[OneMoreTime]

Actually it works fairly well and the sync'ing of the 2 engines is not a big deal as all one needs to do is index the cranks together and make sure you are running the same timing on both of them..the throttle linkage is made with the small heim joints and the carbs or injectors are set up similar to a dual four or tri-power setup..the main issue back in the day was tires as we did not have the kind of tires we have today.

Weight is also a factor as the single engine guys has less of that to deal with and of course with the modern engine tech some fantastic HP is available..If I were to build for the tractor pulls dual or multiple engines are the way to go as that is a torque game to move those loads that they pull..

Sam

[bentwings]

With the advent of the coupler rather than the chain drive connecting the engines was not a problem. Small blocks still had a weak crank snout however.
The Freight Train with 2 small block was very consistant and very popular. They may have had either welded or billit cranks with BBC sized snouts. The 392's however were starting to take over as the tire tech caught up and larger tires were available the last year that twins were run. The 2 speed non overdrive trans was also available.

The reason that the twins began to dominate the Top Gas was that we weighed about 1450 rolling. The twins simply added about 700 pouns for the motor and no significant additional chassis weight. So the power to weight ratio immediately went to the twins. Add bigger tires and a transmission and us single guys simply got left in the dust. Granted there were a very few singles that managed to stay one mistake behind but on a dead even start money went to the twin.

Now even the twins ran hard so they occasionaly burned pistons and their reliability was quite a bit lower so they sometimes got left holding the bag with only 1 motor. We never missed a chance to eat their lunch on those days. haha The twins had the motors set way back so when running on only one they were at a disadvantage due to the cg position and too large of tire. The clutch was adjustable but not easily for this much power change.

[jalopy45]

Here's what we use on our twin dragster ,

[jalopy45]

That is a coupler used on trailer mounted industrial waste pumps and allows indexing every 22.5 degrees The rail is a twin engine 4 cylinder rail and the timing is set so 45 degrees after cylinder one fires on the front engine cylinder 2 fires on number 2 engine and allows me to use one distributor to fire both engines., ,

[cobalt327]

Originally Posted by jalopy45

That is a coupler used on trailer mounted industrial waste pumps and allows indexing every 22.5 degrees The rail is a twin engine 4 cylinder rail and the timing is set so 45 degrees after cylinder one fires on the front engine cylinder 2 fires on number 2 engine and allows me to use one distributor to fire both engines.

VERY cool. The first picture looked really "industrial", almost like it was made by Caterpillar or something, but seeing it from a different prospective changes that perception.

What kind of times and speeds does it run? Does it 60' well?

[dinger]

Jalopy, do the number 1 cylinders fire at the same time? I am a bit confused. If they do, is the spark strong enough to fire both cylinders at the same time. That is one interesting set-up, do you ever get to Famoso with the car?

[jalopy45]

The front engine fires cylinder one, 45 degrees later the rear engine fires cylinder one and so on down the line, the firing orders on both engines are stock (1-3-4-2) so it works out 1 cylinder fires every 45 degrees (45X8=360), it smooths out the harmonics as well, use this sme method on V8 and you could fire the engines every 22.5 degrees.

[bentwings]

I see you have a ground wire between the block and the head on each motor. Interesting concept. I have that also on my SBC. This has been an off and on again thing for years. It sometimes cures mysterious electrical problems. Sure doesn't hurt.

[malc]

Saw on the BS Blog and thought it´d be just right for this thread.
Building a Twin Engine Dragster From Scratch

[ogre]

very interesting setup jalopy.
2 engines 1 dist.

this post get more interesting all the time..

[Studebaker]

Ok, That is serious cool, looks like 153 chevy 4 cylinders but does the SBC valve cover fit these engines? Thats what the covers look like. So the coupler you used is like the coupler between the motor and pump on like a septic tank pumper truck?. This what hot rodding is all about, never gets dull!

[jalopy45]

Those are SBC valve covers but attached using adaptors. those industrial connnectors are availale with a miriad of spline combinations.

[Jake_Dragon]

Originally Posted by muddbogg

So with that I would like to know about setting up a engine in the front and back of something using caddy or olds like that....Fiero?VW?

Well the Fiero uses a front wheel drive transmission so you could build a car with 2 of them.
I have a SBC 350 bored 60 over and used an adapter plate to mount it to the stock 5 speed.

[sqzbox]

Originally Posted by jalopy45

That is a coupler used on trailer mounted industrial waste pumps and allows indexing every 22.5 degrees The rail is a twin engine 4 cylinder rail and the timing is set so 45 degrees after cylinder one fires on the front engine cylinder 2 fires on number 2 engine and allows me to use one distributor to fire both engines

One would think that coupling two engines like that would create a lot of vibration. How do you dampen that?

[jalopy45]

Originally Posted by sqzbox

One would think that coupling two engines like that would create a lot of vibration. How do you dampen that?

I do use a FluidDamper on each engine but I'm not wholly convinced I needed them. The original engines did not use a vibration damper and with the 2 engines phased the way they are it runs smoother than a single 4 cylinder firing every 90 degrees., ,