Rallye_Mark
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 posted on 20/8/07 at 07:33 PM |
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Making a Bike engine Cradle.
I have sourced an R1 engine for my Locost and have just got a Granada Scorpio Cosworth LSD Diff. What I was wondering was how you make the engine
cradle so everthing is in the right place?
The way I thought you could do it is attach the diff to the chassis, attach the prop to the diff and gearbox output. Have the chassis on a few bricks
and have the sump on the floor and making the cradle around that so that the prop is straight. Does that sound ok or is there a "proper"
way to do it?
Cheers Mark
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StevieB
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| posted on 20/8/07 at 07:46 PM |
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Sounds about the best way to me - throw in a bit of measuring, checking and testing and that's about it.
It's probably how all the manufacturers got the first setup for the jigs made up anyway!
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Avoneer
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| posted on 20/8/07 at 07:46 PM |
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You can't get the prop straight with a BEC and will need a slight "kink" in it or the UJ's will wear out very quickly.
Fix the diff in as this won't move.
Fix the engine in with sump just below the chassis and with the prop adaptor parallel to the diff flange.
Buy new prop to suit - it will need a centre bearing and TRT. From the engine to the centre bearing, the prop will be on an angle and from the centre
bearing to the diff, the prop will be dead straight or on a slight decline towards the diff.
Pat...
[Edited on 20/8/07 by Avoneer]
No trees were killed in the sending of this message.
However a large number of electrons were terribly inconvenienced.
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Peteff
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| posted on 20/8/07 at 07:47 PM |
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Put the differential in, the engine is fitted where you want it and then make the propshaft to fit between the two, not work round the propshaft.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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SeaBass
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| posted on 20/8/07 at 07:49 PM |
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Sounds about right to me. Ideal considerations as far as I can see are;
Sprocket adapter in line with tranny tunnel,
Sump level with the floor,
Airbox Under the Bonnet,
Exhaust easily exiting past side chassis rails,
Enough room to facilitate shift mechanism.
This should all be fairly easy as the BE is pretty compact. Mango has recently fitted his BEC in an MK de dion chassis he might be the man to speak
to. He's in Fife and very friendly + I'm in the borders (just - about 1/2hour from the bypass) if you want a hand.
Cheers
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locoboy
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| posted on 20/8/07 at 07:51 PM |
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Dont forget about the exhaust headers.
if fabbing your own then fine make it after mounting the engine.
If going with a manufactured one then buy/borrow the headers, or preferably the whole system and bolt it o your engine and use that as a guide to
getting it in the right place in the engine bay.
ATB
Locoboy
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madman280
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| posted on 21/8/07 at 12:13 AM |
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I agree pretty much with the above. I've done it in this order:
1. Jack the chassis up so you can easily get beneth it and then support it. Jack stands or very solid and secure blocks. You don't want it
moving around or falling on you. Try to get it as level as you can.
2. Assemble as much as you can to the engine and lower it into the chassis and support it from below. You don't want to be working on it
dangling from just a chain. Blocks of wood and short planks are fine.
3. Fit the headers and anything else you couldn't fit before. If you don't have any part you'll be using on the finished car- find
out exaclty how it fits and how big it is.
4. Check and adjust clearances between the steering, frame rails, brake masters, firewall etc. Maintain clearances with small blocks of wood or
plastic.
5. Fine tune the engine height and the clearance to the hood and below the frame. You can either raise and lower the engine or the chassis here.
Support it all again.
6. Fine tune the centerline of the output flange parallel with the chassis centerline using a square on the output flange.
7. Fine tune the front to back tilt of the engine so the output centerline is 1-2 degrees different to the pinion angle of the diff. You don't
want them the same or too far apart.
8. Stand back and give it a good look, adjust as necesary then walk away. Come back later and give it another good look. Fresh eyes often see things
missed previously. Measure twice cut once sort of thing.
9. Make the cradle and tack weld it together until everything is finalized. Its easier to knock tack welds apart then have to grind it apart or start
over
10.Make the tabs to fit the engine with the hole slightly larger than the bolts to account for slight heat distortion after welding. You can always
enlarge the hole after welding if you leave room on the tab. .
11. Finish weld the cradle when your happy with it. I'd not do it with the engine in place. The heat from a tack weld should't do damage,
but the heat from welding most likly will.
11. Have a profesional build a driveshaft to fit. Not a place for short cuts or letting safety come second to thriftiness.
Might be talkin out the wrong hole, but it worked for me on a couple projects.
[Edited on 21/8/07 by madman280]
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Rallye_Mark
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| posted on 21/8/07 at 05:46 AM |
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Ah right, so you get a prop shaft made to fit the way you want the engine to sit? I thought you get a prop that is approx the correct size so you can
line everything up?
Whats a TRT?
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StevieB
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| posted on 21/8/07 at 07:16 AM |
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quote:
Originally posted by Rallye_Mark
Whats a TRT?
Without getting too techy about it, it's a type of prop that takes away the clunkiness of the BEC gearbox that you'd otherwise get from a
normal prop.
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