X-2sbc

[leegrady]

Along with my other projects, like the 81 GMC K2500, and my 95 T-Bird, and the replica 65 Daytona Coupe, (actually that's done) I've been experimenting with coupling two small block Chevy 350's together end to end. That's one right in front of the other.

So far I've welded the flywheel of the lead engine to the harmonic balancer of the trailing engine, and have it "installed" in a highly modified front end of a 71 Nova.

It runs, as long as I keep the rpm's down, but in a short period of time I'm "encouraged" to shut it down. They seem to want to rip each other apart, fighting each other because I can never get them to run in sync.

Eventually, I plan to run these twins in a early model GM truck. 60's, 70's, or early 80's square body. Full frame don't ya know. Make it streetable. Just the front clip is...well, longer.

My question is: I think my answer could be a viscous coupling. Perhaps a NP-203? Perhaps there are some tractor pull guys, gals, who might know of a small unit I could use between my two engines, or any other ideas. I've been to quite a bit of web-sites, but really don't know the engineering behind multi-engine machines.

Any suggestions will be greatly appreciated.

Thanks.

[69BBsuburban]

Ya need a line-up bar...a bar machined to fit the main bearings of both engines. Then an adapter can be made to bolt the two engines together. This ensures both engines are square to each other...
If the two engines aren't dead nuts "on", they'll eat the mains....even with a coupler....

[Damien]

Could a lovejoy coupler be used instead of a solid couple. this would allow for a little misalignment between the engines.
How did you set the engines up? Did you make it so both number 1 cylinders are firing at the same time? I think the phasing of the engines is the key. This guy in the link will not say how he does his,but he gives options on how "some people" do it.
http://www.holy-cow.org/faq.html#1

[leegrady]

Thanks for the reply. Very informative link. Thinking too the line up bar is simple. I like simple. Shouldn't be too much of a problem getting the two dead on. Still, the lovejoy coupler has no doubt been invented for a reason.

I thought of developing a way so that one distributor fires all 16 cylinders. Some kind of way to split the spark so that, for example, number 1 cyl. on the leading engine fires number 1 cyl. on the trailing engine using a high performance ignition system or magneto.

As it is I just fire 'um up, and see what happens. It didn't work out very well.

[slipkorn34]

some research on the v12 702 might help too since gm did the same thing with 2 351 v6 engines, but it has 2 distributors both in the front

that has one crankshaft though and maybe one cam. anyway theres a few people on here who have rebuilt them

[69BBsuburban]

Originally Posted by leegrady

Still, the lovejoy coupler has no doubt been invented for a reason.

Lovejoy couplers are for industrial applications.....low RPM and ease of removing engine from what ever the engine is turning, usually a hyd. or water pump....
There's no way in hell I'd trust a Lovejoy between a pair of high winding small blocks...the higher the RPM's, the closer yer tolerances need to be...and Lovejoy style couplers are sloppy.

[slipkorn34]

i wonder if you could attatch something like a flywheel or flex plate to the seccond motor essentially making it like it had one crank with the flywheel in the center, youd have to support the engines perfectly alligned to eachother of course but if you know someone with a copy mill that shouldnt be extremely hard....just very very hard haha

[liftmeup]

Get on the pulling tractor/truck sites lots of twin SB and BBC on there ! all the info you will ever need.