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briang
United Kingdom
218 Posts |
 Posted - 14/06/2010 : 23:12:28
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I plan to make a sump guard to protect my J2's very pretty little sump on trials hills.
Common sense suggests a folded mild steel plate, bolted across the chassis rails
I would think it should also have a sloping piece at the front to allow me to surf along
And maybe even a similarly sloped rear, for going back down when I fail to get to the top...!
Any other design considerations I haven't thought of?
Anyone know of a dimensioned drawing available?
Is it worth trying to protect any other vital bits of undercarriage?
Brian |
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Bob Stringfield
United Kingdom
854 Posts |
Posted - 15/06/2010 : 15:22:30
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| My I.S.D.T ( The motor cycle Olympics) 250 Cross-Country M.Z. motor cycle has a triangular sump-guard with an outer frame of steel tubing fore and aft, the actual bash plate made of steel drilled with Icm. holes, letting water out and cooling air in. That construction seems ideal. |
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PeterL
United Kingdom
1722 Posts |
Posted - 15/06/2010 : 19:03:44
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You might want to consider keeping the distributor dry too...
Cheers
P |
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JMH
United Kingdom
911 Posts |
Posted - 15/06/2010 : 20:15:15
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I'm pretty sure you can get to fit a J2 on the market - there's one in the back of our garage. I think it weighs about as much as the J2! If I recall, it's all steel, so an alloy version would probably be a good idea. I'll take a photo next time I'm up the hill & send it to you. Hope you've got a blower........
JH |
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David R
United Kingdom
289 Posts |
Posted - 16/06/2010 : 22:07:59
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Brian
I spent many years doing some serious rallying in everything from an MGA to a 6R4 Metro,and I am sure some of the car preparation would apply equally to a Trials car.I also have done many Production Car Trials.
The aim of underbody preparation is obviously to have everything as smooth as possible to ride obstacles and to prevent crucial bits being damaged or knocked off. Therefore time lying underneath having a look at everything is not wasted.Starting at the front the number plate needs to be lifted out of the way.Sumpguards need to be at least an 1/8th inch thick or preferably 1/4 inch,and obviously because of the weight alloy is preferable to steel.The guard should be smoothly curved at the front and drilled with cooling holes in the curved part even upto an inch in diameter.I do not think it necessary to curve the rear of the guard,indeed I do not see it would be practible.However,beware of stones getting trapped between the sump and guard and do not pack foam rubber between.Airflow is crucial and a compromise with ground clearance.Do not mount the guard on anything much weaker or you will damage the mounting points.Try to bolt the guard to the sides of rails or at least avoid the mounting bolts hanging down where they can get bent or snapped off or at least have the bolt heads and not the nuts protruding.The guard can be extended with lighter gauge metal to provide a gearbox guard if only to protect the drain plug.
The silencer needs protecting at its forward end by a lightweight triangular plate welded to the exhaust pipe and back to the bottom edges of the box to minimize any impact.If you can fabricate a similar skid plate at the lowest extremity of the down pipe,so much the better.Extra exhaust mountings are a good idea,preferably flexible fabric or rubber ones and not the rubber ring type.
The battery is also vulnerable but you probably can't raise it much.We used to lift Mini battery boxes into the boot.All you can probably do on a J2 is make sure the carrier is sound and firmly fixed and put an 1/8th inch plate on the bottom of it.Make sure the terminals are well insulated and cannot easily be knocked into any part of the body.
Cables and pipes ideally should run through the car or at least be firmly clipped out of the way.If necessary protect vulnerable bits with light plates.
Generally make sure as little as possible hangs down underneath,and bolt heads rather than nuts and surplus bolt threads protrude. Wire lock anything that could vibrate loose and check everything regularly for tightness. Waterproof electrics,the distributor with a rubber cover as suggested but also the coil and crucial connections such as the starter switch and the dynamo and starter terminals with rubber terminal covers packed with suitable water repellant.
Hope some of this is helpful. Certainly brings back memories of a mis-spent youth (and middle-age!).
David R
(J 3355)
The silencer bo |
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