Technical > Matt Shaff's Engine Shop

Coupling 2 engines

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denverflatheader:
JrFuel Hayden - very useful information, certainly clears the water.  "71 US Nats...  Freight Train, wish I could of been near the starting line to seen that race.  Thank you DF

ricardo1967:
Thanks Jon! Good info and nice pictures.

Welcome to the Front Engine Dragsters forum. Your knowledge will be very valuable here.

MaggiFinn:
This is on my "to do list"  8)

 I have heard you should clock the crankshafts 22.5° apart, so the rear crank only endures one powerstroke at a time.

 i have also gathered that its not hp+hp, but more like hp+hp x 0.75.

 For scientific facts, I've got nothing.

JrFuel Hayden:
Magnus, I agree 22.5° makes sense if only to allow the cranks to live longer. In 70-72 there were no RacePak computers like I use on our NHRA Heritage Jr Fuel now.  I would have loved to have all that feedback that I get now, back then. So clocking the cranks may be a good idea on flat heads, since there is a big difference with Flat Head cranks and BBC cranks.
When ever we raced the Top Gas car we always were asked "doesn't one of the engines hold back the other" but we always thought the extra engine added to the rear engine, "cup half empty vs cup half full" stuff. Again we didn't have any crankshaft issues, just valve train, because we were always trying to run more RPM. Like when we had a match race in Minn in 72, and we ran alky and it went real fast MPH and the motors got up over 10,000 rpm, = bent valves. Ah, another learning curve !

Bill, I don't remember Richie, but then again we never ran further East than Ohio back then, since I was living in Milwaukee Wisc.
The furthest East I ever raced was EnglishTown driving Jerry Newman's Top Fuel  John Buttera build RED on the way to our 73' Div 3 Top Fuel Championship.  Yes, "back-in-the-day" NHRA used to race Top Fuel at Division events.
 Maybe they should offer Nostalgia Top Fuel and N/FC to run Div races, that would put "butts in the seats".

Good Luck with the Flat Head project.
Jon     

janjon:
 I have heard you should clock the crankshafts 22.5° apart, so the rear crank only endures one powerstroke at a time.

 i have also gathered that its not hp+hp, but more like hp+hp x 0.75.

 For scientific facts, I've got nothing.


Maybe not scientific, but sounds pretty darn logical from an "eyeball engineering" standpoint. Which is all I have to rely on...

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