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Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Mon Jan 23, 2023 7:11 pm
by agertz1
4L. Rovers, maybe 250 hp. ea. Snout of rear engine is splined and is plugged directly into rear of front crank. Indexed for firing at every 45 deg.
Harmonics should be "nodal" at this location ? Plan to use 2" and 2.3" journals on front crank and 2.188"/ 2.5" on rear crank,( even less harmonics) ?
Dry sump pump, distributors/ etc., driven in same area( aluminum casting between front/rear). Common girdle for both blocks,( deep Y).
Entire drive train is stress mounted in frame. Total vehicle weight about 1,600 lbs.
Suggestions ? Thanks, Art. :D

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Mon Jan 23, 2023 7:22 pm
by PackardV8
All I remember is what I was told fifty years ago from a guy who raced something similar. He said, 45-degrees seems like it should be the way to go, but keeping them in line at 90-degrees is what actually works best.

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Mon Jan 23, 2023 7:39 pm
by David Redszus
PackardV8 wrote: Mon Jan 23, 2023 7:22 pm All I remember is what I was told fifty years ago from a guy who raced something similar. He said, 45-degrees seems like it should be the way to go, but keeping them in line at 90-degrees is what actually works best.
Fifty years ago, Porsche linked two 911 engines in series to create the 917. Beat everything in sight.
Pay attention to crankshaft torsional harmonics.

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Mon Jan 23, 2023 8:11 pm
by BOOT

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Mon Jan 23, 2023 8:47 pm
by KnightEngines
PackardV8 wrote: Mon Jan 23, 2023 7:22 pm All I remember is what I was told fifty years ago from a guy who raced something similar. He said, 45-degrees seems like it should be the way to go, but keeping them in line at 90-degrees is what actually works best.
Twin engine race boats the same thing was found, having the engines fire together was much kinder on the coupling.
45 deg apart tore shit up fast.

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Mon Jan 23, 2023 10:14 pm
by jsgarage
Can't remember now-its been quite a while. The Ford GT-90 cocept car had a V-16 with two V-8 blocks welded together but the details of the build escape me.

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Mon Jan 23, 2023 11:04 pm
by Truckedup
I'm one of the very few still running junk like this....two 360 degree twins, front left cylinder fires 5 degrees before the right rear .......like a big twin and the least amount of chain drive harmonics..

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Mon Jan 23, 2023 11:21 pm
by Baprace
At the US Nationals a few guys ran dragsters with inline engines timed at 90-degrees with great success, couple of guy's tried 45 degrees and 45 shook like hell. The twin engines allowed the sbc go 200 mph , IIRC it ran 190 all day long on one engine.

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Tue Jan 24, 2023 8:03 am
by bobmc
we need to hear Mr Knight's twin engine experience on this subject, also the tv show from Nashville maybe called "Engine Power" dynoed 2 engines rigged together

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Tue Jan 24, 2023 9:08 am
by n2omike
PowerNation did a test where they linked two Big Block Chevys together and dyno'd them.
I believe they tried two different ways of linking them... one in synch, the other 45 degrees, maybe?
Going by memory, but here it is.

Linking them together starts around 29 minutes into the video. Beginning is building the engines, dyno separately, discussing differences, etc.
This video is two episodes. The second episode is when they hooked them up phased differently. Neat how they used a mini spool and axles to join the engines.

https://www.youtube.com/watch?v=hKVfl5CfL3U

https://www.youtube.com/watch?v=rHCURLyt2_U

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Tue Jan 24, 2023 1:45 pm
by frnkeore
Chet Herbert ran his tandem, 215 Olds rail, with the engines coupled front to front. Reverse rotation on the front engine, of course. I saw the car in his shop, in the '60's but, I don't know if they were phased but, my guess is that he coupled them, based on the key position.

This picture was taken at Loins, I believe.

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Tue Jan 24, 2023 6:34 pm
by panic
Herbert did a 2 X 400 SBC, and remarked that he thought the bad vibrations were due to separate distributors. He was looking fo a Marmon, etc. V16 distributor.

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Tue Jan 24, 2023 6:59 pm
by agertz1
Using a dragster, twin-plug set-up. Two distributors on a common drive. Idea is somewhat old-school look, with some smarts added. Rocker cover,
spanning both engines, will be stress mounted, each side. Anyone have a good drive ratio, crank to dry-sump pump ?
Thanks, Art.

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Tue Jan 24, 2023 8:37 pm
by Tuner
Gene Adams is the guy to ask about this.

Re: Mating Two V8's, ( Freight Train) vs. Harmonics

Posted: Tue Jan 24, 2023 10:40 pm
by panic
Gene Adams, one of the greats, passed away last year.