Author Topic: YouTube video of my flat crank SB Chevy barn find build and run  (Read 9193 times)

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Offline desotoman

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Re: YouTube video of my flat crank SB Chevy barn find build and run
« Reply #15 on: July 24, 2018, 09:57:48 PM »
Somebody please school me on the supposed advantages attributed to the flat crank.

Here you go Stan, advantages vs. disadvantages. Long strokes flat cranks are very hard on mains.

Tom G.


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Offline racergeo

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Re: YouTube video of my flat crank SB Chevy barn find build and run
« Reply #16 on: July 26, 2018, 11:23:09 PM »
   If you're not going to make SW I would appreciate a pre-entry. Thanks

Offline John Burk

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Re: YouTube video of my flat crank SB Chevy barn find build and run
« Reply #17 on: July 27, 2018, 02:46:34 PM »
The advantage of firing 2 pistons at once is fewer , stronger pulses to the drive tires for a traction advantage . Like anti lock brake pulsing . Dirt track motorcycles realized long ago that singles cornered faster than twins . Lots of mechanical problems and misinformation on this .

Offline harky

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Re: YouTube video of my flat crank SB Chevy barn find build and run
« Reply #18 on: July 27, 2018, 07:37:43 PM »
interesting thread
Repco engine developments ( in Australia ) made a flat plane crank for their F5000 engine
it was part of the Repco Holden F5000 project
( the engine was an Australian made 308 ci V8 , by the Australian devision  of GM —- called GMH )
these engines made over 500 hp , but had the vibration issues that have been discussed
I came on the scene after they had been used ( 1973/4 ) so the stories are second hand
needles fell off the tacho , the fuel tanks were part of the monocoque chassis. ( befor bag tanks ) and the vibrations caused them to leak , the driver complained of his vision be blurred.
the were reported to sound Fablous @ full noise , and were only used in competition for a very short time ,may be only once .
Repco was known for some of their other projects —- Repco Brabham , powered Jack Brabham F1 cars
« Last Edit: July 27, 2018, 07:41:19 PM by harky »
old mechanic
getting slower , but still interested in anything that goes FAST

Offline Rex Schimmer

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Re: YouTube video of my flat crank SB Chevy barn find build and run
« Reply #19 on: August 03, 2018, 04:03:33 PM »
I know that I have told this story before but it is worth another pass. Back in the late 70s sprint car racing at Ascot was pretty much "run what you brung"! No cu. inch limit, blowers were OK too. Well one team had a KB aluminum hemi of large proportions with a flat crank. It sounded great, but I was there one Saturday night when they were running. Drove it hard down into 3 and when he picked up the throttle there was a bang and then complete silence the car rolled to a stop after running over the crank with 8 rods and pistons laying on the ground! Hard on the mains is an understatement! It never returned as I remember.

Rex
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Offline jdincau

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Re: YouTube video of my flat crank SB Chevy barn find build and run
« Reply #20 on: August 03, 2018, 05:01:16 PM »
I know that I have told this story before but it is worth another pass. Back in the late 70s sprint car racing at Ascot was pretty much "run what you brung"! No cu. inch limit, blowers were OK too. Well one team had a KB aluminum hemi of large proportions with a flat crank. It sounded great, but I was there one Saturday night when they were running. Drove it hard down into 3 and when he picked up the throttle there was a bang and then complete silence the car rolled to a stop after running over the crank with 8 rods and pistons laying on the ground! Hard on the mains is an understatement! It never returned as I remember.

Rex
That's the one I remember, the sound was awesome.
Unless it's crazy, ambitious and delusional, it's not worth our time!

Offline racergeo

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Re: YouTube video of my flat crank SB Chevy barn find build and run
« Reply #21 on: February 11, 2019, 09:50:01 PM »
  Rex me boy, I heard that car. Back in the day I knew of the original sprint car "outlaw" Jan Opperman from a sprint car publication I got. He won about every race he went to. He was so good they offered him an Indy ride. I think it was contingent on him cutting his hair :roll: He qualified and finished well as I remember.  When my local dirt track brought him and a few CRA guys in for an "outlaw" against the locals race I went. The hemi car was about 5 octaves above all the other engines. It didn't go real fast but no one had heard of a hemi sprint car and it was quit novel. Opperman drove one of the locals cars and lapped the field. Afterwards he held kind of a religious revival for the fans that stayed to hear him. I had forgotten about that till reading your post. Was an honor to see such a gifted driver. Later I saw the hemi car at a CRA race on the old Ascot track in Cal. If I could come back as any kind of racer and have a supportive family and money and all the elements that make for success I would definitely choose "sprint car racer". :-)

Offline racergeo

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Re: YouTube video of my flat crank SB Chevy barn find build and run
« Reply #22 on: June 01, 2019, 02:05:40 AM »
   Unreal!!! On the "comments" of my YouTube Flat Plane video, several have doubted the claim I make that my engine was from the 50's.  I just found the cam card (on an 81/2 by 11 sheet) that the fellow send me at my request so I could have the firing order etc. I will be make another video with a picture of it showing the date 4-15-58 and the manufacturers description  CAM POSITIONS FOR 180* SINGLE PLANE C'SHAFT.  Neener neener neener. Oh and it just hit 125,000 views and over 2 million minutes viewing. Wow

Offline panic

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Re: YouTube video of my flat crank SB Chevy barn find build and run
« Reply #23 on: June 01, 2019, 08:50:43 AM »
The advantage of firing 2 pistons at once
Not how it works