more dramatically from the correct high RPM curve?

Mr. Redszus, amongst all the files and data logs you have accumulated in Motec and dyno results isn't there a means to ascertain a trend relating spark advance to this short vs. long rod issue?
Your simply amazing...been at it since the 50’s

What do you think about high gear retard making a car run better?

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Re: Engine Masters rod ratio test results

Post by Walter R. Malik » Sun Mar 15, 2020 5:11 pm

Little Mouse wrote:
Sun Mar 15, 2020 4:20 pm
Walter R. What type and size 18 degree head was used on the 309 cu.
They were Chevrolet "BowTie" low port and high port heads depending upon what that team owner wanted. All those engines used the same Reed cam grind and Ryan Falconer steel, 1.6/1 rocker arms.
Of course, a lot of other teams had engines built elsewhere.
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