Unusual Gearbox Problem!

[Guest JonLeeper]

I have tried a search but come up with nothing like this, so here goes!

 

I am rebuilding an 80's kit car, Eagle SS, that is based on a VW Beetle floorpan. When I was investigating ways of actually making it work properly I decided that the best drive-line would be a mid mounted FWD engine and box driving the rear wheels. I was given a complete 306 S16, (XU10J4) so having investigated the engine, here on these forums, I decided that it was exactly what I needed. (It was reliable provided lots of torque and could be tuned (read turbocharged) easily later.) There was also a lot of good information available on the web for it.

 

I have finished preparing the chassis and have fitted the rear suspension arms off a Porsche 944, a common upgrade for VW Beetles to improve handling, and yesterday offered the engine up to see where the mounts would have to be. That is where I hit a major problem. The engine fitted first time and I thought all was well until i went to measure up for the mounting locations and realised that the engine was back to front. The bad news is that there is not enough room to fit the engine and gearbox the correct way round without fouling the suspension arms. This means that I can only make it fit with one forwards and five reverse gears! I stripped the gearbox off and tried offering it up to the block upside down but the differential housing and starter motor foul on the sump and I can only line up one mounting hole so that is not an act of war!

 

So after all that ramble my question is this, can I change the final drive rotation of the gearbox? Is it possible to reverse the crown wheel or some other part of the drive to give me the correct drive direction. The other line of attack would be to find a gearbox that rotates the opposite way and manufacture a method to fit that, but again my lack of knowledge means that I am not getting any luck here either.

 

I know that this is not a usual question for this forum but I am asking in as many places as I can hoping that someone will have a good idea. Any assistance or suggestions would be gratefully received.

 

Many thanks,

 

Jon

[ORB 227 1 Cars]

run the engine backwards

[Guest JonLeeper]

I did think about that but in reality I am not sure of the impact it would have on the engine.

 

To do all it would require is to wire up a starter motor that runs in the opposite direction which would spin the flywheel the wrong way. The crank and pistons would all still do the same thing just backwards. The cams are ground so that it should not make any difference, I think, and it would work. What effect it would have on the oil pump and other engine related systems I have absolutely no idea!

 

I'm pretty sure someone will be along soon and tell me why I am completely wrong and it cannot be done but I am reasonably sure it should not!

 

Jon

[M@tt 77]

wouldn't work i'm afraid

http://answers.yahoo.com/question/index?qi...04201048AAO6Hj7

 

oil pump would be blowing rather than sucking for one thing

 

your cams would need regrinding and you'd need verniers to set the timing.

 

also i'm not sure how parctical it would be to rewire the starter as the starter is earthed through the engine block so you'd either have to make your engine block live!! or insualte the starter from the block and fit an additional terminal to be able to reverse the polarity feeding it

Edited February 5, 2009 by M@tt

[tracktoy 0]

i'm sure i've read somewhere about a honda engine that runs backwards?? would probably cause more problems than it solves though lol

 

can you not fit the engine to a trans axle?- rear engine or mid

 

other than that i think its a case of redesigning the suspension around what you have

[GLPoomobile 958]

Prior to Honda's current K series engines, they previously ran in the opposite direction to what is conventional. That's why they had the gearbox on the drivers side. I believe they did this so that it gave better weight distribution, with the engine block on the passenger side. This is why until in recent years it was difficult to supercharge Honda engines (the Jackson Racing supercharge was about the only option), because they would spin the charger in the wrong direction unless a lot of custom work was put in to get the charge mounted correctly. Totally off topic, but I find it interesting

 

Another problem with running your engine in the wrong direction is that your smaller exhaust valves would become your inlet valves, and vice versa.

 

Have a look in to getting a Honda B, D, H or F series engine. Plentiful, strong and reliable engines, great gearboxes, and much more common to Turbocharge them than it has been to do so on Pug engines, so far more parts and knowledge about. Whether it will solve your problem I don't know, but worth checking out.

[timb1046 1]

nothing can be done on the diff? you seem to be looking at the direct output, im pretty sure that something would be possible away from the gearbox. such as on the diff?